On Mon, Feb 13, 2017 at 10:19:35PM -0800, Jaghathiswari Rankappagounder
Natarajan wrote:
> This binding provides interface for adding values related to ASPEED
> AST2400/2500 PWM and Fan tach controller support.
> The PWM controller can support upto 8 PWM output ports.
> The Fan tach controller can support upto 16 tachometer inputs.
>
> Signed-off-by: Jaghathiswari Rankappagounder Natarajan <ja...@google.com>
> ---
> v3:
> Made the structure more common
>
> .../devicetree/bindings/hwmon/aspeed-pwm-tacho.txt | 73
> ++++++++++++++++++++++
> 1 file changed, 73 insertions(+)
> create mode 100644
> Documentation/devicetree/bindings/hwmon/aspeed-pwm-tacho.txt
>
> diff --git a/Documentation/devicetree/bindings/hwmon/aspeed-pwm-tacho.txt
> b/Documentation/devicetree/bindings/hwmon/aspeed-pwm-tacho.txt
> new file mode 100644
> index 000000000000..c2de3709e554
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/hwmon/aspeed-pwm-tacho.txt
> @@ -0,0 +1,73 @@
> +ASPEED AST2400/AST2500 PWM and Fan Tacho controller device driver
> +
> +The ASPEED PWM controller can support upto 8 PWM outputs. The ASPEED Fan
> Tacho
> +controller can support upto 16 Fan tachometer inputs.
> +
> +There can be upto 8 fans supported. Each fan can have one PWM output and
> +one/two Fan tach inputs.
> +
> +Required properties for pwm-tacho node:
> +- #address-cells : should be 1.
> +
> +- #size-cells : should be 1.
> +
> +- reg : address and length of the register set for the device.
> +
> +- pinctrl-names : a pinctrl state named "default" must be defined.
> +
> +- pinctrl-0 : phandle referencing pin configuration of the PWM ports.
> +
> +- compatible : should be "aspeed,aspeed2400-pwm-tacho" for AST2400 or
> + "aspeed,aspeed2500-pwm-tacho" for AST2500.
> +
> +- clocks : a fixed clock providing input clock frequency(PWM
> + and Fan Tach clock)
> +
> +fan subnode format:
> +========================
> +Under fan subnode there can upto 8 child nodes, with each child node
> +representing a fan. If there are 8 fans each fan can have one PWM port and
> +one/two Fan tach inputs.
> +
> +Required properties for each child node(starting from PWM A through PWM H):
> +- pwm-port : should specify PWM source port.
> + integer value in the range 0 to 7 with 0 indicating PWM port
> + A and 7 indicating PWM port H.
> +
> +- fan-ctrl-gpios : should specify the tachometer input GPIO pin on the
> hardware.
> + Fan Tachometer function can only work when GPIO is in
> + ”input mode”.
This still sounds like pin muxing, not actual GPIO usage.
> +
> +- fan-tach-ch : should specify the Fan tach input channel.
> + integer value in the range 0 through 15, with 0 indicating
> + Fan tach channel 0 and 15 indicating Fan tach channel 15.
> +
> +Examples:
> +
> +pwm-tacho-fixed-clk: fixedclk {
> + compatible = "fixed-clock";
> + #clock-cells = <0>;
> + clock-frequency = <24000000>;
> +}
> +
> +pwm-tacho: pwm-tacho-controller@1e786000 {
> + #address-cells = <1>;
> + #size-cells = <1>;
> + reg = <0x1E786000 0x1000>;
> + compatible = "aspeed,aspeed2500-pwm-tacho";
> + clocks = <&pwm-tacho-fixed-clk>;
> + pinctrl-names = "default";
> + pinctrl-0 = <&pinctrl_pwm0_default &pinctrl_pwm1_default>;
> +
> + fan0 {
> + pwm-port = /bits/ 8 <0x00>;
Since fans and pwms are 1-1, I'd just use reg here.
I still think this should probably use PWM binding, but given this is
all self contained it is okay.
> + fan-ctrl-gpios = <&gpio ASPEED_GPIO(O, 0) GPIO_ACTIVE_HIGH>;
> + fan-tach-ch = /bits/ 8 <0x00>;
> + };
> +
> + fan1 {
> + pwm-port = /bits/ 8 <0x01>;
> + fan-ctrl-gpios = <&gpio ASPEED_GPIO(O, 1) GPIO_ACTIVE_HIGH>;
> + fan-tach-ch = /bits/ 8 <0x01>;
> + };
> +};
> --
> 2.11.0.483.g087da7b7c-goog
>
