[PATCH 2/4] input: tm2-touchkey: Add touchkey driver support for TM2

[Jaechul Lee]

This patch adds support for the TM2 touch key and led
functionlity.

The driver interfaces with userspace through an input device and
reports KEY_PHONE and KEY_BACK event types. LED brightness can be
controlled by "/sys/class/leds/tm2-touchkey/brightness".

Signed-off-by: Jaechul Lee <jcsing.lee@xxxxxxxxxxx>
Signed-off-by: Beomho Seo <beomho.seo@xxxxxxxxxxx>
---
 drivers/input/keyboard/Kconfig        |  11 ++
 drivers/input/keyboard/Makefile       |   1 +
 drivers/input/keyboard/tm2-touchkey.c | 326 ++++++++++++++++++++++++++++++++++
 3 files changed, 338 insertions(+)
 create mode 100644 drivers/input/keyboard/tm2-touchkey.c

diff --git a/drivers/input/keyboard/Kconfig b/drivers/input/keyboard/Kconfig
index cbd75cf..72c0ba1 100644
--- a/drivers/input/keyboard/Kconfig
+++ b/drivers/input/keyboard/Kconfig
@@ -666,6 +666,17 @@ config KEYBOARD_TC3589X
 	  To compile this driver as a module, choose M here: the
 	  module will be called tc3589x-keypad.
 
+config KEYBOARD_TM2_TOUCHKEY
+	tristate "tm2-touchkey support"
+	depends on I2C
+	help
+	  Say Y here to enable the tm2-touchkey.
+	  touchkey driver for tm2. This driver can enable
+	  the interrupt and make input events and control led brightness.
+
+	  To compile this driver as a module, choose M here.
+	  module will be called tm2-touchkey
+
 config KEYBOARD_TWL4030
 	tristate "TI TWL4030/TWL5030/TPS659x0 keypad support"
 	depends on TWL4030_CORE
diff --git a/drivers/input/keyboard/Makefile b/drivers/input/keyboard/Makefile
index d9f4cfc..7d9acff 100644
--- a/drivers/input/keyboard/Makefile
+++ b/drivers/input/keyboard/Makefile
@@ -61,6 +61,7 @@ obj-$(CONFIG_KEYBOARD_SUN4I_LRADC)	+= sun4i-lradc-keys.o
 obj-$(CONFIG_KEYBOARD_SUNKBD)		+= sunkbd.o
 obj-$(CONFIG_KEYBOARD_TC3589X)		+= tc3589x-keypad.o
 obj-$(CONFIG_KEYBOARD_TEGRA)		+= tegra-kbc.o
+obj-$(CONFIG_KEYBOARD_TM2_TOUCHKEY)	+= tm2-touchkey.o
 obj-$(CONFIG_KEYBOARD_TWL4030)		+= twl4030_keypad.o
 obj-$(CONFIG_KEYBOARD_XTKBD)		+= xtkbd.o
 obj-$(CONFIG_KEYBOARD_W90P910)		+= w90p910_keypad.o
diff --git a/drivers/input/keyboard/tm2-touchkey.c b/drivers/input/keyboard/tm2-touchkey.c
new file mode 100644
index 0000000..d9575d8
--- /dev/null
+++ b/drivers/input/keyboard/tm2-touchkey.c
@@ -0,0 +1,326 @@
+/*
+ * Driver for keys on GPIO lines capable of generating interrupts.
+ *
+ * Copyright 2005 Phil Blundell
+ * Copyright 2016 Samsung Electronics Co., Ltd.
