+++ /dev/null
-/*
- * 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);
-
- gpiochip_remove(&glc->gc);
- return 0;
-}
-
-
-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);
projects / openwrt / staging / wigyori.git / blobdiff