Hi, The Motorola Droid 4 has a vibrator, that is connected to two GPIOs. Motorola's stock kernel names them vib_en and vib_dir, which probably stand for vibrator_enable and vibrator_direction. In their stock kernel both GPIOs are toggled using a hrtimer and a custom vibrator "misc" device is provided to userspace. Thankfully the hardware designers the used GPIOs can also be used from OMAP's dmtimers, so that they can be driven as PWM output instead saving some CPU cycles (and code). The driver is loosely based on an old patch from Dmitry, that I found in the internet(tm) [0]. Since PATCHv4 the Droid 4 also uses the generic PWM compatible and the one specific to Motorola has been dropped. Also I wrote a small tool to test the vibrator running at different strength levels, since fftest(1) used a fixed one. Changes since PATCHv3: * Fix kernel doc comment * Use switch for error handling of direction pwm * Drop spin_lock_irqsave in suspend/resume handler * Drop Droid 4 specific code & binding * Add direction-duty-cycle-ns DT property * Dropped Tested-by due to restructuring Changes since PATCHv2: * Add Kconfig dependency on INPUT_FF_MEMLESS * Add Tested-by from Tiny Lindgren 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 [0] https://lkml.org/lkml/2012/4/10/41 [1] https://git.collabora.com/cgit/user/sre/rumble-test.git/plain/rumble-test.c -- Sebastian Sebastian Reichel (3): dt-bindings: input: add pwm-vibrator Input: pwm-vibra: new driver ARM: dts: omap4-droid4: Add vibrator .../devicetree/bindings/input/pwm-vibrator.txt | 66 +++++ arch/arm/boot/dts/omap4-droid4-xt894.dts | 40 +++ drivers/input/misc/Kconfig | 12 + drivers/input/misc/Makefile | 1 + drivers/input/misc/pwm-vibra.c | 267 +++++++++++++++++++++ 5 files changed, 386 insertions(+) create mode 100644 Documentation/devicetree/bindings/input/pwm-vibrator.txt create mode 100644 drivers/input/misc/pwm-vibra.c -- 2.13.2 -- To unsubscribe from this list: send the line "unsubscribe linux-input" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
