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 <corbet@lwn.net>
Cc: Harry Wei <harryxiyou@gmail.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: linux-doc@vger.kernel.org
Cc: linux-kernel@zh-kernel.org
Cc: linux-arch@vger.kernel.org
Signed-off-by: Johan Hovold <johan@kernel.org>
Reviewed-by: Alexandre Courbot <acourbot@nvidia.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

diff --git a/Documentation/gpio/gpio-legacy.txt b/Documentation/gpio/gpio-legacy.txt
index 6f83fa965b4b6e6975fda4459c72f9711ea73159..79ab5648d69b3e39a198c108c739eb1a08c20b06 100644 (file)
--- 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 c2c3a97f8ff7c26f17a90fde416212f02882be94..535b6a8a7a7cca8ffdc37a272d8e6ad434cab7da 100644 (file)
--- 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 d5b8f01833f41365689bc78258770eecebd46f36..bce9725210659de9a7c1d3c97cb9d8374dc0d581 100644 (file)
--- 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 aeb73ef2955e05af419f340fe7415a1f7d6437ed..9dcd346a20fbe375eac830dffe0200c03ef66e34 100644 (file)
--- 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);
@@ -680,50 +680,6 @@ 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 9bb0d11729c9cef15cf9ca1e5b6f6c18528da27d..40ec1433f05de25d15cedaeaf2388b2cc8d0298c 100644 (file)
--- 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 ab81339a8590a8bb8f4b889b501e7eb928878cc5..d12b5d566e4b11c725aa79dae8f2301364d3b9a9 100644 (file)
--- 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 3a7c9ffd5ab930b46e7341adfdcc0c5cc446224a..09a7fb0062a6ed74c780bc14d91215c627ca69b6 100644 (file)
--- 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)
 {
 }