Input: add driver for Maxim max11801 touchscreen controller

Add MAXI max11801 resistive touchscreen controller driver. This driver
uses Auto Mode and Aperture Mode.

Support for other max1180x devices can be added to this driver as well,
as they use almost the same register addresses and codes.

You can find data sheet here:
http://www.maxim-ic.com/datasheet/index.mvp/id/5943

Signed-off-by: Zhang Jiejing <jiejing.zhang@freescale.com>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>

drivers/input/touchscreen/Kconfig

@@ -248,6 +248,18 @@ config TOUCHSCREEN_LPC32XX
 	  To compile this driver as a module, choose M here: the
 	  module will be called lpc32xx_ts.
 
+config TOUCHSCREEN_MAX11801
+	tristate "MAX11801 based touchscreens"
+	depends on I2C
+	help
+	  Say Y here if you have a MAX11801 based touchscreen
+	  controller.
+
+	  If unsure, say N.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called max11801_ts.
+
 config TOUCHSCREEN_MCS5000
 	tristate "MELFAS MCS-5000 touchscreen"
 	depends on I2C

drivers/input/touchscreen/Makefile

@@ -27,6 +27,7 @@ obj-$(CONFIG_TOUCHSCREEN_FUJITSU)	+= fujitsu_ts.o
 obj-$(CONFIG_TOUCHSCREEN_INEXIO)	+= inexio.o
 obj-$(CONFIG_TOUCHSCREEN_INTEL_MID)	+= intel-mid-touch.o
 obj-$(CONFIG_TOUCHSCREEN_LPC32XX)	+= lpc32xx_ts.o
+obj-$(CONFIG_TOUCHSCREEN_MAX11801)	+= max11801_ts.o
 obj-$(CONFIG_TOUCHSCREEN_MC13783)	+= mc13783_ts.o
 obj-$(CONFIG_TOUCHSCREEN_MCS5000)	+= mcs5000_ts.o
 obj-$(CONFIG_TOUCHSCREEN_MIGOR)		+= migor_ts.o

