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....@samsung.com>
Signed-off-by: Jaechul Lee <jcsing....@samsung.com>
Reviewed-by: Javier Martinez Canillas <jav...@osg.samsung.com>
Reviewed-by: Andi Shyti <andi.sh...@samsung.com>
---
 drivers/input/keyboard/Kconfig        |  11 ++
 drivers/input/keyboard/Makefile       |   1 +
 drivers/input/keyboard/tm2-touchkey.c | 280 ++++++++++++++++++++++++++++++++++
 3 files changed, 292 insertions(+)
 create mode 100644 drivers/input/keyboard/tm2-touchkey.c

diff --git a/drivers/input/keyboard/Kconfig b/drivers/input/keyboard/Kconfig
index cbd75cf..e6e9858 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..92eacb6
--- /dev/null
+++ b/drivers/input/keyboard/tm2-touchkey.c
@@ -0,0 +1,280 @@
+/*
+ * TM2 touchkey device driver
+ *
+ * Copyright 2005 Phil Blundell
+ * Copyright 2016 Samsung Electronics Co., Ltd.
+ *
+ * Author: Beomho Seo <beomho....@samsung.com>
+ * Author: Jaechul Lee <jcsing....@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/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,
+};
+
+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[1].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[0].supply = "vcc";
+       touchkey->regulators[1].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 = "samsung,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....@samsung.com>");
+MODULE_AUTHOR("Jaechul Lee <jcsing....@samsung.com>");
+MODULE_DESCRIPTION("Samsung touchkey driver");
+MODULE_LICENSE("GPL v2");
-- 
2.7.4

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