diff mbox series

[09/21] gpiolib: reluctantly provide gpio_device_get_chip()

Message ID 20230905185309.131295-10-brgl@bgdev.pl
State New
Headers show
Series gpio: convert users to gpio_device_find() and remove gpiochip_find() | expand

Commit Message

Bartosz Golaszewski Sept. 5, 2023, 6:52 p.m. UTC 
From: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

The process of converting all unauthorized users of struct gpio_chip to
using dedicated struct gpio_device function will be long so in the
meantime we must provide a way of retrieving the pointer to struct
gpio_chip from a GPIO device.

Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
---
 drivers/gpio/gpiolib.c      | 18 ++++++++++++++++++
 include/linux/gpio/driver.h |  1 +
 2 files changed, 19 insertions(+)

Comments

Linus Walleij Sept. 7, 2023, 7:19 a.m. UTC | #1 
On Tue, Sep 5, 2023 at 8:53 PM Bartosz Golaszewski <brgl@bgdev.pl> wrote:

> From: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
>
> The process of converting all unauthorized users of struct gpio_chip to
> using dedicated struct gpio_device function will be long so in the
> meantime we must provide a way of retrieving the pointer to struct
> gpio_chip from a GPIO device.
>
> Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

Yeah, sigh. Maybe add a notice to drivers/gpio/TODO that this needs
to happen long time.

Reviewed-by: Linus Walleij <linus.walleij@linaro.org>

Yours,
Linus Walleij
diff mbox series

Patch

diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index 9715bbc698e9..408f8a7753f9 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -246,6 +246,24 @@  int gpio_device_get_base(struct gpio_device *gdev)
 }
 EXPORT_SYMBOL_GPL(gpio_device_get_base);
 
+/**
+ * gpio_device_get_chip() - Get the gpio_chip implementation of this GPIO device
+ * @gdev: GPIO device
+ *
+ * Until we can get rid of all non-driver users struct gpio_chip, we must
+ * provide a way of retrieving the pointer to it from struct gpio_device. This
+ * is *NOT* safe as the GPIO API is considered to be hot-unpluggable and the
+ * chip can dissapear at any moment (unlike reference-counted struct
+ * gpio_device).
+ *
+ * Use at your own risk.
+ */
+struct gpio_chip *gpio_device_get_chip(struct gpio_device *gdev)
+{
+	return gdev->chip;
+}
+EXPORT_SYMBOL_GPL(gpio_device_get_chip);
+
 /* dynamic allocation of GPIOs, e.g. on a hotplugged device */
 static int gpiochip_find_base(int ngpio)
 {
diff --git a/include/linux/gpio/driver.h b/include/linux/gpio/driver.h
index 47906bc56b3d..bb9ec741bfda 100644
--- a/include/linux/gpio/driver.h
+++ b/include/linux/gpio/driver.h
@@ -782,6 +782,7 @@  struct gpio_device *gpiod_to_device(struct gpio_desc *desc);
 
 /* struct gpio_device getters */
 int gpio_device_get_base(struct gpio_device *gdev);
+struct gpio_chip *gpio_device_get_chip(struct gpio_device *gdev);
 
 #else /* CONFIG_GPIOLIB */