Input: add a driver for PWM controllable vibrators

Provide a simple driver for PWM controllable vibrators.
It will be used by Motorola Droid 4.
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.co.uk>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

Documentation/devicetree/bindings/input/pwm-vibrator.txt

+* PWM vibrator device tree bindings
+
+Registers a PWM device as vibrator. It is expected, that the vibrator's
+strength increases based on the duty cycle of the enable PWM channel
+(100% duty cycle meaning strongest vibration, 0% meaning no vibration).
+
+The binding supports an optional direction PWM channel, that can be
+driven at fixed duty cycle. If available this is can be used to increase
+the vibration effect of some devices.
+
+Required properties:
+- compatible: should contain "pwm-vibrator"
+- pwm-names: Should contain "enable" and optionally "direction"
+- pwms: Should contain a PWM handle for each entry in pwm-names
+
+Optional properties:
+- vcc-supply: Phandle for the regulator supplying power
+- direction-duty-cycle-ns: Duty cycle of the direction PWM channel in
+                           nanoseconds, defaults to 50% of the channel's
+			   period.
+
+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";
+		direction-duty-cycle-ns = <1000000000>;
+	};
+};

drivers/input/misc/Kconfig

@@ -581,6 +581,18 @@ config INPUT_PWM_BEEPER
 	  To compile this driver as a module, choose M here: the module will be
 	  called pwm-beeper.
 
+config INPUT_PWM_VIBRA
+	tristate "PWM vibrator support"
+	depends on PWM
+	select INPUT_FF_MEMLESS
+	help
+	  Say Y here to get support for PWM based vibrator devices.
+
+	  If unsure, say N.
+
+	  To compile this driver as a module, choose M here: the module will be
+	  called pwm-vibra.
+
 config INPUT_RK805_PWRKEY
 	tristate "Rockchip RK805 PMIC power key support"
 	depends on MFD_RK808

drivers/input/misc/Makefile

@@ -59,6 +59,7 @@ obj-$(CONFIG_INPUT_PM8XXX_VIBRATOR)	+= pm8xxx-vibrator.o
 obj-$(CONFIG_INPUT_PMIC8XXX_PWRKEY)	+= pmic8xxx-pwrkey.o
 obj-$(CONFIG_INPUT_POWERMATE)		+= powermate.o
 obj-$(CONFIG_INPUT_PWM_BEEPER)		+= pwm-beeper.o
+obj-$(CONFIG_INPUT_PWM_VIBRA)		+= pwm-vibra.o
 obj-$(CONFIG_INPUT_RB532_BUTTON)	+= rb532_button.o
 obj-$(CONFIG_INPUT_REGULATOR_HAPTIC)	+= regulator-haptic.o
 obj-$(CONFIG_INPUT_RETU_PWRBUTTON)	+= retu-pwrbutton.o

