Re: [PATCH 5/8] gpiolib: remove legacy gpio_export

From: Andy Shevchenko
Date: Thu Jan 26 2023 - 09:02:58 EST

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On Thu, Jan 26, 2023 at 02:27:58PM +0100, Arnd Bergmann wrote:
> From: Arnd Bergmann <arnd@xxxxxxxx>
>
> There are only a handful of users of gpio_export() and
> related functions.
>
> As these are just wrappers around the modern gpiod_export()
> helper, remove the wrappers and open-code the gpio_to_desc
> in all callers to shrink the legacy API.

A couple of comments below, after addressing:
Reviewed-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>

> Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>
> ---
> Documentation/admin-guide/gpio/sysfs.rst | 2 +-
> Documentation/driver-api/gpio/legacy.rst | 21 ---------------
> .../zh_CN/driver-api/gpio/legacy.rst | 20 --------------
> Documentation/translations/zh_TW/gpio.txt | 18 -------------
> arch/arm/mach-omap2/pdata-quirks.c | 9 ++++---
> arch/sh/boards/mach-ap325rxa/setup.c | 7 ++---
> drivers/gpio/gpiolib-sysfs.c | 4 +--
> drivers/media/pci/sta2x11/sta2x11_vip.c | 10 ++++---
> drivers/net/ieee802154/ca8210.c | 3 ++-
> include/linux/gpio.h | 27 -------------------
> 10 files changed, 21 insertions(+), 100 deletions(-)
>
> diff --git a/Documentation/admin-guide/gpio/sysfs.rst b/Documentation/admin-guide/gpio/sysfs.rst
> index ec09ffd983e7..35171d15f78d 100644
> --- a/Documentation/admin-guide/gpio/sysfs.rst
> +++ b/Documentation/admin-guide/gpio/sysfs.rst
> @@ -145,7 +145,7 @@ requested using gpio_request()::
> /* export the GPIO to userspace */
> int gpiod_export(struct gpio_desc *desc, bool direction_may_change);
>
> - /* reverse gpio_export() */
> + /* reverse gpiod_export() */
> void gpiod_unexport(struct gpio_desc *desc);
>
> /* create a sysfs link to an exported GPIO node */
> diff --git a/Documentation/driver-api/gpio/legacy.rst b/Documentation/driver-api/gpio/legacy.rst
> index e0306e78e34b..78372853c6d4 100644
> --- a/Documentation/driver-api/gpio/legacy.rst
> +++ b/Documentation/driver-api/gpio/legacy.rst
> @@ -714,27 +714,6 @@ gpiochip nodes (possibly in conjunction with schematics) to determine
> the correct GPIO number to use for a given signal.
>
>
> -Exporting from Kernel code
> ---------------------------
> -Kernel code can explicitly manage exports of GPIOs which have already been
> -requested using gpio_request()::
> -
> - /* export the GPIO to userspace */
> - int gpio_export(unsigned gpio, bool direction_may_change);
> -
> - /* reverse gpio_export() */
> - void gpio_unexport();
> -
> -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
> -from accidentally clobbering important system state.
> -
> -This explicit exporting can help with debugging (by making some kinds
> -of experiments easier), or can provide an always-there interface that's
> -suitable for documenting as part of a board support package.
> -
> -
> API Reference
> =============
>
> diff --git a/Documentation/translations/zh_CN/driver-api/gpio/legacy.rst b/Documentation/translations/zh_CN/driver-api/gpio/legacy.rst
> index 74fa473bb504..2164999077a6 100644
> --- a/Documentation/translations/zh_CN/driver-api/gpio/legacy.rst
> +++ b/Documentation/translations/zh_CN/driver-api/gpio/legacy.rst
> @@ -654,26 +654,6 @@ GPIO 控制器的路径类似 /sys/class/gpio/gpiochip42/ (对于从#42 GPIO
> 确定给定信号所用的 GPIO 编号。
>
>
> -从内核代码中导出
> -----------------
> -
> -内核代码可以明确地管理那些已通过 gpio_request()申请的 GPIO 的导出::
> -
> - /* 导出 GPIO 到用户空间 */
> - int gpio_export(unsigned gpio, bool direction_may_change);
> -
> - /* gpio_export()的逆操作 */
> - void gpio_unexport();
> -
> -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。
> -
> -这个明确的导出有助于(通过使某些实验更容易来)调试，也可以提供一个始终存在的接口，
> -与文档配合作为板级支持包的一部分。
> -
> -

> -API参考

Mistakenly removed?

