1329 lines
48 KiB
C
1329 lines
48 KiB
C
/*
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* Copyright (C) 2005 David Brownell
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*/
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#ifndef __LINUX_SPI_H
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#define __LINUX_SPI_H
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#include <linux/device.h>
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#include <linux/mod_devicetable.h>
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#include <linux/slab.h>
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#include <linux/kthread.h>
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#include <linux/completion.h>
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#include <linux/scatterlist.h>
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struct dma_chan;
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struct spi_master;
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struct spi_transfer;
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struct spi_flash_read_message;
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/*
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* INTERFACES between SPI master-side drivers and SPI infrastructure.
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* (There's no SPI slave support for Linux yet...)
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*/
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extern struct bus_type spi_bus_type;
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/**
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* struct spi_statistics - statistics for spi transfers
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* @lock: lock protecting this structure
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*
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* @messages: number of spi-messages handled
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* @transfers: number of spi_transfers handled
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* @errors: number of errors during spi_transfer
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* @timedout: number of timeouts during spi_transfer
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*
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* @spi_sync: number of times spi_sync is used
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* @spi_sync_immediate:
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* number of times spi_sync is executed immediately
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* in calling context without queuing and scheduling
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* @spi_async: number of times spi_async is used
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*
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* @bytes: number of bytes transferred to/from device
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* @bytes_tx: number of bytes sent to device
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* @bytes_rx: number of bytes received from device
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*
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* @transfer_bytes_histo:
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* transfer bytes histogramm
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*
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* @transfers_split_maxsize:
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* number of transfers that have been split because of
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* maxsize limit
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*/
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struct spi_statistics {
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spinlock_t lock; /* lock for the whole structure */
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unsigned long messages;
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unsigned long transfers;
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unsigned long errors;
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unsigned long timedout;
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unsigned long spi_sync;
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unsigned long spi_sync_immediate;
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unsigned long spi_async;
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unsigned long long bytes;
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unsigned long long bytes_rx;
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unsigned long long bytes_tx;
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#define SPI_STATISTICS_HISTO_SIZE 17
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unsigned long transfer_bytes_histo[SPI_STATISTICS_HISTO_SIZE];
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unsigned long transfers_split_maxsize;
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};
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void spi_statistics_add_transfer_stats(struct spi_statistics *stats,
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struct spi_transfer *xfer,
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struct spi_master *master);
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#define SPI_STATISTICS_ADD_TO_FIELD(stats, field, count) \
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do { \
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unsigned long flags; \
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spin_lock_irqsave(&(stats)->lock, flags); \
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(stats)->field += count; \
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spin_unlock_irqrestore(&(stats)->lock, flags); \
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} while (0)
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#define SPI_STATISTICS_INCREMENT_FIELD(stats, field) \
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SPI_STATISTICS_ADD_TO_FIELD(stats, field, 1)
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/**
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* struct spi_device - Master side proxy for an SPI slave device
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* @dev: Driver model representation of the device.
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* @master: SPI controller used with the device.
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* @max_speed_hz: Maximum clock rate to be used with this chip
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* (on this board); may be changed by the device's driver.
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* The spi_transfer.speed_hz can override this for each transfer.
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* @chip_select: Chipselect, distinguishing chips handled by @master.
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* @mode: The spi mode defines how data is clocked out and in.
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* This may be changed by the device's driver.
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* The "active low" default for chipselect mode can be overridden
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* (by specifying SPI_CS_HIGH) as can the "MSB first" default for
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* each word in a transfer (by specifying SPI_LSB_FIRST).
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* @bits_per_word: Data transfers involve one or more words; word sizes
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* like eight or 12 bits are common. In-memory wordsizes are
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* powers of two bytes (e.g. 20 bit samples use 32 bits).
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* This may be changed by the device's driver, or left at the
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* default (0) indicating protocol words are eight bit bytes.
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* The spi_transfer.bits_per_word can override this for each transfer.
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* @irq: Negative, or the number passed to request_irq() to receive
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* interrupts from this device.
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* @controller_state: Controller's runtime state
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* @controller_data: Board-specific definitions for controller, such as
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* FIFO initialization parameters; from board_info.controller_data
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* @modalias: Name of the driver to use with this device, or an alias
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* for that name. This appears in the sysfs "modalias" attribute
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* for driver coldplugging, and in uevents used for hotplugging
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* @cs_gpio: gpio number of the chipselect line (optional, -ENOENT when
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* when not using a GPIO line)
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*
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* @statistics: statistics for the spi_device
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*
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* A @spi_device is used to interchange data between an SPI slave
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* (usually a discrete chip) and CPU memory.
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*
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* In @dev, the platform_data is used to hold information about this
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* device that's meaningful to the device's protocol driver, but not
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* to its controller. One example might be an identifier for a chip
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* variant with slightly different functionality; another might be
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* information about how this particular board wires the chip's pins.
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*/
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struct spi_device {
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struct device dev;
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struct spi_master *master;
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u32 max_speed_hz;
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u8 chip_select;
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u8 bits_per_word;
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u16 mode;
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#define SPI_CPHA 0x01 /* clock phase */
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#define SPI_CPOL 0x02 /* clock polarity */
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#define SPI_MODE_0 (0|0) /* (original MicroWire) */
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#define SPI_MODE_1 (0|SPI_CPHA)
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#define SPI_MODE_2 (SPI_CPOL|0)
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#define SPI_MODE_3 (SPI_CPOL|SPI_CPHA)
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#define SPI_CS_HIGH 0x04 /* chipselect active high? */
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#define SPI_LSB_FIRST 0x08 /* per-word bits-on-wire */
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#define SPI_3WIRE 0x10 /* SI/SO signals shared */
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#define SPI_LOOP 0x20 /* loopback mode */
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#define SPI_NO_CS 0x40 /* 1 dev/bus, no chipselect */
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#define SPI_READY 0x80 /* slave pulls low to pause */
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#define SPI_TX_DUAL 0x100 /* transmit with 2 wires */
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#define SPI_TX_QUAD 0x200 /* transmit with 4 wires */
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#define SPI_RX_DUAL 0x400 /* receive with 2 wires */
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#define SPI_RX_QUAD 0x800 /* receive with 4 wires */
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#define SPI_LSBYTE_FIRST 0x1000 /* per-word bytes-on-wire */
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int irq;
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void *controller_state;
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void *controller_data;
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char modalias[SPI_NAME_SIZE];
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int cs_gpio; /* chip select gpio */
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/* the statistics */
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struct spi_statistics statistics;
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/*
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* likely need more hooks for more protocol options affecting how
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* the controller talks to each chip, like:
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* - memory packing (12 bit samples into low bits, others zeroed)
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* - priority
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* - drop chipselect after each word
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* - chipselect delays
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* - ...
