mirror of https://github.com/hak5/openwrt.git
220 lines
4.6 KiB
C
220 lines
4.6 KiB
C
/*
|
|
* GPIO latch driver
|
|
*
|
|
* Copyright (C) 2014 Gabor Juhos <juhosg@openwrt.org>
|
|
*
|
|
* 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.
|
|
*/
|
|
|
|
#include <linux/kernel.h>
|
|
#include <linux/init.h>
|
|
#include <linux/module.h>
|
|
#include <linux/types.h>
|
|
#include <linux/gpio.h>
|
|
#include <linux/slab.h>
|
|
#include <linux/platform_device.h>
|
|
|
|
#include <linux/platform_data/gpio-latch.h>
|
|
|
|
struct gpio_latch_chip {
|
|
struct gpio_chip gc;
|
|
|
|
struct mutex mutex;
|
|
struct mutex latch_mutex;
|
|
bool latch_enabled;
|
|
int le_gpio;
|
|
bool le_active_low;
|
|
int *gpios;
|
|
};
|
|
|
|
static inline struct gpio_latch_chip *to_gpio_latch_chip(struct gpio_chip *gc)
|
|
{
|
|
return container_of(gc, struct gpio_latch_chip, gc);
|
|
}
|
|
|
|
static void gpio_latch_lock(struct gpio_latch_chip *glc, bool enable)
|
|
{
|
|
mutex_lock(&glc->mutex);
|
|
|
|
if (enable)
|
|
glc->latch_enabled = true;
|
|
|
|
if (glc->latch_enabled)
|
|
mutex_lock(&glc->latch_mutex);
|
|
}
|
|
|
|
static void gpio_latch_unlock(struct gpio_latch_chip *glc, bool disable)
|
|
{
|
|
if (glc->latch_enabled)
|
|
mutex_unlock(&glc->latch_mutex);
|
|
|
|
if (disable)
|
|
glc->latch_enabled = true;
|
|
|
|
mutex_unlock(&glc->mutex);
|
|
}
|
|
|
|
static int
|
|
gpio_latch_get(struct gpio_chip *gc, unsigned offset)
|
|
{
|
|
struct gpio_latch_chip *glc = to_gpio_latch_chip(gc);
|
|
int ret;
|
|
|
|
gpio_latch_lock(glc, false);
|
|
ret = gpio_get_value(glc->gpios[offset]);
|
|
gpio_latch_unlock(glc, false);
|
|
|
|
return ret;
|
|
}
|
|
|
|
static void
|
|
gpio_latch_set(struct gpio_chip *gc, unsigned offset, int value)
|
|
{
|
|
struct gpio_latch_chip *glc = to_gpio_latch_chip(gc);
|
|
bool enable_latch = false;
|
|
bool disable_latch = false;
|
|
int gpio;
|
|
|
|
gpio = glc->gpios[offset];
|
|
|
|
if (gpio == glc->le_gpio) {
|
|
enable_latch = value ^ glc->le_active_low;
|
|
disable_latch = !enable_latch;
|
|
}
|
|
|
|
gpio_latch_lock(glc, enable_latch);
|
|
gpio_set_value(gpio, value);
|
|
gpio_latch_unlock(glc, disable_latch);
|
|
}
|
|
|
|
static int
|
|
gpio_latch_direction_input(struct gpio_chip *gc, unsigned offset)
|
|
{
|
|
struct gpio_latch_chip *glc = to_gpio_latch_chip(gc);
|
|
int ret;
|
|
|
|
gpio_latch_lock(glc, false);
|
|
ret = gpio_direction_input(glc->gpios[offset]);
|
|
gpio_latch_unlock(glc, false);
|
|
|
|
return ret;
|
|
}
|
|
|
|
static int
|
|
gpio_latch_direction_output(struct gpio_chip *gc, unsigned offset, int value)
|
|
{
|
|
struct gpio_latch_chip *glc = to_gpio_latch_chip(gc);
|
|
bool enable_latch = false;
|