drivers/input/misc/pwm-vibra.c

+/*
+ *  PWM vibrator driver
+ *
+ *  Copyright (C) 2017 Collabora Ltd.
+ *
+ *  Based on previous work from:
+ *  Copyright (C) 2012 Dmitry Torokhov <dmitry.torokhov@gmail.com>
+ *
+ *  Based on PWM beeper driver:
+ *  Copyright (C) 2010, Lars-Peter Clausen <lars@metafoo.de>
+ *
+ *  This program is free software; you can redistribute it and/or modify it
+ *  under  the terms of the GNU General  Public License as published by the
+ *  Free Software Foundation;  either version 2 of the License, or (at your
+ *  option) any later version.
+ */
+
+#include <linux/input.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+#include <linux/property.h>
+#include <linux/pwm.h>
+#include <linux/regulator/consumer.h>
+#include <linux/slab.h>
+
+struct pwm_vibrator {
+	struct input_dev *input;
+	struct pwm_device *pwm;
+	struct pwm_device *pwm_dir;
+	struct regulator *vcc;
+
+	struct work_struct play_work;
+	u16 level;
+	u32 direction_duty_cycle;
+};
+
+static int pwm_vibrator_start(struct pwm_vibrator *vibrator)
+{
+	struct device *pdev = vibrator->input->dev.parent;
+	struct pwm_state state;
+	int err;
+
+	err = regulator_enable(vibrator->vcc);
+	if (err) {
+		dev_err(pdev, "failed to enable regulator: %d", err);
+		return err;
+	}
+
+	pwm_get_state(vibrator->pwm, &state);
+	pwm_set_relative_duty_cycle(&state, vibrator->level, 0xffff);
+	state.enabled = true;
+
+	err = pwm_apply_state(vibrator->pwm, &state);
+	if (err) {
+		dev_err(pdev, "failed to apply pwm state: %d", err);
+		return err;
+	}
+
+	if (vibrator->pwm_dir) {
+		pwm_get_state(vibrator->pwm_dir, &state);
+		state.duty_cycle = vibrator->direction_duty_cycle;
+		state.enabled = true;
+
+		err = pwm_apply_state(vibrator->pwm_dir, &state);
+		if (err) {
+			dev_err(pdev, "failed to apply dir-pwm state: %d", err);
+			pwm_disable(vibrator->pwm);
+			return err;
+		}
+	}
+
+	return 0;
+}
+
+static void pwm_vibrator_stop(struct pwm_vibrator *vibrator)
+{
+	regulator_disable(vibrator->vcc);
+
+	if (vibrator->pwm_dir)
+		pwm_disable(vibrator->pwm_dir);
+	pwm_disable(vibrator->pwm);
+}
+
+static void pwm_vibrator_play_work(struct work_struct *work)
+{
+	struct pwm_vibrator *vibrator = container_of(work,
+					struct pwm_vibrator, play_work);
+
+	if (vibrator->level)
+		pwm_vibrator_start(vibrator);
+	else
+		pwm_vibrator_stop(vibrator);
+}
+
+static int pwm_vibrator_play_effect(struct input_dev *dev, void *data,
+				    struct ff_effect *effect)
+{
+	struct pwm_vibrator *vibrator = input_get_drvdata(dev);
+
+	vibrator->level = effect->u.rumble.strong_magnitude;
+	if (!vibrator->level)
+		vibrator->level = effect->u.rumble.weak_magnitude;
+
+	schedule_work(&vibrator->play_work);
+
+	return 0;
+}
+
+static void pwm_vibrator_close(struct input_dev *input)
+{
+	struct pwm_vibrator *vibrator = input_get_drvdata(input);
+
+	cancel_work_sync(&vibrator->play_work);
+	pwm_vibrator_stop(vibrator);
+}
+
+static int pwm_vibrator_probe(struct platform_device *pdev)
+{
+	struct pwm_vibrator *vibrator;
+	struct pwm_state state;
+	int err;
+
+	vibrator = devm_kzalloc(&pdev->dev, sizeof(*vibrator), GFP_KERNEL);
+	if (!vibrator)
+		return -ENOMEM;
+
+	vibrator->input = devm_input_allocate_device(&pdev->dev);
+	if (!vibrator->input)
+		return -ENOMEM;
+
+	vibrator->vcc = devm_regulator_get(&pdev->dev, "vcc");
+	err = PTR_ERR_OR_ZERO(vibrator->vcc);
+	if (err) {
