[PATCH] input: add mpr121 capacitive touchkey driver

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From: Zhang Jiejing <jiejing.zhang@xxxxxxxxxxxxx>

This touchkey driver is based on Freescale mpr121 capacitive
touch sensor controller.

It can support up to 12 keys, it use i2c interface.

The product infomation(data sheet, application notes) can
be found under this link:
http://www.freescale.com/webapp/sps/site/prod_summary.jsp?code=MPR121

Signed-off-by: Zhang Jiejing <jiejing.zhang@xxxxxxxxxxxxx>
---
 drivers/input/keyboard/Kconfig  |   12 ++
 drivers/input/keyboard/Makefile |    1 +
 drivers/input/keyboard/mpr121.c |  301 +++++++++++++++++++++++++++++++++++++++
 include/linux/i2c/mpr.h         |   64 ++++++++
 4 files changed, 378 insertions(+), 0 deletions(-)
 create mode 100644 drivers/input/keyboard/mpr121.c
 create mode 100644 include/linux/i2c/mpr.h

diff --git a/drivers/input/keyboard/Kconfig b/drivers/input/keyboard/Kconfig
index b16bed0..0666e1e 100644
--- a/drivers/input/keyboard/Kconfig
+++ b/drivers/input/keyboard/Kconfig
@@ -520,6 +520,18 @@ config KEYBOARD_XTKBD
 	  To compile this driver as a module, choose M here: the
 	  module will be called xtkbd.
 
