Add device tree bindings documentation for Renesas RZ/A1 gpio and pin
controller.
Signed-off-by: Jacopo Mondi <jacopo+renesas@xxxxxxxxxx>
---
.../bindings/pinctrl/renesas,rza1-pinctrl.txt | 221 +++++++++++++++++++++
1 file changed, 221 insertions(+)
create mode 100644 Documentation/devicetree/bindings/pinctrl/renesas,rza1-pinctrl.txt
diff --git a/Documentation/devicetree/bindings/pinctrl/renesas,rza1-pinctrl.txt b/Documentation/devicetree/bindings/pinctrl/renesas,rza1-pinctrl.txt
new file mode 100644
index 0000000..43e21474
--- /dev/null
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+Renesas RZ/A1 combined Pin and GPIO controller
+
+The Renesas SoCs of the RZ/A1 family feature a combined Pin and GPIO controller,
+named "Ports" in the hardware reference manual.
+Pin multiplexing and GPIO configuration is performed on a per-pin basis
+writing configuration values to per-port register sets.
+Each "port" features up to 16 pins, each of them configurable for GPIO
+function (port mode) or in alternate function mode.
+Up to 8 different alternate function modes exist for each single pin.
+
+Pin controller node
+-------------------
+
+Required properties:
+ - compatible
+ this shall be "renesas,r7s72100-ports".
+
+ - reg
+ address base and length of the memory area where the pin controller
+ hardware is mapped to.
+
+Example:
+Pin controller node for RZ/A1H SoC (r7s72100)
+
+pinctrl: pin-controller@fcfe3000 {
+ compatible = "renesas,r7s72100-ports";
+
+ reg = <0xfcfe3000 0x4230>;
+};
+
+Sub-nodes
+---------
+
+The child nodes of the pin controller node describe a pin multiplexing
+function or a GPIO controller alternatively.
+
+- Pin multiplexing sub-nodes:
+ A pin multiplexing sub-node describes how to configure a set of
+ (or a single) pin in some desired alternate function mode.
+ A single sub-node may define several pin configurations.
+ A few alternate function require special pin configuration flags to be
+ supplied along with the alternate function configuration number.
+ The hardware reference manual specifies when a pin function requires
+ "software IO driven" mode to be specified. To do so use the generic
+ properties from the <include/linux/pinctrl/pinconf_generic.h> header file
+ to instruct the pin controller to perform the desired pin configuration
+ operation.
+ Please refer to pinctrl-bindings.txt to get to know more on generic
+ pin properties usage.
+
+ The allowed generic formats for a pin multiplexing sub-node are the
+ following ones:
+
+ node-1 {
+ pinmux = <PIN_ID_AND_MUX>, <PIN_ID_AND_MUX>, ... ;
+ GENERIC_PINCONFIG;
+ };
+
+ node-2 {
+ sub-node-1 {
+ pinmux = <PIN_ID_AND_MUX>, <PIN_ID_AND_MUX>, ... ;
+ GENERIC_PINCONFIG;
+ };
+
+ sub-node-2 {
+ pinmux = <PIN_ID_AND_MUX>, <PIN_ID_AND_MUX>, ... ;
+ GENERIC_PINCONFIG;
+ };
+
+ ...
+
+ sub-node-n {
+ pinmux = <PIN_ID_AND_MUX>, <PIN_ID_AND_MUX>, ... ;
+ GENERIC_PINCONFIG;
+ };
+ };
+
+ Use the second format when pins part of the same logical group need to have
+ different generic pin configuration flags applied.
+
+ Client sub-nodes shall refer to pin multiplexing sub-nodes using the phandle
+ of the most external one.
+
+ Eg.
+
+ client-1 {
+ ...
+ pinctrl-0 = <&node-1>;
+ ...
+ };
+
+ client-2 {
+ ...
+ pinctrl-0 = <&node-2>;
+ ...
+ };
+
+ Required properties:
+ - pinmux:
+ integer array representing pin number and pin multiplexing configuration.
+ When a pin has to be configured in alternate function mode, use this
+ property to identify the pin by its global index, and provide its
+ alternate function configuration number along with it.
+ When multiple pins are required to be configured as part of the same
+ alternate function they shall be specified as members of the same
+ argument list of a single "pinmux" property.
