+++ /dev/null
-/*
- * DAC driver for the Apex Embedded Systems STX104
- * Copyright (C) 2016 William Breathitt Gray
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License, version 2, as
- * published by the Free Software Foundation.
- *
- * This program is distributed in the hope that it will be useful, but
- * WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
- * General Public License for more details.
- */
-#include <linux/bitops.h>
-#include <linux/device.h>
-#include <linux/errno.h>
-#include <linux/gpio/driver.h>
-#include <linux/iio/iio.h>
-#include <linux/iio/types.h>
-#include <linux/io.h>
-#include <linux/ioport.h>
-#include <linux/isa.h>
-#include <linux/module.h>
-#include <linux/moduleparam.h>
-#include <linux/spinlock.h>
-
-#define STX104_NUM_CHAN 2
-
-#define STX104_CHAN(chan) { \
- .type = IIO_VOLTAGE, \
- .channel = chan, \
- .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
- .indexed = 1, \
- .output = 1 \
-}
-
-#define STX104_EXTENT 16
-
-static unsigned int base[max_num_isa_dev(STX104_EXTENT)];
-static unsigned int num_stx104;
-module_param_array(base, uint, &num_stx104, 0);
-MODULE_PARM_DESC(base, "Apex Embedded Systems STX104 base addresses");
-
-/**
- * struct stx104_iio - IIO device private data structure
- * @chan_out_states: channels' output states
- * @base: base port address of the IIO device
- */
-struct stx104_iio {
- unsigned chan_out_states[STX104_NUM_CHAN];
- unsigned base;
-};
-
-/**
- * struct stx104_gpio - GPIO device private data structure
- * @chip: instance of the gpio_chip
- * @lock: synchronization lock to prevent I/O race conditions
- * @base: base port address of the GPIO device
- * @out_state: output bits state
- */
-struct stx104_gpio {
- struct gpio_chip chip;
- spinlock_t lock;
- unsigned int base;
- unsigned int out_state;
-};
-
-static int stx104_read_raw(struct iio_dev *indio_dev,
- struct iio_chan_spec const *chan, int *val, int *val2, long mask)
-{
- struct stx104_iio *const priv = iio_priv(indio_dev);
-
- if (mask != IIO_CHAN_INFO_RAW)
- return -EINVAL;
-
- *val = priv->chan_out_states[chan->channel];
-
- return IIO_VAL_INT;
-}
-
-static int stx104_write_raw(struct iio_dev *indio_dev,
- struct iio_chan_spec const *chan, int val, int val2, long mask)
-{
- struct stx104_iio *const priv = iio_priv(indio_dev);
- const unsigned chan_addr_offset = 2 * chan->channel;
-
- if (mask != IIO_CHAN_INFO_RAW)
- return -EINVAL;
-
- priv->chan_out_states[chan->channel] = val;
- outw(val, priv->base + 4 + chan_addr_offset);
-
- return 0;
-}
-
-static const struct iio_info stx104_info = {
- .driver_module = THIS_MODULE,
- .read_raw = stx104_read_raw,
- .write_raw = stx104_write_raw
-};
-
-static const struct iio_chan_spec stx104_channels[STX104_NUM_CHAN] = {
- STX104_CHAN(0),
- STX104_CHAN(1)
-};
-
-static int stx104_gpio_get_direction(struct gpio_chip *chip,
- unsigned int offset)
-{
- if (offset < 4)
- return 1;
-
- return 0;
-}
-
-static int stx104_gpio_direction_input(struct gpio_chip *chip,
- unsigned int offset)
-{
- if (offset >= 4)
- return -EINVAL;
-
- return 0;
-}
-
-static int stx104_gpio_direction_output(struct gpio_chip *chip,
- unsigned int offset, int value)
-{
- if (offset < 4)
