--- /dev/null
+/*
+ * mcs_touchkey.c - Touchkey driver for MELFAS MCS5000/5080 controller
+ *
+ * Copyright (C) 2010 Samsung Electronics Co.Ltd
+ * Author: HeungJun Kim <riverful.kim@samsung.com>
+ * Author: Joonyoung Shim <jy0922.shim@samsung.com>
+ *
+ * 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/module.h>
+#include <linux/init.h>
+#include <linux/i2c.h>
+#include <linux/i2c/mcs.h>
+#include <linux/interrupt.h>
+#include <linux/input.h>
+#include <linux/irq.h>
+#include <linux/slab.h>
+
+/* MCS5000 Touchkey */
+#define MCS5000_TOUCHKEY_STATUS                0x04
+#define MCS5000_TOUCHKEY_STATUS_PRESS  7
+#define MCS5000_TOUCHKEY_FW            0x0a
+#define MCS5000_TOUCHKEY_BASE_VAL      0x61
+
+/* MCS5080 Touchkey */
+#define MCS5080_TOUCHKEY_STATUS                0x00
+#define MCS5080_TOUCHKEY_STATUS_PRESS  3
+#define MCS5080_TOUCHKEY_FW            0x01
+#define MCS5080_TOUCHKEY_BASE_VAL      0x1
+
+enum mcs_touchkey_type {
+       MCS5000_TOUCHKEY,
+       MCS5080_TOUCHKEY,
+};
+
+struct mcs_touchkey_chip {
+       unsigned int status_reg;
+       unsigned int pressbit;
+       unsigned int press_invert;
+       unsigned int baseval;
+};
+
+struct mcs_touchkey_data {
+       struct i2c_client *client;
+       struct input_dev *input_dev;
+       struct mcs_touchkey_chip chip;
+       unsigned int key_code;
+       unsigned int key_val;
+       unsigned short keycodes[];
+};
+
+static irqreturn_t mcs_touchkey_interrupt(int irq, void *dev_id)
+{
+       struct mcs_touchkey_data *data = dev_id;
+       struct mcs_touchkey_chip *chip = &data->chip;
+       struct i2c_client *client = data->client;
+       struct input_dev *input = data->input_dev;
+       unsigned int key_val;
+       unsigned int pressed;
+       int val;
+
+       val = i2c_smbus_read_byte_data(client, chip->status_reg);
+       if (val < 0) {
+               dev_err(&client->dev, "i2c read error [%d]\n", val);
+               goto out;
+       }
+
+       pressed = (val & (1 << chip->pressbit)) >> chip->pressbit;
+       if (chip->press_invert)
+               pressed ^= chip->press_invert;
+
+       /* key_val is 0 when released, so we should use key_val of press. */
+       if (pressed) {
+               key_val = val & (0xff >> (8 - chip->pressbit));
+               if (!key_val)
+                       goto out;
+               key_val -= chip->baseval;
+               data->key_code = data->keycodes[key_val];
+               data->key_val = key_val;
+       }
+
+       input_event(input, EV_MSC, MSC_SCAN, data->key_val);
+       input_report_key(input, data->key_code, pressed);
+       input_sync(input);
+
+       dev_dbg(&client->dev, "key %d %d %s\n", data->key_val, data->key_code,
+               pressed ? "pressed" : "released");
+
+ out:
+       return IRQ_HANDLED;
+}
+
+static int __devinit mcs_touchkey_probe(struct i2c_client *client,
+               const struct i2c_device_id *id)
+{
+       const struct mcs_platform_data *pdata;
+       struct mcs_touchkey_data *data;
+       struct input_dev *input_dev;
+       unsigned int fw_reg;
+       int fw_ver;
+       int error;
+       int i;
+
+       pdata = client->dev.platform_data;
+       if (!pdata) {
+               dev_err(&client->dev, "no platform data defined\n");
+               return -EINVAL;
+       }
+
+       data = kzalloc(sizeof(struct mcs_touchkey_data) +
+                       sizeof(data->keycodes[0]) * (pdata->key_maxval + 1),
+                       GFP_KERNEL);
+       input_dev = input_allocate_device();
+       if (!data || !input_dev) {
+               dev_err(&client->dev, "Failed to allocate memory\n");
+               error = -ENOMEM;
+               goto err_free_mem;
+       }
+
+       data->client = client;
+       data->input_dev = input_dev;
