[Feature]add MT2731_MP2_MR2_SVN388 baseline version
Change-Id: Ief04314834b31e27effab435d3ca8ba33b499059
diff --git a/src/kernel/linux/v4.14/Documentation/gpio/board.txt b/src/kernel/linux/v4.14/Documentation/gpio/board.txt
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+GPIO Mappings
+=============
+
+This document explains how GPIOs can be assigned to given devices and functions.
+Note that it only applies to the new descriptor-based interface. For a
+description of the deprecated integer-based GPIO interface please refer to
+gpio-legacy.txt (actually, there is no real mapping possible with the old
+interface; you just fetch an integer from somewhere and request the
+corresponding GPIO).
+
+All platforms can enable the GPIO library, but if the platform strictly
+requires GPIO functionality to be present, it needs to select GPIOLIB from its
+Kconfig. Then, how GPIOs are mapped depends on what the platform uses to
+describe its hardware layout. Currently, mappings can be defined through device
+tree, ACPI, and platform data.
+
+Device Tree
+-----------
+GPIOs can easily be mapped to devices and functions in the device tree. The
+exact way to do it depends on the GPIO controller providing the GPIOs, see the
+device tree bindings for your controller.
+
+GPIOs mappings are defined in the consumer device's node, in a property named
+<function>-gpios, where <function> is the function the driver will request
+through gpiod_get(). For example:
+
+ foo_device {
+ compatible = "acme,foo";
+ ...
+ led-gpios = <&gpio 15 GPIO_ACTIVE_HIGH>, /* red */
+ <&gpio 16 GPIO_ACTIVE_HIGH>, /* green */
+ <&gpio 17 GPIO_ACTIVE_HIGH>; /* blue */
+
+ power-gpios = <&gpio 1 GPIO_ACTIVE_LOW>;
+ };
+
+Properties named <function>-gpio are also considered valid and old bindings use
+it but are only supported for compatibility reasons and should not be used for
+newer bindings since it has been deprecated.
+
+This property will make GPIOs 15, 16 and 17 available to the driver under the
+"led" function, and GPIO 1 as the "power" GPIO:
+
+ struct gpio_desc *red, *green, *blue, *power;
+
+ red = gpiod_get_index(dev, "led", 0, GPIOD_OUT_HIGH);
+ green = gpiod_get_index(dev, "led", 1, GPIOD_OUT_HIGH);
+ blue = gpiod_get_index(dev, "led", 2, GPIOD_OUT_HIGH);
+
+ power = gpiod_get(dev, "power", GPIOD_OUT_HIGH);
+
+The led GPIOs will be active-high, while the power GPIO will be active-low (i.e.
+gpiod_is_active_low(power) will be true).
+
+The second parameter of the gpiod_get() functions, the con_id string, has to be
+the <function>-prefix of the GPIO suffixes ("gpios" or "gpio", automatically
+looked up by the gpiod functions internally) used in the device tree. With above
+"led-gpios" example, use the prefix without the "-" as con_id parameter: "led".
+
+Internally, the GPIO subsystem prefixes the GPIO suffix ("gpios" or "gpio")
+with the string passed in con_id to get the resulting string
+(snprintf(... "%s-%s", con_id, gpio_suffixes[]).
+
+ACPI
+----
+ACPI also supports function names for GPIOs in a similar fashion to DT.
