Re: [PATCH v1 2/5] dt-bindings: clock: renesas,r9a06g032-pinctrl: documentation

From: jacopo mondi
Date: Thu Jun 14 2018 - 08:05:07 EST


Hi Michel,

On Thu, Jun 14, 2018 at 12:00:18PM +0100, Michel Pollet wrote:
> The Renesas R9A06G032 PINCTRL node description.
>
> Signed-off-by: Michel Pollet <michel.pollet@xxxxxxxxxxxxxx>
> ---
> .../bindings/pinctrl/renesas,r9a06g032-pinctrl.txt | 124 +++++++++++++++++++++
> 1 file changed, 124 insertions(+)
> create mode 100644 Documentation/devicetree/bindings/pinctrl/renesas,r9a06g032-pinctrl.txt
>
> diff --git a/Documentation/devicetree/bindings/pinctrl/renesas,r9a06g032-pinctrl.txt b/Documentation/devicetree/bindings/pinctrl/renesas,r9a06g032-pinctrl.txt
> new file mode 100644
> index 0000000..f63696f
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/pinctrl/renesas,r9a06g032-pinctrl.txt
> @@ -0,0 +1,124 @@
> +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.

This is a plain copy of the RZ/A1 pin controller documentation.
I don't know RZ/N devices and cannot tell if it applies here too, but
this needs an s/A1/N at the least.

From a very superficial look at the proposed bindings and pinctrl
driver, I wonder if the rza1 pinctrl driver could be expanded and re-used.
Have you considered that before starting one from scratch?

Thanks
j

> +
> +Pin controller node
> +-------------------
> +
> +Required properties:
> + - compatible: should be:
> + - "renesas,r9a05g032-pinctrl"
> + - reg
> + address base and length of the memory area where the pin controller
> + hardware is mapped to.
> +
> +Example:
> + pinctrl: pinctrl@40067000 {
> + compatible = "renesas,r9a06g032-pinctrl";
> + reg = <0x40067000 0x1000>, <0x51000000 0x800>;
> + clocks = <&sysctrl R9A06G032_HCLK_PINCONFIG>;
> + clock-names = "bus";
> + status = "okay";
> + };
> +
> +
> +Sub-nodes
> +---------
> + The child nodes of the pin controller node describe a pin multiplexing
> + group that can be used by driver 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.
> +
> + The allowed generic formats for a pin multiplexing sub-node are the
> + following ones:
> +
> + 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:
> + - renesas,rzn1-pinctrl:
> + Array of integers representing each 'pin' and it's configuration.
> +
> + A 'pin number' does not correspond 1:1 to the hardware manual notion of
> + PL_GPIO directly. Numbers 0...169 are PL_GPIOs, however there is also two
> + extra 170 and 171 that corresponds to the MDIO0 and MDIO1 bus config.
> +
> + A 'function' also does not correspond 1:1 to the hardware manual. There
> + are 2 levels of pin muxing, Level 1, level 2 -- to this are added the
> + MDIO configurations.
> +
> + Helper macros to ease assembling the pin index and function identifier
> + are provided by the pin controller header file at:
> + <include/dt-bindings/pinctrl/r9a06g032-pinctrl.h>
> +
> +Example #1:
> + A simple case configuring only the function for a given 'pin' works as follow:
> + #include <include/dt-bindings/pinctrl/r9a06g032-pinctrl.h>
> + &pinctrl {
> + pinsuart0: pinsuart0 {
> + renesas,rzn1-pinmux-ids = <
> + RZN1_MUX(103, UART0_I) /* UART0_TXD */
> + RZN1_MUX(104, UART0_I) /* UART0_RXD */
> + >;
> + };
> + };
> +
> + &uart0 {
> + status = "okay";
> + pinctrl-names = "default";
> + pinctrl-0 = <&pinsuart0>;
> + };
> + Note that in this case the other functions of the pins are not changed.
> +
> +Example #2:
> + Here we also set the pullups on the RXD pin:
> + &pinctrl {
> + pinsuart0: pinsuart0 {
> + renesas,rzn1-pinmux-ids = <
> + RZN1_MUX(103, UART0_I) /* UART0_TXD */
> + RZN1_MUX_PUP(104, UART0_I) /* UART0_RXD */
> + >;
> + };
> + };
> + There are many alternative macros to set the pullup/down/none and the drive
> + strenght in the r9a06g032-pinctrl.h header file.
> +
> +Example #3:
> + The Soc has two configurable MDIO muxes, these can also be configured
> + with this interface using the 'special' MDIO constants:
> +
> + &pinctrl {
> + mdio_mux: mdiomux {
> + renesas,rzn1-pinmux-ids = <
> + RZN1_MUX(RZN1_MDIO_BUS0, RZN1_FUNC_MDIO_MUX_MAC0)
> + RZN1_MUX(RZN1_MDIO_BUS1, RZN1_FUNC_MDIO_MUX_SWITCH)
> + >;
> + };
> + };
> + Clearly the pull/up/none and drive constants will be ignored, even if
> + specified.
> +
> +Note that Renesas provides an extensive webapp that can generates a device tree
> +file for your board. See their website for this part number for details.
> --
> 2.7.4
>

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