> =======
>
> 本节中列出的函数已被废弃。在新的代码中应该使用基于GPIO描述符的API。
> diff --git a/Documentation/translations/zh_TW/gpio.txt b/Documentation/translations/zh_TW/gpio.txt
> index 1b986bbb0909..79076f535faa 100644
> --- a/Documentation/translations/zh_TW/gpio.txt
> +++ b/Documentation/translations/zh_TW/gpio.txt
> @@ -615,21 +615,3 @@ GPIO 控制器的路徑類似 /sys/class/gpio/gpiochip42/ (對於從#42 GPIO
> 固定的,例如在擴展卡上的 GPIO會根據所使用的主板或所在堆疊架構中其他的板子而
> 有所不同。在這種情況下,你可能需要使用 gpiochip 節點(儘可能地結合電路圖)來
> 確定給定信號所用的 GPIO 編號。
> -
> -
> -從內核代碼中導出
> --------------
> -內核代碼可以明確地管理那些已通過 gpio_request()申請的 GPIO 的導出:
> -
> - /* 導出 GPIO 到用戶空間 */
> - int gpio_export(unsigned gpio, bool direction_may_change);
> -
> - /* gpio_export()的逆操作 */
> - void gpio_unexport();
> -
> -在一個內核驅動申請一個 GPIO 之後，它可以通過 gpio_export()使其在 sysfs
> -接口中可見。該驅動可以控制信號方向是否可修改。這有助於防止用戶空間代碼無意間
> -破壞重要的系統狀態。
> -
> -這個明確的導出有助於(通過使某些實驗更容易來)調試，也可以提供一個始終存在的接口，
> -與文檔配合作爲板級支持包的一部分。
> diff --git a/arch/arm/mach-omap2/pdata-quirks.c b/arch/arm/mach-omap2/pdata-quirks.c
> index 248478af5bfa..ee90fb42c955 100644
> --- a/arch/arm/mach-omap2/pdata-quirks.c
> +++ b/arch/arm/mach-omap2/pdata-quirks.c
> @@ -6,6 +6,7 @@
> */
> #include <linux/clk.h>
> #include <linux/davinci_emac.h>
> +#include <linux/gpio/consumer.h>
> #include <linux/gpio.h>
> #include <linux/init.h>
> #include <linux/kernel.h>
> @@ -108,7 +109,7 @@ static int omap3_sbc_t3730_twl_callback(struct device *dev,
> if (res)
> return res;
>
> - gpio_export(gpio, 0);
> + gpiod_export(gpio_to_desc(gpio), 0);
>
> return 0;
> }
> @@ -123,7 +124,7 @@ static void __init omap3_sbc_t3x_usb_hub_init(int gpio, char *hub_name)
> return;
> }
>
> - gpio_export(gpio, 0);
> + gpiod_export(gpio_to_desc(gpio), 0);
>
> udelay(10);
> gpio_set_value(gpio, 1);
> @@ -200,8 +201,8 @@ static void __init omap3_sbc_t3517_wifi_init(void)
> return;
> }
>
> - gpio_export(cm_t3517_wlan_gpios[0].gpio, 0);
> - gpio_export(cm_t3517_wlan_gpios[1].gpio, 0);
> + gpiod_export(gpio_to_desc(cm_t3517_wlan_gpios[0].gpio), 0);
> + gpiod_export(gpio_to_desc(cm_t3517_wlan_gpios[1].gpio), 0);
>
> msleep(100);
> gpio_set_value(cm_t3517_wlan_gpios[1].gpio, 0);
> diff --git a/arch/sh/boards/mach-ap325rxa/setup.c b/arch/sh/boards/mach-ap325rxa/setup.c
> index 6e66ac194f7d..48055991152c 100644
> --- a/arch/sh/boards/mach-ap325rxa/setup.c
> +++ b/arch/sh/boards/mach-ap325rxa/setup.c
> @@ -18,6 +18,7 @@
> #include <linux/delay.h>
> #include <linux/device.h>
> #include <linux/gpio.h>
> +#include <linux/gpio/consumer.h>
> #include <linux/gpio/machine.h>
> #include <linux/i2c.h>
> #include <linux/init.h>
> @@ -411,16 +412,16 @@ static int __init ap325rxa_devices_setup(void)
> /* LD3 and LD4 LEDs */
> gpio_request(GPIO_PTX5, NULL); /* RUN */
> gpio_direction_output(GPIO_PTX5, 1);
> - gpio_export(GPIO_PTX5, 0);
> + gpiod_export(gpio_to_desc(GPIO_PTX5), 0);
>
> gpio_request(GPIO_PTX4, NULL); /* INDICATOR */
> gpio_direction_output(GPIO_PTX4, 0);
> - gpio_export(GPIO_PTX4, 0);
> + gpiod_export(gpio_to_desc(GPIO_PTX4), 0);
>
> /* SW1 input */
> gpio_request(GPIO_PTF7, NULL); /* MODE */
> gpio_direction_input(GPIO_PTF7);
> - gpio_export(GPIO_PTF7, 0);
> + gpiod_export(gpio_to_desc(GPIO_PTF7), 0);
>
> /* LCDC */
> gpio_request(GPIO_FN_LCDD15, NULL);
> diff --git a/drivers/gpio/gpiolib-sysfs.c b/drivers/gpio/gpiolib-sysfs.c
> index cd27bf173dec..cee135eb768e 100644
> --- a/drivers/gpio/gpiolib-sysfs.c
> +++ b/drivers/gpio/gpiolib-sysfs.c
> @@ -491,7 +491,7 @@ static ssize_t unexport_store(struct class *class,
> goto done;
>
> desc = gpio_to_desc(gpio);
> - /* reject bogus commands (gpio_unexport ignores them) */
> + /* reject bogus commands (gpiod_unexport ignores them) */