+config KEYBOARD_MPR121
+	tristate "Freescale MPR121 Touchkey Driver"
+	depends on I2C
+	help
+	  Say Y here if you have the  touchkey Freescale mpr121 capacitive
+	  touch sensor controller in your system.
+
+	  If unsure, say N.
+
+	  To compile this driver as a module, choose M here
+endif
+
 config KEYBOARD_W90P910
 	tristate "W90P910 Matrix Keypad support"
 	depends on ARCH_W90X900
diff --git a/drivers/input/keyboard/Makefile b/drivers/input/keyboard/Makefile
index 878e6c2..b110ca8 100644
--- a/drivers/input/keyboard/Makefile
+++ b/drivers/input/keyboard/Makefile
@@ -47,4 +47,5 @@ obj-$(CONFIG_KEYBOARD_TEGRA)		+= tegra-kbc.o
 obj-$(CONFIG_KEYBOARD_TNETV107X)	+= tnetv107x-keypad.o
 obj-$(CONFIG_KEYBOARD_TWL4030)		+= twl4030_keypad.o
 obj-$(CONFIG_KEYBOARD_XTKBD)		+= xtkbd.o
+obj-$(CONFIG_KEYBOARD_MPR121)		+= mpr121.o
 obj-$(CONFIG_KEYBOARD_W90P910)		+= w90p910_keypad.o
diff --git a/drivers/input/keyboard/mpr121.c b/drivers/input/keyboard/mpr121.c
new file mode 100644
index 0000000..ee149a8
--- /dev/null
+++ b/drivers/input/keyboard/mpr121.c
@@ -0,0 +1,301 @@
+/*
+ * Touchkey driver for Freescale MPR121 Controllor
+ *
+ * Copyright (C) 2011 Freescale Semiconductor, Inc.
+ * Author: Zhang Jiejing <jiejing.zhang@xxxxxxxxxxxxx>
+ *
+ * Based on mcs_touchkey.c
+ *
+ * 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/module.h>
+#include <linux/init.h>
+#include <linux/i2c.h>
+#include <linux/i2c/mpr.h>
+#include <linux/interrupt.h>
+#include <linux/input.h>
+#include <linux/irq.h>
+#include <linux/slab.h>
+#include <linux/delay.h>
+#include <linux/bitops.h>
+
+struct mpr121_touchkey_data {
+	struct i2c_client	*client;
+	struct input_dev	*input_dev;
+	unsigned int		key_val;
+	int			statusbits;
+	int			keycount;
+	u16			keycodes[MPR121_MAX_KEY_COUNT];
+};
+
+struct mpr121_init_register {
+	int addr;
+	u8 val;
+};
+
+static struct mpr121_init_register init_reg_table[] = {
+	{MHD_RISING_ADDR,	0x1},
+	{NHD_RISING_ADDR,	0x1},
+	{MHD_FALLING_ADDR,	0x1},
+	{NHD_FALLING_ADDR,	0x1},
+	{NCL_FALLING_ADDR,	0xff},
+	{FDL_FALLING_ADDR,	0x02},
+	{FILTER_CONF_ADDR,	0x04},
+	{AFE_CONF_ADDR,		0x0b},
+	{AUTO_CONFIG_CTRL_ADDR, 0x0b},
+};
+
+static irqreturn_t mpr_touchkey_interrupt(int irq, void *dev_id)
+{
+	struct mpr121_touchkey_data *data = dev_id;
+	struct i2c_client *client = data->client;
+	struct input_dev *input = data->input_dev;
+	unsigned int key_num, pressed;
+	int reg;
+
+	reg = i2c_smbus_read_byte_data(client, ELE_TOUCH_STATUS_1_ADDR);
+	if (reg < 0) {
+		dev_err(&client->dev, "i2c read error [%d]\n", reg);
+		goto out;
+	}
+
+	reg <<= 8;
+	reg |= i2c_smbus_read_byte_data(client, ELE_TOUCH_STATUS_0_ADDR);
+	if (reg < 0) {
+		dev_err(&client->dev, "i2c read error [%d]\n", reg);
+		goto out;
+	}
+
+	reg &= TOUCH_STATUS_MASK;
+	/* use old press bit to figure out which bit changed */
+	key_num = ffs(reg ^ data->statusbits) - 1;
+	/* use the bit check the press status */
+	pressed = (reg & (1 << (key_num))) >> key_num;
+	data->statusbits = reg;
+	data->key_val = data->keycodes[key_num];
+
+	input_event(input, EV_MSC, MSC_SCAN, data->key_val);
+	input_report_key(input, data->key_val, pressed);
+	input_sync(input);
+
+	dev_dbg(&client->dev, "key %d %d %s\n", key_num, data->key_val,
+		pressed ? "pressed" : "released");
+
+out:
+	return IRQ_HANDLED;
+}
+
+static int mpr121_phys_init(struct mpr121_platform_data *pdata,
+			    struct mpr121_touchkey_data *data,
+			    struct i2c_client *client)
+{
+	struct mpr121_init_register *reg;
+	unsigned char usl, lsl, tl;
+	int i, t, vdd, ret;
+
+	/* setup touch/release threshold for ele0-ele11 */
+	for (i = 0; i <= MPR121_MAX_KEY_COUNT; i++) {