+ *
+ * Author: Beomho Seo <beomho.seo@xxxxxxxxxxx>
+ * Author: Jaechul Lee <jcsing.lee@xxxxxxxxxxx>
+ *
+ * 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/bitops.h>
+#include <linux/delay.h>
+#include <linux/device.h>
+#include <linux/i2c.h>
+#include <linux/input.h>
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+#include <linux/leds.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/pm.h>
+#include <linux/regulator/consumer.h>
+#include <linux/workqueue.h>
+
+#define TM2_TOUCHKEY_DEV_NAME			"tm2-touchkey"
+#define TM2_TOUCHKEY_KEYCODE_REG			0x03
+#define TM2_TOUCHKEY_BASE_REG			0x00
+#define TM2_TOUCHKEY_CMD_LED_ON			0x10
+#define TM2_TOUCHKEY_CMD_LED_OFF			0x20
+#define TM2_TOUCHKEY_BIT_PRESS_EV			BIT(3)
+#define TM2_TOUCHKEY_BIT_KEYCODE			GENMASK(2, 0)
+#define TM2_TOUCHKEY_LED_VOLTAGE_MIN			2500000
+#define TM2_TOUCHKEY_LED_VOLTAGE_MAX			3300000
+
+enum {
+	TM2_TOUCHKEY_KEY_MENU = 0x1,
+	TM2_TOUCHKEY_KEY_BACK,
+};
+
+#define tm2_touchkey_power_enable(x) __tm2_touchkey_power_onoff(x, 1)
+#define tm2_touchkey_power_disable(x) __tm2_touchkey_power_onoff(x, 0)
+
+struct tm2_touchkey_data {
+	struct i2c_client *client;
+	struct input_dev *input_dev;
+	struct led_classdev led_dev;
+
+	u8 keycode_type;
+	u8 pressed;
+	struct work_struct irq_work;
+
+	bool power_onoff;
+	struct regulator *regulator_vcc;	/* 1.8V */
+	struct regulator *regulator_vdd;	/* 3.3V */
+};
+
+static void tm2_touchkey_led_brightness_set(struct led_classdev *led_dev,
+						enum led_brightness brightness)
+{
+	struct tm2_touchkey_data *samsung_touchkey =
+	    container_of(led_dev, struct tm2_touchkey_data, led_dev);
+	u32 volt;
+	u8 data;
+
+	if (brightness == LED_OFF) {
+		volt = TM2_TOUCHKEY_LED_VOLTAGE_MIN;
+		data = TM2_TOUCHKEY_CMD_LED_OFF;
+	} else {
+		volt = TM2_TOUCHKEY_LED_VOLTAGE_MAX;
+		data = TM2_TOUCHKEY_CMD_LED_ON;
+	}
+
+	regulator_set_voltage(samsung_touchkey->regulator_vdd, volt, volt);
+	i2c_smbus_write_byte_data(samsung_touchkey->client,
+				  TM2_TOUCHKEY_BASE_REG, data);
+}
+
+static int __tm2_touchkey_power_onoff(struct tm2_touchkey_data
+					  *samsung_touchkey, bool onoff)
+{
+	int ret = 0;
+
+	if (samsung_touchkey->power_onoff == onoff)
+		return ret;
+
+	if (onoff) {
+		ret = regulator_enable(samsung_touchkey->regulator_vcc);
+		if (ret)
+			return ret;
+
+		ret = regulator_enable(samsung_touchkey->regulator_vdd);
+		if (ret) {
+			regulator_disable(samsung_touchkey->regulator_vcc);
+			return ret;
+		}
+		msleep(150);
+	} else {
+		int err;
+
+		err = regulator_disable(samsung_touchkey->regulator_vcc);
+		if (err)
+			ret = err;
+
+		err = regulator_disable(samsung_touchkey->regulator_vdd);
+		if (err && !ret)
+			ret = err;
+	}
+	samsung_touchkey->power_onoff = onoff;
+
+	return ret;
+}
+
+static void tm2_touchkey_irq_work(struct work_struct *irq_work)
+{
+	struct tm2_touchkey_data *samsung_touchkey =
+	    container_of(irq_work, struct tm2_touchkey_data, irq_work);
+
+	if (!samsung_touchkey->pressed) {