While at it,

/* reject bogus commands (gpiod_unexport() ignores them) */

> if (!desc) {
> pr_warn("%s: invalid GPIO %ld\n", __func__, gpio);
> return -EINVAL;
> @@ -790,7 +790,7 @@ static int __init gpiolib_sysfs_init(void)
> * early (e.g. before the class_register above was called).
> *
> * We run before arch_initcall() so chip->dev nodes can have
> - * registered, and so arch_initcall() can always gpio_export().
> + * registered, and so arch_initcall() can always gpiod_export().
> */
> spin_lock_irqsave(&gpio_lock, flags);
> list_for_each_entry(gdev, &gpio_devices, list) {
> diff --git a/drivers/media/pci/sta2x11/sta2x11_vip.c b/drivers/media/pci/sta2x11/sta2x11_vip.c
> index 8535e49a4c4f..e4cf9d63e926 100644
> --- a/drivers/media/pci/sta2x11/sta2x11_vip.c
> +++ b/drivers/media/pci/sta2x11/sta2x11_vip.c
> @@ -18,6 +18,7 @@
> #include <linux/pci.h>
> #include <linux/interrupt.h>
> #include <linux/io.h>
> +#include <linux/gpio/consumer.h>
> #include <linux/gpio.h>
> #include <linux/i2c.h>
> #include <linux/delay.h>
> @@ -889,6 +890,7 @@ static int sta2x11_vip_init_controls(struct sta2x11_vip *vip)
> static int vip_gpio_reserve(struct device *dev, int pin, int dir,
> const char *name)
> {
> + struct gpio_desc *desc = gpio_to_desc(pin);
> int ret = -ENODEV;
>
> if (!gpio_is_valid(pin))
> @@ -900,7 +902,7 @@ static int vip_gpio_reserve(struct device *dev, int pin, int dir,
> return ret;
> }
>
> - ret = gpio_direction_output(pin, dir);
> + ret = gpiod_direction_output(desc, dir);
> if (ret) {
> dev_err(dev, "Failed to set direction for pin %d (%s)\n",
> pin, name);
> @@ -908,7 +910,7 @@ static int vip_gpio_reserve(struct device *dev, int pin, int dir,
> return ret;
> }
>
> - ret = gpio_export(pin, false);
> + ret = gpiod_export(desc, false);
> if (ret) {
> dev_err(dev, "Failed to export pin %d (%s)\n", pin, name);
> gpio_free(pin);
> @@ -928,8 +930,10 @@ static int vip_gpio_reserve(struct device *dev, int pin, int dir,
> static void vip_gpio_release(struct device *dev, int pin, const char *name)
> {
> if (gpio_is_valid(pin)) {
> + struct gpio_desc *desc = gpio_to_desc(pin);
> +
> dev_dbg(dev, "releasing pin %d (%s)\n", pin, name);
> - gpio_unexport(pin);
> + gpiod_unexport(desc);
> gpio_free(pin);
> }
> }
> diff --git a/drivers/net/ieee802154/ca8210.c b/drivers/net/ieee802154/ca8210.c
> index e1a569b99e4a..5c0be6a3ec5e 100644