+		if (err != -EPROBE_DEFER)
+			dev_err(&pdev->dev, "Failed to request regulator: %d",
+				err);
+		return err;
+	}
+
+	vibrator->pwm = devm_pwm_get(&pdev->dev, "enable");
+	err = PTR_ERR_OR_ZERO(vibrator->pwm);
+	if (err) {
+		if (err != -EPROBE_DEFER)
+			dev_err(&pdev->dev, "Failed to request main pwm: %d",
+				err);
+		return err;
+	}
+
+	INIT_WORK(&vibrator->play_work, pwm_vibrator_play_work);
+
+	/* Sync up PWM state and ensure it is off. */
+	pwm_init_state(vibrator->pwm, &state);
+	state.enabled = false;
+	err = pwm_apply_state(vibrator->pwm, &state);
+	if (err) {
+		dev_err(&pdev->dev, "failed to apply initial PWM state: %d",
+			err);
+		return err;
+	}
+
+	vibrator->pwm_dir = devm_pwm_get(&pdev->dev, "direction");
+	err = PTR_ERR_OR_ZERO(vibrator->pwm_dir);
+	switch (err) {
+	case 0:
+		/* Sync up PWM state and ensure it is off. */
+		pwm_init_state(vibrator->pwm_dir, &state);
+		state.enabled = false;
+		err = pwm_apply_state(vibrator->pwm_dir, &state);
+		if (err) {
+			dev_err(&pdev->dev, "failed to apply initial PWM state: %d",
+				err);
+			return err;
+		}
+
+		vibrator->direction_duty_cycle =
+			pwm_get_period(vibrator->pwm_dir) / 2;
+		device_property_read_u32(&pdev->dev, "direction-duty-cycle-ns",
+					 &vibrator->direction_duty_cycle);
+		break;
+
+	case -ENODATA:
+		/* Direction PWM is optional */
+		vibrator->pwm_dir = NULL;
+		break;
+
+	default:
+		dev_err(&pdev->dev, "Failed to request direction pwm: %d", err);
+		/* Fall through */
+
+	case -EPROBE_DEFER:
+		return err;
+	}
+
+	vibrator->input->name = "pwm-vibrator";
+	vibrator->input->id.bustype = BUS_HOST;
+	vibrator->input->dev.parent = &pdev->dev;
+	vibrator->input->close = pwm_vibrator_close;
+
+	input_set_drvdata(vibrator->input, vibrator);
+	input_set_capability(vibrator->input, EV_FF, FF_RUMBLE);
+
+	err = input_ff_create_memless(vibrator->input, NULL,
+				      pwm_vibrator_play_effect);
+	if (err) {
+		dev_err(&pdev->dev, "Couldn't create FF dev: %d", err);
+		return err;
+	}
+
+	err = input_register_device(vibrator->input);
+	if (err) {
+		dev_err(&pdev->dev, "Couldn't register input dev: %d", err);
+		return err;
+	}
+
+	platform_set_drvdata(pdev, vibrator);
+
+	return 0;
+}
+
+static int __maybe_unused pwm_vibrator_suspend(struct device *dev)
+{
+	struct pwm_vibrator *vibrator = dev_get_drvdata(dev);
+
+	cancel_work_sync(&vibrator->play_work);
+	if (vibrator->level)
+		pwm_vibrator_stop(vibrator);
+
+	return 0;
+}
+
+static int __maybe_unused pwm_vibrator_resume(struct device *dev)
+{
+	struct pwm_vibrator *vibrator = dev_get_drvdata(dev);
+
+	if (vibrator->level)
+		pwm_vibrator_start(vibrator);
+
+	return 0;
+}
+
+static SIMPLE_DEV_PM_OPS(pwm_vibrator_pm_ops,
+			 pwm_vibrator_suspend, pwm_vibrator_resume);
+
+#ifdef CONFIG_OF
+static const struct of_device_id pwm_vibra_dt_match_table[] = {
+	{ .compatible = "pwm-vibrator" },
+	{},
+};
+MODULE_DEVICE_TABLE(of, pwm_vibra_dt_match_table);
+#endif
+
+static struct platform_driver pwm_vibrator_driver = {
+	.probe	= pwm_vibrator_probe,
+	.driver	= {
+		.name	= "pwm-vibrator",
+		.pm	= &pwm_vibrator_pm_ops,
+		.of_match_table = of_match_ptr(pwm_vibra_dt_match_table),
+	},
+};
+module_platform_driver(pwm_vibrator_driver);
+
+MODULE_AUTHOR("Sebastian Reichel <sre@kernel.org>");
+MODULE_DESCRIPTION("PWM vibrator driver");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:pwm-vibrator");