Re: [PATCH 1/3] dt-bindings: pwm: msm-vibrator: new bindings for MSM vibrator driver

From: Brian Masney <masneyb@onstation.org>
To: Rob Herring <robh@kernel.org>
Cc: thierry.reding@gmail.com, linux-pwm@vger.kernel.org,
	andy.gross@linaro.org, david.brown@linaro.org,
	mark.rutland@arm.com, linux-arm-msm@vger.kernel.org,
	linux-soc@vger.kernel.org, devicetree@vger.kernel.org,
	linux-kernel@vger.kernel.org, sebastian.reichel@collabora.co.uk
Subject: Re: [PATCH 1/3] dt-bindings: pwm: msm-vibrator: new bindings for MSM vibrator driver
Date: Tue, 25 Sep 2018 16:40:02 -0400	[thread overview]
Message-ID: <20180925204002.upoxfm5udmepgz4e@232b6f9c30d0> (raw)
In-Reply-To: <5baa1af9.1c69fb81.73ad9.3bd5@mx.google.com>

Hi Rob,

On Mon, Sep 24, 2018 at 03:01:11PM -0700, Rob Herring wrote:
> On Wed, Sep 19, 2018 at 11:09:10AM -0400, Brian Masney wrote:
> > This patch adds the device tree bindings for the pwm-msm-vibrator.c
> > driver that supports the vibrator found on various Qualcomm MSM SOCs.
> 
> Bindings are for h/w, not some driver.

OK, I will fix this and the other references in v2.

> > +Required properties:
> > +
> > +  - compatible: Should be one of
> > +		"qcom,msm8226-pwm-vibrator"
> > +		"qcom,msm8974-pwm-vibrator"
> 
> The block only works for a vibrator?

Yes.

I cannot find a publicly-available datasheet for the MSM8974 to see if
there are other uses for this particular PWM available. The only thing
that I have to work with right now is the downstream Android sources at
https://android.googlesource.com/kernel/msm/+/android-msm-lenok-3.10-lollipop-wear-release/drivers/misc/msm_pwm_vibrator.c.

> > +  - reg: the base address and length of the IO memory for the registers.
> > +  - #pwm-cells: set to 3.
> > +  - pinctrl-names: set to default.
> > +  - pinctrl-0: phandles pointing to pin configuration nodes. See
> > +               Documentation/devicetree/bindings/pinctrl/pinctrl-bindings.txt
> > +  - clock-names: set to pwm
> > +  - clocks: phandle of the clock used by the PWM module. See
> > +            Documentation/devicetree/bindings/clock/clock-bindings.txt
> > +  - enable-gpios: GPIO that enables the vibrator.
> 
> Shouldn't this go in the vibrator node as it is connected to the 
> vibrator.

This should be labeled "GPIO that enables the PWM".

Brian

> > +
> > +Optional properties:
> > +
> > +  - vcc-supply: phandle to the regulator that provides power to the sensor.
> > +
> > +Example from a LG Nexus 5 (hammerhead) phone:
> > +
> > +msm_pwm_vibrator_enable: msm_pwm_vibrator@fd8c3450 {
> 
> pwm@...
> 
> > +	reg = <0xfd8c3450 0x400>;
> > +	compatible = "qcom,msm8974-pwm-vibrator";
> > +	#pwm-cells = <3>;
> > +
> > +	vcc-supply = <&pm8941_l19>;
> > +
> > +	clocks = <&mmcc CAMSS_GP1_CLK>;
> > +	clock-names = "pwm";
> > +
> > +	enable-gpios = <&msmgpio 60 GPIO_ACTIVE_HIGH>;
> > +
> > +	pinctrl-names = "default";
> > +	pinctrl-0 = <&vibrator_pin>;
> > +};
> > -- 
> > 2.17.1
> > 