| Message ID | 20230927142931.19798-5-brgl@bgdev.pl |
|---|---|
| State | New |
| Headers | show |
| Series | gpiolib: work towards removing gpiochip_find() | expand |
On Wed, Sep 27, 2023 at 04:29:24PM +0200, Bartosz Golaszewski wrote: > From: Bartosz Golaszewski <bartosz.golaszewski@linaro.org> > > By far the most common way of looking up GPIO devices is using their > label. Provide a helpers for that to avoid every user implementing their > own matching function. ... > +struct gpio_device *gpio_device_find_by_label(const char *label) > +{ > + return gpio_device_find((void *)label, gpio_chip_match_by_label); > +} Are we expecting that data referenced by the first parameter to the gpio_device_find() can be altered? If not, why not using const void * there and here as well?
On Mon, Oct 2, 2023 at 11:44 AM Andy Shevchenko <andriy.shevchenko@linux.intel.com> wrote: > > On Wed, Sep 27, 2023 at 04:29:24PM +0200, Bartosz Golaszewski wrote: > > From: Bartosz Golaszewski <bartosz.golaszewski@linaro.org> > > > > By far the most common way of looking up GPIO devices is using their > > label. Provide a helpers for that to avoid every user implementing their > > own matching function. > > ... > > > +struct gpio_device *gpio_device_find_by_label(const char *label) > > +{ > > + return gpio_device_find((void *)label, gpio_chip_match_by_label); > > +} > > Are we expecting that data referenced by the first parameter to the > gpio_device_find() can be altered? If not, why not using const void * > there and here as well? > I guess it's a good idea. Bart
On Mon, Oct 2, 2023 at 11:53 AM Bartosz Golaszewski <brgl@bgdev.pl> wrote: > > On Mon, Oct 2, 2023 at 11:44 AM Andy Shevchenko > <andriy.shevchenko@linux.intel.com> wrote: > > > > On Wed, Sep 27, 2023 at 04:29:24PM +0200, Bartosz Golaszewski wrote: > > > From: Bartosz Golaszewski <bartosz.golaszewski@linaro.org> > > > > > > By far the most common way of looking up GPIO devices is using their > > > label. Provide a helpers for that to avoid every user implementing their > > > own matching function. > > > > ... > > > > > +struct gpio_device *gpio_device_find_by_label(const char *label) > > > +{ > > > + return gpio_device_find((void *)label, gpio_chip_match_by_label); > > > +} > > > > Are we expecting that data referenced by the first parameter to the > > gpio_device_find() can be altered? If not, why not using const void * > > there and here as well? > > > > I guess it's a good idea. > > Bart Scratch that. When we know that we're passing a label, it's fine to have it const but almost treewide, various matching functions take "void *data" as argument. I'll leave it this way. Bart
diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c index 0371d23f0a46..9f20311e4c1a 100644 --- a/drivers/gpio/gpiolib.c +++ b/drivers/gpio/gpiolib.c @@ -20,6 +20,7 @@ #include <linux/seq_file.h> #include <linux/slab.h> #include <linux/spinlock.h> +#include <linux/string.h> #include <linux/gpio.h> #include <linux/gpio/driver.h> @@ -1081,6 +1082,26 @@ struct gpio_device *gpio_device_find(void *data, } EXPORT_SYMBOL_GPL(gpio_device_find); +static int gpio_chip_match_by_label(struct gpio_chip *gc, void *label) +{ + return gc->label && !strcmp(gc->label, label); +} + +/** + * gpio_device_find_by_label() - wrapper around gpio_device_find() finding the + * GPIO device by its backing chip's label + * @label: Label to lookup + * + * Returns: + * Reference to the GPIO device or NULL. Reference must be released with + * gpio_device_put(). + */ +struct gpio_device *gpio_device_find_by_label(const char *label) +{ + return gpio_device_find((void *)label, gpio_chip_match_by_label); +} +EXPORT_SYMBOL_GPL(gpio_device_find_by_label); + static int gpiochip_match_name(struct gpio_chip *gc, void *data) { const char *name = data; diff --git a/include/linux/gpio/driver.h b/include/linux/gpio/driver.h index 6ad1f1a8ef2e..24996cba6465 100644 --- a/include/linux/gpio/driver.h +++ b/include/linux/gpio/driver.h @@ -610,6 +610,7 @@ struct gpio_chip *gpiochip_find(void *data, struct gpio_device *gpio_device_find(void *data, int (*match)(struct gpio_chip *gc, void *data)); +struct gpio_device *gpio_device_find_by_label(const char *label); struct gpio_device *gpio_device_get(struct gpio_device *gdev); void gpio_device_put(struct gpio_device *gdev);