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*/
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};
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static inline struct spi_device *to_spi_device(struct device *dev)
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{
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return dev ? container_of(dev, struct spi_device, dev) : NULL;
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}
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/* most drivers won't need to care about device refcounting */
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static inline struct spi_device *spi_dev_get(struct spi_device *spi)
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{
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return (spi && get_device(&spi->dev)) ? spi : NULL;
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}
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static inline void spi_dev_put(struct spi_device *spi)
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{
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if (spi)
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put_device(&spi->dev);
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}
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/* ctldata is for the bus_master driver's runtime state */
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static inline void *spi_get_ctldata(struct spi_device *spi)
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{
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return spi->controller_state;
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}
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static inline void spi_set_ctldata(struct spi_device *spi, void *state)
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{
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spi->controller_state = state;
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}
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/* device driver data */
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static inline void spi_set_drvdata(struct spi_device *spi, void *data)
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{
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dev_set_drvdata(&spi->dev, data);
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}
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static inline void *spi_get_drvdata(struct spi_device *spi)
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{
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return dev_get_drvdata(&spi->dev);
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}
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struct spi_message;
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struct spi_transfer;
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/**
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* struct spi_driver - Host side "protocol" driver
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* @id_table: List of SPI devices supported by this driver
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* @probe: Binds this driver to the spi device. Drivers can verify
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* that the device is actually present, and may need to configure
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* characteristics (such as bits_per_word) which weren't needed for
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* the initial configuration done during system setup.
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* @remove: Unbinds this driver from the spi device
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* @shutdown: Standard shutdown callback used during system state
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* transitions such as powerdown/halt and kexec
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* @driver: SPI device drivers should initialize the name and owner
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* field of this structure.
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*
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* This represents the kind of device driver that uses SPI messages to
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* interact with the hardware at the other end of a SPI link. It's called
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* a "protocol" driver because it works through messages rather than talking
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* directly to SPI hardware (which is what the underlying SPI controller
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* driver does to pass those messages). These protocols are defined in the
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* specification for the device(s) supported by the driver.
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*
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* As a rule, those device protocols represent the lowest level interface
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* supported by a driver, and it will support upper level interfaces too.
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* Examples of such upper levels include frameworks like MTD, networking,
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* MMC, RTC, filesystem character device nodes, and hardware monitoring.
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*/
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struct spi_driver {
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const struct spi_device_id *id_table;
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int (*probe)(struct spi_device *spi);
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int (*remove)(struct spi_device *spi);
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void (*shutdown)(struct spi_device *spi);
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struct device_driver driver;
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};
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static inline struct spi_driver *to_spi_driver(struct device_driver *drv)
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{
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return drv ? container_of(drv, struct spi_driver, driver) : NULL;
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}
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extern int __spi_register_driver(struct module *owner, struct spi_driver *sdrv);
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/**
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* spi_unregister_driver - reverse effect of spi_register_driver
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* @sdrv: the driver to unregister
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* Context: can sleep
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*/
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static inline void spi_unregister_driver(struct spi_driver *sdrv)
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{
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if (sdrv)
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driver_unregister(&sdrv->driver);
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}
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/* use a define to avoid include chaining to get THIS_MODULE */
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#define spi_register_driver(driver) \
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__spi_register_driver(THIS_MODULE, driver)
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/**
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* module_spi_driver() - Helper macro for registering a SPI driver
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* @__spi_driver: spi_driver struct
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*
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* Helper macro for SPI drivers which do not do anything special in module
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* init/exit. This eliminates a lot of boilerplate. Each module may only
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* use this macro once, and calling it replaces module_init() and module_exit()
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*/
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#define module_spi_driver(__spi_driver) \
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module_driver(__spi_driver, spi_register_driver, \
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spi_unregister_driver)
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/**
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* struct spi_master - interface to SPI master controller
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* @dev: device interface to this driver
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* @list: link with the global spi_master list
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* @bus_num: board-specific (and often SOC-specific) identifier for a
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* given SPI controller.
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* @num_chipselect: chipselects are used to distinguish individual
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* SPI slaves, and are numbered from zero to num_chipselects.
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* each slave has a chipselect signal, but it's common that not
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* every chipselect is connected to a slave.
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* @dma_alignment: SPI controller constraint on DMA buffers alignment.
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* @mode_bits: flags understood by this controller driver
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* @bits_per_word_mask: A mask indicating which values of bits_per_word are
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* supported by the driver. Bit n indicates that a bits_per_word n+1 is
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* supported. If set, the SPI core will reject any transfer with an
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* unsupported bits_per_word. If not set, this value is simply ignored,
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* and it's up to the individual driver to perform any validation.
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* @min_speed_hz: Lowest supported transfer speed
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* @max_speed_hz: Highest supported transfer speed
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* @flags: other constraints relevant to this driver
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* @max_transfer_size: function that returns the max transfer size for
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* a &spi_device; may be %NULL, so the default %SIZE_MAX will be used.
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* @max_message_size: function that returns the max message size for
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* a &spi_device; may be %NULL, so the default %SIZE_MAX will be used.
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* @io_mutex: mutex for physical bus access
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* @bus_lock_spinlock: spinlock for SPI bus locking
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* @bus_lock_mutex: mutex for exclusion of multiple callers
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* @bus_lock_flag: indicates that the SPI bus is locked for exclusive use
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* @setup: updates the device mode and clocking records used by a
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* device's SPI controller; protocol code may call this. This
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* must fail if an unrecognized or unsupported mode is requested.
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* It's always safe to call this unless transfers are pending on
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* the device whose settings are being modified.
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* @transfer: adds a message to the controller's transfer queue.
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* @cleanup: frees controller-specific state
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* @can_dma: determine whether this master supports DMA
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* @queued: whether this master is providing an internal message queue
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* @kworker: thread struct for message pump
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* @kworker_task: pointer to task for message pump kworker thread
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* @pump_messages: work struct for scheduling work to the message pump
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* @queue_lock: spinlock to syncronise access to message queue
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* @queue: message queue
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* @idling: the device is entering idle state
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* @cur_msg: the currently in-flight message
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* @cur_msg_prepared: spi_prepare_message was called for the currently
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* in-flight message
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* @cur_msg_mapped: message has been mapped for DMA
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* @xfer_completion: used by core transfer_one_message()
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* @busy: message pump is busy
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* @running: message pump is running
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* @rt: whether this queue is set to run as a realtime task
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* @auto_runtime_pm: the core should ensure a runtime PM reference is held
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* while the hardware is prepared, using the parent
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* device for the spidev
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* @max_dma_len: Maximum length of a DMA transfer for the device.
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* @prepare_transfer_hardware: a message will soon arrive from the queue
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* so the subsystem requests the driver to prepare the transfer hardware
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* by issuing this call
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* @transfer_one_message: the subsystem calls the driver to transfer a single
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* message while queuing transfers that arrive in the meantime. When the
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* driver is finished with this message, it must call
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* spi_finalize_current_message() so the subsystem can issue the next
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* message
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* @unprepare_transfer_hardware: there are currently no more messages on the
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* queue so the subsystem notifies the driver that it may relax the
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* hardware by issuing this call
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* @set_cs: set the logic level of the chip select line. May be called
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* from interrupt context.
