Re: [PATCH] ACPI / GPIO: Driver GPIO mappings for ACPI GPIOs

[Alexandre Courbot]

On Sat, Oct 25, 2014 at 7:05 AM, Rafael J. Wysocki <rjw@xxxxxxxxxxxxx> wrote:
> From: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
>
> Provide a way for device drivers using GPIOs described by ACPI
> GpioIo resources in _CRS to tell the GPIO subsystem what names
> (connection IDs) to associate with specific GPIO pins defined
> in there.
>
> To do that, a driver needs to define a mapping table as a
> NULL-terminated array of struct acpi_gpio_mapping objects
> that each contain a name, a pointer to an array of pin data
> (struct acpi_gpio_params) objects and the size of that array.
>
> Each struct acpi_gpio_params object consists of three fields,
> crs_entry_index, pin_index, active_low, representing the index of
> the target GpioIo()/GpioInt() resource in _CRS starting from zero,
> the index of the target pin in that resource starting from zero,
> and the active-low flag for that pin, respectively.
>
> Next, the mapping table needs to be passed as the second argument to
> acpi_dev_add_driver_gpios() that will register it with the ACPI device
> object pointed to by its first argument.  That object must represent
> the ACPI namespace node containing the _CRS object referred to by the
> GPIO mapping.  That should be done in the driver's .probe() routine.
>
> On removal, the driver should unregister its GPIO mapping table
> by calling acpi_dev_remove_driver_gpios() on the ACPI device
> object where that table was previously registered.
>
> Included are fixes from Mika Westerberg.

Acked-by: Alexandre Courbot <acourbot@xxxxxxxxxx>

As we discussed already, this is a great idea. The only thing that is
missing is a paragraph in Documentation/gpio/consumer.txt with an
explanation of the global mechanism and a simple example to illustrate
how and when this should be used.
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/