+		input_report_key(samsung_touchkey->input_dev, KEY_PHONE, 0);
+		input_report_key(samsung_touchkey->input_dev, KEY_BACK, 0);
+	} else {
+		if (samsung_touchkey->keycode_type == TM2_TOUCHKEY_KEY_MENU)
+			input_report_key(samsung_touchkey->input_dev,
+					 KEY_PHONE, 1);
+		else
+			input_report_key(samsung_touchkey->input_dev,
+					 KEY_BACK, 1);
+	}
+	input_sync(samsung_touchkey->input_dev);
+}
+
+static irqreturn_t tm2_touchkey_irq_handler(int irq, void *devid)
+{
+	struct tm2_touchkey_data *samsung_touchkey = devid;
+	u32 data;
+
+	data = i2c_smbus_read_byte_data(samsung_touchkey->client,
+					TM2_TOUCHKEY_KEYCODE_REG);
+
+	if (data < 0) {
+		dev_err(&samsung_touchkey->client->dev, "Failed to read i2c data\n");
+		return IRQ_HANDLED;
+	}
+
+	samsung_touchkey->keycode_type = data & TM2_TOUCHKEY_BIT_KEYCODE;
+	samsung_touchkey->pressed = !(data & TM2_TOUCHKEY_BIT_PRESS_EV);
+
+	if (samsung_touchkey->keycode_type != TM2_TOUCHKEY_KEY_MENU &&
+	    samsung_touchkey->keycode_type != TM2_TOUCHKEY_KEY_BACK)
+		return IRQ_HANDLED;
+
+	schedule_work(&samsung_touchkey->irq_work);
+
+	return IRQ_HANDLED;
+}
+
+static int tm2_touchkey_probe(struct i2c_client *client,
+				  const struct i2c_device_id *id)
+{
+	struct tm2_touchkey_data *samsung_touchkey;
+	int ret;
+
+	ret = i2c_check_functionality(client->adapter,
+				      I2C_FUNC_SMBUS_BYTE |
+				      I2C_FUNC_SMBUS_BYTE_DATA);
+	if (!ret) {
+		dev_err(&client->dev, "No I2C functionality found\n");
+		return -ENODEV;
+	}
+
+	samsung_touchkey = devm_kzalloc(&client->dev,
+			sizeof(struct tm2_touchkey_data), GFP_KERNEL);
+
+	if (!samsung_touchkey) {
+		dev_err(&client->dev, "Failed to allocate memory.\n");
+		return -ENOMEM;
+	}
+
+	samsung_touchkey->client = client;
+	i2c_set_clientdata(client, samsung_touchkey);
+	INIT_WORK(&samsung_touchkey->irq_work, tm2_touchkey_irq_work);
+
+	/* regulator */
+	samsung_touchkey->regulator_vcc =
+				devm_regulator_get(&client->dev, "vcc");
+	if (IS_ERR(samsung_touchkey->regulator_vcc)) {
+		dev_err(&client->dev, "Failed to get vcc regulator\n");
+		return PTR_ERR(samsung_touchkey->regulator_vcc);
+	}
+
+	samsung_touchkey->regulator_vdd =
+				devm_regulator_get(&client->dev, "vdd");
+	if (IS_ERR(samsung_touchkey->regulator_vdd)) {
+		dev_err(&client->dev, "Failed to get vdd regulator\n");
+		return PTR_ERR(samsung_touchkey->regulator_vcc);
+	}
+
+	/* power */
+	ret = tm2_touchkey_power_enable(samsung_touchkey);
+	if (ret) {
+		dev_err(&client->dev, "Failed to enable power\n");
+		return ret;
+	}
+
+	/* irq */
+	ret = devm_request_threaded_irq(&client->dev,
+					client->irq, NULL,
+					tm2_touchkey_irq_handler,
+					IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
+					TM2_TOUCHKEY_DEV_NAME,
+					samsung_touchkey);
+	if (ret) {
+		dev_err(&client->dev, "Failed to request threaded irq\n");
+		return ret;
+	}
+
+	/* input device */
+	samsung_touchkey->input_dev = devm_input_allocate_device(&client->dev);