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* @prepare_message: set up the controller to transfer a single message,
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* for example doing DMA mapping. Called from threaded
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* context.
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* @transfer_one: transfer a single spi_transfer.
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* - return 0 if the transfer is finished,
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* - return 1 if the transfer is still in progress. When
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* the driver is finished with this transfer it must
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* call spi_finalize_current_transfer() so the subsystem
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* can issue the next transfer. Note: transfer_one and
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* transfer_one_message are mutually exclusive; when both
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* are set, the generic subsystem does not call your
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* transfer_one callback.
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* @handle_err: the subsystem calls the driver to handle an error that occurs
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* in the generic implementation of transfer_one_message().
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* @unprepare_message: undo any work done by prepare_message().
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* @spi_flash_read: to support spi-controller hardwares that provide
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* accelerated interface to read from flash devices.
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* @flash_read_supported: spi device supports flash read
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* @cs_gpios: Array of GPIOs to use as chip select lines; one per CS
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* number. Any individual value may be -ENOENT for CS lines that
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* are not GPIOs (driven by the SPI controller itself).
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* @statistics: statistics for the spi_master
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* @dma_tx: DMA transmit channel
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* @dma_rx: DMA receive channel
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* @dummy_rx: dummy receive buffer for full-duplex devices
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* @dummy_tx: dummy transmit buffer for full-duplex devices
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* @fw_translate_cs: If the boot firmware uses different numbering scheme
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* what Linux expects, this optional hook can be used to translate
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* between the two.
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*
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* Each SPI master controller can communicate with one or more @spi_device
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* children. These make a small bus, sharing MOSI, MISO and SCK signals
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* but not chip select signals. Each device may be configured to use a
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* different clock rate, since those shared signals are ignored unless
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* the chip is selected.
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*
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* The driver for an SPI controller manages access to those devices through
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* a queue of spi_message transactions, copying data between CPU memory and
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* an SPI slave device. For each such message it queues, it calls the
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* message's completion function when the transaction completes.
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*/
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struct spi_master {
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struct device dev;
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struct list_head list;
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/* other than negative (== assign one dynamically), bus_num is fully
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* board-specific. usually that simplifies to being SOC-specific.
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* example: one SOC has three SPI controllers, numbered 0..2,
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* and one board's schematics might show it using SPI-2. software
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* would normally use bus_num=2 for that controller.
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*/
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s16 bus_num;
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/* chipselects will be integral to many controllers; some others
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* might use board-specific GPIOs.
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*/
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u16 num_chipselect;
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/* some SPI controllers pose alignment requirements on DMAable
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* buffers; let protocol drivers know about these requirements.
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*/
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u16 dma_alignment;
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/* spi_device.mode flags understood by this controller driver */
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u16 mode_bits;
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/* bitmask of supported bits_per_word for transfers */
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u32 bits_per_word_mask;
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#define SPI_BPW_MASK(bits) BIT((bits) - 1)
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#define SPI_BIT_MASK(bits) (((bits) == 32) ? ~0U : (BIT(bits) - 1))
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#define SPI_BPW_RANGE_MASK(min, max) (SPI_BIT_MASK(max) - SPI_BIT_MASK(min - 1))
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/* limits on transfer speed */
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u32 min_speed_hz;
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u32 max_speed_hz;
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/* other constraints relevant to this driver */
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u16 flags;
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#define SPI_MASTER_HALF_DUPLEX BIT(0) /* can't do full duplex */
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#define SPI_MASTER_NO_RX BIT(1) /* can't do buffer read */
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#define SPI_MASTER_NO_TX BIT(2) /* can't do buffer write */
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#define SPI_MASTER_MUST_RX BIT(3) /* requires rx */
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#define SPI_MASTER_MUST_TX BIT(4) /* requires tx */
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/*
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* on some hardware transfer / message size may be constrained
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* the limit may depend on device transfer settings
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*/
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size_t (*max_transfer_size)(struct spi_device *spi);
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size_t (*max_message_size)(struct spi_device *spi);
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/* I/O mutex */
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struct mutex io_mutex;
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/* lock and mutex for SPI bus locking */
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spinlock_t bus_lock_spinlock;
|
|
struct mutex bus_lock_mutex;
|
|
|
|
/* flag indicating that the SPI bus is locked for exclusive use */
|
|
bool bus_lock_flag;
|
|
|
|
/* Setup mode and clock, etc (spi driver may call many times).
|
|
*
|
|
* IMPORTANT: this may be called when transfers to another
|
|
* device are active. DO NOT UPDATE SHARED REGISTERS in ways
|
|
* which could break those transfers.
|
|
*/
|
|
int (*setup)(struct spi_device *spi);
|
|
|
|
/* bidirectional bulk transfers
|
|
*
|
|
* + The transfer() method may not sleep; its main role is
|
|
* just to add the message to the queue.
|
|
* + For now there's no remove-from-queue operation, or
|
|
* any other request management
|
|
* + To a given spi_device, message queueing is pure fifo
|
|
*
|
|
* + The master's main job is to process its message queue,
|
|
* selecting a chip then transferring data
|
|
* + If there are multiple spi_device children, the i/o queue
|
|
* arbitration algorithm is unspecified (round robin, fifo,
|
|
* priority, reservations, preemption, etc)
|
|
*
|
|
* + Chipselect stays active during the entire message
|
|
* (unless modified by spi_transfer.cs_change != 0).
|
|
* + The message transfers use clock and SPI mode parameters
|
|
* previously established by setup() for this device
|
|
*/
|
|
int (*transfer)(struct spi_device *spi,
|
|
struct spi_message *mesg);
|
|
|
|
/* called on release() to free memory provided by spi_master */
|
|
void (*cleanup)(struct spi_device *spi);
|
|
|
|
/*
|
|
* Used to enable core support for DMA handling, if can_dma()
|
|
* exists and returns true then the transfer will be mapped
|
|
* prior to transfer_one() being called. The driver should
|
|
* not modify or store xfer and dma_tx and dma_rx must be set
|
|
* while the device is prepared.
|
|
*/
|
|
bool (*can_dma)(struct spi_master *master,
|
|
struct spi_device *spi,
|
|
struct spi_transfer *xfer);
|
|
|
|
/*
|
|
* These hooks are for drivers that want to use the generic
|
|
* master transfer queueing mechanism. If these are used, the
|
|
* transfer() function above must NOT be specified by the driver.
|
|
* Over time we expect SPI drivers to be phased over to this API.
