[RFC PATCH v2 3/3] Add Device Tree Bindings for mikroBUS port

[Vaishnav M A <vaishnav@beagleboard.org>]

This patch adds device tree bindings for the mikroBUS port,
device tree overlays for the mikrobus Port on the BeagleBoard.org
PocketBeagle is available here :
github.com/beagleboard/bb.org-overlays/blob/master/src/arm/PB-MIKROBUS-0.dts

Signed-off-by: Vaishnav M A <vaishnav@beagleboard.org>
---
 .../bindings/misc/linux,mikrobus.txt          | 81 +++++++++++++++++++
 1 file changed, 81 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/misc/linux,mikrobus.txt

diff --git a/Documentation/devicetree/bindings/misc/linux,mikrobus.txt b/Documentation/devicetree/bindings/misc/linux,mikrobus.txt
new file mode 100644
index 000000000000..99f75caf5f35
--- /dev/null
+++ b/Documentation/devicetree/bindings/misc/linux,mikrobus.txt
@@ -0,0 +1,81 @@
+mikroBUS add-on board socket
+
+Required properties:
+- compatible: Must be "linux,mikrobus"
+- i2c-adapter:  phandle to the i2c adapter attached to the mikrobus socket.
+- spi-master: spi bus number of the spi-master attached to the mikrobus socket.
+- spi-cs: spi chip-select numbers corresponding to the chip-selects
+	  on the mikrobus socket(0 -> chip select corresponding to CS pin
+	  1 -> chip select corresponding to RST pin).
+- serdev-controller:  phandle to the uart port attached to the mikrobus socket.
+- pwms: phandle to the pwm-controller corresponding to the mikroBUS PWM pin.
+- mikrobus-gpios: gpios array corresponding to GPIOs on the mikroBUS port,
+		  for targets not supporting the AN pin on the mikroBUS port as
+		  GPIO, the length of the gpios array can be 11, otherwise it
+		  should be 12.
+- pinctrl-names: pinctrl state names to support additional pin usage/deviations
+		 from mikroBUS socket standard usage, must be "default",
+		 "pwm_default", "pwm_gpio", "uart_default", "uart_gpio",
+		 "i2c_default", "i2c_gpio", "spi_default", "spi_gpio", these
+		 pinctrl names should have corresponding pinctrl-N entries which
+		 corresponds to the pinmux state for the pingroup, for example,
+		 i2c_default corresponds to the state where the I2C pin group
+		 (SCL,SDA) are configured in I2C mode and i2c_gpio mode corresponds
+		 to the pinmux state where these pins are configured as GPIO.
+- pinctrl-N : pinctrl-(0-8) corresponds to the pinctrl states for the states described
+	      above.
+
+Example:
+	mikrobus-0 {
+		compatible = "linux,mikrobus";
+		status = "okay";
+		pinctrl-names = "default", "pwm_default", "pwm_gpio",
+				"uart_default", "uart_gpio", "i2c_default",
+				"i2c_gpio", "spi_default", "spi_gpio";
+		pinctrl-0 = <
+			&P2_03_gpio_input_pin
+			&P1_04_gpio_pin
+			&P1_02_gpio_pin
+		>;
+		pinctrl-1 = <&P2_01_pwm_pin>;
+		pinctrl-2 = <&P2_01_gpio_pin>;
+		pinctrl-3 = <
+			&P2_05_uart_pin
+			&P2_07_uart_pin
+		>;
+		pinctrl-4 = <
+			&P2_05_gpio_pin
+			&P2_07_gpio_pin
+		>;
+		pinctrl-5 = <
+			&P2_09_i2c_pin
+			&P2_11_i2c_pin
+		>;
+		pinctrl-6 = <
+			&P2_09_gpio_pin
+			&P2_11_gpio_pin
+		>;
+		pinctrl-7 = <
+			&P1_12_spi_pin
+			&P1_10_spi_pin
+			&P1_08_spi_sclk_pin
+			&P1_06_spi_cs_pin
+		>;
+		pinctrl-8 = <
+			&P1_12_gpio_pin
+			&P1_10_gpio_pin
+			&P1_08_gpio_pin
+			&P1_06_gpio_pin
+		>;
+		i2c-adapter = <&i2c1>;
+		spi-master = <0>;
+		spi-cs = <0 1>;
+		serdev-controller = <&uart4>;
+		pwms = <&ehrpwm1 0 500000 0>;
+		mikrobus-gpios = <&gpio1 18 0> , <&gpio0 23 0>,
+					<&gpio0 30 0> , <&gpio0 31 0>,
+					<&gpio0 15 0> , <&gpio0 14 0>,
+					<&gpio0 4 0> , <&gpio0 3 0>,
+					<&gpio0 2 0> , <&gpio0 5 0>,
+					<&gpio2 25 0>  , <&gpio2 3 0>;
+	};
\ No newline at end of file
-- 
2.25.1