From 166a85e44245d771bd7042f3ad72aa0e12bb53bd Mon Sep 17 00:00:00 2001 From: Johan Hovold Date: Mon, 4 May 2015 17:10:33 +0200 Subject: gpio: remove gpiod_sysfs_set_active_low Remove gpiod_sysfs_set_active_low (and gpio_sysfs_set_active_low) which allowed code to change the polarity of a gpio line even after it had been exported through sysfs. Drivers should not care, and generally does not know, about gpio-line polarity which is a hardware feature that needs to be described by firmware. It is currently possible to define gpio-line polarity in device-tree and acpi firmware or using platform data. Userspace can also change the polarity through sysfs. Note that drivers using the legacy gpio interface could still use GPIOF_ACTIVE_LOW to change the polarity before exporting the gpio. There are no in-kernel users of this interface. Cc: Jonathan Corbet Cc: Harry Wei Cc: Arnd Bergmann Cc: linux-doc@vger.kernel.org Cc: linux-kernel@zh-kernel.org Cc: linux-arch@vger.kernel.org Signed-off-by: Johan Hovold Reviewed-by: Alexandre Courbot Signed-off-by: Linus Walleij diff --git a/Documentation/gpio/gpio-legacy.txt b/Documentation/gpio/gpio-legacy.txt index 6f83fa9..79ab564 100644 --- a/Documentation/gpio/gpio-legacy.txt +++ b/Documentation/gpio/gpio-legacy.txt @@ -751,9 +751,6 @@ requested using gpio_request(): int gpio_export_link(struct device *dev, const char *name, unsigned gpio) - /* change the polarity of a GPIO node in sysfs */ - int gpio_sysfs_set_active_low(unsigned gpio, int value); - After a kernel driver requests a GPIO, it may only be made available in the sysfs interface by gpio_export(). The driver can control whether the signal direction may change. This helps drivers prevent userspace code @@ -767,9 +764,3 @@ After the GPIO has been exported, gpio_export_link() allows creating symlinks from elsewhere in sysfs to the GPIO sysfs node. Drivers can use this to provide the interface under their own device in sysfs with a descriptive name. - -Drivers can use gpio_sysfs_set_active_low() to hide GPIO line polarity -differences between boards from user space. This only affects the -sysfs interface. Polarity change can be done both before and after -gpio_export(), and previously enabled poll(2) support for either -rising or falling edge will be reconfigured to follow this setting. diff --git a/Documentation/gpio/sysfs.txt b/Documentation/gpio/sysfs.txt index c2c3a97..535b6a8 100644 --- a/Documentation/gpio/sysfs.txt +++ b/Documentation/gpio/sysfs.txt @@ -132,9 +132,6 @@ requested using gpio_request(): int gpiod_export_link(struct device *dev, const char *name, struct gpio_desc *desc); - /* change the polarity of a GPIO node in sysfs */ - int gpiod_sysfs_set_active_low(struct gpio_desc *desc, int value); - After a kernel driver requests a GPIO, it may only be made available in the sysfs interface by gpiod_export(). The driver can control whether the signal direction may change. This helps drivers prevent userspace code @@ -148,8 +145,3 @@ After the GPIO has been exported, gpiod_export_link() allows creating symlinks from elsewhere in sysfs to the GPIO sysfs node. Drivers can use this to provide the interface under their own device in sysfs with a descriptive name. - -Drivers can use gpiod_sysfs_set_active_low() to hide GPIO line polarity -differences between boards from user space. Polarity change can be done both -before and after gpiod_export(), and previously enabled poll(2) support for -either rising or falling edge will be reconfigured to follow this setting. diff --git a/Documentation/zh_CN/gpio.txt b/Documentation/zh_CN/gpio.txt index d5b8f01..bce9725 100644 --- a/Documentation/zh_CN/gpio.txt +++ b/Documentation/zh_CN/gpio.txt @@ -638,9 +638,6 @@ GPIO 控制器的路径类似 /sys/class/gpio/gpiochip42/ (对于从#42 GPIO int gpio_export_link(struct device *dev, const char *name, unsigned gpio) - /* 改变 sysfs 中的一个 GPIO 节点的极性 */ - int gpio_sysfs_set_active_low(unsigned gpio, int value); - 在一个内核驱动申请一个 GPIO 之后，它可以通过 gpio_export()使其在 sysfs 接口中可见。该驱动可以控制信号方向是否可修改。这有助于防止用户空间代码无意间 破坏重要的系统状态。 @@ -651,8 +648,3 @@ GPIO 控制器的路径类似 /sys/class/gpio/gpiochip42/ (对于从#42 GPIO 在 GPIO 被导出之后，gpio_export_link()允许在 sysfs 文件系统的任何地方 创建一个到这个 GPIO sysfs 节点的符号链接。