Re: [PATCH 4/4] Documentation: Add device tree bindings for Freescale FTM PWM

[Kumar Gala <galak@kernel.crashing.org>]

Should have at least something w/regards to a commit message.

On Aug 20, 2013, at 10:07 PM, Xiubo Li wrote:

> Signed-off-by: Xiubo Li <Li.Xiubo@freescale.com>
> ---
> .../devicetree/bindings/pwm/fsl-ftm-pwm.txt        | 52 ++++++++++++++++++++++
> 1 file changed, 52 insertions(+)
> create mode 100644 Documentation/devicetree/bindings/pwm/fsl-ftm-pwm.txt
> 
> diff --git a/Documentation/devicetree/bindings/pwm/fsl-ftm-pwm.txt b/Documentation/devicetree/bindings/pwm/fsl-ftm-pwm.txt
> new file mode 100644
> index 0000000..698965b
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/pwm/fsl-ftm-pwm.txt
> @@ -0,0 +1,52 @@
> +Freescale FTM PWM controller
> +
> +Required properties:
> +- compatible: should be "fsl,vf610-ftm-pwm"
> +- reg: physical base address and length of the controller's registers
> +- #pwm-cells: Should be 3. Number of cells being used to specify PWM property.
> +  First cell specifies the per-chip channel index of the PWM to use, the
> +  second cell is the period in nanoseconds and bit 0 in the third cell is
> +  used to encode the polarity of PWM output. Set bit 0 of the third in PWM
> +  specifier to 1 for inverse polarity & set to 0 for normal polarity.
> +- fsl,pwm-clk-ps: the ftm0 pwm clock's prescaler, divide-by 2^n(n = 0 ~ 7).
> +- fsl,pwm-cpwm: Center-Aligned PWM (CPWM) mode.

Should describe this in more detail, what does the value actually mean for what modes there are?

> +- fsl,pwm-number: the number of PWM devices, and is must equal to the number
> +  of "fsl,pwm-channels".

If they must be equal why do we need both?

> +- fsl,pwm-channels: the channels' order which is be used for pwm in ftm0
> +  module, and they must be one or some of 0 ~ 7, because the ftm0 only has
> +  8 channels can be used.
> +- for very channel, the revlatived the pinctrl should be at least two state

revlatived?

> +  {"enN", "dsN"}, which "en" means "enable", "ds" means "disable" and "N"
> +  means the order of the channel.
> +
> +Example:
> +
> +pwm0: pwm@40038000 {
> +	      compatible = "fsl,vf610-ftm-pwm";
> +	      reg = <0x40038000 0x1000>;
> +	      #pwm-cells = <3>;
> +	      pinctrl-names = "en0", "ds0", "en3", "ds3";
> +	      pinctrl-0 = <&pinctrl_pwm0_ch0_en>;
> +	      pinctrl-1 = <&pinctrl_pwm0_ch0_ds>;
> +	      pinctrl-2 = <&pinctrl_pwm0_ch3_en>;
> +	      pinctrl-3 = <&pinctrl_pwm0_ch3_ds>;
> +	      fsl,pwm-clk-ps = <7>;
> +	      fsl,pwm-cpwm = <0>;
> +	      fsl,pwm-number = <2>;
> +	      fsl,pwm-channels = <0 3>;
> +	      ...
> +      };
> +
> +leds {
> +	compatible = "pwm-leds";
> +	led {
> +		label = "fsl_led";
> +		pwms = <&pwm0 0 10000000 0>;
> +		max-brightness = <127>;
> +	};
> +	backlight {
> +		label = "fsl_backlight";
> +		pwms = <&pwm0 3 10000000 1>;
> +		max-brightness = <100>;
> +	};
> +};
> -- 
> 1.8.0
> 
> 
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