Commit 765550e4 authored by William Breathitt Gray's avatar William Breathitt Gray Committed by Jonathan Cameron
Browse files

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

drivers/iio/dac/Kconfig

+6 −5
Original line number Diff line number Diff line
@@ -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"

drivers/iio/dac/stx104.c

+123 −2
Original line number Diff line number Diff line
@@ -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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