+		t = ELE0_TOUCH_THRESHOLD_ADDR + (i * 2);
+		ret = i2c_smbus_write_byte_data(client, t, TOUCH_THRESHOLD);
+		if (ret < 0)
+			goto err_i2c_write;
+		ret = i2c_smbus_write_byte_data(client, t + 1,
+						RELEASE_THRESHOLD);
+		if (ret < 0)
+			goto err_i2c_write;
+	}
+	/* setup init register */
+	for (i = 0; i < ARRAY_SIZE(init_reg_table); i++) {
+		reg = &init_reg_table[i];
+		ret = i2c_smbus_write_byte_data(client, reg->addr, reg->val);
+		if (ret < 0)
+			goto err_i2c_write;
+	}
+	/* setup auto-register by vdd,the formula please ref: AN3889
+	 * These register *must* set acrodding your VDD voltage supply
+	 * to the chip*/
+	vdd = pdata->vdd_uv / 1000;
+	usl = ((vdd - 700) * 256) / vdd;
+	lsl = (usl * 65) / 100;
+	tl = (usl * 90) / 100;
+	ret = i2c_smbus_write_byte_data(client, AUTO_CONFIG_USL_ADDR, usl);
+	ret |= i2c_smbus_write_byte_data(client, AUTO_CONFIG_LSL_ADDR, lsl);
+	ret |= i2c_smbus_write_byte_data(client, AUTO_CONFIG_TL_ADDR, tl);
+	ret |= i2c_smbus_write_byte_data(client, ELECTRODE_CONF_ADDR,
+					data->keycount);
+	if (ret != 0)
+		goto err_i2c_write;
+
+	dev_info(&client->dev, "mpr121: config as enable %x of electrode.\n",
+		 data->keycount);
+
+	return 0;
+
+err_i2c_write:
+	dev_err(&client->dev, "i2c write error: %d\n", ret);
+	return ret;
+}
+
+static int __devinit mpr_touchkey_probe(struct i2c_client *client,
+					const struct i2c_device_id *id)
+{
+	struct mpr121_platform_data *pdata;
+	struct mpr121_touchkey_data *data;
+	struct input_dev *input_dev;
+	int error;
+	int i;
+
+	pdata = client->dev.platform_data;
+	if (!pdata) {
+		dev_err(&client->dev, "no platform data defined\n");
+		return -EINVAL;
+	}
+
+	if (!client->irq) {
+		dev_err(&client->dev, "The irq number should not be zero\n");
+		return -EINVAL;
+	}
+
+	data = kzalloc(sizeof(struct mpr121_touchkey_data), GFP_KERNEL);
+	input_dev = input_allocate_device();
+	if (!data || !input_dev) {
+		dev_err(&client->dev, "Falied to allocate memory\n");
+		error = -ENOMEM;
+		goto err_free_mem;
+	}
+
+	data->client = client;
+	data->input_dev = input_dev;
+	data->keycount = pdata->keycount;
+
+	if (data->keycount > MPR121_MAX_KEY_COUNT) {
+		dev_err(&client->dev, "Too many key defined\n");
+		error = -EINVAL;
+		goto err_free_mem;
+	}
+
+	error = mpr121_phys_init(pdata, data, client);
+	if (error) {
+		dev_err(&client->dev, "Failed to init register\n");
+		goto err_free_mem;
+	}
+
+	i2c_set_clientdata(client, data);
+
+	input_dev->name = "FSL MPR121 Touchkey";
+	input_dev->id.bustype = BUS_I2C;
+	input_dev->dev.parent = &client->dev;
+	input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_REP);
+	input_dev->keycode = pdata->matrix;
+	input_dev->keycodesize = sizeof(pdata->matrix[0]);
+	input_dev->keycodemax = data->keycount;
+
+	for (i = 0; i < input_dev->keycodemax; i++) {
+		__set_bit(pdata->matrix[i], input_dev->keybit);
+		data->keycodes[i] = pdata->matrix[i];
+	}
+
+	input_set_capability(input_dev, EV_MSC, MSC_SCAN);
+	input_set_drvdata(input_dev, data);
+
+	error = request_threaded_irq(client->irq, NULL,
+				     mpr_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);
+	device_init_wakeup(&client->dev, pdata->wakeup);
+	dev_info(&client->dev, "Mpr121 touch keyboard init success.\n");
+	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 mpr_touchkey_remove(struct i2c_client *client)
+{
+	struct mpr121_touchkey_data *data = i2c_get_clientdata(client);
+
+	free_irq(client->irq, data);
+	input_unregister_device(data->input_dev);
+	kfree(data);
+
+	return 0;
+}
+
+#ifdef CONFIG_PM_SLEEP
+static int mpr_suspend(struct device *dev)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+
