[PATCH v6 2/3] input: tm2-touchkey: Add touchkey driver support for TM2

[Jaechul Lee]

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

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: Beomho Seo <beomho.seo@xxxxxxxxxxx>
Signed-off-by: Jaechul Lee <jcsing.lee@xxxxxxxxxxx>
Reviewed-by: Javier Martinez Canillas <javier@xxxxxxxxxxxxxxx>
Reviewed-by: Andi Shyti <andi.shyti@xxxxxxxxxxx>
Acked-by: Krzysztof Kozlowski <krzk@xxxxxxxxxx>
---
 drivers/input/keyboard/Kconfig        |  11 ++
 drivers/input/keyboard/Makefile       |   1 +
 drivers/input/keyboard/tm2-touchkey.c | 287 ++++++++++++++++++++++++++++++++++
 3 files changed, 299 insertions(+)
 create mode 100644 drivers/input/keyboard/tm2-touchkey.c

diff --git a/drivers/input/keyboard/Kconfig b/drivers/input/keyboard/Kconfig
index cbd75cf..97acd65 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
+	depends on LEDS_CLASS
+	help
+	  Say Y here to enable device driver for tm2-touchkey with
+	  LED control for the Exynos5433 TM2 board.
+
+	  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..e927d06
--- /dev/null
+++ b/drivers/input/keyboard/tm2-touchkey.c
@@ -0,0 +1,287 @@
+/*
+ * TM2 touchkey device driver
+ *
+ * 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>
+
+#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,
+};
+
+enum {
+	TM2_TOUCHKEY_SUPPLIES_VCC,
+	TM2_TOUCHKEY_SUPPLIES_VDD,
+};
+
+struct tm2_touchkey_data {
+	struct i2c_client *client;
+	struct input_dev *input_dev;
+	struct led_classdev led_dev;
+	struct regulator_bulk_data regulators[2];
+
+	u8 keycode_type;
+	u8 pressed;
+};
+
+static void tm2_touchkey_led_brightness_set(struct led_classdev *led_dev,
+						enum led_brightness brightness)
+{
+	struct tm2_touchkey_data *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(
+		touchkey->regulators[TM2_TOUCHKEY_SUPPLIES_VDD].consumer,
+		volt, volt);
+	i2c_smbus_write_byte_data(touchkey->client,
+						TM2_TOUCHKEY_BASE_REG, data);
+}
+
+static int tm2_touchkey_power_enable(struct tm2_touchkey_data *touchkey)
+{
+	int ret = 0;
+
+	ret = regulator_bulk_enable(ARRAY_SIZE(touchkey->regulators),
+						touchkey->regulators);
+	if (ret)
+		return ret;
+
+	/* waiting for device initialization, at least 150ms */
+	msleep(150);
+
+	return 0;
+}
+
+static void tm2_touchkey_power_disable(void *data)
+{
+	struct tm2_touchkey_data *touchkey = data;
+
+	regulator_bulk_disable(ARRAY_SIZE(touchkey->regulators),
+						touchkey->regulators);
+}
+
+static irqreturn_t tm2_touchkey_irq_handler(int irq, void *devid)
+{
+	struct tm2_touchkey_data *touchkey = devid;
+	u32 data;
+
+	data = i2c_smbus_read_byte_data(touchkey->client,
+					TM2_TOUCHKEY_KEYCODE_REG);
+
+	if (data < 0) {
+		dev_err(&touchkey->client->dev, "Failed to read i2c data\n");
+		return IRQ_HANDLED;
+	}
+
+	touchkey->keycode_type = data & TM2_TOUCHKEY_BIT_KEYCODE;
+	touchkey->pressed = !(data & TM2_TOUCHKEY_BIT_PRESS_EV);
+
+	if (touchkey->keycode_type != TM2_TOUCHKEY_KEY_MENU &&
+	    touchkey->keycode_type != TM2_TOUCHKEY_KEY_BACK) {
+		dev_warn(&touchkey->client->dev, "Skip unhandled keycode(%d)\n",
+							touchkey->keycode_type);
+		return IRQ_HANDLED;
+	}
+
+	if (!touchkey->pressed) {
+		input_report_key(touchkey->input_dev, KEY_PHONE, 0);
+		input_report_key(touchkey->input_dev, KEY_BACK, 0);
+	} else {
+		if (touchkey->keycode_type == TM2_TOUCHKEY_KEY_MENU)
+			input_report_key(touchkey->input_dev,
