PINCTRL: stm32f7: add pin control driver

This driver uses the same pin control binding as that of linux, binding
document of this patch is copied from linux. One addition done is for
GPIO input and output mode configuration which was missing.

Signed-off-by: Vikas Manocha <vikas.manocha@st.com>
Reviewed-by: Simon Glass <sjg@chromium.org>

1 files changed, 133 insertions, 0 deletions

diff --git a/doc/device-tree-bindings/pinctrl/st,stm32-pinctrl.txt b/doc/device-tree-bindings/pinctrl/st,stm32-pinctrl.txt
new file mode 100644
index 0000000000..c41ae91f7a
--- /dev/null
+++ b/doc/device-tree-bindings/pinctrl/st,stm32-pinctrl.txt
@@ -0,0 +1,133 @@
+* STM32 GPIO and Pin Mux/Config controller
+
+STMicroelectronics's STM32 MCUs intregrate a GPIO and Pin mux/config hardware
+controller. It controls the input/output settings on the available pins and
+also provides ability to multiplex and configure the output of various on-chip
+controllers onto these pads.
+
+Pin controller node:
+Required properies:
+ - compatible: value should be one of the following:
+   (a) "st,stm32f429-pinctrl"
+   (b) "st,stm32f746-pinctrl"
+ - #address-cells: The value of this property must be 1
+ - #size-cells	: The value of this property must be 1
+ - ranges	: defines mapping between pin controller node (parent) to
+   gpio-bank node (children).
+ - pins-are-numbered: Specify the subnodes are using numbered pinmux to
+   specify pins.
+
+GPIO controller/bank node:
+Required properties:
+ - gpio-controller : Indicates this device is a GPIO controller
+ - #gpio-cells	  : Should be two.
+			The first cell is the pin number
+			The second one is the polarity:
+				- 0 for active high
+				- 1 for active low
+ - reg		  : The gpio address range, relative to the pinctrl range
+ - clocks	  : clock that drives this bank
+ - st,bank-name	  : Should be a name string for this bank as specified in
+   the datasheet
+
+Optional properties:
+ - reset:	  : Reference to the reset controller
+ - interrupt-parent: phandle of the interrupt parent to which the external
+   GPIO interrupts are forwarded to.
+ - st,syscfg: Should be phandle/offset pair. The phandle to the syscon node
+   which includes IRQ mux selection register, and the offset of the IRQ mux
+   selection register.
+
+Example:
+#include <dt-bindings/pinctrl/stm32f429-pinfunc.h>
+...
+
+	pin-controller {
+		#address-cells = <1>;
+		#size-cells = <1>;
+		compatible = "st,stm32f429-pinctrl";
+		ranges = <0 0x40020000 0x3000>;
+		pins-are-numbered;
+
+		gpioa: gpio@40020000 {
+			gpio-controller;
+			#gpio-cells = <2>;
+			reg = <0x0 0x400>;
+			resets = <&reset_ahb1 0>;
+			st,bank-name = "GPIOA";
+		};
+		...
+		pin-functions nodes follow...
+	};
+
+Contents of function subnode node:
+----------------------------------
+Subnode format
+A pinctrl node should contain at least one subnode representing the
+pinctrl group available on the machine. Each subnode will list the
+pins it needs, and how they should be configured, with regard to muxer
+configuration, pullups, drive, output high/low and output speed.
+
+    node {
+	pinmux = <PIN_NUMBER_PINMUX>;
+	GENERIC_PINCONFIG;
+    };
+
+Required properties:
+- pinmux: integer array, represents gpio pin number and mux setting.
+  Supported pin number and mux varies for different SoCs, and are defined in
+  dt-bindings/pinctrl/<soc>-pinfunc.h directly.
+  These defines are calculated as:
+    ((port * 16 + line) << 8) | function
+  With:
+    - port: The gpio port index (PA = 0, PB = 1, ..., PK = 11)
+    - line: The line offset within the port (PA0 = 0, PA1 = 1, ..., PA15 = 15)
+    - function: The function number, can be:
+      * 0 : GPIO IN
+      * 1 : Alternate Function 0
+      * 2 : Alternate Function 1
+      * 3 : Alternate Function 2
+      * ...
+      * 16 : Alternate Function 15
+      * 17 : Analog
+      * 18 : GPIO OUT
+
+Optional properties:
+- GENERIC_PINCONFIG: is the generic pinconfig options to use.
+  Available options are:
+   - bias-disable,
+   - bias-pull-down,
+   - bias-pull-up,
+   - drive-push-pull,
+   - drive-open-drain,
+   - output-low
+   - output-high
+   - slew-rate = <x>, with x being:
+       < 0 > : Low speed
+       < 1 > : Medium speed
+       < 2 > : Fast speed
+       < 3 > : High speed
+
+Example:
+
+pin-controller {
+...
+	usart1_pins_a: usart1@0 {
+		pins1 {
+			pinmux = <STM32F429_PA9_FUNC_USART1_TX>;
+			bias-disable;
+			drive-push-pull;
+			slew-rate = <0>;
+		};
+		pins2 {
+			pinmux = <STM32F429_PA10_FUNC_USART1_RX>;
+			bias-disable;
+		};
+	};
+};
+
+&usart1 {
+	pinctrl-0 = <&usart1_pins_a>;
+	pinctrl-names = "default";
+	status = "okay";
+};