+ Helper macros to ease assembling the pin index from its position
+ (port where it sits on and pin number) and alternate function identifier
+ are provided by the pin controller header file at:
+ <include/dt-bindings/pinctrl/r7s72100-pinctrl.h>
+ Integers values in "pinmux" argument list are assembled as:
+ ((PORT * 16 + PIN) | MUX_FUNC << 16)
+
+ Optional generic properties:
+ - input-enable:
+ enable input bufer for pins requiring software driven IO input
+ operations.
+ - output-high:
+ enable output buffer for pins requiring software driven IO output
+ operations. output-low can be used alternatively, as line value is
+ ignored by the driver.
+
+ The hardware reference manual specifies when a pin has to be configured to
+ work in bi-directional mode and when the IO direction has to be specified
+ by software. Bi-directional pins are managed by the pin controller driver
+ internally, while software driven IO direction has to be explicitly
+ selected when multiple options are available.
+
+ Example:
+ A serial communication interface with a TX output pin and an RX input pin.
+
+ &pinctrl {
+ scif2_pins: serial2 {
+ pinmux = <RZA1_PINMUX(3, 0, 6)>, <RZA1_PINMUX(3, 2, 4)>;
+ };
+ };
+
+ Pin #0 on port #3 is configured as alternate function #6.
+ Pin #2 on port #3 is configured as alternate function #4.
+
+ Example 2:
+ I2c master: both SDA and SCL pins need bi-directional operations
+
+ &pinctrl {
+ i2c2_pins: i2c2 {
+ pinmux = <RZA1_PINMUX(1, 4, 1)>, <RZA1_PINMUX(1, 5, 1)>;
+ };
+ };
+
+ Pin #4 on port #1 is configured as alternate function #1.
+ Pin #5 on port #1 is configured as alternate function #1.
+ Both need to work in bi-directional mode, the driver manages this internally.
+
+ Example 3:
+ Multi-function timer input and output compare pins.
+ Configure TIOC0A as software driven input and TIOC0B as software driven
+ output.
+
+ &pinctrl {
+ tioc0_pins: tioc0 {
+ tioc0_input_pins {
+ pinumx = <RZA1_PINMUX(4, 0, 2)>;
+ input-enable;
+ };
+
+ tioc0_output_pins {
+ pinmux = <RZA1_PINMUX(4, 1, 1)>;
+ output-enable;
+ };
+ };
+ };
+
+ &tioc0 {
+ ...
+ pinctrl-0 = <&tioc0_pins>;
+ ...
+ };
+
+ Pin #0 on port #4 is configured as alternate function #2 with IO direction
+ specified by software as input.
+ Pin #1 on port #4 is configured as alternate function #1 with IO direction
+ specified by software as output.
+
+- GPIO controller sub-nodes:
+ Each port of the r7s72100 pin controller hardware is itself a GPIO controller.
+ Different SoCs have different numbers of available pins per port, but
+ generally speaking, each of them can be configured in GPIO ("port") mode
+ on this hardware.
+ Describe GPIO controllers using sub-nodes with the following properties.
+
+ Required properties:
+ - gpio-controller
+ empty property as defined by the GPIO bindings documentation.
+ - #gpio-cells
+ number of cells required to identify and configure a GPIO.
+ Shall be 2.
+ - gpio-ranges
+ Describes a GPIO controller specifying its specific pin base, the pin
+ base in the global pin numbering space, and the number of controlled
+ pins, as defined by the GPIO bindings documentation. Refer to
+ Documentation/devicetree/bindings/gpio/gpio.txt file for a more detailed
+ description.
+
+ Example:
+ A GPIO controller node, controlling 16 pins indexed from 0.
+ The GPIO controller base in the global pin indexing space is pin 48, thus
+ pins [0 - 15] on this controller map to pins [48 - 63] in the global pin
+ indexing space.
+
+ port3: gpio-3 {
+ gpio-controller;
+ #gpio-cells = <2>;
+ gpio-ranges = <&pinctrl 0 48 16>;
+ };
+
+ A device node willing to use pins controlled by this GPIO controller, shall
+ refer to it as follows:
+
+ led1 {
+ gpios = <&port3 10 GPIO_ACTIVE_LOW>;
+ };
--
2.7.4
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