+					 KEY_PHONE, 1);
+		else
+			input_report_key(touchkey->input_dev,
+					 KEY_BACK, 1);
+	}
+	input_sync(touchkey->input_dev);
+
+	return IRQ_HANDLED;
+}
+
+static int tm2_touchkey_probe(struct i2c_client *client,
+					const struct i2c_device_id *id)
+{
+	struct tm2_touchkey_data *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;
+	}
+
+	touchkey = devm_kzalloc(&client->dev, sizeof(*touchkey), GFP_KERNEL);
+	if (!touchkey)
+		return -ENOMEM;
+
+	touchkey->client = client;
+	i2c_set_clientdata(client, touchkey);
+
+	/* regulators */
+	touchkey->regulators[TM2_TOUCHKEY_SUPPLIES_VCC].supply = "vcc";
+	touchkey->regulators[TM2_TOUCHKEY_SUPPLIES_VDD].supply = "vdd";
+	ret = devm_regulator_bulk_get(&client->dev,
+					ARRAY_SIZE(touchkey->regulators),
+					touchkey->regulators);
+	if (ret) {
+		dev_err(&client->dev, "Failed to get regulators\n");
+		return ret;
+	}
+
+	/* power */
+	ret = tm2_touchkey_power_enable(touchkey);
+	if (ret) {
+		dev_err(&client->dev, "Failed to enable power\n");
+		return ret;
+	}
+
+	ret = devm_add_action_or_reset(&client->dev,
+					tm2_touchkey_power_disable, touchkey);
+	if (ret)
+		return ret;
+
+	/* input device */
+	touchkey->input_dev = devm_input_allocate_device(&client->dev);
+	if (!touchkey->input_dev) {
+		dev_err(&client->dev, "Failed to alloc input device\n");
+		return -ENOMEM;
+	}
+	touchkey->input_dev->name = TM2_TOUCHKEY_DEV_NAME;
+	touchkey->input_dev->id.bustype = BUS_I2C;
+
+	set_bit(EV_KEY, touchkey->input_dev->evbit);
+	input_set_capability(touchkey->input_dev, EV_KEY, KEY_PHONE);
+	input_set_capability(touchkey->input_dev, EV_KEY, KEY_BACK);
+
+	input_set_drvdata(touchkey->input_dev, touchkey);
+
+	ret = input_register_device(touchkey->input_dev);
+	if (ret) {
+		dev_err(&client->dev, "Failed to register input device\n");
+		return ret;
+	}
+
+	/* irq */
+	ret = devm_request_threaded_irq(&client->dev,
+					client->irq, NULL,
+					tm2_touchkey_irq_handler,
+					IRQF_ONESHOT, TM2_TOUCHKEY_DEV_NAME,
+					touchkey);
+	if (ret) {
+		dev_err(&client->dev, "Failed to request threaded irq\n");
+		return ret;
+	}
+
+	/* led device */
+	touchkey->led_dev.name = TM2_TOUCHKEY_DEV_NAME;
+	touchkey->led_dev.brightness = LED_FULL;
+	touchkey->led_dev.max_brightness = LED_FULL;
+	touchkey->led_dev.brightness_set = tm2_touchkey_led_brightness_set;
+
+	ret = devm_led_classdev_register(&client->dev, &touchkey->led_dev);
+	if (ret < 0) {
+		dev_err(&client->dev, "Failed to register touchkey led\n");
+		return ret;
+	}
+
+	return 0;
+}
+
+static int __maybe_unused tm2_touchkey_suspend(struct device *dev)
+{
+	struct tm2_touchkey_data *touchkey = dev_get_drvdata(dev);
+
+	disable_irq(touchkey->client->irq);
+	tm2_touchkey_power_disable(touchkey);
+
+	return 0;
+}
+
+static int __maybe_unused tm2_touchkey_resume(struct device *dev)
+{
+	struct tm2_touchkey_data *touchkey = dev_get_drvdata(dev);
+	int ret;
+
+	enable_irq(touchkey->client->irq);
+	ret = tm2_touchkey_power_enable(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},
+	{},
+};
+MODULE_DEVICE_TABLE(i2c, tm2_touchkey_id_table);
+
+static const struct of_device_id tm2_touchkey_of_match[] = {
+	{.compatible = "cypress,tm2-touchkey",},
+	{},
+};
+MODULE_DEVICE_TABLE(of, tm2_touchkey_of_match);
+
+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,
+	.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