Input: add regulator haptic driver

This change adds support for haptic driver controlled by voltage of a
regulator. Userspace can control the device via Force Feedback interface
from input framework.

Signed-off-by: Jaewon Kim <jaewon02.kim@samsung.com>
Signed-off-by: Hyunhee Kim <hyunhee.kim@samsung.com>
Acked-by: Kyungmin Park <kyungmin.park@samsung.com>
Tested-by: Chanwoo Choi <cw00.choi@samsung.com>
Reviewed-by: Chanwoo Choi <cw00.choi@samsung.com>
Reviewed-by: Pankaj Dubey <pankaj.dubey@samsung.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

3 files changed, 292 insertions, 0 deletions

diff --git a/drivers/input/misc/Kconfig b/drivers/input/misc/Kconfig
index 23297ab6163f..1da0a20c42ea 100644
--- a/drivers/input/misc/Kconfig
+++ b/drivers/input/misc/Kconfig
@@ -394,6 +394,18 @@ config INPUT_CM109
           To compile this driver as a module, choose M here: the module will be
           called cm109.
 
+config INPUT_REGULATOR_HAPTIC
+        tristate "Regulator haptics support"
+        depends on REGULATOR
+        select INPUT_FF_MEMLESS
+        help
+          This option enables device driver support for the haptic controlled
+          by a regulator. This driver supports ff-memless interface
+          from input framework.
+
+          To compile this driver as a module, choose M here: the
+          module will be called regulator-haptic.
+
 config INPUT_RETU_PWRBUTTON
         tristate "Retu Power button Driver"
         depends on MFD_RETU
diff --git a/drivers/input/misc/Makefile b/drivers/input/misc/Makefile
index 19c760361f80..1f135af4af01 100644
--- a/drivers/input/misc/Makefile
+++ b/drivers/input/misc/Makefile
@@ -53,6 +53,7 @@ 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_RB532_BUTTON)        += rb532_button.o
+obj-$(CONFIG_INPUT_REGULATOR_HAPTIC)    += regulator-haptic.o
 obj-$(CONFIG_INPUT_RETU_PWRBUTTON)      += retu-pwrbutton.o
 obj-$(CONFIG_INPUT_GPIO_ROTARY_ENCODER) += rotary_encoder.o
 obj-$(CONFIG_INPUT_SGI_BTNS)            += sgi_btns.o
diff --git a/drivers/input/misc/regulator-haptic.c b/drivers/input/misc/regulator-haptic.c
new file mode 100644
index 000000000000..942622189bee
--- /dev/null
+++ b/drivers/input/misc/regulator-haptic.c
@@ -0,0 +1,279 @@
+/*
+ * Regulator haptic driver
+ *
+ * Copyright (c) 2014 Samsung Electronics Co., Ltd.
+ * Author: Jaewon Kim <jaewon02.kim@samsung.com>
+ * Author: Hyunhee Kim <hyunhee.kim@samsung.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/input.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_data/regulator-haptic.h>
+#include <linux/platform_device.h>
+#include <linux/regulator/consumer.h>
+#include <linux/slab.h>
+
+#define MAX_MAGNITUDE_SHIFT     16
+
+struct regulator_haptic {
+        struct device *dev;
+        struct input_dev *input_dev;
+        struct regulator *regulator;
+
+        struct work_struct work;
+        struct mutex mutex;
+
+        bool active;
+        bool suspended;
+
+        unsigned int max_volt;
+        unsigned int min_volt;
+        unsigned int magnitude;
+};
+
+static int regulator_haptic_toggle(struct regulator_haptic *haptic, bool on)
+{
+        int error;
+
+        if (haptic->active != on) {
+
+                error = on ? regulator_enable(haptic->regulator) :
+                             regulator_disable(haptic->regulator);
+                if (error) {
+                        dev_err(haptic->dev,
+                                "failed to switch regulator %s: %d\n",
+                                on ? "on" : "off", error);
+                        return error;
+                }
+
+                haptic->active = on;
+        }
+
+        return 0;
+}
+
+static int regulator_haptic_set_voltage(struct regulator_haptic *haptic,
+                                         unsigned int magnitude)
+{
+        u64 volt_mag_multi;
+        unsigned int intensity;
+        int error;
+
+        volt_mag_multi = (u64)(haptic->max_volt - haptic->min_volt) * magnitude;
+        intensity = (unsigned int)(volt_mag_multi >> MAX_MAGNITUDE_SHIFT);
+
+        error = regulator_set_voltage(haptic->regulator,
+                                      intensity + haptic->min_volt,
+                                      haptic->max_volt);
+        if (error) {
+                dev_err(haptic->dev, "cannot set regulator voltage to %d: %d\n",
+                        intensity + haptic->min_volt, error);
+                return error;
+        }
+
+        return 0;
+}
+
+static void regulator_haptic_work(struct work_struct *work)
+{
+        struct regulator_haptic *haptic = container_of(work,
+                                        struct regulator_haptic, work);
+        unsigned int magnitude;
+        int error;
+
+        mutex_lock(&haptic->mutex);
+
+        if (haptic->suspended)
+                goto out;
+
+        magnitude = ACCESS_ONCE(haptic->magnitude);
+
+        error = regulator_haptic_set_voltage(haptic, magnitude);
+        if (error)
+                goto out;
+
+        regulator_haptic_toggle(haptic, magnitude != 0);
+
+out:
+        mutex_unlock(&haptic->mutex);
+}
+
+static int regulator_haptic_play_effect(struct input_dev *input, void *data,
+                                        struct ff_effect *effect)
+{
+        struct regulator_haptic *haptic = input_get_drvdata(input);
+
+        haptic->magnitude = effect->u.rumble.strong_magnitude;
