1134 lines
28 KiB
C
1134 lines
28 KiB
C
/*
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* Copyright (C) 2009 ST-Ericsson SA
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* Copyright (C) 2009 STMicroelectronics
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*
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* I2C master mode controller driver, used in Nomadik 8815
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* and Ux500 platforms.
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*
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* Author: Srinidhi Kasagar <srinidhi.kasagar@stericsson.com>
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* Author: Sachin Verma <sachin.verma@st.com>
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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 version 2, as
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* published by the Free Software Foundation.
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*/
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#include <linux/init.h>
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#include <linux/module.h>
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#include <linux/amba/bus.h>
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#include <linux/slab.h>
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#include <linux/interrupt.h>
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#include <linux/i2c.h>
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#include <linux/err.h>
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#include <linux/clk.h>
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#include <linux/io.h>
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#include <linux/pm_runtime.h>
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#include <linux/of.h>
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#include <linux/pinctrl/consumer.h>
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#define DRIVER_NAME "nmk-i2c"
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/* I2C Controller register offsets */
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#define I2C_CR (0x000)
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#define I2C_SCR (0x004)
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#define I2C_HSMCR (0x008)
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#define I2C_MCR (0x00C)
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#define I2C_TFR (0x010)
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#define I2C_SR (0x014)
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#define I2C_RFR (0x018)
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#define I2C_TFTR (0x01C)
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#define I2C_RFTR (0x020)
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#define I2C_DMAR (0x024)
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#define I2C_BRCR (0x028)
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#define I2C_IMSCR (0x02C)
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#define I2C_RISR (0x030)
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#define I2C_MISR (0x034)
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#define I2C_ICR (0x038)
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/* Control registers */
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#define I2C_CR_PE (0x1 << 0) /* Peripheral Enable */
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#define I2C_CR_OM (0x3 << 1) /* Operating mode */
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#define I2C_CR_SAM (0x1 << 3) /* Slave addressing mode */
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#define I2C_CR_SM (0x3 << 4) /* Speed mode */
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#define I2C_CR_SGCM (0x1 << 6) /* Slave general call mode */
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#define I2C_CR_FTX (0x1 << 7) /* Flush Transmit */
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#define I2C_CR_FRX (0x1 << 8) /* Flush Receive */
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#define I2C_CR_DMA_TX_EN (0x1 << 9) /* DMA Tx enable */
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#define I2C_CR_DMA_RX_EN (0x1 << 10) /* DMA Rx Enable */
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#define I2C_CR_DMA_SLE (0x1 << 11) /* DMA sync. logic enable */
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#define I2C_CR_LM (0x1 << 12) /* Loopback mode */
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#define I2C_CR_FON (0x3 << 13) /* Filtering on */
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#define I2C_CR_FS (0x3 << 15) /* Force stop enable */
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/* Master controller (MCR) register */
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#define I2C_MCR_OP (0x1 << 0) /* Operation */
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#define I2C_MCR_A7 (0x7f << 1) /* 7-bit address */
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#define I2C_MCR_EA10 (0x7 << 8) /* 10-bit Extended address */
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#define I2C_MCR_SB (0x1 << 11) /* Extended address */
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#define I2C_MCR_AM (0x3 << 12) /* Address type */
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#define I2C_MCR_STOP (0x1 << 14) /* Stop condition */
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#define I2C_MCR_LENGTH (0x7ff << 15) /* Transaction length */
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/* Status register (SR) */
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#define I2C_SR_OP (0x3 << 0) /* Operation */
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#define I2C_SR_STATUS (0x3 << 2) /* controller status */
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#define I2C_SR_CAUSE (0x7 << 4) /* Abort cause */
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#define I2C_SR_TYPE (0x3 << 7) /* Receive type */
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#define I2C_SR_LENGTH (0x7ff << 9) /* Transfer length */
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/* Interrupt mask set/clear (IMSCR) bits */
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#define I2C_IT_TXFE (0x1 << 0)
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#define I2C_IT_TXFNE (0x1 << 1)
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#define I2C_IT_TXFF (0x1 << 2)
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#define I2C_IT_TXFOVR (0x1 << 3)
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#define I2C_IT_RXFE (0x1 << 4)
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#define I2C_IT_RXFNF (0x1 << 5)
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#define I2C_IT_RXFF (0x1 << 6)
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#define I2C_IT_RFSR (0x1 << 16)
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#define I2C_IT_RFSE (0x1 << 17)
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#define I2C_IT_WTSR (0x1 << 18)
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#define I2C_IT_MTD (0x1 << 19)
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#define I2C_IT_STD (0x1 << 20)
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#define I2C_IT_MAL (0x1 << 24)
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#define I2C_IT_BERR (0x1 << 25)
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#define I2C_IT_MTDWS (0x1 << 28)
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#define GEN_MASK(val, mask, sb) (((val) << (sb)) & (mask))
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/* some bits in ICR are reserved */
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#define I2C_CLEAR_ALL_INTS 0x131f007f
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/* first three msb bits are reserved */
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#define IRQ_MASK(mask) (mask & 0x1fffffff)
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/* maximum threshold value */
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#define MAX_I2C_FIFO_THRESHOLD 15
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enum i2c_freq_mode {
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I2C_FREQ_MODE_STANDARD, /* up to 100 Kb/s */
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I2C_FREQ_MODE_FAST, /* up to 400 Kb/s */
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I2C_FREQ_MODE_HIGH_SPEED, /* up to 3.4 Mb/s */
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I2C_FREQ_MODE_FAST_PLUS, /* up to 1 Mb/s */
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};
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/**
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* struct i2c_vendor_data - per-vendor variations
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* @has_mtdws: variant has the MTDWS bit
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* @fifodepth: variant FIFO depth
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*/
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struct i2c_vendor_data {
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bool has_mtdws;
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u32 fifodepth;
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};
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enum i2c_status {
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I2C_NOP,
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I2C_ON_GOING,
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I2C_OK,
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I2C_ABORT
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};
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/* operation */
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enum i2c_operation {
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I2C_NO_OPERATION = 0xff,
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I2C_WRITE = 0x00,
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I2C_READ = 0x01
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};
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/**
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* struct i2c_nmk_client - client specific data
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* @slave_adr: 7-bit slave address
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* @count: no. bytes to be transferred
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* @buffer: client data buffer
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* @xfer_bytes: bytes transferred till now
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* @operation: current I2C operation
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*/
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struct i2c_nmk_client {
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unsigned short slave_adr;
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unsigned long count;
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unsigned char *buffer;
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unsigned long xfer_bytes;
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enum i2c_operation operation;
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};
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/**
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* struct nmk_i2c_dev - private data structure of the controller.