|
|
*/
|
|
bool queued;
|
|
struct kthread_worker kworker;
|
|
struct task_struct *kworker_task;
|
|
struct kthread_work pump_messages;
|
|
spinlock_t queue_lock;
|
|
struct list_head queue;
|
|
struct spi_message *cur_msg;
|
|
bool idling;
|
|
bool busy;
|
|
bool running;
|
|
bool rt;
|
|
bool auto_runtime_pm;
|
|
bool cur_msg_prepared;
|
|
bool cur_msg_mapped;
|
|
struct completion xfer_completion;
|
|
size_t max_dma_len;
|
|
|
|
int (*prepare_transfer_hardware)(struct spi_master *master);
|
|
int (*transfer_one_message)(struct spi_master *master,
|
|
struct spi_message *mesg);
|
|
int (*unprepare_transfer_hardware)(struct spi_master *master);
|
|
int (*prepare_message)(struct spi_master *master,
|
|
struct spi_message *message);
|
|
int (*unprepare_message)(struct spi_master *master,
|
|
struct spi_message *message);
|
|
int (*spi_flash_read)(struct spi_device *spi,
|
|
struct spi_flash_read_message *msg);
|
|
bool (*flash_read_supported)(struct spi_device *spi);
|
|
|
|
/*
|
|
* These hooks are for drivers that use a generic implementation
|
|
* of transfer_one_message() provied by the core.
|
|
*/
|
|
void (*set_cs)(struct spi_device *spi, bool enable);
|
|
int (*transfer_one)(struct spi_master *master, struct spi_device *spi,
|
|
struct spi_transfer *transfer);
|
|
void (*handle_err)(struct spi_master *master,
|
|
struct spi_message *message);
|
|
|
|
/* gpio chip select */
|
|
int *cs_gpios;
|
|
|
|
/* statistics */
|
|
struct spi_statistics statistics;
|
|
|
|
/* DMA channels for use with core dmaengine helpers */
|
|
struct dma_chan *dma_tx;
|
|
struct dma_chan *dma_rx;
|
|
|
|
/* dummy data for full duplex devices */
|
|
void *dummy_rx;
|
|
void *dummy_tx;
|
|
|
|
int (*fw_translate_cs)(struct spi_master *master, unsigned cs);
|
|
int (*spi_cs_low)(struct spi_device *spi, bool state);
|
|
};
|
|
|
|
static inline void *spi_master_get_devdata(struct spi_master *master)
|
|
{
|
|
return dev_get_drvdata(&master->dev);
|
|
}
|
|
|
|
static inline void spi_master_set_devdata(struct spi_master *master, void *data)
|
|
{
|
|
dev_set_drvdata(&master->dev, data);
|
|
}
|
|
|
|
static inline struct spi_master *spi_master_get(struct spi_master *master)
|
|
{
|
|
if (!master || !get_device(&master->dev))
|
|
return NULL;
|
|
return master;
|
|
}
|
|
|
|
static inline void spi_master_put(struct spi_master *master)
|
|
{
|
|
if (master)
|
|
put_device(&master->dev);
|
|
}
|
|
|
|
/* PM calls that need to be issued by the driver */
|
|
extern int spi_master_suspend(struct spi_master *master);
|
|
extern int spi_master_resume(struct spi_master *master);
|
|
|
|
/* Calls the driver make to interact with the message queue */
|
|
extern struct spi_message *spi_get_next_queued_message(struct spi_master *master);
|
|
extern void spi_finalize_current_message(struct spi_master *master);
|
|
extern void spi_finalize_current_transfer(struct spi_master *master);
|
|
|
|
/* the spi driver core manages memory for the spi_master classdev */
|
|
extern struct spi_master *
|
|
spi_alloc_master(struct device *host, unsigned size);
|
|
extern struct spi_master *
|
|
devm_spi_alloc_master(struct device *dev, unsigned int size);
|
|
|
|
extern int spi_register_master(struct spi_master *master);
|
|
extern int devm_spi_register_master(struct device *dev,
|
|
struct spi_master *master);
|
|
extern void spi_unregister_master(struct spi_master *master);
|
|
|
|
extern struct spi_master *spi_busnum_to_master(u16 busnum);
|
|
|
|
/*
|
|
* SPI resource management while processing a SPI message
|
|
*/
|
|
|
|
typedef void (*spi_res_release_t)(struct spi_master *master,
|
|
struct spi_message *msg,
|
|
void *res);
|
|
|
|
/**
|
|
* struct spi_res - spi resource management structure
|
|
* @entry: list entry
|
|
* @release: release code called prior to freeing this resource
|
|
* @data: extra data allocated for the specific use-case
|
|
*
|
|
* this is based on ideas from devres, but focused on life-cycle
|
|
* management during spi_message processing
|
|
*/
|
|
struct spi_res {
|
|
struct list_head entry;
|
|
spi_res_release_t release;
|
|
unsigned long long data[]; /* guarantee ull alignment */
|
|
};
|
|
|
|
extern void *spi_res_alloc(struct spi_device *spi,
|
|
spi_res_release_t release,
|
|
size_t size, gfp_t gfp);
|
|
extern void spi_res_add(struct spi_message *message, void *res);
|
|
extern void spi_res_free(void *res);
|
|
|
|
extern void spi_res_release(struct spi_master *master,
|
|
struct spi_message *message);
|
|
|
|
/*---------------------------------------------------------------------------*/
|
|
|
|
/*
|
|
* I/O INTERFACE between SPI controller and protocol drivers
|
|
*
|
|
* Protocol drivers use a queue of spi_messages, each transferring data
|
|
* between the controller and memory buffers.
|
|
*
|
|
* The spi_messages themselves consist of a series of read+write transfer
|
|
* segments. Those segments always read the same number of bits as they
|
|
* write; but one or the other is easily ignored by passing a null buffer
|
|
* pointer. (This is unlike most types of I/O API, because SPI hardware
|
|
* is full duplex.)
|
|
*
|
|
* NOTE: Allocation of spi_transfer and spi_message memory is entirely
|
|
* up to the protocol driver, which guarantees the integrity of both (as
|
|
* well as the data buffers) for as long as the message is queued.
|
|
*/
|
|
|
|
/**
|
|
* struct spi_transfer - a read/write buffer pair
|
|
* @tx_buf: data to be written (dma-safe memory), or NULL
|
|
* @rx_buf: data to be read (dma-safe memory), or NULL
|
|
* @tx_dma: DMA address of tx_buf, if @spi_message.is_dma_mapped
|
|
* @rx_dma: DMA address of rx_buf, if @spi_message.is_dma_mapped
|
|
* @tx_nbits: number of bits used for writing. If 0 the default
|
|
* (SPI_NBITS_SINGLE) is used.
|
|
* @rx_nbits: number of bits used for reading. If 0 the default
|
|
* (SPI_NBITS_SINGLE) is used.
|
|
* @len: size of rx and tx buffers (in bytes)
|
|
* @speed_hz: Select a speed other than the device default for this
|
|
* transfer. If 0 the default (from @spi_device) is used.
