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![]() 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. Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com> Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Signed-off-by: Linus Walleij <linus.walleij@linaro.org> |
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Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. Please read the Documentation/process/changes.rst file, as it contains the requirements for building and running the kernel, and information about the problems which may result by upgrading your kernel.