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* @vendor: vendor data for this variant.
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* @adev: parent amba device.
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* @adap: corresponding I2C adapter.
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* @irq: interrupt line for the controller.
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* @virtbase: virtual io memory area.
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* @clk: hardware i2c block clock.
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* @cli: holder of client specific data.
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* @clk_freq: clock frequency for the operation mode
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* @tft: Tx FIFO Threshold in bytes
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* @rft: Rx FIFO Threshold in bytes
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* @timeout Slave response timeout (ms)
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* @sm: speed mode
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* @stop: stop condition.
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* @xfer_complete: acknowledge completion for a I2C message.
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* @result: controller propogated result.
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*/
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struct nmk_i2c_dev {
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struct i2c_vendor_data *vendor;
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struct amba_device *adev;
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struct i2c_adapter adap;
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int irq;
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void __iomem *virtbase;
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struct clk *clk;
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struct i2c_nmk_client cli;
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u32 clk_freq;
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unsigned char tft;
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unsigned char rft;
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int timeout;
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enum i2c_freq_mode sm;
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int stop;
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struct completion xfer_complete;
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int result;
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};
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/* controller's abort causes */
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static const char *abort_causes[] = {
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"no ack received after address transmission",
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"no ack received during data phase",
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"ack received after xmission of master code",
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"master lost arbitration",
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"slave restarts",
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"slave reset",
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"overflow, maxsize is 2047 bytes",
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};
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static inline void i2c_set_bit(void __iomem *reg, u32 mask)
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{
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writel(readl(reg) | mask, reg);
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}
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static inline void i2c_clr_bit(void __iomem *reg, u32 mask)
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{
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writel(readl(reg) & ~mask, reg);
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}
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/**
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* flush_i2c_fifo() - This function flushes the I2C FIFO
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* @dev: private data of I2C Driver
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*
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* This function flushes the I2C Tx and Rx FIFOs. It returns
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* 0 on successful flushing of FIFO
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*/
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static int flush_i2c_fifo(struct nmk_i2c_dev *dev)
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{
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#define LOOP_ATTEMPTS 10
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int i;
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unsigned long timeout;
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/*
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* flush the transmit and receive FIFO. The flushing
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* operation takes several cycles before to be completed.
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* On the completion, the I2C internal logic clears these
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* bits, until then no one must access Tx, Rx FIFO and
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* should poll on these bits waiting for the completion.
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*/
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writel((I2C_CR_FTX | I2C_CR_FRX), dev->virtbase + I2C_CR);
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for (i = 0; i < LOOP_ATTEMPTS; i++) {
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timeout = jiffies + dev->adap.timeout;
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while (!time_after(jiffies, timeout)) {
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if ((readl(dev->virtbase + I2C_CR) &
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(I2C_CR_FTX | I2C_CR_FRX)) == 0)
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return 0;
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}
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}
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dev_err(&dev->adev->dev,
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"flushing operation timed out giving up after %d attempts",
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LOOP_ATTEMPTS);
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return -ETIMEDOUT;
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}
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/**
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* disable_all_interrupts() - Disable all interrupts of this I2c Bus
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* @dev: private data of I2C Driver
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*/
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static void disable_all_interrupts(struct nmk_i2c_dev *dev)
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{
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u32 mask = IRQ_MASK(0);
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writel(mask, dev->virtbase + I2C_IMSCR);
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}
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/**
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* clear_all_interrupts() - Clear all interrupts of I2C Controller
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* @dev: private data of I2C Driver
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*/
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static void clear_all_interrupts(struct nmk_i2c_dev *dev)
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{
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u32 mask;
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mask = IRQ_MASK(I2C_CLEAR_ALL_INTS);
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writel(mask, dev->virtbase + I2C_ICR);
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}
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/**
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* init_hw() - initialize the I2C hardware
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* @dev: private data of I2C Driver
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*/
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static int init_hw(struct nmk_i2c_dev *dev)
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{
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int stat;
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stat = flush_i2c_fifo(dev);
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if (stat)
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goto exit;
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/* disable the controller */
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i2c_clr_bit(dev->virtbase + I2C_CR , I2C_CR_PE);
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disable_all_interrupts(dev);
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clear_all_interrupts(dev);
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dev->cli.operation = I2C_NO_OPERATION;
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exit:
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return stat;
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}
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/* enable peripheral, master mode operation */
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#define DEFAULT_I2C_REG_CR ((1 << 1) | I2C_CR_PE)
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/**
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* load_i2c_mcr_reg() - load the MCR register
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* @dev: private data of controller
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* @flags: message flags
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*/
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static u32 load_i2c_mcr_reg(struct nmk_i2c_dev *dev, u16 flags)
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{
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u32 mcr = 0;
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unsigned short slave_adr_3msb_bits;
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mcr |= GEN_MASK(dev->cli.slave_adr, I2C_MCR_A7, 1);
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if (unlikely(flags & I2C_M_TEN)) {
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/* 10-bit address transaction */
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mcr |= GEN_MASK(2, I2C_MCR_AM, 12);
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/*
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* Get the top 3 bits.