+	if (!samsung_touchkey->input_dev) {
+		dev_err(&client->dev, "Failed to alloc input device.\n");
+		return -ENOMEM;
+	}
+	samsung_touchkey->input_dev->name = TM2_TOUCHKEY_DEV_NAME;
+	samsung_touchkey->input_dev->id.bustype = BUS_I2C;
+	samsung_touchkey->input_dev->dev.parent = &client->dev;
+
+	set_bit(EV_KEY, samsung_touchkey->input_dev->evbit);
+	set_bit(KEY_PHONE, samsung_touchkey->input_dev->keybit);
+	set_bit(KEY_BACK, samsung_touchkey->input_dev->keybit);
+	input_set_drvdata(samsung_touchkey->input_dev, samsung_touchkey);
+
+	ret = input_register_device(samsung_touchkey->input_dev);
+	if (ret) {
+		dev_err(&client->dev, "Failed to register input device.\n");
+		return ret;
+	}
+
+	/* led device */
+	samsung_touchkey->led_dev.name = TM2_TOUCHKEY_DEV_NAME;
+	samsung_touchkey->led_dev.brightness = LED_FULL;
+	samsung_touchkey->led_dev.max_brightness = LED_FULL;
+	samsung_touchkey->led_dev.brightness_set =
+						tm2_touchkey_led_brightness_set;
+
+	ret = devm_led_classdev_register(&client->dev,
+					 &samsung_touchkey->led_dev);
+	if (ret < 0) {
+		dev_err(&client->dev, "Failed to register touchkey led\n");
+		return ret;
+	}
+
+	return 0;
+}
+
+static void tm2_touchkey_shutdown(struct i2c_client *client)
+{
+	struct tm2_touchkey_data *samsung_touchkey =
+						i2c_get_clientdata(client);
+	int ret;
+
+	disable_irq(client->irq);
+	ret = tm2_touchkey_power_disable(samsung_touchkey);
+	if (ret)
+		dev_err(&client->dev, "Failed to disable power\n");
+}
+
+static int tm2_touchkey_suspend(struct device *dev)
+{
+	struct tm2_touchkey_data *samsung_touchkey = dev_get_drvdata(dev);
+	int ret;
+
+	disable_irq(samsung_touchkey->client->irq);
+	ret = tm2_touchkey_power_disable(samsung_touchkey);
+	if (ret)
+		dev_err(dev, "Failed to disable power\n");
+
+	return ret;
+}
+
+static int tm2_touchkey_resume(struct device *dev)
+{
+	struct tm2_touchkey_data *samsung_touchkey = dev_get_drvdata(dev);
+	int ret;
+
+	enable_irq(samsung_touchkey->client->irq);
+	ret = tm2_touchkey_power_enable(samsung_touchkey);
+	if (ret)
+		dev_err(dev, "Failed to enable power\n");
+
+	return ret;
+}
+
+static SIMPLE_DEV_PM_OPS(tm2_touchkey_pm_ops, tm2_touchkey_suspend,
+							tm2_touchkey_resume);
+
+static const struct i2c_device_id tm2_touchkey_id_table[] = {
+	{TM2_TOUCHKEY_DEV_NAME, 0},
+	{},
+};
+
+static const struct of_device_id tm2_touchkey_of_match[] = {
+	{.compatible = "samsung,tm2-touchkey",},
+	{},
+};
+
+static struct i2c_driver tm2_touchkey_driver = {
+	.driver = {
+		.name = TM2_TOUCHKEY_DEV_NAME,
+		.pm = &tm2_touchkey_pm_ops,
+		.of_match_table = of_match_ptr(tm2_touchkey_of_match),
+	},
+	.probe = tm2_touchkey_probe,
+	.shutdown = tm2_touchkey_shutdown,
+	.id_table = tm2_touchkey_id_table,
+};
+
+module_i2c_driver(tm2_touchkey_driver);
+
+MODULE_AUTHOR("Beomho Seo <beomho.seo@xxxxxxxxxxx>");
+MODULE_AUTHOR("Jaechul Lee <jcsing.lee@xxxxxxxxxxx>");
+MODULE_DESCRIPTION("Samsung touchkey driver");
+MODULE_LICENSE("GPL v2");
-- 
2.7.4