381 lines
9.5 KiB
C
381 lines
9.5 KiB
C
/*
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* IIO driver for the Apex Embedded Systems STX104
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* Copyright (C) 2016 William Breathitt Gray
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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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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*/
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#include <linux/bitops.h>
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#include <linux/device.h>
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#include <linux/errno.h>
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#include <linux/gpio/driver.h>
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#include <linux/iio/iio.h>
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#include <linux/iio/types.h>
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#include <linux/io.h>
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#include <linux/ioport.h>
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#include <linux/isa.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/moduleparam.h>
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#include <linux/spinlock.h>
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#define STX104_OUT_CHAN(chan) { \
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.type = IIO_VOLTAGE, \
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.channel = chan, \
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.info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
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.indexed = 1, \
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.output = 1 \
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}
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#define STX104_IN_CHAN(chan, diff) { \
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.type = IIO_VOLTAGE, \
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.channel = chan, \
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.channel2 = chan, \
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.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_HARDWAREGAIN) | \
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BIT(IIO_CHAN_INFO_OFFSET) | BIT(IIO_CHAN_INFO_SCALE), \
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.info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
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.indexed = 1, \
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.differential = diff \
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}
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#define STX104_NUM_OUT_CHAN 2
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#define STX104_EXTENT 16
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static unsigned int base[max_num_isa_dev(STX104_EXTENT)];
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static unsigned int num_stx104;
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module_param_array(base, uint, &num_stx104, 0);
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MODULE_PARM_DESC(base, "Apex Embedded Systems STX104 base addresses");
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/**
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* struct stx104_iio - IIO device private data structure
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* @chan_out_states: channels' output states
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* @base: base port address of the IIO device
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*/
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struct stx104_iio {
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unsigned int chan_out_states[STX104_NUM_OUT_CHAN];
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unsigned int base;
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};
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/**
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* struct stx104_gpio - GPIO device private data structure
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* @chip: instance of the gpio_chip
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* @lock: synchronization lock to prevent I/O race conditions
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* @base: base port address of the GPIO device
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* @out_state: output bits state
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*/
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struct stx104_gpio {
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struct gpio_chip chip;
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spinlock_t lock;
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unsigned int base;
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unsigned int out_state;
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};
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/**
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* struct stx104_dev - STX104 device private data structure
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* @indio_dev: IIO device
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* @chip: instance of the gpio_chip
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*/
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struct stx104_dev {
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struct iio_dev *indio_dev;
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struct gpio_chip *chip;
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};
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static int stx104_read_raw(struct iio_dev *indio_dev,
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struct iio_chan_spec const *chan, int *val, int *val2, long mask)
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{
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struct stx104_iio *const priv = iio_priv(indio_dev);
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unsigned int adc_config;
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int adbu;
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int gain;
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switch (mask) {
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case IIO_CHAN_INFO_HARDWAREGAIN:
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/* get gain configuration */
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adc_config = inb(priv->base + 11);
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gain = adc_config & 0x3;
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*val = 1 << gain;
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return IIO_VAL_INT;
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case IIO_CHAN_INFO_RAW:
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if (chan->output) {
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*val = priv->chan_out_states[chan->channel];
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return IIO_VAL_INT;
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}
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/* select ADC channel */
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outb(chan->channel | (chan->channel << 4), priv->base + 2);
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/* trigger ADC sample capture and wait for completion */
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outb(0, priv->base);
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while (inb(priv->base + 8) & BIT(7));
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*val = inw(priv->base);
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return IIO_VAL_INT;
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case IIO_CHAN_INFO_OFFSET:
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/* get ADC bipolar/unipolar configuration */
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adc_config = inb(priv->base + 11);
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adbu = !(adc_config & BIT(2));
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*val = -32768 * adbu;
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return IIO_VAL_INT;
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case IIO_CHAN_INFO_SCALE:
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/* get ADC bipolar/unipolar and gain configuration */
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adc_config = inb(priv->base + 11);
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adbu = !(adc_config & BIT(2));
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gain = adc_config & 0x3;
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*val = 5;
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*val2 = 15 - adbu + gain;
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return IIO_VAL_FRACTIONAL_LOG2;
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}
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return -EINVAL;
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}
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static int stx104_write_raw(struct iio_dev *indio_dev,
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struct iio_chan_spec const *chan, int val, int val2, long mask)
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{
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struct stx104_iio *const priv = iio_priv(indio_dev);
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switch (mask) {
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case IIO_CHAN_INFO_HARDWAREGAIN:
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/* Only four gain states (x1, x2, x4, x8) */
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switch (val) {
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case 1:
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outb(0, priv->base + 11);
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break;
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case 2:
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outb(1, priv->base + 11);
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break;
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case 4:
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outb(2, priv->base + 11);
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break;
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case 8:
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outb(3, priv->base + 11);
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break;
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default:
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return -EINVAL;
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}
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return 0;
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case IIO_CHAN_INFO_RAW:
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if (chan->output) {
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/* DAC can only accept up to a 16-bit value */
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if ((unsigned int)val > 65535)
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return -EINVAL;
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priv->chan_out_states[chan->channel] = val;
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outw(val, priv->base + 4 + 2 * chan->channel);
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return 0;
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}
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return -EINVAL;
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}
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return -EINVAL;
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}
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static const struct iio_info stx104_info = {
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.driver_module = THIS_MODULE,
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.read_raw = stx104_read_raw,
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.write_raw = stx104_write_raw
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};
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/* single-ended input channels configuration */
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static const struct iio_chan_spec stx104_channels_sing[] = {
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STX104_OUT_CHAN(0), STX104_OUT_CHAN(1),
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STX104_IN_CHAN(0, 0), STX104_IN_CHAN(1, 0), STX104_IN_CHAN(2, 0),
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STX104_IN_CHAN(3, 0), STX104_IN_CHAN(4, 0), STX104_IN_CHAN(5, 0),
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STX104_IN_CHAN(6, 0), STX104_IN_CHAN(7, 0), STX104_IN_CHAN(8, 0),
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STX104_IN_CHAN(9, 0), STX104_IN_CHAN(10, 0), STX104_IN_CHAN(11, 0),
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STX104_IN_CHAN(12, 0), STX104_IN_CHAN(13, 0), STX104_IN_CHAN(14, 0),
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STX104_IN_CHAN(15, 0)
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};
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/* differential input channels configuration */
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static const struct iio_chan_spec stx104_channels_diff[] = {
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STX104_OUT_CHAN(0), STX104_OUT_CHAN(1),
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STX104_IN_CHAN(0, 1), STX104_IN_CHAN(1, 1), STX104_IN_CHAN(2, 1),
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STX104_IN_CHAN(3, 1), STX104_IN_CHAN(4, 1), STX104_IN_CHAN(5, 1),
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STX104_IN_CHAN(6, 1), STX104_IN_CHAN(7, 1)
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};
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static int stx104_gpio_get_direction(struct gpio_chip *chip,
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unsigned int offset)
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{
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/* GPIO 0-3 are input only, while the rest are output only */
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if (offset < 4)
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return 1;
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return 0;
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}
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static int stx104_gpio_direction_input(struct gpio_chip *chip,
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unsigned int offset)
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{
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if (offset >= 4)
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return -EINVAL;
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return 0;
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}
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static int stx104_gpio_direction_output(struct gpio_chip *chip,
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unsigned int offset, int value)
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{
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if (offset < 4)
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return -EINVAL;
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chip->set(chip, offset, value);
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return 0;
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}
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static int stx104_gpio_get(struct gpio_chip *chip, unsigned int offset)
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{
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struct stx104_gpio *const stx104gpio = gpiochip_get_data(chip);
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if (offset >= 4)
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return -EINVAL;
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return !!(inb(stx104gpio->base) & BIT(offset));
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}
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static void stx104_gpio_set(struct gpio_chip *chip, unsigned int offset,
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int value)
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{
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struct stx104_gpio *const stx104gpio = gpiochip_get_data(chip);
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const unsigned int mask = BIT(offset) >> 4;