这样驱动就可以通过一个描述性的 名字，在 sysfs 中他们所拥有的设备下提供一个(到这个 GPIO sysfs 节点的)接口。 - -驱动可以使用 gpio_sysfs_set_active_low() 来在用户空间隐藏电路板之间 -GPIO 线的极性差异。这个仅对 sysfs 接口起作用。极性的改变可以在 gpio_export() -前后进行,且之前使能的轮询操作(poll(2))支持(上升或下降沿)将会被重新配置来遵循 -这个设置。 diff --git a/drivers/gpio/gpiolib-sysfs.c b/drivers/gpio/gpiolib-sysfs.c index aeb73ef..9dcd346 100644 --- a/drivers/gpio/gpiolib-sysfs.c +++ b/drivers/gpio/gpiolib-sysfs.c @@ -308,8 +308,8 @@ static int sysfs_set_active_low(struct gpio_desc *desc, struct device *dev, clear_bit(FLAG_ACTIVE_LOW, &desc->flags); /* reconfigure poll(2) support if enabled on one edge only */ - if (dev != NULL && (!!test_bit(FLAG_TRIG_RISE, &desc->flags) ^ - !!test_bit(FLAG_TRIG_FALL, &desc->flags))) { + if (!!test_bit(FLAG_TRIG_RISE, &desc->flags) ^ + !!test_bit(FLAG_TRIG_FALL, &desc->flags)) { unsigned long trigger_flags = desc->flags & GPIO_TRIGGER_MASK; gpio_setup_irq(desc, dev, 0); @@ -681,50 +681,6 @@ int gpiod_export_link(struct device *dev, const char *name, EXPORT_SYMBOL_GPL(gpiod_export_link); /** - * gpiod_sysfs_set_active_low - set the polarity of gpio sysfs value - * @gpio: gpio to change - * @value: non-zero to use active low, i.e. inverted values - * - * Set the polarity of /sys/class/gpio/gpioN/value sysfs attribute. - * The GPIO does not have to be exported yet. If poll(2) support has - * been enabled for either rising or falling edge, it will be - * reconfigured to follow the new polarity. - * - * Returns zero on success, else an error. - */ -int gpiod_sysfs_set_active_low(struct gpio_desc *desc, int value) -{ - struct device *dev = NULL; - int status = -EINVAL; - - if (!desc) { - pr_warn("%s: invalid GPIO\n", __func__); - return -EINVAL; - } - - mutex_lock(&sysfs_lock); - - if (test_bit(FLAG_EXPORT, &desc->flags)) { - dev = class_find_device(&gpio_class, NULL, desc, match_export); - if (dev == NULL) { - status = -ENODEV; - goto unlock; - } - } - - status = sysfs_set_active_low(desc, dev, value); - put_device(dev); -unlock: - mutex_unlock(&sysfs_lock); - - if (status) - gpiod_dbg(desc, "%s: status %d\n", __func__, status); - - return status; -} -EXPORT_SYMBOL_GPL(gpiod_sysfs_set_active_low); - -/** * gpiod_unexport - reverse effect of gpio_export() * @gpio: gpio to make unavailable * diff --git a/include/asm-generic/gpio.h b/include/asm-generic/gpio.h index 9bb0d11..40ec143 100644 --- a/include/asm-generic/gpio.h +++ b/include/asm-generic/gpio.h @@ -128,11 +128,6 @@ static inline int gpio_export_link(struct device *dev, const char *name, return gpiod_export_link(dev, name, gpio_to_desc(gpio)); } -static inline int gpio_sysfs_set_active_low(unsigned gpio, int value) -{ - return gpiod_sysfs_set_active_low(gpio_to_desc(gpio), value); -} - static inline void gpio_unexport(unsigned gpio) { gpiod_unexport(gpio_to_desc(gpio)); diff --git a/include/linux/gpio.h b/include/linux/gpio.h index ab81339..d12b5d5 100644 --- a/include/linux/gpio.h +++ b/include/linux/gpio.h @@ -196,13 +196,6 @@ static inline int gpio_export_link(struct device *dev, const char *name, return -EINVAL; } -static inline int gpio_sysfs_set_active_low(unsigned gpio, int value) -{ - /* GPIO can never have been requested */ - WARN_ON(1); - return -EINVAL; -} - static inline void gpio_unexport(unsigned gpio) { /* GPIO can never have been exported */ diff --git a/include/linux/gpio/consumer.h b/include/linux/gpio/consumer.h index 3a7c9ff..09a7fb0 100644 --- a/include/linux/gpio/consumer.h +++ b/include/linux/gpio/consumer.h @@ -449,7 +449,6 @@ static inline int desc_to_gpio(const struct gpio_desc *desc) int gpiod_export(struct gpio_desc *desc, bool direction_may_change); int gpiod_export_link(struct device *dev, const char *name, struct gpio_desc *desc); -int gpiod_sysfs_set_active_low(struct gpio_desc *desc, int value); void gpiod_unexport(struct gpio_desc *desc); #else /* CONFIG_GPIOLIB && CONFIG_GPIO_SYSFS */ @@ -466,11 +465,6 @@ static inline int gpiod_export_link(struct device *dev, const char *name, return -ENOSYS; } -static inline int gpiod_sysfs_set_active_low(struct gpio_desc *desc, int value) -{ - return -ENOSYS; -} - static inline void gpiod_unexport(struct gpio_desc *desc) { } -- cgit v0.10.2