Re: [PATCH v4 1/2] dt-binding: hwmon: Add NPCM7xx PWM and Fan controller documentation

[Tomer Maimon <tmaimon77@gmail.com>]

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Hi Rob,


On 25 June 2018 at 20:14, Rob Herring <robh@kernel.org> wrote:

> On Sun, Jun 24, 2018 at 03:41:54PM +0300, Tomer Maimon wrote:
> > Added device tree binding documentation for Nuvoton BMC
> > NPCM7xx Pulse Width Modulation (PWM)  and Fan tach controller.
> > The PWM controller can support upto 8 PWM output ports.
> > The Fan tach controller can support upto 16 tachometer inputs.
> >
> > Signed-off-by: Tomer Maimon <tmaimon77@gmail.com>
> > ---
> >  .../devicetree/bindings/hwmon/npcm750-pwm-fan.txt  | 84
> ++++++++++++++++++++++
> >  1 file changed, 84 insertions(+)
> >  create mode 100644 Documentation/devicetree/bindings/hwmon/npcm750-pwm-
> fan.txt
> >
> > diff --git a/Documentation/devicetree/bindings/hwmon/npcm750-pwm-fan.txt
> b/Documentation/devicetree/bindings/hwmon/npcm750-pwm-fan.txt
> > new file mode 100644
> > index 000000000000..a9eacda34f92
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/hwmon/npcm750-pwm-fan.txt
> > @@ -0,0 +1,84 @@
> > +Nuvoton NPCM7xx PWM and Fan Tacho controller device driver
>
> Bindings are for h/w, not drivers.
>
> > +
> > +The NPCM7xx has two identical Pulse-width modulation (PWM) controller
> modules,
> > +Each PWM module has four PWM controller outputs, Totally 8 PWM
> controller outputs.
> > +
> > +The NPCM7xx has eight identical Fan tachometer controller modules,
> > +Each Fan module has two Fan controller inputs, Totally 16 Fan
> controller inputs.
>
> Have you looked at other fan ctrlr bindings?f This looks like similar
> h/w to ASpeed. Really, I'd like to see a common doc that describes the
>

We do not have the same H/W as Aspeed, I believe in the near future we will
need to add
more DT properties that will used only in the NPCM7xx module.

structure and common properties.
>

what do you mean by common structure and common properties?


> > +
> > +Required properties for pwm-fan node:
> > +- compatible : "nuvoton,npcm750-pwm-fan" for Poleg NPCM7XX.
> > +- reg                        : specifies physical base address and size
> of the registers.
> > +- reg-names  : must contain:
> > +                                     * "pwm-base" for the PWM registers.
> > +                                     * "fan-base" for the Fan registers.
>
> '-base' is redundant. And your example doesn't match.
>
> > +- clocks             : phandle of reference clocks.
> > +- clock-names        : must contain
> > +                                     * "clk_apb3" for clock of PWM
> controller.
> > +                                     * "clk_apb4" for clock of Fan
> controller.
> > +- interrupts : contain the Fan interrupts with flags for falling edge.
> > +- pinctrl-names      : a pinctrl state named "default" must be defined.
> > +- pinctrl-0  : phandle referencing pin configuration of the PWM and Fan
> > +                                     controller ports.
> > +
> > +pwm subnode format:
> > +===================
> > +Under pwm subnode can be upto 8 child nodes, each child node
> representing a PWM channel.
> > +Each pwm subnode must have one PWM channel and atleast one Fan tach
> channel.
> > +
> > +For PWM channel can be configured cooling-levels to create cooling
> device.
> > +Cooling device could be bound to a thermal zone for the thermal control.
> > +
> > +Required properties for each child node:
> > +- pwm-ch : specify the PWM output channel.
> > +                     integer value in the range 0 through 7, that
> represent
> > +                     the PWM channel number that used.
> > +
> > +- fan-ch : specify the Fan input channel.
> > +                     integer value in the range 0 through 15, that
> represent
> > +                     the Fan channel number that used.
>
> This is really the tach channel.
>
>
> > +
> > +                     At least one Fan tach input channel is required
> > +
> > +Optional property for each child node:
> > +- cooling-levels: PWM duty cycle values in a range from 0 to 255
> > +                  which correspond to thermal cooling states.
> > +
> > +Examples:
> > +
> > +pwm_fan:pwm_fan_controller@103000 {
>
> fan-controller@...
>
> > +     compatible = "nuvoton,npcm750-pwm-fan";
> > +     reg = <0x103000 0x2000>,
> > +             <0x180000 0x8000>;
> > +     reg-names = "pwm_base", "fan_base";
> > +     clocks = <&clk NPCM7XX_CLK_APB3>,
> > +             <&clk NPCM7XX_CLK_APB4>;
> > +     clock-names = "clk_apb3","clk_apb4";
> > +     interrupts = <GIC_SPI 96 IRQ_TYPE_LEVEL_HIGH>,
> > +                     <GIC_SPI 97 IRQ_TYPE_LEVEL_HIGH>,
> > +                     <GIC_SPI 98 IRQ_TYPE_LEVEL_HIGH>,
> > +                     <GIC_SPI 99 IRQ_TYPE_LEVEL_HIGH>,
> > +                     <GIC_SPI 100 IRQ_TYPE_LEVEL_HIGH>,
> > +                     <GIC_SPI 101 IRQ_TYPE_LEVEL_HIGH>,
> > +                     <GIC_SPI 102 IRQ_TYPE_LEVEL_HIGH>,
> > +                     <GIC_SPI 103 IRQ_TYPE_LEVEL_HIGH>;
> > +     pinctrl-names = "default";
> > +     pinctrl-0 = <&pwm0_pins &pwm1_pins &pwm2_pins
> > +                     &fanin0_pins &fanin1_pins &fanin2_pins
> > +                     &fanin3_pins &fanin4_pins>;
> > +
> > +                     pwm@0 {
>
> The sub-nodes should be "fan" nodes.
>
> A unit-address without reg property is not valid.
>
> > +                             pwm-ch = /bits/ 8 <0x00>;
>
> Use 'reg' like ASpeed binding.
>
> > +                             fan-ch = /bits/ 8 <0x00 0x01>;
> > +                             cooling-levels = <127 255>;
> > +                             };
> > +                     pwm@1 {
> > +                             pwm-ch = /bits/ 8 <0x01>;
> > +                             fan-ch = /bits/ 8 <0x02 0x03>;
> > +                             };
> > +                     pwm@2 {
> > +                             pwm-ch = /bits/ 8 <0x02>;
> > +                             fan-ch = /bits/ 8 <0x04>;
> > +                             };
> > +
> > +};
> > \ No newline at end of file
>
> ^^^
>
> > --
> > 2.14.1
> >
> > --
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Thanks!

Tomer

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