Re: [PATCHv3 1/2] Input: pwm-vibra: new driver

From: Sebastian Reichel
Date: Mon May 08 2017 - 14:39:06 EST


Hi Rob,

On Mon, May 08, 2017 at 12:31:21PM -0500, Rob Herring wrote:
> On Fri, May 05, 2017 at 11:28:22AM +0200, Sebastian Reichel wrote:
> > Provide a simple driver for PWM controllable vibrators. It
> > will be used by Motorola Droid 4.
> >
> > Tested-by: Tony Lindgren <tony@xxxxxxxxxxx>
> > Signed-off-by: Sebastian Reichel <sebastian.reichel@xxxxxxxxxxxxxxx>
> > ---
> > Changes since PATCHv1:
> > - move driver removal code to input->close function
> > - mark PM functions __maybe_unused and drop #ifdef CONFIG_PM_SLEEP
> > - remove duplicate NULL check for vibrator in probe function
> > - cancel work in suspend function
> > Changes since PATCHv2:
> > - Add Kconfig dependency on INPUT_FF_MEMLESS
> > - Add Tested-by from Tiny Lindgren
> > ---
> > .../devicetree/bindings/input/pwm-vibrator.txt | 60 ++++
> > drivers/input/misc/Kconfig | 12 +
> > drivers/input/misc/Makefile | 1 +
> > drivers/input/misc/pwm-vibra.c | 343 +++++++++++++++++++++
> > 4 files changed, 416 insertions(+)
> > create mode 100644 Documentation/devicetree/bindings/input/pwm-vibrator.txt
> > create mode 100644 drivers/input/misc/pwm-vibra.c
> >
> > diff --git a/Documentation/devicetree/bindings/input/pwm-vibrator.txt b/Documentation/devicetree/bindings/input/pwm-vibrator.txt
> > new file mode 100644
> > index 000000000000..c35be4691366
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/input/pwm-vibrator.txt
> > @@ -0,0 +1,60 @@
> > +* PWM vibrator device tree bindings
> > +
> > +Registers a PWM device as vibrator.
> > +
> > +Required properties:
> > +- compatible: should be
> > + * "pwm-vibrator"
> > + For vibrators controlled using the PWM channel's duty cycle (higher duty means
> > + the vibrator becomes stronger).
> > + * "motorola,mapphone-pwm-vibrator"
> > + For vibrator found in Motorola Droid 4. This vibrator generates a pulse for
> > + every rising edge, so its controlled using a duty cycle of 50% and changing
>
> s/its/it's/
>
> > + the period time.
>
> What does "controlled" mean? strength? Shorter period is stronger?

well it controls pulses / second. Basically more pulses / second
result in smother vibration effect, but reduced strength.

> > +- pwm-names: Should contain "enable" and optionally "direction"
>
> What does direction mean? Does that apply to both compatibles.

I don't know for sure (I took over the names from stock kernel), but
I assume, that the rotation direction of the vibrator is changed.

> > +- pwms: Should contain a PWM handle for each entry in pwm-names

-- Sebastian

> > +
> > +Example from Motorola Droid 4:
> > +
> > +&omap4_pmx_core {
> > + vibrator_direction_pin: pinmux_vibrator_direction_pin {
> > + pinctrl-single,pins = <
> > + OMAP4_IOPAD(0x1ce, PIN_OUTPUT | MUX_MODE1) /* dmtimer8_pwm_evt (gpio_27) */
> > + >;
> > + };
> > +
> > + vibrator_enable_pin: pinmux_vibrator_enable_pin {
> > + pinctrl-single,pins = <
> > + OMAP4_IOPAD(0X1d0, PIN_OUTPUT | MUX_MODE1) /* dmtimer9_pwm_evt (gpio_28) */
> > + >;
> > + };
> > +};
> > +
> > +/ {
> > + pwm8: dmtimer-pwm {
> > + pinctrl-names = "default";
> > + pinctrl-0 = <&vibrator_direction_pin>;
> > +
> > + compatible = "ti,omap-dmtimer-pwm";
> > + #pwm-cells = <3>;
> > + ti,timers = <&timer8>;
> > + ti,clock-source = <0x01>;
> > + };
> > +
> > + pwm9: dmtimer-pwm {
> > + pinctrl-names = "default";
> > + pinctrl-0 = <&vibrator_enable_pin>;
> > +
> > + compatible = "ti,omap-dmtimer-pwm";
> > + #pwm-cells = <3>;
> > + ti,timers = <&timer9>;
> > + ti,clock-source = <0x01>;
> > + };
> > +
> > + vibrator {
> > + compatible = "pwm-vibrator";
> > + pwms = <&pwm8 0 1000000000 0>,
> > + <&pwm9 0 1000000000 0>;
> > + pwm-names = "enable", "direction";
> > + };
> > +};

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