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* EA10 represents extended address in MCR. This includes
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* the extension (MSB bits) of the 7 bit address loaded
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* in A7
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*/
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slave_adr_3msb_bits = (dev->cli.slave_adr >> 7) & 0x7;
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mcr |= GEN_MASK(slave_adr_3msb_bits, I2C_MCR_EA10, 8);
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} else {
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/* 7-bit address transaction */
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mcr |= GEN_MASK(1, I2C_MCR_AM, 12);
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}
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/* start byte procedure not applied */
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mcr |= GEN_MASK(0, I2C_MCR_SB, 11);
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/* check the operation, master read/write? */
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if (dev->cli.operation == I2C_WRITE)
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mcr |= GEN_MASK(I2C_WRITE, I2C_MCR_OP, 0);
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else
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mcr |= GEN_MASK(I2C_READ, I2C_MCR_OP, 0);
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/* stop or repeated start? */
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if (dev->stop)
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mcr |= GEN_MASK(1, I2C_MCR_STOP, 14);
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else
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mcr &= ~(GEN_MASK(1, I2C_MCR_STOP, 14));
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mcr |= GEN_MASK(dev->cli.count, I2C_MCR_LENGTH, 15);
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return mcr;
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}
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/**
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* setup_i2c_controller() - setup the controller
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* @dev: private data of controller
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*/
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static void setup_i2c_controller(struct nmk_i2c_dev *dev)
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{
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u32 brcr1, brcr2;
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u32 i2c_clk, div;
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u32 ns;
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u16 slsu;
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writel(0x0, dev->virtbase + I2C_CR);
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writel(0x0, dev->virtbase + I2C_HSMCR);
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writel(0x0, dev->virtbase + I2C_TFTR);
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writel(0x0, dev->virtbase + I2C_RFTR);
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writel(0x0, dev->virtbase + I2C_DMAR);
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i2c_clk = clk_get_rate(dev->clk);
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/*
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* set the slsu:
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*
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* slsu defines the data setup time after SCL clock
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* stretching in terms of i2c clk cycles + 1 (zero means
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* "wait one cycle"), the needed setup time for the three
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* modes are 250ns, 100ns, 10ns respectively.
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*
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* As the time for one cycle T in nanoseconds is
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* T = (1/f) * 1000000000 =>
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* slsu = cycles / (1000000000 / f) + 1
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*/
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ns = DIV_ROUND_UP_ULL(1000000000ULL, i2c_clk);
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switch (dev->sm) {
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case I2C_FREQ_MODE_FAST:
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case I2C_FREQ_MODE_FAST_PLUS:
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slsu = DIV_ROUND_UP(100, ns); /* Fast */
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break;
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case I2C_FREQ_MODE_HIGH_SPEED:
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slsu = DIV_ROUND_UP(10, ns); /* High */
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break;
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case I2C_FREQ_MODE_STANDARD:
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default:
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slsu = DIV_ROUND_UP(250, ns); /* Standard */
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break;
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}
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slsu += 1;
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dev_dbg(&dev->adev->dev, "calculated SLSU = %04x\n", slsu);
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writel(slsu << 16, dev->virtbase + I2C_SCR);
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/*
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* The spec says, in case of std. mode the divider is
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* 2 whereas it is 3 for fast and fastplus mode of
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* operation. TODO - high speed support.
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*/
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div = (dev->clk_freq > 100000) ? 3 : 2;
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/*
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* generate the mask for baud rate counters. The controller
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* has two baud rate counters. One is used for High speed
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* operation, and the other is for std, fast mode, fast mode
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* plus operation. Currently we do not supprt high speed mode
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* so set brcr1 to 0.
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*/
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brcr1 = 0 << 16;
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brcr2 = (i2c_clk/(dev->clk_freq * div)) & 0xffff;
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/* set the baud rate counter register */
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writel((brcr1 | brcr2), dev->virtbase + I2C_BRCR);
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/*
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* set the speed mode. Currently we support
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* only standard and fast mode of operation
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* TODO - support for fast mode plus (up to 1Mb/s)
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* and high speed (up to 3.4 Mb/s)
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*/
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if (dev->sm > I2C_FREQ_MODE_FAST) {
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dev_err(&dev->adev->dev,
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"do not support this mode defaulting to std. mode\n");
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brcr2 = i2c_clk/(100000 * 2) & 0xffff;
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writel((brcr1 | brcr2), dev->virtbase + I2C_BRCR);
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writel(I2C_FREQ_MODE_STANDARD << 4,
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dev->virtbase + I2C_CR);
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}
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writel(dev->sm << 4, dev->virtbase + I2C_CR);
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/* set the Tx and Rx FIFO threshold */
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writel(dev->tft, dev->virtbase + I2C_TFTR);
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writel(dev->rft, dev->virtbase + I2C_RFTR);
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}
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/**
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* read_i2c() - Read from I2C client device
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* @dev: private data of I2C Driver
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* @flags: message flags
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*
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* This function reads from i2c client device when controller is in
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* master mode. There is a completion timeout. If there is no transfer
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* before timeout error is returned.
