From 43723e6db9a5fca33ccdc1f9344cc6f7cf04e7df Mon Sep 17 00:00:00 2001 From: Denis Kalashnikov Date: Thu, 27 May 2021 11:16:44 +0300 Subject: ath79: add gpio-latch driver for MikroTik RouterBOARDs This is a slighty modified version of ar71xx gpio-latch driver written by Gabor Juhos . Changes: * DTS support, * New gpio API (gpiod_*). Reviewed-by: Sergey Ryazanov Signed-off-by: Denis Kalashnikov (cherry-picked from commit 7b8931678c36c8d8c333b446258a653b1358bf70) --- target/linux/ath79/files/drivers/gpio/gpio-latch.c | 203 +++++++++++++++++++++ 1 file changed, 203 insertions(+) create mode 100644 target/linux/ath79/files/drivers/gpio/gpio-latch.c (limited to 'target/linux/ath79/files') diff --git a/target/linux/ath79/files/drivers/gpio/gpio-latch.c b/target/linux/ath79/files/drivers/gpio/gpio-latch.c new file mode 100644 index 0000000000..f3545a663e --- /dev/null +++ b/target/linux/ath79/files/drivers/gpio/gpio-latch.c @@ -0,0 +1,203 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * GPIO latch driver + * + * Copyright (C) 2014 Gabor Juhos + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#define GPIO_LATCH_DRIVER_NAME "gpio-latch" +#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_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; + + 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(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; + struct device_node *of_node = dev->of_node; + int i, n; + + glc = devm_kzalloc(dev, sizeof(*glc), GFP_KERNEL); + if (!glc) + return -ENOMEM; + + mutex_init(&glc->mutex); + mutex_init(&glc->latch_mutex); + + n = gpiod_count(dev, NULL); + if (n <= 0) { + dev_err(dev, "failed to get gpios: %d\n", n); + return n; + } else if (n != GPIO_LATCH_LINES) { + dev_err(dev, "expected %d gpios\n", 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])) { + dev_err(dev, "failed to get gpio %d: %d\n", i, + PTR_ERR(glc->gpios[i])); + return PTR_ERR(glc->gpios[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->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; + gc->of_node = of_node; + + platform_set_drvdata(pdev, glc); + + i = gpiochip_add(&glc->gc); + if (i) { + dev_err(dev, "gpiochip_add() failed: %d\n", i); + return i; + } + + 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 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, + .remove = gpio_latch_remove, + .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 "); +MODULE_AUTHOR("Denis Kalashnikov "); +MODULE_LICENSE("GPL v2"); +MODULE_ALIAS("platform:" GPIO_LATCH_DRIVER_NAME); -- cgit v1.2.3