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unsigned long flags;
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if (offset < 4)
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return;
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spin_lock_irqsave(&stx104gpio->lock, flags);
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if (value)
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stx104gpio->out_state |= mask;
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else
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stx104gpio->out_state &= ~mask;
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outb(stx104gpio->out_state, stx104gpio->base);
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spin_unlock_irqrestore(&stx104gpio->lock, flags);
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}
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static int stx104_probe(struct device *dev, unsigned int id)
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{
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struct iio_dev *indio_dev;
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struct stx104_iio *priv;
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struct stx104_gpio *stx104gpio;
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struct stx104_dev *stx104dev;
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int err;
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indio_dev = devm_iio_device_alloc(dev, sizeof(*priv));
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if (!indio_dev)
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return -ENOMEM;
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stx104gpio = devm_kzalloc(dev, sizeof(*stx104gpio), GFP_KERNEL);
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if (!stx104gpio)
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return -ENOMEM;
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stx104dev = devm_kzalloc(dev, sizeof(*stx104dev), GFP_KERNEL);
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if (!stx104dev)
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return -ENOMEM;
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if (!devm_request_region(dev, base[id], STX104_EXTENT,
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dev_name(dev))) {
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dev_err(dev, "Unable to lock port addresses (0x%X-0x%X)\n",
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base[id], base[id] + STX104_EXTENT);
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return -EBUSY;
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}
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indio_dev->info = &stx104_info;
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indio_dev->modes = INDIO_DIRECT_MODE;
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/* determine if differential inputs */
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if (inb(base[id] + 8) & BIT(5)) {
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indio_dev->num_channels = ARRAY_SIZE(stx104_channels_diff);
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indio_dev->channels = stx104_channels_diff;
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} else {
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indio_dev->num_channels = ARRAY_SIZE(stx104_channels_sing);
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indio_dev->channels = stx104_channels_sing;
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}
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indio_dev->name = dev_name(dev);
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priv = iio_priv(indio_dev);
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priv->base = base[id];
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/* configure device for software trigger operation */
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outb(0, base[id] + 9);
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/* initialize gain setting to x1 */
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outb(0, base[id] + 11);
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/* initialize DAC output to 0V */
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outw(0, base[id] + 4);
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outw(0, base[id] + 6);
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stx104gpio->chip.label = dev_name(dev);
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stx104gpio->chip.parent = dev;
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stx104gpio->chip.owner = THIS_MODULE;
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stx104gpio->chip.base = -1;
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stx104gpio->chip.ngpio = 8;
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stx104gpio->chip.get_direction = stx104_gpio_get_direction;
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stx104gpio->chip.direction_input = stx104_gpio_direction_input;
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stx104gpio->chip.direction_output = stx104_gpio_direction_output;
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stx104gpio->chip.get = stx104_gpio_get;
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stx104gpio->chip.set = stx104_gpio_set;
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stx104gpio->base = base[id] + 3;
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stx104gpio->out_state = 0x0;
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spin_lock_init(&stx104gpio->lock);
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stx104dev->indio_dev = indio_dev;
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stx104dev->chip = &stx104gpio->chip;
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dev_set_drvdata(dev, stx104dev);
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err = gpiochip_add_data(&stx104gpio->chip, stx104gpio);
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if (err) {
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dev_err(dev, "GPIO registering failed (%d)\n", err);
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return err;
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}
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err = iio_device_register(indio_dev);
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if (err) {
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dev_err(dev, "IIO device registering failed (%d)\n", err);
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gpiochip_remove(&stx104gpio->chip);
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return err;
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}
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return 0;
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}
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static int stx104_remove(struct device *dev, unsigned int id)
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{
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struct stx104_dev *const stx104dev = dev_get_drvdata(dev);
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iio_device_unregister(stx104dev->indio_dev);
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gpiochip_remove(stx104dev->chip);
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return 0;
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}
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static struct isa_driver stx104_driver = {
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.probe = stx104_probe,
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.driver = {
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.name = "stx104"
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},
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.remove = stx104_remove
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};
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module_isa_driver(stx104_driver, num_stx104);
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MODULE_AUTHOR("William Breathitt Gray <vilhelm.gray@gmail.com>");
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MODULE_DESCRIPTION("Apex Embedded Systems STX104 IIO driver");
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MODULE_LICENSE("GPL v2");
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