Commit 765550e4 authored by William Breathitt Gray's avatar William Breathitt Gray Committed by Jonathan Cameron
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iio: stx104: Add GPIO support for the Apex Embedded Systems STX104



The Apex Embedded Systems STX104 device features eight lines of digital
I/O (four digital inputs and four digital outputs). This patch adds GPIO
support for these eight lines of digital I/O via GPIOLIB.

Cc: Alexandre Courbot <gnurou@gmail.com>
Signed-off-by: default avatarWilliam Breathitt Gray <vilhelm.gray@gmail.com>
Reviewed-by: default avatarLinus Walleij <linus.walleij@linaro.org>
Signed-off-by: default avatarJonathan Cameron <jic23@kernel.org>
parent 22ed1a1c
......@@ -246,13 +246,14 @@ config MCP4922
will be called mcp4922.
config STX104
tristate "Apex Embedded Systems STX104 DAC driver"
tristate "Apex Embedded Systems STX104 driver"
depends on ISA
select GPIOLIB
help
Say yes here to build support for the 2-channel DAC on the Apex
Embedded Systems STX104 integrated analog PC/104 card. The base port
addresses for the devices may be configured via the "base" module
parameter array.
Say yes here to build support for the 2-channel DAC and GPIO on the
Apex Embedded Systems STX104 integrated analog PC/104 card. The base
port addresses for the devices may be configured via the base array
module parameter.
config VF610_DAC
tristate "Vybrid vf610 DAC driver"
......
......@@ -14,6 +14,7 @@
#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>
......@@ -21,6 +22,7 @@
#include <linux/isa.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/spinlock.h>
#define STX104_NUM_CHAN 2
......@@ -56,6 +58,20 @@ struct stx104_iio {
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)
{
......@@ -95,15 +111,81 @@ static const struct iio_chan_spec stx104_channels[STX104_NUM_CHAN] = {
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",
......@@ -124,14 +206,53 @@ static int stx104_probe(struct device *dev, unsigned int id)
outw(0, base[id] + 4);
outw(0, base[id] + 6);
return devm_iio_device_register(dev, indio_dev);
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
};
static void __exit stx104_exit(void)
......
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