openwrt/target/linux/ath79/files/drivers/gpio/gpio-latch-mikrotik.c
Rosen Penev d51353db26 ath79: gpio-latch-mikrotik: use devm_mutex_init
Avoids needing to call mutex_destroy in error paths, which is missing
anyway.

Signed-off-by: Rosen Penev <rosenp@gmail.com>
Link: https://github.com/openwrt/openwrt/pull/16620
Signed-off-by: Robert Marko <robimarko@gmail.com>
2024-10-07 15:15:27 +02:00

188 lines
4.3 KiB
C

// SPDX-License-Identifier: GPL-2.0-or-later
/*
* GPIO latch driver
*
* Copyright (C) 2014 Gabor Juhos <juhosg@openwrt.org>
*/
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/types.h>
#include <linux/gpio/consumer.h>
#include <linux/gpio/driver.h>
#include <linux/platform_device.h>
#include <linux/of_platform.h>
#include <linux/of_gpio.h>
#define GPIO_LATCH_DRIVER_NAME "gpio-latch-mikrotik"
#define GPIO_LATCH_LINES 9
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;
struct gpio_desc *gpios[GPIO_LATCH_LINES];
};
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 = gpiod_get_raw_value_cansleep(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;
if (offset == glc->le_gpio) {
enable_latch = value ^ glc->le_active_low;
disable_latch = !enable_latch;
}
gpio_latch_lock(glc, enable_latch);
gpiod_set_raw_value_cansleep(glc->gpios[offset], value);
gpio_latch_unlock(glc, disable_latch);
}
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 ret;
if (offset == glc->le_gpio) {
enable_latch = value ^ glc->le_active_low;
disable_latch = !enable_latch;
}
gpio_latch_lock(glc, enable_latch);
ret = gpiod_direction_output_raw(glc->gpios[offset], 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_chip *gc;
struct device *dev = &pdev->dev;
int err, i, n;
glc = devm_kzalloc(dev, sizeof(*glc), GFP_KERNEL);
if (!glc)
return -ENOMEM;
err = devm_mutex_init(&pdev->dev, &glc->mutex);
if (err)
return err;
err = devm_mutex_init(&pdev->dev, &glc->latch_mutex);
if (err)
return err;
n = gpiod_count(dev, NULL);
if (n <= 0)
return dev_err_probe(dev, n, "failed to get gpios");
if (n != GPIO_LATCH_LINES) {
dev_err(dev, "expected %d gpios", GPIO_LATCH_LINES);
return -EINVAL;
}
for (i = 0; i < n; i++) {
glc->gpios[i] = devm_gpiod_get_index_optional(dev, NULL, i,
GPIOD_OUT_LOW);
if (IS_ERR(glc->gpios[i]))
return dev_err_probe(dev, PTR_ERR(glc->gpios[i]),
"failed to get gpio %d", i);
}
glc->le_gpio = 8;
glc->le_active_low = gpiod_is_active_low(glc->gpios[glc->le_gpio]);
if (!glc->gpios[glc->le_gpio]) {
dev_err(dev, "missing required latch-enable gpio %d\n",
glc->le_gpio);
return -EINVAL;
}
gc = &glc->gc;
gc->label = GPIO_LATCH_DRIVER_NAME;
gc->parent = dev;
gc->can_sleep = true;
gc->base = -1;
gc->ngpio = GPIO_LATCH_LINES;
gc->get = gpio_latch_get;
gc->set = gpio_latch_set;
gc->direction_output = gpio_latch_direction_output;
return devm_gpiochip_add_data(dev, gc, glc);
}
static const struct of_device_id gpio_latch_match[] = {
{ .compatible = GPIO_LATCH_DRIVER_NAME },
{},
};
MODULE_DEVICE_TABLE(of, gpio_latch_match);
static struct platform_driver gpio_latch_driver = {
.probe = gpio_latch_probe,
.driver = {
.name = GPIO_LATCH_DRIVER_NAME,
.owner = THIS_MODULE,
.of_match_table = gpio_latch_match,
},
};
module_platform_driver(gpio_latch_driver);
MODULE_DESCRIPTION("GPIO latch driver");
MODULE_AUTHOR("Gabor Juhos <juhosg@openwrt.org>");
MODULE_AUTHOR("Denis Kalashnikov <denis281089@gmail.com>");
MODULE_LICENSE("GPL v2");
MODULE_ALIAS("platform:" GPIO_LATCH_DRIVER_NAME);