- return -EINVAL;
-
- chip->set(chip, offset, value);
- return 0;
-}
-
-static int stx104_gpio_get(struct gpio_chip *chip, unsigned int offset)
-{
- struct stx104_gpio *const stx104gpio = gpiochip_get_data(chip);
-
- if (offset >= 4)
- return -EINVAL;
-
- return !!(inb(stx104gpio->base) & BIT(offset));
-}
-
-static void stx104_gpio_set(struct gpio_chip *chip, unsigned int offset,
- int value)
-{
- struct stx104_gpio *const stx104gpio = gpiochip_get_data(chip);
- const unsigned int mask = BIT(offset) >> 4;
- unsigned long flags;
-
- if (offset < 4)
- return;
-
- spin_lock_irqsave(&stx104gpio->lock, flags);
-
- if (value)
- stx104gpio->out_state |= mask;
- else
- stx104gpio->out_state &= ~mask;
-
- outb(stx104gpio->out_state, stx104gpio->base);
-
- spin_unlock_irqrestore(&stx104gpio->lock, flags);
-}
-
-static int stx104_probe(struct device *dev, unsigned int id)
-{
- struct iio_dev *indio_dev;
- struct stx104_iio *priv;
- struct stx104_gpio *stx104gpio;
- int err;
-
- indio_dev = devm_iio_device_alloc(dev, sizeof(*priv));
- if (!indio_dev)
- return -ENOMEM;
-
- stx104gpio = devm_kzalloc(dev, sizeof(*stx104gpio), GFP_KERNEL);
- if (!stx104gpio)
- return -ENOMEM;
-
- if (!devm_request_region(dev, base[id], STX104_EXTENT,
- dev_name(dev))) {
- dev_err(dev, "Unable to lock port addresses (0x%X-0x%X)\n",
- base[id], base[id] + STX104_EXTENT);
- return -EBUSY;
- }
-
- indio_dev->info = &stx104_info;
- indio_dev->modes = INDIO_DIRECT_MODE;
- indio_dev->channels = stx104_channels;
- indio_dev->num_channels = STX104_NUM_CHAN;
- indio_dev->name = dev_name(dev);
-
- priv = iio_priv(indio_dev);
- priv->base = base[id];
-
- /* initialize DAC output to 0V */
- outw(0, base[id] + 4);
- outw(0, base[id] + 6);
-
- err = devm_iio_device_register(dev, indio_dev);
- if (err) {
- dev_err(dev, "IIO device registering failed (%d)\n", err);
- return err;
- }
-
- stx104gpio->chip.label = dev_name(dev);
- stx104gpio->chip.parent = dev;
- stx104gpio->chip.owner = THIS_MODULE;
- stx104gpio->chip.base = -1;
- stx104gpio->chip.ngpio = 8;
- stx104gpio->chip.get_direction = stx104_gpio_get_direction;
- stx104gpio->chip.direction_input = stx104_gpio_direction_input;
- stx104gpio->chip.direction_output = stx104_gpio_direction_output;
- stx104gpio->chip.get = stx104_gpio_get;
- stx104gpio->chip.set = stx104_gpio_set;
- stx104gpio->base = base[id] + 3;
- stx104gpio->out_state = 0x0;
-
- spin_lock_init(&stx104gpio->lock);
-
- dev_set_drvdata(dev, stx104gpio);
-
- err = gpiochip_add_data(&stx104gpio->chip, stx104gpio);
- if (err) {
- dev_err(dev, "GPIO registering failed (%d)\n", err);
- return err;
- }
-
- return 0;
-}
-
-static int stx104_remove(struct device *dev, unsigned int id)
-{
- struct stx104_gpio *const stx104gpio = dev_get_drvdata(dev);
-
- gpiochip_remove(&stx104gpio->chip);
-
- return 0;
-}
-
-static struct isa_driver stx104_driver = {
- .probe = stx104_probe,
- .driver = {
- .name = "stx104"
- },
- .remove = stx104_remove
-};
-
-module_isa_driver(stx104_driver, num_stx104);
-
-MODULE_AUTHOR("William Breathitt Gray <vilhelm.gray@gmail.com>");
-MODULE_DESCRIPTION("Apex Embedded Systems STX104 DAC driver");
-MODULE_LICENSE("GPL v2");
projects / cascardo / linux.git / blobdiff