+
+       if (id->driver_data == MCS5000_TOUCHKEY) {
+               data->chip.status_reg = MCS5000_TOUCHKEY_STATUS;
+               data->chip.pressbit = MCS5000_TOUCHKEY_STATUS_PRESS;
+               data->chip.baseval = MCS5000_TOUCHKEY_BASE_VAL;
+               fw_reg = MCS5000_TOUCHKEY_FW;
+       } else {
+               data->chip.status_reg = MCS5080_TOUCHKEY_STATUS;
+               data->chip.pressbit = MCS5080_TOUCHKEY_STATUS_PRESS;
+               data->chip.press_invert = 1;
+               data->chip.baseval = MCS5080_TOUCHKEY_BASE_VAL;
+               fw_reg = MCS5080_TOUCHKEY_FW;
+       }
+
+       fw_ver = i2c_smbus_read_byte_data(client, fw_reg);
+       if (fw_ver < 0) {
+               error = fw_ver;
+               dev_err(&client->dev, "i2c read error[%d]\n", error);
+               goto err_free_mem;
+       }
+       dev_info(&client->dev, "Firmware version: %d\n", fw_ver);
+
+       input_dev->name = "MELPAS MCS Touchkey";
+       input_dev->id.bustype = BUS_I2C;
+       input_dev->dev.parent = &client->dev;
+       input_dev->evbit[0] = BIT_MASK(EV_KEY);
+       if (!pdata->no_autorepeat)
+               input_dev->evbit[0] |= BIT_MASK(EV_REP);
+       input_dev->keycode = data->keycodes;
+       input_dev->keycodesize = sizeof(data->keycodes[0]);
+       input_dev->keycodemax = pdata->key_maxval + 1;
+
+       for (i = 0; i < pdata->keymap_size; i++) {
+               unsigned int val = MCS_KEY_VAL(pdata->keymap[i]);
+               unsigned int code = MCS_KEY_CODE(pdata->keymap[i]);
+
+               data->keycodes[val] = code;
+               __set_bit(code, input_dev->keybit);
+       }
+
+       input_set_capability(input_dev, EV_MSC, MSC_SCAN);
+       input_set_drvdata(input_dev, data);
+
+       if (pdata->cfg_pin)
+               pdata->cfg_pin();
+
+       error = request_threaded_irq(client->irq, NULL, mcs_touchkey_interrupt,
+                       IRQF_TRIGGER_FALLING, client->dev.driver->name, data);
+       if (error) {
+               dev_err(&client->dev, "Failed to register interrupt\n");
+               goto err_free_mem;
+       }
+
+       error = input_register_device(input_dev);
+       if (error)
+               goto err_free_irq;
+
+       i2c_set_clientdata(client, data);
+       return 0;
+
+err_free_irq:
+       free_irq(client->irq, data);
+err_free_mem:
+       input_free_device(input_dev);
+       kfree(data);
+       return error;
+}
+
+static int __devexit mcs_touchkey_remove(struct i2c_client *client)
+{
+       struct mcs_touchkey_data *data = i2c_get_clientdata(client);
+
+       free_irq(client->irq, data);
+       input_unregister_device(data->input_dev);
+       kfree(data);
+
+       return 0;
+}
+
+static const struct i2c_device_id mcs_touchkey_id[] = {
+       { "mcs5000_touchkey", MCS5000_TOUCHKEY },
+       { "mcs5080_touchkey", MCS5080_TOUCHKEY },
+       { }
+};
+MODULE_DEVICE_TABLE(i2c, mcs_touchkey_id);
+
+static struct i2c_driver mcs_touchkey_driver = {
+       .driver = {
+               .name   = "mcs_touchkey",
+               .owner  = THIS_MODULE,
+       },
+       .probe          = mcs_touchkey_probe,
+       .remove         = __devexit_p(mcs_touchkey_remove),
+       .id_table       = mcs_touchkey_id,
+};
+
+static int __init mcs_touchkey_init(void)
+{
+       return i2c_add_driver(&mcs_touchkey_driver);
+}
+
+static void __exit mcs_touchkey_exit(void)
+{
+       i2c_del_driver(&mcs_touchkey_driver);
+}
+
+module_init(mcs_touchkey_init);
+module_exit(mcs_touchkey_exit);
+
+/* Module information */
+MODULE_AUTHOR("Joonyoung Shim <jy0922.shim@samsung.com>");
+MODULE_AUTHOR("HeungJun Kim <riverful.kim@samsung.com>");
+MODULE_DESCRIPTION("Touchkey driver for MELFAS MCS5000/5080 controller");
+MODULE_LICENSE("GPL");