+The above DT example can be converted to an equivalent ACPI description
+with the help of _DSD (Device Specific Data), introduced in ACPI 5.1:
+
+ Device (FOO) {
+ Name (_CRS, ResourceTemplate () {
+ GpioIo (Exclusive, ..., IoRestrictionOutputOnly,
+ "\\_SB.GPI0") {15} // red
+ GpioIo (Exclusive, ..., IoRestrictionOutputOnly,
+ "\\_SB.GPI0") {16} // green
+ GpioIo (Exclusive, ..., IoRestrictionOutputOnly,
+ "\\_SB.GPI0") {17} // blue
+ GpioIo (Exclusive, ..., IoRestrictionOutputOnly,
+ "\\_SB.GPI0") {1} // power
+ })
+
+ Name (_DSD, Package () {
+ ToUUID("daffd814-6eba-4d8c-8a91-bc9bbf4aa301"),
+ Package () {
+ Package () {
+ "led-gpios",
+ Package () {
+ ^FOO, 0, 0, 1,
+ ^FOO, 1, 0, 1,
+ ^FOO, 2, 0, 1,
+ }
+ },
+ Package () {
+ "power-gpios",
+ Package () {^FOO, 3, 0, 0},
+ },
+ }
+ })
+ }
+
+For more information about the ACPI GPIO bindings see
+Documentation/acpi/gpio-properties.txt.
+
+Platform Data
+-------------
+Finally, GPIOs can be bound to devices and functions using platform data. Board
+files that desire to do so need to include the following header:
+
+ #include <linux/gpio/machine.h>
+
+GPIOs are mapped by the means of tables of lookups, containing instances of the
+gpiod_lookup structure. Two macros are defined to help declaring such mappings:
+
+ GPIO_LOOKUP(chip_label, chip_hwnum, con_id, flags)
+ GPIO_LOOKUP_IDX(chip_label, chip_hwnum, con_id, idx, flags)
+
+where
+
+ - chip_label is the label of the gpiod_chip instance providing the GPIO
+ - chip_hwnum is the hardware number of the GPIO within the chip
+ - con_id is the name of the GPIO function from the device point of view. It
+ can be NULL, in which case it will match any function.
+ - idx is the index of the GPIO within the function.
+ - flags is defined to specify the following properties:
+ * GPIOF_ACTIVE_LOW - to configure the GPIO as active-low
+ * GPIOF_OPEN_DRAIN - GPIO pin is open drain type.
+ * GPIOF_OPEN_SOURCE - GPIO pin is open source type.
+
+In the future, these flags might be extended to support more properties.
+
+Note that GPIO_LOOKUP() is just a shortcut to GPIO_LOOKUP_IDX() where idx = 0.
+
+A lookup table can then be defined as follows, with an empty entry defining its
+end. The 'dev_id' field of the table is the identifier of the device that will
+make use of these GPIOs. It can be NULL, in which case it will be matched for
+calls to gpiod_get() with a NULL device.
+
+struct gpiod_lookup_table gpios_table = {
+ .dev_id = "foo.0",
+ .table = {
+ GPIO_LOOKUP_IDX("gpio.0", 15, "led", 0, GPIO_ACTIVE_HIGH),
+ GPIO_LOOKUP_IDX("gpio.0", 16, "led", 1, GPIO_ACTIVE_HIGH),
+ GPIO_LOOKUP_IDX("gpio.0", 17, "led", 2, GPIO_ACTIVE_HIGH),
+ GPIO_LOOKUP("gpio.0", 1, "power", GPIO_ACTIVE_LOW),
+ { },
+ },
+};
+
+And the table can be added by the board code as follows:
+
+ gpiod_add_lookup_table(&gpios_table);
+
+The driver controlling "foo.0" will then be able to obtain its GPIOs as follows:
+
+ struct gpio_desc *red, *green, *blue, *power;
+
+ red = gpiod_get_index(dev, "led", 0, GPIOD_OUT_HIGH);
+ green = gpiod_get_index(dev, "led", 1, GPIOD_OUT_HIGH);
+ blue = gpiod_get_index(dev, "led", 2, GPIOD_OUT_HIGH);
+
+ power = gpiod_get(dev, "power", GPIOD_OUT_HIGH);
+
+Since the "led" GPIOs are mapped as active-high, this example will switch their
+signals to 1, i.e. enabling the LEDs. And for the "power" GPIO, which is mapped
+as active-low, its actual signal will be 0 after this code. Contrary to the
+legacy integer GPIO interface, the active-low property is handled during
+mapping and is thus transparent to GPIO consumers.
+
+A set of functions such as gpiod_set_value() is available to work with
+the new descriptor-oriented interface.