On Mon, Feb 22, 2021 at 3:13 PM Daniel Scally <djrscally@xxxxxxxxx> wrote:
>
> I need to be able to translate GPIO resources in an ACPI device's _CRS
I -> we
> into GPIO descriptor array. Those are represented in _CRS as a pathname
> to a GPIO device plus the pin's index number: this function is perfect
Which one? "the acpi_...() function"
> for that purpose.
>
> As it's currently only used internally within the GPIO layer, provide and
> export a wrapper function that additionally holds a reference to the GPIO
> device.
Reviewed-by: Andy Shevchenko <andy.shevchenko@xxxxxxxxx>
after addressing above and beyond :-)
>
> Signed-off-by: Daniel Scally <djrscally@xxxxxxxxx>
> ---
> Changes in v3:
>
> - Having realised that it wasn't taking a reference to the GPIO device,
> I decided the best thing to do was leave the existing function as-is
> (apart from renaming) and provide a wrapper that simply passes
> through to the original and takes a reference before returning the
> struct gpio_desc
>
> Because of the change to that functionality, I dropped the R-b's from
> the last version.
>
> drivers/gpio/gpiolib-acpi.c | 36 +++++++++++++++++++++++++++++++----
> include/linux/gpio/consumer.h | 7 +++++++
> 2 files changed, 39 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/gpio/gpiolib-acpi.c b/drivers/gpio/gpiolib-acpi.c
> index e4d728fda982..0cc7cc327757 100644
> --- a/drivers/gpio/gpiolib-acpi.c
> +++ b/drivers/gpio/gpiolib-acpi.c
> @@ -102,7 +102,8 @@ static int acpi_gpiochip_find(struct gpio_chip *gc, void *data)
> }
>
> /**
> - * acpi_get_gpiod() - Translate ACPI GPIO pin to GPIO descriptor usable with GPIO API
> + * __acpi_get_gpiod() - Translate ACPI GPIO pin to GPIO descriptor usable with
Can we rename it better, i.e. w/o __, like "acpi_gpio_pin_to_gpiod()" or so?
> + * GPIO API
> * @path: ACPI GPIO controller full path name, (e.g. "\\_SB.GPO1")
> * @pin: ACPI GPIO pin number (0-based, controller-relative)
> *
> @@ -111,7 +112,7 @@ static int acpi_gpiochip_find(struct gpio_chip *gc, void *data)
> * controller does not have GPIO chip registered at the moment. This is to
> * support probe deferral.
> */
> -static struct gpio_desc *acpi_get_gpiod(char *path, int pin)
> +static struct gpio_desc *__acpi_get_gpiod(char *path, int pin)
> {
> struct gpio_chip *chip;
> acpi_handle handle;
> @@ -128,6 +129,33 @@ static struct gpio_desc *acpi_get_gpiod(char *path, int pin)
> return gpiochip_get_desc(chip, pin);
> }
>
> +/**
> + * acpi_get_gpiod() - Translate ACPI GPIO pin to GPIO descriptor usable with
> + * GPIO API, and hold a refcount to the GPIO device.
> + * @path: ACPI GPIO controller full path name, (e.g. "\\_SB.GPO1")
> + * @pin: ACPI GPIO pin number (0-based, controller-relative)
> + * @label: Label to pass to gpiod_request()
> + *
> + * This function is a simple pass-through to __acpi_get_gpiod(), except that as
> + * it is intended for use outside of the GPIO layer (in a similar fashion to
> + * gpiod_get_index() for example) it also holds a reference to the GPIO device.
> + */
> +struct gpio_desc *acpi_get_gpiod(char *path, int pin, char *label)
Name better to reflect the action, perhaps
"acpi_gpio_get_and_request_desc()" or so.
> +{
> + struct gpio_desc *gpio = __acpi_get_gpiod(path, pin);
Please, split it, so the assignment goes...
> + int ret;
...here.
> + if (IS_ERR(gpio))
> + return gpio;
> +
> + ret = gpiod_request(gpio, label);
> + if (ret)
> + return ERR_PTR(ret);
> +
> + return gpio;
> +}
> +EXPORT_SYMBOL_GPL(acpi_get_gpiod);
> +
> static irqreturn_t acpi_gpio_irq_handler(int irq, void *data)
> {
> struct acpi_gpio_event *event = data;
> @@ -689,8 +717,8 @@ static int acpi_populate_gpio_lookup(struct acpi_resource *ares, void *data)
> if (pin_index >= agpio->pin_table_length)
> return 1;
>
> - lookup->desc = acpi_get_gpiod(agpio->resource_source.string_ptr,
> - agpio->pin_table[pin_index]);
> + lookup->desc = __acpi_get_gpiod(agpio->resource_source.string_ptr,
> + agpio->pin_table[pin_index]);
> lookup->info.pin_config = agpio->pin_config;
> lookup->info.debounce = agpio->debounce_timeout;
> lookup->info.gpioint = gpioint;
> diff --git a/include/linux/gpio/consumer.h b/include/linux/gpio/consumer.h
> index ef49307611d2..6eee751f44dd 100644
> --- a/include/linux/gpio/consumer.h
> +++ b/include/linux/gpio/consumer.h
> @@ -690,6 +690,8 @@ int devm_acpi_dev_add_driver_gpios(struct device *dev,
> const struct acpi_gpio_mapping *gpios);
> void devm_acpi_dev_remove_driver_gpios(struct device *dev);
>
> +struct gpio_desc *acpi_get_gpiod(char *path, int pin, char *label);
> +
> #else /* CONFIG_GPIOLIB && CONFIG_ACPI */
>
> struct acpi_device;
> @@ -708,6 +710,11 @@ static inline int devm_acpi_dev_add_driver_gpios(struct device *dev,
> }
> static inline void devm_acpi_dev_remove_driver_gpios(struct device *dev) {}
>
> +struct gpio_desc *acpi_get_gpiod(char *path, int pin, char *label)
> +{
> + return NULL;
> +}
> +
> #endif /* CONFIG_GPIOLIB && CONFIG_ACPI */
>
>
> --
> 2.25.1
>
--
With Best Regards,
Andy Shevchenko
