[PATCH v3 06/11] gpiolib: reluctantly provide gpio_device_get_chip()

Bartosz Golaszewski
2023-09-15T15:03:51Z

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>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
---
drivers/gpio/gpiolib.c | 21 +++++++++++++++++++++
include/linux/gpio/driver.h | 2 ++
2 files changed, 23 insertions(+)

diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index 7d2574b3dbe5..e26cbd10a246 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -220,6 +220,27 @@ struct gpio_chip *gpiod_to_chip(const struct gpio_desc *desc)
}
EXPORT_SYMBOL_GPL(gpiod_to_chip);

+/**
+ * gpio_device_get_chip() - Get the gpio_chip implementation of this GPIO device
+ * @gdev: GPIO device
+ *
+ * Returns:
+ * Address of the GPIO chip backing this device.
+ *
+ * Until we can get rid of all non-driver users of 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 3fdf3f14bb13..f8ad7f40100c 100644
--- a/include/linux/gpio/driver.h
+++ b/include/linux/gpio/driver.h
@@ -773,6 +773,8 @@ struct gpio_desc *gpiochip_get_desc(struct gpio_chip *gc, unsigned int hwnum);
struct gpio_desc *
gpio_device_get_desc(struct gpio_device *gdev, unsigned int hwnum);

+struct gpio_chip *gpio_device_get_chip(struct gpio_device *gdev);
+
#ifdef CONFIG_GPIOLIB

/* lock/unlock as IRQ */
--
2.39.2