On Mon, Nov 27, 2017 at 2:54 PM, Mika Westerberg <mika.westerberg@xxxxxxxxxxxxxxx> wrote: > We added acpi_gpiochip_pin_to_gpio_offset() because there was a need to > translate from ACPI GpioIo/GpioInt number to Linux GPIO number in the > Cherryview pinctrl driver. This translation is necessary because > Cherryview has gaps in the pin list and the driver used continuous GPIO > number space in Linux side as follows: > > created GPIO range 0->7 ==> INT33FF:03 PIN 0->7 > created GPIO range 8->19 ==> INT33FF:03 PIN 15->26 > created GPIO range 20->25 ==> INT33FF:03 PIN 30->35 > created GPIO range 26->33 ==> INT33FF:03 PIN 45->52 > created GPIO range 34->43 ==> INT33FF:03 PIN 60->69 > created GPIO range 44->54 ==> INT33FF:03 PIN 75->85 > > For example when ACPI GpioInt resource refers to GPIO 81 (SDMMC3_CD_B) > we translate from pin 81 to the corresponding Linux GPIO number, which > is 50. This number is then used when the GPIO is accessed through gpiolib. > > It turns out, this is not necessary at all. We can just pass 1:1 mapping > between Linux GPIO numbers and pin numbers (including gaps) and the > pinctrl core handles all the details automatically: > > created GPIO range 0->7 ==> INT33FF:03 PIN 0->7 > created GPIO range 15->26 ==> INT33FF:03 PIN 15->26 > created GPIO range 30->35 ==> INT33FF:03 PIN 30->35 > created GPIO range 45->52 ==> INT33FF:03 PIN 45->52 > created GPIO range 60->69 ==> INT33FF:03 PIN 60->69 > created GPIO range 75->85 ==> INT33FF:03 PIN 75->85 > > Here GPIO 81 is exactly same than the hardware pin 81 (SDMMC3_CD_B). > > As an added bonus this simplifies both the ACPI GPIO core code and the > Cherryview pinctrl driver. Cool! Acked-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx> -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