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*/
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static int read_i2c(struct nmk_i2c_dev *dev, u16 flags)
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{
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int status = 0;
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u32 mcr, irq_mask;
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unsigned long timeout;
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mcr = load_i2c_mcr_reg(dev, flags);
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writel(mcr, dev->virtbase + I2C_MCR);
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/* load the current CR value */
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writel(readl(dev->virtbase + I2C_CR) | DEFAULT_I2C_REG_CR,
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dev->virtbase + I2C_CR);
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/* enable the controller */
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i2c_set_bit(dev->virtbase + I2C_CR, I2C_CR_PE);
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init_completion(&dev->xfer_complete);
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/* enable interrupts by setting the mask */
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irq_mask = (I2C_IT_RXFNF | I2C_IT_RXFF |
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I2C_IT_MAL | I2C_IT_BERR);
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|
|
if (dev->stop || !dev->vendor->has_mtdws)
|
|
irq_mask |= I2C_IT_MTD;
|
|
else
|
|
irq_mask |= I2C_IT_MTDWS;
|
|
|
|
irq_mask = I2C_CLEAR_ALL_INTS & IRQ_MASK(irq_mask);
|
|
|
|
writel(readl(dev->virtbase + I2C_IMSCR) | irq_mask,
|
|
dev->virtbase + I2C_IMSCR);
|
|
|
|
timeout = wait_for_completion_timeout(
|
|
&dev->xfer_complete, dev->adap.timeout);
|
|
|
|
if (timeout == 0) {
|
|
/* Controller timed out */
|
|
dev_err(&dev->adev->dev, "read from slave 0x%x timed out\n",
|
|
dev->cli.slave_adr);
|
|
status = -ETIMEDOUT;
|
|
}
|
|
return status;
|
|
}
|
|
|
|
static void fill_tx_fifo(struct nmk_i2c_dev *dev, int no_bytes)
|
|
{
|
|
int count;
|
|
|
|
for (count = (no_bytes - 2);
|
|
(count > 0) &&
|
|
(dev->cli.count != 0);
|
|
count--) {
|
|
/* write to the Tx FIFO */
|
|
writeb(*dev->cli.buffer,
|
|
dev->virtbase + I2C_TFR);
|
|
dev->cli.buffer++;
|
|
dev->cli.count--;
|
|
dev->cli.xfer_bytes++;
|
|
}
|
|
|
|
}
|
|
|
|
/**
|
|
* write_i2c() - Write data to I2C client.
|
|
* @dev: private data of I2C Driver
|
|
* @flags: message flags
|
|
*
|
|
* This function writes data to I2C client
|
|
*/
|
|
static int write_i2c(struct nmk_i2c_dev *dev, u16 flags)
|
|
{
|
|
u32 status = 0;
|
|
u32 mcr, irq_mask;
|
|
unsigned long timeout;
|
|
|
|
mcr = load_i2c_mcr_reg(dev, flags);
|
|
|
|
writel(mcr, dev->virtbase + I2C_MCR);
|
|
|
|
/* load the current CR value */
|
|
writel(readl(dev->virtbase + I2C_CR) | DEFAULT_I2C_REG_CR,
|
|
dev->virtbase + I2C_CR);
|
|
|
|
/* enable the controller */
|
|
i2c_set_bit(dev->virtbase + I2C_CR , I2C_CR_PE);
|
|
|
|
init_completion(&dev->xfer_complete);
|
|
|
|
/* enable interrupts by settings the masks */
|
|
irq_mask = (I2C_IT_TXFOVR | I2C_IT_MAL | I2C_IT_BERR);
|
|
|
|
/* Fill the TX FIFO with transmit data */
|
|
fill_tx_fifo(dev, MAX_I2C_FIFO_THRESHOLD);
|
|
|
|
if (dev->cli.count != 0)
|
|
irq_mask |= I2C_IT_TXFNE;
|
|
|
|
/*
|
|
* check if we want to transfer a single or multiple bytes, if so
|
|
* set the MTDWS bit (Master Transaction Done Without Stop)
|
|
* to start repeated start operation
|
|
*/
|
|
if (dev->stop || !dev->vendor->has_mtdws)
|
|
irq_mask |= I2C_IT_MTD;
|
|
else
|
|
irq_mask |= I2C_IT_MTDWS;
|
|
|
|
irq_mask = I2C_CLEAR_ALL_INTS & IRQ_MASK(irq_mask);
|
|
|
|
writel(readl(dev->virtbase + I2C_IMSCR) | irq_mask,
|
|
dev->virtbase + I2C_IMSCR);
|
|
|
|
timeout = wait_for_completion_timeout(
|
|
&dev->xfer_complete, dev->adap.timeout);
|
|
|
|
if (timeout == 0) {
|
|
/* Controller timed out */
|
|
dev_err(&dev->adev->dev, "write to slave 0x%x timed out\n",
|
|
dev->cli.slave_adr);
|
|
status = -ETIMEDOUT;
|
|
}
|
|
|
|
return status;
|
|
}
|
|
|
|
/**
|
|
* nmk_i2c_xfer_one() - transmit a single I2C message
|
|
* @dev: device with a message encoded into it
|
|
* @flags: message flags
|
|
*/
|
|
static int nmk_i2c_xfer_one(struct nmk_i2c_dev *dev, u16 flags)
|
|
{
|
|
int status;
|
|
|
|
if (flags & I2C_M_RD) {
|
|
/* read operation */
|
|
dev->cli.operation = I2C_READ;
|
|
status = read_i2c(dev, flags);
|
|
} else {
|
|
/* write operation */
|
|
dev->cli.operation = I2C_WRITE;
|
|
status = write_i2c(dev, flags);
|
|
}
|
|
|
|
if (status || (dev->result)) {
|
|
u32 i2c_sr;
|
|
u32 cause;
|
|
|
|
i2c_sr = readl(dev->virtbase + I2C_SR);
|
|
/*
|
|
* Check if the controller I2C operation status
|
|
* is set to ABORT(11b).
