On Tue, Oct 28, 2014 at 7:34 AM, Rafael J. Wysocki <rjw@xxxxxxxxxxxxx> wrote: > On Monday, October 27, 2014 02:21:23 PM Alexandre Courbot wrote: >> 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. > > Yes, I'm going to provide documentation. > > One question, though. We're already adding gpio-properties.txt under > Documentation/acpi/ containing analogous information for _DSD-based > mappings. I thought I'd add a section to that file and a short paragraph > pointing to it into consumer.txt, would that work? Definitely yes, since this is ACPI-specific. Thanks! -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
