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 | 143 +++++++++++++++++++++ 1 file changed, 143 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..69aafd1 --- /dev/null +++ b/Documentation/devicetree/bindings/pinctrl/renesas,rza1-pinctrl.txt @@ -0,0 +1,143 @@ +Renesas RZ/A1 combined Pin and GPIO controller + +The Renesas SoCs of RZ/A1 family feature a combined Pin and GPIO controller +hardware 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". + + - #pinctrl-cells + as defined by pinctrl-bindings.txt, this is the number + of cells (in addition to pin index) required to configure a single pin. + Shall be set to 1. + + - reg + address base and length of the memory area where pin controller + hardware is mapped to. + +Example: +Pin controller node for RZ/A1H SoC (r7s72100) + +pinctrl: pinctrl@fcfe3000 { + compatible = "renesas,r7s72100-ports"; + + #pinctrl-cells = <1>; + + 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 groups. + + Required properties: + - renesas,pins + describes an array of pin multiplexing configurations. + 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 description along with it. + When multiple pins are required to be configured as part of the same + alternate function (odds are single-pin alternate functions exist) they + shall be specified as members of the same argument list of a single + "renesas-pins" property. + Helper macros to ease calculating the pin index from its position + (port where it sits on and pin offset), and alternate function + configuration options are provided in the pin controller header file at: + include/dt-bindings/pinctrl/r7s72100-pinctrl.h + + Example: + A serial communication interface with a TX output pin and an RX input pin. + + &pinctrl { + scif2_pins: serial2 { + renesas,pins = <PIN(3, 0) 6>, <PIN(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 { + renesas,pins = <PIN(1, 4) (1 | BI_DIR)>, + <PIN(1, 5) (1 | BI_DIR)>; + }; + } + + 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. + + Example 3: + Multi-function timer input and output compare pins. + The hardware manual prescribes this pins to have input/output direction + specified by software. Configure TIOC0A as input and TIOC0B as output. + + &pinctrl { + tioc0_pins: tioc0 { + renesas,pins = <PIN(4, 0) (2 | SWIO_IN)>, + <PIN(4, 1) (2 | SWIO_OUT)>; + }; + } + + 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 number 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 this 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 -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html