|
|
*/
|
|
if (((i2c_sr >> 2) & 0x3) == 0x3) {
|
|
/* get the abort cause */
|
|
cause = (i2c_sr >> 4) & 0x7;
|
|
dev_err(&dev->adev->dev, "%s\n",
|
|
cause >= ARRAY_SIZE(abort_causes) ?
|
|
"unknown reason" :
|
|
abort_causes[cause]);
|
|
}
|
|
|
|
(void) init_hw(dev);
|
|
|
|
status = status ? status : dev->result;
|
|
}
|
|
|
|
return status;
|
|
}
|
|
|
|
/**
|
|
* nmk_i2c_xfer() - I2C transfer function used by kernel framework
|
|
* @i2c_adap: Adapter pointer to the controller
|
|
* @msgs: Pointer to data to be written.
|
|
* @num_msgs: Number of messages to be executed
|
|
*
|
|
* This is the function called by the generic kernel i2c_transfer()
|
|
* or i2c_smbus...() API calls. Note that this code is protected by the
|
|
* semaphore set in the kernel i2c_transfer() function.
|
|
*
|
|
* NOTE:
|
|
* READ TRANSFER : We impose a restriction of the first message to be the
|
|
* index message for any read transaction.
|
|
* - a no index is coded as '0',
|
|
* - 2byte big endian index is coded as '3'
|
|
* !!! msg[0].buf holds the actual index.
|
|
* This is compatible with generic messages of smbus emulator
|
|
* that send a one byte index.
|
|
* eg. a I2C transation to read 2 bytes from index 0
|
|
* idx = 0;
|
|
* msg[0].addr = client->addr;
|
|
* msg[0].flags = 0x0;
|
|
* msg[0].len = 1;
|
|
* msg[0].buf = &idx;
|
|
*
|
|
* msg[1].addr = client->addr;
|
|
* msg[1].flags = I2C_M_RD;
|
|
* msg[1].len = 2;
|
|
* msg[1].buf = rd_buff
|
|
* i2c_transfer(adap, msg, 2);
|
|
*
|
|
* WRITE TRANSFER : The I2C standard interface interprets all data as payload.
|
|
* If you want to emulate an SMBUS write transaction put the
|
|
* index as first byte(or first and second) in the payload.
|
|
* eg. a I2C transation to write 2 bytes from index 1
|
|
* wr_buff[0] = 0x1;
|
|
* wr_buff[1] = 0x23;
|
|
* wr_buff[2] = 0x46;
|
|
* msg[0].flags = 0x0;
|
|
* msg[0].len = 3;
|
|
* msg[0].buf = wr_buff;
|
|
* i2c_transfer(adap, msg, 1);
|
|
*
|
|
* To read or write a block of data (multiple bytes) using SMBUS emulation
|
|
* please use the i2c_smbus_read_i2c_block_data()
|
|
* or i2c_smbus_write_i2c_block_data() API
|
|
*/
|
|
static int nmk_i2c_xfer(struct i2c_adapter *i2c_adap,
|
|
struct i2c_msg msgs[], int num_msgs)
|
|
{
|
|
int status = 0;
|
|
int i;
|
|
struct nmk_i2c_dev *dev = i2c_get_adapdata(i2c_adap);
|
|
int j;
|
|
|
|
pm_runtime_get_sync(&dev->adev->dev);
|
|
|
|
/* Attempt three times to send the message queue */
|
|
for (j = 0; j < 3; j++) {
|
|
/* setup the i2c controller */
|
|
setup_i2c_controller(dev);
|
|
|
|
for (i = 0; i < num_msgs; i++) {
|
|
dev->cli.slave_adr = msgs[i].addr;
|
|
dev->cli.buffer = msgs[i].buf;
|
|
dev->cli.count = msgs[i].len;
|
|
dev->stop = (i < (num_msgs - 1)) ? 0 : 1;
|
|
dev->result = 0;
|
|
|
|
status = nmk_i2c_xfer_one(dev, msgs[i].flags);
|
|
if (status != 0)
|
|
break;
|
|
}
|
|
if (status == 0)
|
|
break;
|
|
}
|
|
|
|
pm_runtime_put_sync(&dev->adev->dev);
|
|
|
|
/* return the no. messages processed */
|
|
if (status)
|
|
return status;
|
|
else
|
|
return num_msgs;
|
|
}
|
|
|
|
/**
|
|
* disable_interrupts() - disable the interrupts
|
|
* @dev: private data of controller
|
|
* @irq: interrupt number
|
|
*/
|
|
static int disable_interrupts(struct nmk_i2c_dev *dev, u32 irq)
|
|
{
|
|
irq = IRQ_MASK(irq);
|
|
writel(readl(dev->virtbase + I2C_IMSCR) & ~(I2C_CLEAR_ALL_INTS & irq),
|
|
dev->virtbase + I2C_IMSCR);
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* i2c_irq_handler() - interrupt routine
|
|
* @irq: interrupt number
|
|
* @arg: data passed to the handler
|
|
*
|
|
* This is the interrupt handler for the i2c driver. Currently
|
|
* it handles the major interrupts like Rx & Tx FIFO management
|
|
* interrupts, master transaction interrupts, arbitration and
|
|
* bus error interrupts. The rest of the interrupts are treated as
|
|
* unhandled.
