diff options
Diffstat (limited to 'target/linux/ath79/files/drivers/gpio/gpio-rb91x-key.c')
-rw-r--r-- | target/linux/ath79/files/drivers/gpio/gpio-rb91x-key.c | 218 |
1 files changed, 218 insertions, 0 deletions
diff --git a/target/linux/ath79/files/drivers/gpio/gpio-rb91x-key.c b/target/linux/ath79/files/drivers/gpio/gpio-rb91x-key.c new file mode 100644 index 0000000000..ee8359e774 --- /dev/null +++ b/target/linux/ath79/files/drivers/gpio/gpio-rb91x-key.c @@ -0,0 +1,218 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Driver for reset key gpio line on MikroTik RB91x board series. + * This line is shared between NAND ALE (goes through a latch), + * NAND IO7 and reset key. We make 3 virtual gpio lines from the + * single physical one: + * 1) Capable output one for NAND, + * 2) Capable input one for reset key, + * 3) And capable output one, aka "key-poll-disable", + * for NAND -- to syncronise NAND operation and key polling. + * + * Copyright (C) 2021 Denis Kalashnikov <denis281089@gmail.com> + */ + +#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> +#include <linux/delay.h> + +#define GPIO_RB91X_KEY_DRIVER_NAME "gpio-rb91x-key" + +enum gpio_rb91x_key_gpios { + GPIO_RB91X_KEY_NAND, + GPIO_RB91X_KEY_POLL, + GPIO_RB91X_KEY_PDIS, + + GPIO_RB91X_KEY_NGPIOS, +}; + +struct gpio_rb91x_key { + struct gpio_chip gc; + struct mutex mutex; + struct mutex poll_mutex; + int polling_disabled; + struct gpio_desc *gpio; +}; + +static inline struct gpio_rb91x_key *to_gpio_rb91x_key(struct gpio_chip *gc) +{ + return container_of(gc, struct gpio_rb91x_key, gc); +} + +static int gpio_rb91x_key_get(struct gpio_chip *gc, unsigned offset) +{ + struct gpio_rb91x_key *drvdata = to_gpio_rb91x_key(gc); + struct gpio_desc *gpio = drvdata->gpio; + int val, bak_val; + + switch (offset) { + case GPIO_RB91X_KEY_NAND: + mutex_lock(&drvdata->mutex); + val = gpiod_get_value_cansleep(gpio); + mutex_unlock(&drvdata->mutex); + break; + case GPIO_RB91X_KEY_PDIS: + mutex_lock(&drvdata->mutex); + val = drvdata->polling_disabled; + mutex_unlock(&drvdata->mutex); + break; + case GPIO_RB91X_KEY_POLL: + mutex_lock(&drvdata->poll_mutex); + mutex_lock(&drvdata->mutex); + bak_val = gpiod_get_raw_value_cansleep(gpio); + gpiod_direction_input(gpio); + /* + * Without this delay nothing works. Get it + * from mikrotik RouterOS linux kernel patches. + */ + udelay(200); + val = gpiod_get_raw_value_cansleep(gpio); + gpiod_direction_output_raw(gpio, bak_val); + mutex_unlock(&drvdata->mutex); + mutex_unlock(&drvdata->poll_mutex); + break; + default: + return -EINVAL; + } + + return val; +} + +static int gpio_rb91x_key_direction_input(struct gpio_chip *gc, unsigned offset) +{ + switch (offset) { + case GPIO_RB91X_KEY_POLL: + return 0; + default: + return -EINVAL; + } +} + +static void gpio_rb91x_key_set(struct gpio_chip *gc, unsigned offset, int value) +{ + struct gpio_rb91x_key *drvdata = to_gpio_rb91x_key(gc); + struct gpio_desc *gpio = drvdata->gpio; + + mutex_lock(&drvdata->mutex); + + switch (offset) { + case GPIO_RB91X_KEY_NAND: + gpiod_set_raw_value_cansleep(gpio, value); + break; + case GPIO_RB91X_KEY_PDIS: + if (value) { + if (!drvdata->polling_disabled) { + mutex_lock(&drvdata->poll_mutex); + drvdata->polling_disabled = 1; + } + } else { + if (drvdata->polling_disabled) { + mutex_unlock(&drvdata->poll_mutex); + drvdata->polling_disabled = 0; + } + } + break; + default: + break; + } + + mutex_unlock(&drvdata->mutex); +} + +static int gpio_rb91x_key_direction_output(struct gpio_chip *gc, unsigned offset, + int value) +{ + switch (offset) { + case GPIO_RB91X_KEY_NAND: + case GPIO_RB91X_KEY_PDIS: + gpio_rb91x_key_set(gc, offset, value); + return 0; + default: + return -EINVAL; + } +} + +static int gpio_rb91x_key_probe(struct platform_device *pdev) +{ + struct gpio_rb91x_key *drvdata; + struct gpio_chip *gc; + struct device *dev = &pdev->dev; + struct device_node *of_node = dev->of_node; + int r; + + drvdata = devm_kzalloc(dev, sizeof(*drvdata), GFP_KERNEL); + if (!drvdata) + return -ENOMEM; + + mutex_init(&drvdata->mutex); + mutex_init(&drvdata->poll_mutex); + + drvdata->gpio = devm_gpiod_get(dev, NULL, GPIOD_OUT_LOW); + if (IS_ERR(drvdata->gpio)) { + if (PTR_ERR(drvdata->gpio) != -EPROBE_DEFER) { + dev_err(dev, "failed to get gpio: %ld\n", + PTR_ERR(drvdata->gpio)); + } + return PTR_ERR(drvdata->gpio); + } + + gc = &drvdata->gc; + gc->label = GPIO_RB91X_KEY_DRIVER_NAME; + gc->can_sleep = 1; + gc->base = -1; + gc->ngpio = GPIO_RB91X_KEY_NGPIOS; + gc->get = gpio_rb91x_key_get; + gc->set = gpio_rb91x_key_set; + gc->direction_output = gpio_rb91x_key_direction_output; + gc->direction_input = gpio_rb91x_key_direction_input; + gc->of_node = of_node; + + platform_set_drvdata(pdev, drvdata); + + r = gpiochip_add(&drvdata->gc); + if (r) { + dev_err(dev, "gpiochip_add() failed: %d\n", r); + return r; + } + + return 0; +} + +static int gpio_rb91x_key_remove(struct platform_device *pdev) +{ + struct gpio_rb91x_key *drvdata = platform_get_drvdata(pdev); + + gpiochip_remove(&drvdata->gc); + return 0; +} + +static const struct of_device_id gpio_rb91x_key_match[] = { + { .compatible = "mikrotik,"GPIO_RB91X_KEY_DRIVER_NAME }, + {}, +}; + +MODULE_DEVICE_TABLE(of, gpio_rb91x_key_match); + +static struct platform_driver gpio_rb91x_key_driver = { + .probe = gpio_rb91x_key_probe, + .remove = gpio_rb91x_key_remove, + .driver = { + .name = GPIO_RB91X_KEY_DRIVER_NAME, + .owner = THIS_MODULE, + .of_match_table = gpio_rb91x_key_match, + }, +}; + +module_platform_driver(gpio_rb91x_key_driver); + +MODULE_DESCRIPTION("Driver for reset key gpio line shared with NAND for MikroTik RB91x board series."); +MODULE_AUTHOR("Denis Kalashnikov <denis281089@gmail.com>"); +MODULE_LICENSE("GPL v2"); +MODULE_ALIAS("platform:" GPIO_RB91X_KEY_DRIVER_NAME); |