|
bool disable_latch = false;
|
|
int gpio;
|
|
int ret;
|
|
|
|
gpio = glc->gpios[offset];
|
|
|
|
if (gpio == glc->le_gpio) {
|
|
enable_latch = value ^ glc->le_active_low;
|
|
disable_latch = !enable_latch;
|
|
}
|
|
|
|
gpio_latch_lock(glc, enable_latch);
|
|
ret = gpio_direction_output(gpio, value);
|
|
gpio_latch_unlock(glc, disable_latch);
|
|
|
|
return ret;
|
|
}
|
|
|
|
static int gpio_latch_probe(struct platform_device *pdev)
|
|
{
|
|
struct gpio_latch_chip *glc;
|
|
struct gpio_latch_platform_data *pdata;
|
|
struct gpio_chip *gc;
|
|
int size;
|
|
int ret;
|
|
int i;
|
|
|
|
pdata = dev_get_platdata(&pdev->dev);
|
|
if (!pdata)
|
|
return -EINVAL;
|
|
|
|
if (pdata->le_gpio_index >= pdata->num_gpios ||
|
|
!pdata->num_gpios ||
|
|
!pdata->gpios)
|
|
return -EINVAL;
|
|
|
|
for (i = 0; i < pdata->num_gpios; i++) {
|
|
int gpio = pdata->gpios[i];
|
|
|
|
ret = devm_gpio_request(&pdev->dev, gpio,
|
|
GPIO_LATCH_DRIVER_NAME);
|
|
if (ret)
|
|
return ret;
|
|
}
|
|
|
|
glc = devm_kzalloc(&pdev->dev, sizeof(*glc), GFP_KERNEL);
|
|
if (!glc)
|
|
return -ENOMEM;
|
|
|
|
mutex_init(&glc->mutex);
|
|
mutex_init(&glc->latch_mutex);
|
|
|
|
size = pdata->num_gpios * sizeof(glc->gpios[0]);
|
|
glc->gpios = devm_kzalloc(&pdev->dev, size , GFP_KERNEL);
|
|
if (!glc->gpios)
|
|
return -ENOMEM;
|
|
|
|
memcpy(glc->gpios, pdata->gpios, size);
|
|
|
|
glc->le_gpio = glc->gpios[pdata->le_gpio_index];
|
|
glc->le_active_low = pdata->le_active_low;
|
|
|
|
gc = &glc->gc;
|
|
|
|
gc->label = GPIO_LATCH_DRIVER_NAME;
|
|
gc->base = pdata->base;
|
|
gc->can_sleep = true;
|
|
gc->ngpio = pdata->num_gpios;
|
|
gc->get = gpio_latch_get;
|
|
gc->set = gpio_latch_set;
|
|
gc->direction_input = gpio_latch_direction_input,
|
|
gc->direction_output = gpio_latch_direction_output;
|
|
|
|
platform_set_drvdata(pdev, glc);
|
|
|
|
ret = gpiochip_add(&glc->gc);
|
|
if (ret)
|
|
return ret;
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int gpio_latch_remove(struct platform_device *pdev)
|
|
{
|
|
struct gpio_latch_chip *glc = platform_get_drvdata(pdev);
|
|
|
|
return gpiochip_remove(&glc->gc);;
|
|
}
|
|
|
|
|
|
static struct platform_driver gpio_latch_driver = {
|
|
.probe = gpio_latch_probe,
|
|
.remove = gpio_latch_remove,
|
|
.driver = {
|
|
.name = GPIO_LATCH_DRIVER_NAME,
|
|
.owner = THIS_MODULE,
|
|
},
|
|
};
|
|
|
|
static int __init gpio_latch_init(void)
|
|
{
|
|
return platform_driver_register(&gpio_latch_driver);
|
|
}
|
|
|
|
postcore_initcall(gpio_latch_init);
|
|
|
|
MODULE_DESCRIPTION("GPIO latch driver");
|
|
MODULE_AUTHOR("Gabor Juhos <juhosg@openwrt.org>");
|
|
MODULE_LICENSE("GPL v2");
|
|
MODULE_ALIAS("platform:" GPIO_LATCH_DRIVER_NAME);
|