|
|
* @bits_per_word: select a bits_per_word other than the device default
|
|
* for this transfer. If 0 the default (from @spi_device) is used.
|
|
* @cs_change: affects chipselect after this transfer completes
|
|
* @delay_usecs: microseconds to delay after this transfer before
|
|
* (optionally) changing the chipselect status, then starting
|
|
* the next transfer or completing this @spi_message.
|
|
* @transfer_list: transfers are sequenced through @spi_message.transfers
|
|
* @tx_sg: Scatterlist for transmit, currently not for client use
|
|
* @rx_sg: Scatterlist for receive, currently not for client use
|
|
*
|
|
* SPI transfers always write the same number of bytes as they read.
|
|
* Protocol drivers should always provide @rx_buf and/or @tx_buf.
|
|
* In some cases, they may also want to provide DMA addresses for
|
|
* the data being transferred; that may reduce overhead, when the
|
|
* underlying driver uses dma.
|
|
*
|
|
* If the transmit buffer is null, zeroes will be shifted out
|
|
* while filling @rx_buf. If the receive buffer is null, the data
|
|
* shifted in will be discarded. Only "len" bytes shift out (or in).
|
|
* It's an error to try to shift out a partial word. (For example, by
|
|
* shifting out three bytes with word size of sixteen or twenty bits;
|
|
* the former uses two bytes per word, the latter uses four bytes.)
|
|
*
|
|
* In-memory data values are always in native CPU byte order, translated
|
|
* from the wire byte order (big-endian except with SPI_LSB_FIRST). So
|
|
* for example when bits_per_word is sixteen, buffers are 2N bytes long
|
|
* (@len = 2N) and hold N sixteen bit words in CPU byte order.
|
|
*
|
|
* When the word size of the SPI transfer is not a power-of-two multiple
|
|
* of eight bits, those in-memory words include extra bits. In-memory
|
|
* words are always seen by protocol drivers as right-justified, so the
|
|
* undefined (rx) or unused (tx) bits are always the most significant bits.
|
|
*
|
|
* All SPI transfers start with the relevant chipselect active. Normally
|
|
* it stays selected until after the last transfer in a message. Drivers
|
|
* can affect the chipselect signal using cs_change.
|
|
*
|
|
* (i) If the transfer isn't the last one in the message, this flag is
|
|
* used to make the chipselect briefly go inactive in the middle of the
|
|
* message. Toggling chipselect in this way may be needed to terminate
|
|
* a chip command, letting a single spi_message perform all of group of
|
|
* chip transactions together.
|
|
*
|
|
* (ii) When the transfer is the last one in the message, the chip may
|
|
* stay selected until the next transfer. On multi-device SPI busses
|
|
* with nothing blocking messages going to other devices, this is just
|
|
* a performance hint; starting a message to another device deselects
|
|
* this one. But in other cases, this can be used to ensure correctness.
|
|
* Some devices need protocol transactions to be built from a series of
|
|
* spi_message submissions, where the content of one message is determined
|
|
* by the results of previous messages and where the whole transaction
|
|
* ends when the chipselect goes intactive.
|
|
*
|
|
* When SPI can transfer in 1x,2x or 4x. It can get this transfer information
|
|
* from device through @tx_nbits and @rx_nbits. In Bi-direction, these
|
|
* two should both be set. User can set transfer mode with SPI_NBITS_SINGLE(1x)
|
|
* SPI_NBITS_DUAL(2x) and SPI_NBITS_QUAD(4x) to support these three transfer.
|
|
*
|
|
* The code that submits an spi_message (and its spi_transfers)
|
|
* to the lower layers is responsible for managing its memory.
|
|
* Zero-initialize every field you don't set up explicitly, to
|
|
* insulate against future API updates. After you submit a message
|
|
* and its transfers, ignore them until its completion callback.
|
|
*/
|
|
struct spi_transfer {
|
|
/* it's ok if tx_buf == rx_buf (right?)
|
|
* for MicroWire, one buffer must be null
|
|
* buffers must work with dma_*map_single() calls, unless
|
|
* spi_message.is_dma_mapped reports a pre-existing mapping
|
|
*/
|
|
const void *tx_buf;
|
|
void *rx_buf;
|
|
unsigned len;
|
|
|
|
dma_addr_t tx_dma;
|
|
dma_addr_t rx_dma;
|
|
struct sg_table tx_sg;
|
|
struct sg_table rx_sg;
|
|
|
|
unsigned cs_change:1;
|
|
unsigned tx_nbits:3;
|
|
unsigned rx_nbits:3;
|
|
#define SPI_NBITS_SINGLE 0x01 /* 1bit transfer */
|
|
#define SPI_NBITS_DUAL 0x02 /* 2bits transfer */
|
|
#define SPI_NBITS_QUAD 0x04 /* 4bits transfer */
|
|
u8 bits_per_word;
|
|
u16 delay_usecs;
|
|
u32 speed_hz;
|
|
|
|
struct list_head transfer_list;
|
|
};
|
|
|
|
/**
|
|
* struct spi_message - one multi-segment SPI transaction
|
|
* @transfers: list of transfer segments in this transaction
|
|
* @spi: SPI device to which the transaction is queued
|
|
* @is_dma_mapped: if true, the caller provided both dma and cpu virtual
|
|
* addresses for each transfer buffer
|
|
* @complete: called to report transaction completions
|
|
* @context: the argument to complete() when it's called
|
|
* @frame_length: the total number of bytes in the message
|
|
* @actual_length: the total number of bytes that were transferred in all
|
|
* successful segments
|
|
* @status: zero for success, else negative errno
|
|
* @queue: for use by whichever driver currently owns the message
|
|
* @state: for use by whichever driver currently owns the message
|
|
* @resources: for resource management when the spi message is processed
|
|
*
|
|
* A @spi_message is used to execute an atomic sequence of data transfers,
|
|
* each represented by a struct spi_transfer. The sequence is "atomic"
|
|
* in the sense that no other spi_message may use that SPI bus until that
|
|
* sequence completes. On some systems, many such sequences can execute as
|
|
* as single programmed DMA transfer. On all systems, these messages are
|
|
* queued, and might complete after transactions to other devices. Messages
|
|
* sent to a given spi_device are always executed in FIFO order.
|
|
*
|
|
* The code that submits an spi_message (and its spi_transfers)
|
|
* to the lower layers is responsible for managing its memory.
|
|
* Zero-initialize every field you don't set up explicitly, to
|
|
* insulate against future API updates. After you submit a message
|
|
* and its transfers, ignore them until its completion callback.
|
|
*/
|
|
struct spi_message {
|
|
struct list_head transfers;
|
|
|
|
struct spi_device *spi;
|
|
|
|
unsigned is_dma_mapped:1;
|
|
|
|
/* REVISIT: we might want a flag affecting the behavior of the
|
|
* last transfer ... allowing things like "read 16 bit length L"
|
|
* immediately followed by "read L bytes". Basically imposing
|
|
* a specific message scheduling algorithm.