|
|
*/
|
|
static irqreturn_t i2c_irq_handler(int irq, void *arg)
|
|
{
|
|
struct nmk_i2c_dev *dev = arg;
|
|
u32 tft, rft;
|
|
u32 count;
|
|
u32 misr, src;
|
|
|
|
/* load Tx FIFO and Rx FIFO threshold values */
|
|
tft = readl(dev->virtbase + I2C_TFTR);
|
|
rft = readl(dev->virtbase + I2C_RFTR);
|
|
|
|
/* read interrupt status register */
|
|
misr = readl(dev->virtbase + I2C_MISR);
|
|
|
|
src = __ffs(misr);
|
|
switch ((1 << src)) {
|
|
|
|
/* Transmit FIFO nearly empty interrupt */
|
|
case I2C_IT_TXFNE:
|
|
{
|
|
if (dev->cli.operation == I2C_READ) {
|
|
/*
|
|
* in read operation why do we care for writing?
|
|
* so disable the Transmit FIFO interrupt
|
|
*/
|
|
disable_interrupts(dev, I2C_IT_TXFNE);
|
|
} else {
|
|
fill_tx_fifo(dev, (MAX_I2C_FIFO_THRESHOLD - tft));
|
|
/*
|
|
* if done, close the transfer by disabling the
|
|
* corresponding TXFNE interrupt
|
|
*/
|
|
if (dev->cli.count == 0)
|
|
disable_interrupts(dev, I2C_IT_TXFNE);
|
|
}
|
|
}
|
|
break;
|
|
|
|
/*
|
|
* Rx FIFO nearly full interrupt.
|
|
* This is set when the numer of entries in Rx FIFO is
|
|
* greater or equal than the threshold value programmed
|
|
* in RFT
|
|
*/
|
|
case I2C_IT_RXFNF:
|
|
for (count = rft; count > 0; count--) {
|
|
/* Read the Rx FIFO */
|
|
*dev->cli.buffer = readb(dev->virtbase + I2C_RFR);
|
|
dev->cli.buffer++;
|
|
}
|
|
dev->cli.count -= rft;
|
|
dev->cli.xfer_bytes += rft;
|
|
break;
|
|
|
|
/* Rx FIFO full */
|
|
case I2C_IT_RXFF:
|
|
for (count = MAX_I2C_FIFO_THRESHOLD; count > 0; count--) {
|
|
*dev->cli.buffer = readb(dev->virtbase + I2C_RFR);
|
|
dev->cli.buffer++;
|
|
}
|
|
dev->cli.count -= MAX_I2C_FIFO_THRESHOLD;
|
|
dev->cli.xfer_bytes += MAX_I2C_FIFO_THRESHOLD;
|
|
break;
|
|
|
|
/* Master Transaction Done with/without stop */
|
|
case I2C_IT_MTD:
|
|
case I2C_IT_MTDWS:
|
|
if (dev->cli.operation == I2C_READ) {
|
|
while (!(readl(dev->virtbase + I2C_RISR)
|
|
& I2C_IT_RXFE)) {
|
|
if (dev->cli.count == 0)
|
|
break;
|
|
*dev->cli.buffer =
|
|
readb(dev->virtbase + I2C_RFR);
|
|
dev->cli.buffer++;
|
|
dev->cli.count--;
|
|
dev->cli.xfer_bytes++;
|
|
}
|
|
}
|
|
|
|
disable_all_interrupts(dev);
|
|
clear_all_interrupts(dev);
|
|
|
|
if (dev->cli.count) {
|
|
dev->result = -EIO;
|
|
dev_err(&dev->adev->dev,
|
|
"%lu bytes still remain to be xfered\n",
|
|
dev->cli.count);
|
|
(void) init_hw(dev);
|
|
}
|
|
complete(&dev->xfer_complete);
|
|
|
|
break;
|
|
|
|
/* Master Arbitration lost interrupt */
|
|
case I2C_IT_MAL:
|
|
dev->result = -EIO;
|
|
(void) init_hw(dev);
|
|
|
|
i2c_set_bit(dev->virtbase + I2C_ICR, I2C_IT_MAL);
|
|
complete(&dev->xfer_complete);
|
|
|
|
break;
|
|
|
|
/*
|
|
* Bus Error interrupt.
|
|
* This happens when an unexpected start/stop condition occurs
|
|
* during the transaction.
|
|
*/
|
|
case I2C_IT_BERR:
|
|
dev->result = -EIO;
|
|
/* get the status */
|
|
if (((readl(dev->virtbase + I2C_SR) >> 2) & 0x3) == I2C_ABORT)
|
|
(void) init_hw(dev);
|
|
|
|
i2c_set_bit(dev->virtbase + I2C_ICR, I2C_IT_BERR);
|
|
complete(&dev->xfer_complete);
|
|
|
|
break;
|
|
|
|
/*
|
|
* Tx FIFO overrun interrupt.
|
|
* This is set when a write operation in Tx FIFO is performed and
|
|
* the Tx FIFO is full.