> --- a/drivers/net/ieee802154/ca8210.c
> +++ b/drivers/net/ieee802154/ca8210.c
> @@ -51,6 +51,7 @@
> #include <linux/clk-provider.h>
> #include <linux/debugfs.h>
> #include <linux/delay.h>
> +#include <linux/gpio/consumer.h>
> #include <linux/gpio.h>
> #include <linux/ieee802154.h>
> #include <linux/io.h>
> @@ -2853,7 +2854,7 @@ static int ca8210_interrupt_init(struct spi_device *spi)
> );
> if (ret) {
> dev_crit(&spi->dev, "request_irq %d failed\n", pdata->irq_id);
> - gpio_unexport(pdata->gpio_irq);
> + gpiod_unexport(gpio_to_desc(pdata->gpio_irq));
> gpio_free(pdata->gpio_irq);
> }
>
> diff --git a/include/linux/gpio.h b/include/linux/gpio.h
> index da7a5ae68e47..57ec3975b656 100644
> --- a/include/linux/gpio.h
> +++ b/include/linux/gpio.h
> @@ -127,20 +127,6 @@ extern int gpio_request_one(unsigned gpio, unsigned long flags, const char *labe
> extern int gpio_request_array(const struct gpio *array, size_t num);
> extern void gpio_free_array(const struct gpio *array, size_t num);
>
> -/*
> - * A sysfs interface can be exported by individual drivers if they want,
> - * but more typically is configured entirely from userspace.
> - */
> -static inline int gpio_export(unsigned gpio, bool direction_may_change)
> -{
> - return gpiod_export(gpio_to_desc(gpio), direction_may_change);
> -}
> -
> -static inline void gpio_unexport(unsigned gpio)
> -{
> - gpiod_unexport(gpio_to_desc(gpio));
> -}
> -
> /* CONFIG_GPIOLIB: bindings for managed devices that want to request gpios */
>
> struct device;
> @@ -231,19 +217,6 @@ static inline void gpio_set_value_cansleep(unsigned gpio, int value)
> WARN_ON(1);
> }
>
> -static inline int gpio_export(unsigned gpio, bool direction_may_change)
> -{
> - /* GPIO can never have been requested or set as {in,out}put */
> - WARN_ON(1);
> - return -EINVAL;
> -}
> -
> -static inline void gpio_unexport(unsigned gpio)
> -{
> - /* GPIO can never have been exported */
> - WARN_ON(1);
> -}
> -
> static inline int gpio_to_irq(unsigned gpio)
> {
> /* GPIO can never have been requested or set as input */
> --
> 2.39.0
>

--
With Best Regards,
Andy Shevchenko

Next message: Mark Brown: "Re: [PATCH] ASoC: cs42l56: fix DT probe"
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In reply to: Arnd Bergmann: "[PATCH 5/8] gpiolib: remove legacy gpio_export"
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