|
|
*
|
|
* Some controller drivers (message-at-a-time queue processing)
|
|
* could provide that as their default scheduling algorithm. But
|
|
* others (with multi-message pipelines) could need a flag to
|
|
* tell them about such special cases.
|
|
*/
|
|
|
|
/* completion is reported through a callback */
|
|
void (*complete)(void *context);
|
|
void *context;
|
|
unsigned frame_length;
|
|
unsigned actual_length;
|
|
int status;
|
|
|
|
/* for optional use by whatever driver currently owns the
|
|
* spi_message ... between calls to spi_async and then later
|
|
* complete(), that's the spi_master controller driver.
|
|
*/
|
|
struct list_head queue;
|
|
void *state;
|
|
|
|
/* list of spi_res reources when the spi message is processed */
|
|
struct list_head resources;
|
|
};
|
|
|
|
static inline void spi_message_init_no_memset(struct spi_message *m)
|
|
{
|
|
INIT_LIST_HEAD(&m->transfers);
|
|
INIT_LIST_HEAD(&m->resources);
|
|
}
|
|
|
|
static inline void spi_message_init(struct spi_message *m)
|
|
{
|
|
memset(m, 0, sizeof *m);
|
|
spi_message_init_no_memset(m);
|
|
}
|
|
|
|
static inline void
|
|
spi_message_add_tail(struct spi_transfer *t, struct spi_message *m)
|
|
{
|
|
list_add_tail(&t->transfer_list, &m->transfers);
|
|
}
|
|
|
|
static inline void
|
|
spi_transfer_del(struct spi_transfer *t)
|
|
{
|
|
list_del(&t->transfer_list);
|
|
}
|
|
|
|
/**
|
|
* spi_message_init_with_transfers - Initialize spi_message and append transfers
|
|
* @m: spi_message to be initialized
|
|
* @xfers: An array of spi transfers
|
|
* @num_xfers: Number of items in the xfer array
|
|
*
|
|
* This function initializes the given spi_message and adds each spi_transfer in
|
|
* the given array to the message.
|
|
*/
|
|
static inline void
|
|
spi_message_init_with_transfers(struct spi_message *m,
|
|
struct spi_transfer *xfers, unsigned int num_xfers)
|
|
{
|
|
unsigned int i;
|
|
|
|
spi_message_init(m);
|
|
for (i = 0; i < num_xfers; ++i)
|
|
spi_message_add_tail(&xfers[i], m);
|
|
}
|
|
|
|
/* It's fine to embed message and transaction structures in other data
|
|
* structures so long as you don't free them while they're in use.
|
|
*/
|
|
|
|
static inline struct spi_message *spi_message_alloc(unsigned ntrans, gfp_t flags)
|
|
{
|
|
struct spi_message *m;
|
|
|
|
m = kzalloc(sizeof(struct spi_message)
|
|
+ ntrans * sizeof(struct spi_transfer),
|
|
flags);
|
|
if (m) {
|
|
unsigned i;
|
|
struct spi_transfer *t = (struct spi_transfer *)(m + 1);
|
|
|
|
INIT_LIST_HEAD(&m->transfers);
|
|
for (i = 0; i < ntrans; i++, t++)
|
|
spi_message_add_tail(t, m);
|
|
}
|
|
return m;
|
|
}
|
|
|
|
static inline void spi_message_free(struct spi_message *m)
|
|
{
|
|
kfree(m);
|
|
}
|
|
|
|
extern int spi_setup(struct spi_device *spi);
|
|
extern int spi_async(struct spi_device *spi, struct spi_message *message);
|
|
extern int spi_async_locked(struct spi_device *spi,
|
|
struct spi_message *message);
|
|
|
|
static inline size_t
|
|
spi_max_message_size(struct spi_device *spi)
|
|
{
|
|
struct spi_master *master = spi->master;
|
|
if (!master->max_message_size)
|
|
return SIZE_MAX;
|
|
return master->max_message_size(spi);
|
|
}
|
|
|
|
static inline size_t
|
|
spi_max_transfer_size(struct spi_device *spi)
|
|
{
|
|
struct spi_master *master = spi->master;
|
|
size_t tr_max = SIZE_MAX;
|
|
size_t msg_max = spi_max_message_size(spi);
|
|
|
|
if (master->max_transfer_size)
|
|
tr_max = master->max_transfer_size(spi);
|
|
|
|
/* transfer size limit must not be greater than messsage size limit */
|
|
return min(tr_max, msg_max);
|
|
}
|
|
|
|
/*---------------------------------------------------------------------------*/
|
|
|
|
/* SPI transfer replacement methods which make use of spi_res */
|
|
|
|
struct spi_replaced_transfers;
|
|
typedef void (*spi_replaced_release_t)(struct spi_master *master,
|
|
struct spi_message *msg,
|
|
struct spi_replaced_transfers *res);
|
|
/**
|
|
* struct spi_replaced_transfers - structure describing the spi_transfer
|
|
* replacements that have occurred
|
|
* so that they can get reverted
|
|
* @release: some extra release code to get executed prior to
|
|
* relasing this structure
|
|
* @extradata: pointer to some extra data if requested or NULL
|
|
* @replaced_transfers: transfers that have been replaced and which need
|
|
* to get restored
|
|
* @replaced_after: the transfer after which the @replaced_transfers
|
|
* are to get re-inserted
|
|
* @inserted: number of transfers inserted
|
|
* @inserted_transfers: array of spi_transfers of array-size @inserted,
|
|
* that have been replacing replaced_transfers
|
|
*
|
|
* note: that @extradata will point to @inserted_transfers[@inserted]
|
|
* if some extra allocation is requested, so alignment will be the same
|
|
* as for spi_transfers
|
|
*/
|
|
struct spi_replaced_transfers {
|
|
spi_replaced_release_t release;
|
|
void *extradata;
|
|
struct list_head replaced_transfers;
|
|
struct list_head *replaced_after;
|
|
size_t inserted;
|
|
struct spi_transfer inserted_transfers[];
|
|
};
|
|
|
|
extern struct spi_replaced_transfers *spi_replace_transfers(
|
|
struct spi_message *msg,
|
|
struct spi_transfer *xfer_first,
|
|
size_t remove,
|
|
size_t insert,
|
|
spi_replaced_release_t release,
|
|
size_t extradatasize,
|
|
gfp_t gfp);
|
|
|
|
/*---------------------------------------------------------------------------*/
|
|
|
|
/* SPI transfer transformation methods */
|
|
|
|
extern int spi_split_transfers_maxsize(struct spi_master *master,
|
|
struct spi_message *msg,
|
|
size_t maxsize,
|
|
gfp_t gfp);
|
|
|
|
/*---------------------------------------------------------------------------*/
|
|
|
|
/* All these synchronous SPI transfer routines are utilities layered
|
|
* over the core async transfer primitive. Here, "synchronous" means
|
|
* they will sleep uninterruptibly until the async transfer completes.
