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:

quoted

Provide a simple driver for PWM controllable vibrators. It
will be used by Motorola Droid 4.

Tested-by: Tony Lindgren <redacted>
Signed-off-by: Sebastian Reichel <sebastian.reichel-ZGY8ohtN/8pPYcu2f3hruQ@public.gmane.org>
---
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/

quoted

+     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.

quoted

+- 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.

quoted

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

-- Sebastian

quoted

+
+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";
+	};
+};