|
|
*/
|
|
case I2C_IT_TXFOVR:
|
|
dev->result = -EIO;
|
|
(void) init_hw(dev);
|
|
|
|
dev_err(&dev->adev->dev, "Tx Fifo Over run\n");
|
|
complete(&dev->xfer_complete);
|
|
|
|
break;
|
|
|
|
/* unhandled interrupts by this driver - TODO*/
|
|
case I2C_IT_TXFE:
|
|
case I2C_IT_TXFF:
|
|
case I2C_IT_RXFE:
|
|
case I2C_IT_RFSR:
|
|
case I2C_IT_RFSE:
|
|
case I2C_IT_WTSR:
|
|
case I2C_IT_STD:
|
|
dev_err(&dev->adev->dev, "unhandled Interrupt\n");
|
|
break;
|
|
default:
|
|
dev_err(&dev->adev->dev, "spurious Interrupt..\n");
|
|
break;
|
|
}
|
|
|
|
return IRQ_HANDLED;
|
|
}
|
|
|
|
#ifdef CONFIG_PM_SLEEP
|
|
static int nmk_i2c_suspend_late(struct device *dev)
|
|
{
|
|
int ret;
|
|
|
|
ret = pm_runtime_force_suspend(dev);
|
|
if (ret)
|
|
return ret;
|
|
|
|
pinctrl_pm_select_sleep_state(dev);
|
|
return 0;
|
|
}
|
|
|
|
static int nmk_i2c_resume_early(struct device *dev)
|
|
{
|
|
return pm_runtime_force_resume(dev);
|
|
}
|
|
#endif
|
|
|
|
#ifdef CONFIG_PM
|
|
static int nmk_i2c_runtime_suspend(struct device *dev)
|
|
{
|
|
struct amba_device *adev = to_amba_device(dev);
|
|
struct nmk_i2c_dev *nmk_i2c = amba_get_drvdata(adev);
|
|
|
|
clk_disable_unprepare(nmk_i2c->clk);
|
|
pinctrl_pm_select_idle_state(dev);
|
|
return 0;
|
|
}
|
|
|
|
static int nmk_i2c_runtime_resume(struct device *dev)
|
|
{
|
|
struct amba_device *adev = to_amba_device(dev);
|
|
struct nmk_i2c_dev *nmk_i2c = amba_get_drvdata(adev);
|
|
int ret;
|
|
|
|
ret = clk_prepare_enable(nmk_i2c->clk);
|
|
if (ret) {
|
|
dev_err(dev, "can't prepare_enable clock\n");
|
|
return ret;
|
|
}
|
|
|
|
pinctrl_pm_select_default_state(dev);
|
|
|
|
ret = init_hw(nmk_i2c);
|
|
if (ret) {
|
|
clk_disable_unprepare(nmk_i2c->clk);
|
|
pinctrl_pm_select_idle_state(dev);
|
|
}
|
|
|
|
return ret;
|
|
}
|
|
#endif
|
|
|
|
static const struct dev_pm_ops nmk_i2c_pm = {
|
|
SET_LATE_SYSTEM_SLEEP_PM_OPS(nmk_i2c_suspend_late, nmk_i2c_resume_early)
|
|
SET_RUNTIME_PM_OPS(nmk_i2c_runtime_suspend,
|
|
nmk_i2c_runtime_resume,
|
|
NULL)
|
|
};
|
|
|
|
static unsigned int nmk_i2c_functionality(struct i2c_adapter *adap)
|
|
{
|
|
return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | I2C_FUNC_10BIT_ADDR;
|
|
}
|
|
|
|
static const struct i2c_algorithm nmk_i2c_algo = {
|
|
.master_xfer = nmk_i2c_xfer,
|
|
.functionality = nmk_i2c_functionality
|
|
};
|
|
|
|
static void nmk_i2c_of_probe(struct device_node *np,
|
|
struct nmk_i2c_dev *nmk)
|
|
{
|
|
/* Default to 100 kHz if no frequency is given in the node */
|
|
if (of_property_read_u32(np, "clock-frequency", &nmk->clk_freq))
|
|
nmk->clk_freq = 100000;
|
|
|
|
/* This driver only supports 'standard' and 'fast' modes of operation. */
|
|
if (nmk->clk_freq <= 100000)
|
|
nmk->sm = I2C_FREQ_MODE_STANDARD;
|
|
else
|
|
nmk->sm = I2C_FREQ_MODE_FAST;
|
|
nmk->tft = 1; /* Tx FIFO threshold */
|
|
nmk->rft = 8; /* Rx FIFO threshold */
|
|
nmk->timeout = 200; /* Slave response timeout(ms) */
|
|
}
|
|
|
|
static int nmk_i2c_probe(struct amba_device *adev, const struct amba_id *id)
|
|
{
|
|
int ret = 0;
|
|
struct device_node *np = adev->dev.of_node;
|
|
struct nmk_i2c_dev *dev;
|
|
struct i2c_adapter *adap;
|
|
struct i2c_vendor_data *vendor = id->data;
|
|
u32 max_fifo_threshold = (vendor->fifodepth / 2) - 1;
|
|
|
|
dev = devm_kzalloc(&adev->dev, sizeof(struct nmk_i2c_dev), GFP_KERNEL);
|
|
if (!dev) {
|
|
dev_err(&adev->dev, "cannot allocate memory\n");
|
|
ret = -ENOMEM;
|
|
goto err_no_mem;
|
|
}
|
|
dev->vendor = vendor;
|
|
dev->adev = adev;
|
|
nmk_i2c_of_probe(np, dev);
|
|
|
|
if (dev->tft > max_fifo_threshold) {
|
|