|
|
*/
|
|
|
|
extern int spi_sync(struct spi_device *spi, struct spi_message *message);
|
|
extern int spi_sync_locked(struct spi_device *spi, struct spi_message *message);
|
|
extern int spi_bus_lock(struct spi_master *master);
|
|
extern int spi_bus_unlock(struct spi_master *master);
|
|
|
|
/**
|
|
* spi_sync_transfer - synchronous SPI data transfer
|
|
* @spi: device with which data will be exchanged
|
|
* @xfers: An array of spi_transfers
|
|
* @num_xfers: Number of items in the xfer array
|
|
* Context: can sleep
|
|
*
|
|
* Does a synchronous SPI data transfer of the given spi_transfer array.
|
|
*
|
|
* For more specific semantics see spi_sync().
|
|
*
|
|
* Return: Return: zero on success, else a negative error code.
|
|
*/
|
|
static inline int
|
|
spi_sync_transfer(struct spi_device *spi, struct spi_transfer *xfers,
|
|
unsigned int num_xfers)
|
|
{
|
|
struct spi_message msg;
|
|
|
|
spi_message_init_with_transfers(&msg, xfers, num_xfers);
|
|
|
|
return spi_sync(spi, &msg);
|
|
}
|
|
|
|
/**
|
|
* spi_write - SPI synchronous write
|
|
* @spi: device to which data will be written
|
|
* @buf: data buffer
|
|
* @len: data buffer size
|
|
* Context: can sleep
|
|
*
|
|
* This function writes the buffer @buf.
|
|
* Callable only from contexts that can sleep.
|
|
*
|
|
* Return: zero on success, else a negative error code.
|
|
*/
|
|
static inline int
|
|
spi_write(struct spi_device *spi, const void *buf, size_t len)
|
|
{
|
|
struct spi_transfer t = {
|
|
.tx_buf = buf,
|
|
.len = len,
|
|
};
|
|
|
|
return spi_sync_transfer(spi, &t, 1);
|
|
}
|
|
|
|
/**
|
|
* spi_read - SPI synchronous read
|
|
* @spi: device from which data will be read
|
|
* @buf: data buffer
|
|
* @len: data buffer size
|
|
* Context: can sleep
|
|
*
|
|
* This function reads the buffer @buf.
|
|
* Callable only from contexts that can sleep.
|
|
*
|
|
* Return: zero on success, else a negative error code.
|
|
*/
|
|
static inline int
|
|
spi_read(struct spi_device *spi, void *buf, size_t len)
|
|
{
|
|
struct spi_transfer t = {
|
|
.rx_buf = buf,
|
|
.len = len,
|
|
};
|
|
|
|
return spi_sync_transfer(spi, &t, 1);
|
|
}
|
|
|
|
/* this copies txbuf and rxbuf data; for small transfers only! */
|
|
extern int spi_write_then_read(struct spi_device *spi,
|
|
const void *txbuf, unsigned n_tx,
|
|
void *rxbuf, unsigned n_rx);
|
|
|
|
/**
|
|
* spi_w8r8 - SPI synchronous 8 bit write followed by 8 bit read
|
|
* @spi: device with which data will be exchanged
|
|
* @cmd: command to be written before data is read back
|
|
* Context: can sleep
|
|
*
|
|
* Callable only from contexts that can sleep.
|
|
*
|
|
* Return: the (unsigned) eight bit number returned by the
|
|
* device, or else a negative error code.
|
|
*/
|
|
static inline ssize_t spi_w8r8(struct spi_device *spi, u8 cmd)
|
|
{
|
|
ssize_t status;
|
|
u8 result;
|
|
|
|
status = spi_write_then_read(spi, &cmd, 1, &result, 1);
|
|
|
|
/* return negative errno or unsigned value */
|
|
return (status < 0) ? status : result;
|
|
}
|
|
|
|
/**
|
|
* spi_w8r16 - SPI synchronous 8 bit write followed by 16 bit read
|
|
* @spi: device with which data will be exchanged
|
|
* @cmd: command to be written before data is read back
|
|
* Context: can sleep
|
|
*
|
|
* The number is returned in wire-order, which is at least sometimes
|
|
* big-endian.
|
|
*
|
|
* Callable only from contexts that can sleep.
|
|
*
|
|
* Return: the (unsigned) sixteen bit number returned by the
|
|
* device, or else a negative error code.
|
|
*/
|
|
static inline ssize_t spi_w8r16(struct spi_device *spi, u8 cmd)
|
|
{
|
|
ssize_t status;
|
|
u16 result;
|
|
|
|
status = spi_write_then_read(spi, &cmd, 1, &result, 2);
|
|
|
|
/* return negative errno or unsigned value */
|
|
return (status < 0) ? status : result;
|
|
}
|
|
|
|
/**
|
|
* spi_w8r16be - SPI synchronous 8 bit write followed by 16 bit big-endian read
|
|
* @spi: device with which data will be exchanged
|
|
* @cmd: command to be written before data is read back
|
|
* Context: can sleep
|
|
*
|
|
* This function is similar to spi_w8r16, with the exception that it will
|
|
* convert the read 16 bit data word from big-endian to native endianness.
|
|
*
|
|
* Callable only from contexts that can sleep.
|
|
*
|
|
* Return: the (unsigned) sixteen bit number returned by the device in cpu
|
|
* endianness, or else a negative error code.
|
|
*/
|
|
static inline ssize_t spi_w8r16be(struct spi_device *spi, u8 cmd)
|
|
|
|
{
|
|
ssize_t status;
|
|
__be16 result;
|
|
|
|
status = spi_write_then_read(spi, &cmd, 1, &result, 2);
|
|
if (status < 0)
|
|
return status;
|
|
|
|
return be16_to_cpu(result);
|
|
}
|
|
|
|
/**
|
|
* struct spi_flash_read_message - flash specific information for
|
|
* spi-masters that provide accelerated flash read interfaces
|
|
* @buf: buffer to read data
|
|
* @from: offset within the flash from where data is to be read
|
|
* @len: length of data to be read
|
|
* @retlen: actual length of data read
|
|
* @read_opcode: read_opcode to be used to communicate with flash
|
|
* @addr_width: number of address bytes
|
|
* @dummy_bytes: number of dummy bytes
|
|
* @opcode_nbits: number of lines to send opcode
|
|
* @addr_nbits: number of lines to send address
|
|
* @data_nbits: number of lines for data
|
|
* @rx_sg: Scatterlist for receive data read from flash
|
|
* @cur_msg_mapped: message has been mapped for DMA
|
|
*/
|
|
struct spi_flash_read_message {
|
|
void *buf;
|
|
loff_t from;
|
|
size_t len;
|
|
size_t retlen;
|
|
u8 read_opcode;
|
|
u8 addr_width;
|
|
u8 dummy_bytes;
|
|
u8 opcode_nbits;
|
|
u8 addr_nbits;
|
|
u8 data_nbits;
|
|
struct sg_table rx_sg;
|
|
bool cur_msg_mapped;
|
|
};
|
|
|
|
/* SPI core interface for flash read support */
|
|
static inline bool spi_flash_read_supported(struct spi_device *spi)
|
|
{
|
|
return spi->master->spi_flash_read &&
|
|
(!spi->master->flash_read_supported ||
|
|
spi->master->flash_read_supported(spi));
|
|
}
|
|
|
|
int spi_flash_read(struct spi_device *spi,
|
|
struct spi_flash_read_message *msg);
|
|
|
|
/*---------------------------------------------------------------------------*/
|
|
|
|
/*
|
|
* INTERFACE between board init code and SPI infrastructure.