+        if (!haptic->magnitude)
+                haptic->magnitude = effect->u.rumble.weak_magnitude;
+
+        schedule_work(&haptic->work);
+
+        return 0;
+}
+
+static void regulator_haptic_close(struct input_dev *input)
+{
+        struct regulator_haptic *haptic = input_get_drvdata(input);
+
+        cancel_work_sync(&haptic->work);
+        regulator_haptic_set_voltage(haptic, 0);
+        regulator_haptic_toggle(haptic, false);
+}
+
+static int __maybe_unused
+regulator_haptic_parse_dt(struct device *dev, struct regulator_haptic *haptic)
+{
+        struct device_node *node;
+        int error;
+
+        node = dev->of_node;
+        if(!node) {
+                dev_err(dev, "Missing dveice tree data\n");
+                return -EINVAL;
+        }
+
+        error = of_property_read_u32(node, "max-microvolt", &haptic->max_volt);
+        if (error) {
+                dev_err(dev, "cannot parse max-microvolt\n");
+                return error;
+        }
+
+        error = of_property_read_u32(node, "min-microvolt", &haptic->min_volt);
+        if (error) {
+                dev_err(dev, "cannot parse min-microvolt\n");
+                return error;
+        }
+
+        return 0;
+}
+
+static int regulator_haptic_probe(struct platform_device *pdev)
+{
+        const struct regulator_haptic_data *pdata = dev_get_platdata(&pdev->dev);
+        struct regulator_haptic *haptic;
+        struct input_dev *input_dev;
+        int error;
+
+        haptic = devm_kzalloc(&pdev->dev, sizeof(*haptic), GFP_KERNEL);
+        if (!haptic)
+                return -ENOMEM;
+
+        platform_set_drvdata(pdev, haptic);
+        haptic->dev = &pdev->dev;
+        mutex_init(&haptic->mutex);
+        INIT_WORK(&haptic->work, regulator_haptic_work);
+
+        if (pdata) {
+                haptic->max_volt = pdata->max_volt;
+                haptic->min_volt = pdata->min_volt;
+        } else if (IS_ENABLED(CONFIG_OF)) {
+                error = regulator_haptic_parse_dt(&pdev->dev, haptic);
+                if (error)
+                        return error;
+        } else {
+                dev_err(&pdev->dev, "Missing platform data\n");
+                return -EINVAL;
+        }
+
+        haptic->regulator = devm_regulator_get_exclusive(&pdev->dev, "haptic");
+        if (IS_ERR(haptic->regulator)) {
+                dev_err(&pdev->dev, "failed to get regulator\n");
+                return PTR_ERR(haptic->regulator);
+        }
+
+        input_dev = devm_input_allocate_device(&pdev->dev);
+        if (!input_dev)
+                return  -ENOMEM;
+
+        haptic->input_dev = input_dev;
+        haptic->input_dev->name = "regulator-haptic";
+        haptic->input_dev->dev.parent = &pdev->dev;
+        haptic->input_dev->close = regulator_haptic_close;
+        input_set_drvdata(haptic->input_dev, haptic);
+        input_set_capability(haptic->input_dev, EV_FF, FF_RUMBLE);
+
+        error = input_ff_create_memless(input_dev, NULL,
+                                        regulator_haptic_play_effect);
+        if (error) {
+                dev_err(&pdev->dev, "failed to create force-feedback\n");
+                return error;
+        }
+
+        error = input_register_device(haptic->input_dev);
+        if (error) {
+                dev_err(&pdev->dev, "failed to register input device\n");
+                return error;
+        }
+
+        return 0;
+}
+
+static int __maybe_unused regulator_haptic_suspend(struct device *dev)
+{
+        struct platform_device *pdev = to_platform_device(dev);
+        struct regulator_haptic *haptic = platform_get_drvdata(pdev);
+        int error;
+
+        error = mutex_lock_interruptible(&haptic->mutex);
+        if (error)
+                return error;
+
+        regulator_haptic_set_voltage(haptic, 0);
+        regulator_haptic_toggle(haptic, false);
+
+        haptic->suspended = true;
+
+        mutex_unlock(&haptic->mutex);
+
+        return 0;
+}
+
+static int __maybe_unused regulator_haptic_resume(struct device *dev)
+{
+        struct platform_device *pdev = to_platform_device(dev);
+        struct regulator_haptic *haptic = platform_get_drvdata(pdev);
+        unsigned int magnitude;
+
+        mutex_lock(&haptic->mutex);
+
+        haptic->suspended = false;
+
+        magnitude = ACCESS_ONCE(haptic->magnitude);
+        if (magnitude) {
+                regulator_haptic_set_voltage(haptic, magnitude);
+                regulator_haptic_toggle(haptic, true);
+        }
+
+        mutex_unlock(&haptic->mutex);
+
+        return 0;
+}
+
+static SIMPLE_DEV_PM_OPS(regulator_haptic_pm_ops,
+                regulator_haptic_suspend, regulator_haptic_resume);
+
+static struct of_device_id regulator_haptic_dt_match[] = {
+        { .compatible = "regulator-haptic" },
+        { /* sentinel */ },
+};
+
+static struct platform_driver regulator_haptic_driver = {
+        .probe          = regulator_haptic_probe,
+        .driver         = {
+                .name           = "regulator-haptic",
+                .of_match_table = regulator_haptic_dt_match,
+                .pm             = &regulator_haptic_pm_ops,
+        },
+};
+module_platform_driver(regulator_haptic_driver);
+
+MODULE_AUTHOR("Jaewon Kim <jaewon02.kim@samsung.com>");
+MODULE_AUTHOR("Hyunhee Kim <hyunhee.kim@samsung.com>");
+MODULE_DESCRIPTION("Regulator haptic driver");
+MODULE_LICENSE("GPL");