dev_warn(&adev->dev, "requested TX FIFO threshold %u, adjusted down to %u\n",
|
|
dev->tft, max_fifo_threshold);
|
|
dev->tft = max_fifo_threshold;
|
|
}
|
|
|
|
if (dev->rft > max_fifo_threshold) {
|
|
dev_warn(&adev->dev, "requested RX FIFO threshold %u, adjusted down to %u\n",
|
|
dev->rft, max_fifo_threshold);
|
|
dev->rft = max_fifo_threshold;
|
|
}
|
|
|
|
amba_set_drvdata(adev, dev);
|
|
|
|
dev->virtbase = devm_ioremap(&adev->dev, adev->res.start,
|
|
resource_size(&adev->res));
|
|
if (!dev->virtbase) {
|
|
ret = -ENOMEM;
|
|
goto err_no_mem;
|
|
}
|
|
|
|
dev->irq = adev->irq[0];
|
|
ret = devm_request_irq(&adev->dev, dev->irq, i2c_irq_handler, 0,
|
|
DRIVER_NAME, dev);
|
|
if (ret) {
|
|
dev_err(&adev->dev, "cannot claim the irq %d\n", dev->irq);
|
|
goto err_no_mem;
|
|
}
|
|
|
|
pm_suspend_ignore_children(&adev->dev, true);
|
|
|
|
dev->clk = devm_clk_get(&adev->dev, NULL);
|
|
if (IS_ERR(dev->clk)) {
|
|
dev_err(&adev->dev, "could not get i2c clock\n");
|
|
ret = PTR_ERR(dev->clk);
|
|
goto err_no_mem;
|
|
}
|
|
|
|
ret = clk_prepare_enable(dev->clk);
|
|
if (ret) {
|
|
dev_err(&adev->dev, "can't prepare_enable clock\n");
|
|
goto err_no_mem;
|
|
}
|
|
|
|
init_hw(dev);
|
|
|
|
adap = &dev->adap;
|
|
adap->dev.of_node = np;
|
|
adap->dev.parent = &adev->dev;
|
|
adap->owner = THIS_MODULE;
|
|
adap->class = I2C_CLASS_DEPRECATED;
|
|
adap->algo = &nmk_i2c_algo;
|
|
adap->timeout = msecs_to_jiffies(dev->timeout);
|
|
snprintf(adap->name, sizeof(adap->name),
|
|
"Nomadik I2C at %pR", &adev->res);
|
|
|
|
i2c_set_adapdata(adap, dev);
|
|
|
|
dev_info(&adev->dev,
|
|
"initialize %s on virtual base %p\n",
|
|
adap->name, dev->virtbase);
|
|
|
|
ret = i2c_add_adapter(adap);
|
|
if (ret)
|
|
goto err_no_adap;
|
|
|
|
pm_runtime_put(&adev->dev);
|
|
|
|
return 0;
|
|
|
|
err_no_adap:
|
|
clk_disable_unprepare(dev->clk);
|
|
err_no_mem:
|
|
|
|
return ret;
|
|
}
|
|
|
|
static int nmk_i2c_remove(struct amba_device *adev)
|
|
{
|
|
struct resource *res = &adev->res;
|
|
struct nmk_i2c_dev *dev = amba_get_drvdata(adev);
|
|
|
|
i2c_del_adapter(&dev->adap);
|
|
flush_i2c_fifo(dev);
|
|
disable_all_interrupts(dev);
|
|
clear_all_interrupts(dev);
|
|
/* disable the controller */
|
|
i2c_clr_bit(dev->virtbase + I2C_CR, I2C_CR_PE);
|
|
clk_disable_unprepare(dev->clk);
|
|
if (res)
|
|
release_mem_region(res->start, resource_size(res));
|
|
|
|
return 0;
|
|
}
|
|
|
|
static struct i2c_vendor_data vendor_stn8815 = {
|
|
.has_mtdws = false,
|
|
.fifodepth = 16, /* Guessed from TFTR/RFTR = 7 */
|
|
};
|
|
|
|
static struct i2c_vendor_data vendor_db8500 = {
|
|
.has_mtdws = true,
|
|
.fifodepth = 32, /* Guessed from TFTR/RFTR = 15 */
|
|
};
|
|
|
|
static struct amba_id nmk_i2c_ids[] = {
|
|
{
|
|
.id = 0x00180024,
|
|
.mask = 0x00ffffff,
|
|
.data = &vendor_stn8815,
|
|
},
|
|
{
|
|
.id = 0x00380024,
|
|
.mask = 0x00ffffff,
|
|
.data = &vendor_db8500,
|
|
},
|
|
{},
|
|
};
|
|
|
|
MODULE_DEVICE_TABLE(amba, nmk_i2c_ids);
|
|
|
|
static struct amba_driver nmk_i2c_driver = {
|
|
.drv = {
|
|
.owner = THIS_MODULE,
|
|
.name = DRIVER_NAME,
|
|
.pm = &nmk_i2c_pm,
|
|
},
|
|
.id_table = nmk_i2c_ids,
|
|
.probe = nmk_i2c_probe,
|
|
.remove = nmk_i2c_remove,
|
|
};
|
|
|
|
static int __init nmk_i2c_init(void)
|
|
{
|
|
return amba_driver_register(&nmk_i2c_driver);
|
|
}
|
|
|
|
static void __exit nmk_i2c_exit(void)
|
|
{
|
|
amba_driver_unregister(&nmk_i2c_driver);
|
|
}
|
|
|
|
subsys_initcall(nmk_i2c_init);
|
|
module_exit(nmk_i2c_exit);
|
|
|
|
MODULE_AUTHOR("Sachin Verma, Srinidhi KASAGAR");
|
|
MODULE_DESCRIPTION("Nomadik/Ux500 I2C driver");
|
|
MODULE_LICENSE("GPL");
|