|
|
*
|
|
* No SPI driver ever sees these SPI device table segments, but
|
|
* it's how the SPI core (or adapters that get hotplugged) grows
|
|
* the driver model tree.
|
|
*
|
|
* As a rule, SPI devices can't be probed. Instead, board init code
|
|
* provides a table listing the devices which are present, with enough
|
|
* information to bind and set up the device's driver. There's basic
|
|
* support for nonstatic configurations too; enough to handle adding
|
|
* parport adapters, or microcontrollers acting as USB-to-SPI bridges.
|
|
*/
|
|
|
|
/**
|
|
* struct spi_board_info - board-specific template for a SPI device
|
|
* @modalias: Initializes spi_device.modalias; identifies the driver.
|
|
* @platform_data: Initializes spi_device.platform_data; the particular
|
|
* data stored there is driver-specific.
|
|
* @controller_data: Initializes spi_device.controller_data; some
|
|
* controllers need hints about hardware setup, e.g. for DMA.
|
|
* @irq: Initializes spi_device.irq; depends on how the board is wired.
|
|
* @max_speed_hz: Initializes spi_device.max_speed_hz; based on limits
|
|
* from the chip datasheet and board-specific signal quality issues.
|
|
* @bus_num: Identifies which spi_master parents the spi_device; unused
|
|
* by spi_new_device(), and otherwise depends on board wiring.
|
|
* @chip_select: Initializes spi_device.chip_select; depends on how
|
|
* the board is wired.
|
|
* @mode: Initializes spi_device.mode; based on the chip datasheet, board
|
|
* wiring (some devices support both 3WIRE and standard modes), and
|
|
* possibly presence of an inverter in the chipselect path.
|
|
*
|
|
* When adding new SPI devices to the device tree, these structures serve
|
|
* as a partial device template. They hold information which can't always
|
|
* be determined by drivers. Information that probe() can establish (such
|
|
* as the default transfer wordsize) is not included here.
|
|
*
|
|
* These structures are used in two places. Their primary role is to
|
|
* be stored in tables of board-specific device descriptors, which are
|
|
* declared early in board initialization and then used (much later) to
|
|
* populate a controller's device tree after the that controller's driver
|
|
* initializes. A secondary (and atypical) role is as a parameter to
|
|
* spi_new_device() call, which happens after those controller drivers
|
|
* are active in some dynamic board configuration models.
|
|
*/
|
|
struct spi_board_info {
|
|
/* the device name and module name are coupled, like platform_bus;
|
|
* "modalias" is normally the driver name.
|
|
*
|
|
* platform_data goes to spi_device.dev.platform_data,
|
|
* controller_data goes to spi_device.controller_data,
|
|
* irq is copied too
|
|
*/
|
|
char modalias[SPI_NAME_SIZE];
|
|
const void *platform_data;
|
|
void *controller_data;
|
|
int irq;
|
|
|
|
/* slower signaling on noisy or low voltage boards */
|
|
u32 max_speed_hz;
|
|
|
|
|
|
/* bus_num is board specific and matches the bus_num of some
|
|
* spi_master that will probably be registered later.
|
|
*
|
|
* chip_select reflects how this chip is wired to that master;
|
|
* it's less than num_chipselect.
|
|
*/
|
|
u16 bus_num;
|
|
u16 chip_select;
|
|
|
|
/* mode becomes spi_device.mode, and is essential for chips
|
|
* where the default of SPI_CS_HIGH = 0 is wrong.
|
|
*/
|
|
u16 mode;
|
|
|
|
/* ... may need additional spi_device chip config data here.
|
|
* avoid stuff protocol drivers can set; but include stuff
|
|
* needed to behave without being bound to a driver:
|
|
* - quirks like clock rate mattering when not selected
|
|
*/
|
|
};
|
|
|
|
#ifdef CONFIG_SPI
|
|
extern int
|
|
spi_register_board_info(struct spi_board_info const *info, unsigned n);
|
|
#else
|
|
/* board init code may ignore whether SPI is configured or not */
|
|
static inline int
|
|
spi_register_board_info(struct spi_board_info const *info, unsigned n)
|
|
{ return 0; }
|
|
#endif
|
|
|
|
|
|
/* If you're hotplugging an adapter with devices (parport, usb, etc)
|
|
* use spi_new_device() to describe each device. You can also call
|
|
* spi_unregister_device() to start making that device vanish, but
|
|
* normally that would be handled by spi_unregister_master().
|
|
*
|
|
* You can also use spi_alloc_device() and spi_add_device() to use a two
|
|
* stage registration sequence for each spi_device. This gives the caller
|
|
* some more control over the spi_device structure before it is registered,
|
|
* but requires that caller to initialize fields that would otherwise
|
|
* be defined using the board info.
|
|
*/
|
|
extern struct spi_device *
|
|
spi_alloc_device(struct spi_master *master);
|
|
|
|
extern int
|
|
spi_add_device(struct spi_device *spi);
|
|
|
|
extern struct spi_device *
|
|
spi_new_device(struct spi_master *, struct spi_board_info *);
|
|
|
|
extern void spi_unregister_device(struct spi_device *spi);
|
|
|
|
extern const struct spi_device_id *
|
|
spi_get_device_id(const struct spi_device *sdev);
|
|
|
|
static inline bool
|
|
spi_transfer_is_last(struct spi_master *master, struct spi_transfer *xfer)
|
|
{
|
|
return list_is_last(&xfer->transfer_list, &master->cur_msg->transfers);
|
|
}
|
|
|
|
/**
|
|
* spi_cs_low - set chip select pin state
|
|
* @spi: device for which chip select pin state to be set
|
|
* state: if true chip select pin will be kept low else high
|
|
*/
|
|
extern int spi_cs_low(struct spi_device *spi, bool state);
|
|
|
|
#endif /* __LINUX_SPI_H */
|