linux-kernel - Re: [PATCH v3 07/11] dt-bindings: tegra: Update DFLL binding for PWM regulator

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Date:   Fri, 9 Feb 2018 17:19:54 -0600
From:   Rob Herring <robh@...nel.org>
To:     Peter De Schrijver <pdeschrijver@...dia.com>
Cc:     linux-tegra@...r.kernel.org, linux-clk@...r.kernel.org,
        mturquette@...libre.com, sboyd@...eaurora.org,
        mark.rutland@....com, devicetree@...r.kernel.org,
        lgirdwood@...il.com, broonie@...nel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3 07/11] dt-bindings: tegra: Update DFLL binding for PWM
 regulator

On Tue, Feb 06, 2018 at 06:34:08PM +0200, Peter De Schrijver wrote:
> Add new properties to configure the DFLL PWM regulator support. Also
> add an example and make the I2C clock only required when I2C support is
> used.
> 
> Signed-off-by: Peter De Schrijver <pdeschrijver@...dia.com>
> ---
>  .../bindings/clock/nvidia,tegra124-dfll.txt        | 76 +++++++++++++++++++++-
>  1 file changed, 74 insertions(+), 2 deletions(-)
> 
> diff --git a/Documentation/devicetree/bindings/clock/nvidia,tegra124-dfll.txt b/Documentation/devicetree/bindings/clock/nvidia,tegra124-dfll.txt
> index dff236f..a4903f7 100644
> --- a/Documentation/devicetree/bindings/clock/nvidia,tegra124-dfll.txt
> +++ b/Documentation/devicetree/bindings/clock/nvidia,tegra124-dfll.txt
> @@ -23,7 +23,8 @@ Required properties:
>  - clock-names: Must include the following entries:
>    - soc: Clock source for the DFLL control logic.
>    - ref: The closed loop reference clock
> -  - i2c: Clock source for the integrated I2C master.
> +  - i2c: Clock source for the integrated I2C master (only required when
> +	 using I2C mode).
>  - resets: Must contain an entry for each entry in reset-names.
>    See ../reset/reset.txt for details.
>  - reset-names: Must include the following entries:
> @@ -45,10 +46,28 @@ Required properties for the control loop parameters:
>  Optional properties for the control loop parameters:
>  - nvidia,cg-scale: Boolean value, see the field DFLL_PARAMS_CG_SCALE in the TRM.
>  
> +Optional properties for mode selection:
> +- nvidia,pwm-to-pmic: Use PWM to control regulator rather then I2C.
> +
>  Required properties for I2C mode:
>  - nvidia,i2c-fs-rate: I2C transfer rate, if using full speed mode.
>  
> -Example:
> +Required properties for PWM mode:
> +- nvidia,pwm-period: period of PWM square wave in us.

Add standard unit suffix.

> +- nvidia,init-uv: Regulator voltage in uV when PWM control is disabled.
> +- nvidia,align-offset-uv: Regulator voltage in uV when PWM control is enabled
> +			  and PWM output is low.
> +- nvidia,align-step-uv: Voltage increase in uV corresponding to a 1/33th

Use the standard unit suffix, not a custom one. See property-units.txt.

> +			increase in duty cycle. Eg the voltage for 2/33th duty
> +			cycle would be:
> +			nvidia,align-offset-uv + nvidia,align-step-uv * 2.
> +- pinctrl-0: I/O pad configuration when PWM control is enabled.
> +- pinctrl-1: I/O pad configuration when PWM control is disabled.
> +- pinctrl-names: must include the following entries:
> +  - dvfs_pwm_enable: I/O pad configuration when PWM control is enabled.
> +  - dvfs_pwm_disable: I/O pad configuration when PWM control is disabled.
> +
> +Example for I2C:
>  
>  clock@...10000 {
>          compatible = "nvidia,tegra124-dfll";
> @@ -76,3 +95,56 @@ clock@...10000 {
>  
>          nvidia,i2c-fs-rate = <400000>;
>  };
> +
> +Example for PWM:
> +
> +clock@...10000 {
> +        compatible = "nvidia,tegra124-dfll";
> +        reg = <0 0x70110000 0 0x100>, /* DFLL control */
> +              <0 0x70110000 0 0x100>, /* I2C output control */
> +              <0 0x70110100 0 0x100>, /* Integrated I2C controller */
> +              <0 0x70110200 0 0x100>; /* Look-up table RAM */
> +        interrupts = <GIC_SPI 62 IRQ_TYPE_LEVEL_HIGH>;
> +        clocks = <&tegra_car TEGRA210_CLK_DFLL_SOC>,
> +                 <&tegra_car TEGRA210_CLK_DFLL_REF>;
> +        clock-names = "soc", "ref";
> +        resets = <&tegra_car TEGRA124_RST_DFLL_DVCO>;
> +        reset-names = "dvco";
> +        #clock-cells = <0>;
> +        clock-output-names = "dfllCPU_out";
> +	nvidia,pwm-to-pmic;
> +	nvidia,init-uv = <1000000>;
> +	nvidia,align-step-uv = <19200>; /* 19.2mV */
> +	nvidia,align-offset-uv = <708000>; /* 708mV */
> +	nvidia,sample-rate = <25000>;
> +	nvidia,droop-ctrl = <0x00000f00>;
> +	nvidia,force-mode = <1>;
> +	nvidia,cf = <6>;
> +	nvidia,ci = <0>;
> +	nvidia,cg = <2>;
> +	nvidia,idle-override;
> +	nvidia,one-shot-calibrate;
> +	nvidia,pwm-period = <2500>; /* 2.5us */
> +	pinctrl-names = "dvfs_pwm_enable", "dvfs_pwm_disable";
> +	pinctrl-0 = <&dvfs_pwm_active_state>;
> +	pinctrl-1 = <&dvfs_pwm_inactive_state>;
> +};
> +
> +/* pinmux nodes added for completeness. Binding doc can be found in:
> + * Documentation/devicetree/bindings/pinctrl/nvidia,tegra210-pinmux.txt
> + */
> +
> +pinmux: pinmux@...008d4 {
> +	dvfs_pwm_active_state: dvfs_pwm_active {
> +		dvfs_pwm_pbb1 {
> +			nvidia,pins = "dvfs_pwm_pbb1";
> +			nvidia,tristate = <TEGRA_PIN_DISABLE>;
> +		};
> +	};
> +	dvfs_pwm_inactive_state: dvfs_pwm_inactive {
> +		dvfs_pwm_pbb1 {
> +			nvidia,pins = "dvfs_pwm_pbb1";
> +			nvidia,tristate = <TEGRA_PIN_ENABLE>;
> +		};
> +	};
> +};
> -- 
> 1.9.1
>