+	if (device_may_wakeup(&client->dev))
+		enable_irq_wake(client->irq);
+
+	i2c_smbus_write_byte_data(client, ELECTRODE_CONF_ADDR, 0x00);
+
+	return 0;
+}
+
+static int mpr_resume(struct device *dev)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct mpr121_touchkey_data *data = i2c_get_clientdata(client);
+
+	if (device_may_wakeup(&client->dev))
+		disable_irq_wake(client->irq);
+
+	i2c_smbus_write_byte_data(client, ELECTRODE_CONF_ADDR, data->keycount);
+
+	return 0;
+}
+#endif
+
+static const struct i2c_device_id mpr121_id[] = {
+	{"mpr121_touchkey", 0},
+	{ }
+};
+
+static SIMPLE_DEV_PM_OPS(mpr121_touchkey_pm_ops, mpr_suspend, mpr_resume);
+
+static struct i2c_driver mpr_touchkey_driver = {
+	.driver = {
+		.name	= "mpr121",
+		.owner	= THIS_MODULE,
+		.pm	= &mpr121_touchkey_pm_ops,
+	},
+	.id_table	= mpr121_id,
+	.probe		= mpr_touchkey_probe,
+	.remove		= __devexit_p(mpr_touchkey_remove),
+};
+
+static int __init mpr_touchkey_init(void)
+{
+	return i2c_add_driver(&mpr_touchkey_driver);
+}
+
+static void __exit mpr_touchkey_exit(void)
+{
+	i2c_del_driver(&mpr_touchkey_driver);
+}
+
+module_init(mpr_touchkey_init);
+module_exit(mpr_touchkey_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Zhang Jiejing <jiejing.zhang@xxxxxxxxxxxxx>");
+MODULE_DESCRIPTION("Touch Key driver for FSL MPR121 Chip");
diff --git a/include/linux/i2c/mpr.h b/include/linux/i2c/mpr.h
new file mode 100644
index 0000000..52d6e33
--- /dev/null
+++ b/include/linux/i2c/mpr.h
@@ -0,0 +1,64 @@
+/* mpr.h - Header file for Freescale mpr121 capacitive touch sensor
+ * controllor */
+
+#ifndef MPR_H
+#define MPR_H
+
+/* Register definitions */
+#define ELE_TOUCH_STATUS_0_ADDR	0x0
+#define ELE_TOUCH_STATUS_1_ADDR	0X1
+#define MHD_RISING_ADDR		0x2b
+#define NHD_RISING_ADDR		0x2c
+#define NCL_RISING_ADDR		0x2d
+#define FDL_RISING_ADDR		0x2e
+#define MHD_FALLING_ADDR	0x2f
+#define NHD_FALLING_ADDR	0x30
+#define NCL_FALLING_ADDR	0x31
+#define FDL_FALLING_ADDR	0x32
+#define ELE0_TOUCH_THRESHOLD_ADDR	0x41
+#define ELE0_RELEASE_THRESHOLD_ADDR	0x42
+/* ELE0...ELE11's threshold will set in a loop */
+#define AFE_CONF_ADDR			0x5c
+#define FILTER_CONF_ADDR		0x5d
+
+/* ELECTRODE_CONF: this register is most important register, it
+ * control how many of electrode is enabled. If you set this register
+ * to 0x0, it make the sensor going to suspend mode. Other value(low
+ * bit is non-zero) will make the sensor into Run mode.  This register
+ * should be write at last.
+ */
+#define ELECTRODE_CONF_ADDR		0x5e
+#define AUTO_CONFIG_CTRL_ADDR		0x7b
+/* AUTO_CONFIG_USL: Upper Limit for auto baseline search, this
+ * register is related to VDD supplied on your board, the value of
+ * this register is calc by EQ: `((VDD-0.7)/VDD) * 256`.
+ * AUTO_CONFIG_LSL: Low Limit of auto baseline search. This is 65% of
+ * USL AUTO_CONFIG_TL: The Traget Level of auto baseline search, This
+ * is 90% of USL  */
+#define AUTO_CONFIG_USL_ADDR		0x7d
+#define AUTO_CONFIG_LSL_ADDR		0x7e
+#define AUTO_CONFIG_TL_ADDR		0x7f
+
+/* Threshold of touch/release trigger */
+#define TOUCH_THRESHOLD			0x0f
+#define RELEASE_THRESHOLD		0x0a
+/* Mask Button bits of STATUS_0 & STATUS_1 register */
+#define TOUCH_STATUS_MASK		0xfff
+/* MPR121 have 12 electrodes */
+#define MPR121_MAX_KEY_COUNT		12
+
+
+/**
+ * @keycount: how many key maped
+ * @vdd_uv: voltage of vdd supply the chip in uV
+ * @matrix: maxtrix of keys
+ * @wakeup: can key wake up system.
+ */
+struct mpr121_platform_data {
+	u16 keycount;
+	u16 *matrix;
+	int wakeup;
+	int vdd_uv;
+};
+
+#endif
-- 
1.7.1

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