From 0d9a693cc8619b28f0eeb689a554647d42848fde Mon Sep 17 00:00:00 2001 From: Mika Westerberg Date: Wed, 29 Oct 2014 15:41:01 +0100 Subject: gpio / ACPI: Add support for _DSD device properties With release of ACPI 5.1 and _DSD method we can finally name GPIOs (and other things as well) returned by _CRS. Previously we were only able to use integer index to find the corresponding GPIO, which is pretty error prone if the order changes. With _DSD we can now query GPIOs using name instead of an integer index, like the below example shows: // Bluetooth device with reset and shutdown GPIOs Device (BTH) { Name (_HID, ...) Name (_CRS, ResourceTemplate () { GpioIo (Exclusive, PullUp, 0, 0, IoRestrictionInputOnly, "\\_SB.GPO0", 0, ResourceConsumer) {15} GpioIo (Exclusive, PullUp, 0, 0, IoRestrictionInputOnly, "\\_SB.GPO0", 0, ResourceConsumer) {27, 31} }) Name (_DSD, Package () { ToUUID("daffd814-6eba-4d8c-8a91-bc9bbf4aa301"), Package () { Package () {"reset-gpio", Package() {^BTH, 1, 1, 0 }}, Package () {"shutdown-gpio", Package() {^BTH, 0, 0, 0 }}, } }) } The format of the supported GPIO property is: Package () { "name", Package () { ref, index, pin, active_low }} ref - The device that has _CRS containing GpioIo()/GpioInt() resources, typically this is the device itself (BTH in our case). index - Index of the GpioIo()/GpioInt() resource in _CRS starting from zero. pin - Pin in the GpioIo()/GpioInt() resource. Typically this is zero. active_low - If 1 the GPIO is marked as active_low. Since ACPI GpioIo() resource does not have field saying whether it is active low or high, the "active_low" argument can be used here. Setting it to 1 marks the GPIO as active low. In our Bluetooth example the "reset-gpio" refers to the second GpioIo() resource, second pin in that resource with the GPIO number of 31. This patch implements necessary support to gpiolib for extracting GPIOs using _DSD device properties. Signed-off-by: Mika Westerberg Acked-by: Linus Walleij Acked-by: Grant Likely Signed-off-by: Rafael J. Wysocki --- drivers/gpio/gpiolib.c | 30 ++++++++++++++++++++++++++---- 1 file changed, 26 insertions(+), 4 deletions(-) (limited to 'drivers/gpio/gpiolib.c') diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c index e8e98ca25ec7..2bca0495cb46 100644 --- a/drivers/gpio/gpiolib.c +++ b/drivers/gpio/gpiolib.c @@ -1505,14 +1505,36 @@ static struct gpio_desc *acpi_find_gpio(struct device *dev, const char *con_id, unsigned int idx, enum gpio_lookup_flags *flags) { + static const char * const suffixes[] = { "gpios", "gpio" }; + struct acpi_device *adev = ACPI_COMPANION(dev); struct acpi_gpio_info info; struct gpio_desc *desc; + char propname[32]; + int i; - desc = acpi_get_gpiod_by_index(dev, idx, &info); - if (IS_ERR(desc)) - return desc; + /* Try first from _DSD */ + for (i = 0; i < ARRAY_SIZE(suffixes); i++) { + if (con_id && strcmp(con_id, "gpios")) { + snprintf(propname, sizeof(propname), "%s-%s", + con_id, suffixes[i]); + } else { + snprintf(propname, sizeof(propname), "%s", + suffixes[i]); + } + + desc = acpi_get_gpiod_by_index(adev, propname, idx, &info); + if (!IS_ERR(desc) || (PTR_ERR(desc) == -EPROBE_DEFER)) + break; + } + + /* Then from plain _CRS GPIOs */ + if (IS_ERR(desc)) { + desc = acpi_get_gpiod_by_index(adev, NULL, idx, &info); + if (IS_ERR(desc)) + return desc; + } - if (info.gpioint && info.active_low) + if (info.active_low) *flags |= GPIO_ACTIVE_LOW; return desc; -- cgit v1.2.3