Re: GPIO bindings guidelines (Was: Re: [PATCH v5 10/12] gpio: Support for unified device properties interface)
From: Rafael J. Wysocki
Date: Fri Oct 24 2014 - 17:40:17 EST
On Friday, October 24, 2014 10:34:36 AM Mika Westerberg wrote:
> On Thu, Oct 23, 2014 at 11:51:59PM +0200, Rafael J. Wysocki wrote:
> > OK, let's try to take that a bit farther. :-)
> >
> > With the (untested) patch below applied (which is a replacement for the one
> > sent previously), the driver can use static tables like these:
> >
> > static struct acpi_gpio_params reset_gpios = { 0, 0, false };
> > statuc struct acpi_gpio_params shutdown_gpios = { 1, 0, false };
> >
> > static struct acpi_gpio_mapping my_gpio_mapping[] = {
> > { "reset-gpios", &reset_gpios, 1 },
> > { "shutdown-gpios", &shutdown_gpios, 1 },
> > NULL,
> > };
> >
>
> This is even better :-)
>
> I tried this with few changes:
>
> - constify the mapping parameter
> - check for NULL adev->driver_gpios in acpi_get_driver_gpio_data()
> - check for gm->name instead of gm in acpi_get_driver_gpio_data()
>
> It works just fine. For reference here are my changes to rkill-gpio.c:
>
> diff --git a/net/rfkill/rfkill-gpio.c b/net/rfkill/rfkill-gpio.c
> index 0f62326c0f5e..ec8f5ac53520 100644
> --- a/net/rfkill/rfkill-gpio.c
> +++ b/net/rfkill/rfkill-gpio.c
> @@ -63,6 +63,15 @@ static const struct rfkill_ops rfkill_gpio_ops = {
> .set_block = rfkill_gpio_set_power,
> };
>
> +static const struct acpi_gpio_params reset_gpios = { 0, 0, false };
> +static const struct acpi_gpio_params shutdown_gpios = { 1, 0, false };
> +
> +static const struct acpi_gpio_mapping acpi_rfkill_default_gpios[] = {
> + { "reset-gpios", &reset_gpios, 1 },
> + { "shutdown-gpios", &shutdown_gpios, 1 },
> + { },
> +};
> +
> static int rfkill_gpio_acpi_probe(struct device *dev,
> struct rfkill_gpio_data *rfkill)
> {
> @@ -75,7 +84,8 @@ static int rfkill_gpio_acpi_probe(struct device *dev,
> rfkill->name = dev_name(dev);
> rfkill->type = (unsigned)id->driver_data;
>
> - return 0;
> + return acpi_dev_add_driver_gpios(ACPI_COMPANION(dev),
> + acpi_rfkill_default_gpios);
> }
>
> static int rfkill_gpio_probe(struct platform_device *pdev)
> @@ -110,7 +120,7 @@ static int rfkill_gpio_probe(struct platform_device *pdev)
> rfkill->reset_gpio = gpio;
> }
>
> - gpio = devm_gpiod_get_index(&pdev->dev, "shutdown", 1);
> + gpio = devm_gpiod_get_index(&pdev->dev, "shutdown", 0);
> if (!IS_ERR(gpio)) {
> ret = gpiod_direction_output(gpio, 0);
> if (ret)
> @@ -150,6 +160,8 @@ static int rfkill_gpio_remove(struct platform_device *pdev)
> rfkill_unregister(rfkill->rfkill_dev);
> rfkill_destroy(rfkill->rfkill_dev);
>
> + acpi_dev_remove_driver_gpios(ACPI_COMPANION(&pdev->dev));
> +
> return 0;
> }
>
> And here are the changes on top of your patch:
>
> diff --git a/drivers/gpio/gpiolib-acpi.c b/drivers/gpio/gpiolib-acpi.c
> index 691501b53c5e..4151cd774f2f 100644
> --- a/drivers/gpio/gpiolib-acpi.c
> +++ b/drivers/gpio/gpiolib-acpi.c
> @@ -288,7 +288,7 @@ void acpi_gpiochip_free_interrupts(struct gpio_chip *chip)
> }
>
> int acpi_dev_add_driver_gpios(struct acpi_device *adev,
> - struct acpi_gpio_mapping *gpios)
> + const struct acpi_gpio_mapping *gpios)
> {
> if (adev && gpios) {
> adev->driver_gpios = gpios;
> @@ -302,11 +302,14 @@ static bool acpi_get_driver_gpio_data(struct acpi_device *adev,
> const char *name, int index,
> struct acpi_reference_args *args)
> {
> - struct acpi_gpio_mapping *gm;
> + const struct acpi_gpio_mapping *gm;
>
> - for (gm = adev->driver_gpios; gm; gm++)
> + if (!adev->driver_gpios)
> + return false;
> +
> + for (gm = adev->driver_gpios; gm->name; gm++)
> if (!strcmp(name, gm->name) && gm->data && index < gm->size) {
> - struct acpi_gpio_params *par = gm->data + index;
> + const struct acpi_gpio_params *par = gm->data + index;
>
> args->adev = adev;
> args->args[0] = par->crs_entry_index;
> diff --git a/include/acpi/acpi_bus.h b/include/acpi/acpi_bus.h
> index 2de7a2614c61..98d992062270 100644
> --- a/include/acpi/acpi_bus.h
> +++ b/include/acpi/acpi_bus.h
> @@ -368,7 +368,7 @@ struct acpi_device {
> struct acpi_scan_handler *handler;
> struct acpi_hotplug_context *hp;
> struct acpi_driver *driver;
> - struct acpi_gpio_mapping *driver_gpios;
> + const struct acpi_gpio_mapping *driver_gpios;
> void *driver_data;
> struct device dev;
> unsigned int physical_node_count;
> diff --git a/include/linux/acpi.h b/include/linux/acpi.h
> index 26b7a639f4b9..23f9c55d0331 100644
> --- a/include/linux/acpi.h
> +++ b/include/linux/acpi.h
> @@ -680,13 +680,13 @@ struct acpi_gpio_params {
>
> struct acpi_gpio_mapping {
> const char *name;
> - struct acpi_gpio_params *data;
> + const struct acpi_gpio_params *data;
> unsigned int size;
> };
>
> #if defined(CONFIG_ACPI) && defined(CONFIG_GPIOLIB)
> int acpi_dev_add_driver_gpios(struct acpi_device *adev,
> - struct acpi_gpio_mapping *gpios);
> + const struct acpi_gpio_mapping *gpios);
>
> static inline void acpi_dev_remove_driver_gpios(struct acpi_device *adev)
> {
> @@ -695,7 +695,7 @@ static inline void acpi_dev_remove_driver_gpios(struct acpi_device *adev)
> }
> #else
> static inline int acpi_dev_add_driver_gpios(struct acpi_device *adev,
> - struct acpi_gpio_mapping *gpios)
> + const struct acpi_gpio_mapping *gpios)
> {
> return -ENXIO;
> }
Thanks!
I folded your fixes into my patch and I'm going to send the result, with a
changelog, in a reply to this message.
If everyone is happy with it, I'll add it to the device properties patch
series as it depends on those.
I guess you can add a changelog to your rfkill changes and then we could
add them to that series too if there are no objections.
--
I speak only for myself.
Rafael J. Wysocki, Intel Open Source Technology Center.
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