drivers/input/touchscreen/max11801_ts.c

@@ -0,0 +1,272 @@
+/*
+ * Driver for MAXI MAX11801 - A Resistive touch screen controller with
+ * i2c interface
+ *
+ * Copyright (C) 2011 Freescale Semiconductor, Inc.
+ * Author: Zhang Jiejing <jiejing.zhang@freescale.com>
+ *
+ * Based on mcs5000_ts.c
+ *
+ * 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.
+ */
+
+/*
+ * This driver aims to support the series of MAXI touch chips max11801
+ * through max11803. The main difference between these 4 chips can be
+ * found in the table below:
+ * -----------------------------------------------------
+ * | CHIP     |  AUTO MODE SUPPORT(FIFO) | INTERFACE    |
+ * |----------------------------------------------------|
+ * | max11800 |  YES                     |   SPI        |
+ * | max11801 |  YES                     |   I2C        |
+ * | max11802 |  NO                      |   SPI        |
+ * | max11803 |  NO                      |   I2C        |
+ * ------------------------------------------------------
+ *
+ * Currently, this driver only supports max11801.
+ *
+ * Data Sheet:
+ * http://www.maxim-ic.com/datasheet/index.mvp/id/5943
+ */
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/i2c.h>
+#include <linux/interrupt.h>
+#include <linux/input.h>
+#include <linux/slab.h>
+#include <linux/bitops.h>
+
+/* Register Address define */
+#define GENERNAL_STATUS_REG		0x00
+#define GENERNAL_CONF_REG		0x01
+#define MESURE_RES_CONF_REG		0x02
+#define MESURE_AVER_CONF_REG		0x03
+#define ADC_SAMPLE_TIME_CONF_REG	0x04
+#define PANEL_SETUPTIME_CONF_REG	0x05
+#define DELAY_CONVERSION_CONF_REG	0x06
+#define TOUCH_DETECT_PULLUP_CONF_REG	0x07
+#define AUTO_MODE_TIME_CONF_REG		0x08 /* only for max11800/max11801 */
+#define APERTURE_CONF_REG		0x09 /* only for max11800/max11801 */
+#define AUX_MESURE_CONF_REG		0x0a
+#define OP_MODE_CONF_REG		0x0b
+
+/* FIFO is found only in max11800 and max11801 */
+#define FIFO_RD_CMD			(0x50 << 1)
+#define MAX11801_FIFO_INT		(1 << 2)
+#define MAX11801_FIFO_OVERFLOW		(1 << 3)
+
+#define XY_BUFSIZE			4
+#define XY_BUF_OFFSET			4
+
+#define MAX11801_MAX_X			0xfff
+#define MAX11801_MAX_Y			0xfff
+
+#define MEASURE_TAG_OFFSET		2
+#define MEASURE_TAG_MASK		(3 << MEASURE_TAG_OFFSET)
+#define EVENT_TAG_OFFSET		0
+#define EVENT_TAG_MASK			(3 << EVENT_TAG_OFFSET)
+#define MEASURE_X_TAG			(0 << MEASURE_TAG_OFFSET)
+#define MEASURE_Y_TAG			(1 << MEASURE_TAG_OFFSET)
+
+/* These are the state of touch event state machine */
+enum {
+	EVENT_INIT,
+	EVENT_MIDDLE,
+	EVENT_RELEASE,
+	EVENT_FIFO_END
+};
+
+struct max11801_data {
+	struct i2c_client		*client;
+	struct input_dev		*input_dev;
+};
+
+static u8 read_register(struct i2c_client *client, int addr)
+{
+	/* XXX: The chip ignores LSB of register address */
+	return i2c_smbus_read_byte_data(client, addr << 1);
+}
+
+static int max11801_write_reg(struct i2c_client *client, int addr, int data)
+{
+	/* XXX: The chip ignores LSB of register address */
+	return i2c_smbus_write_byte_data(client, addr << 1, data);
+}
+
+static irqreturn_t max11801_ts_interrupt(int irq, void *dev_id)
+{
+	struct max11801_data *data = dev_id;
+	struct i2c_client *client = data->client;
+	int status, i, ret;
+	u8 buf[XY_BUFSIZE];
+	int x = -1;
+	int y = -1;
+
+	status = read_register(data->client, GENERNAL_STATUS_REG);
+
+	if (status & (MAX11801_FIFO_INT | MAX11801_FIFO_OVERFLOW)) {
+		status = read_register(data->client, GENERNAL_STATUS_REG);
+
+		ret = i2c_smbus_read_i2c_block_data(client, FIFO_RD_CMD,
+						    XY_BUFSIZE, buf);
+
+		/*
+		 * We should get 4 bytes buffer that contains X,Y
+		 * and event tag
+		 */
+		if (ret < XY_BUFSIZE)
+			goto out;
+
+		for (i = 0; i < XY_BUFSIZE; i += XY_BUFSIZE / 2) {
+			if ((buf[i + 1] & MEASURE_TAG_MASK) == MEASURE_X_TAG)
+				x = (buf[i] << XY_BUF_OFFSET) +
+				    (buf[i + 1] >> XY_BUF_OFFSET);
+			else if ((buf[i + 1] & MEASURE_TAG_MASK) == MEASURE_Y_TAG)
+				y = (buf[i] << XY_BUF_OFFSET) +
+				    (buf[i + 1] >> XY_BUF_OFFSET);
+		}
+
+		if ((buf[1] & EVENT_TAG_MASK) != (buf[3] & EVENT_TAG_MASK))
+			goto out;
+
+		switch (buf[1] & EVENT_TAG_MASK) {
+		case EVENT_INIT:
+			/* fall through */
+		case EVENT_MIDDLE:
+			input_report_abs(data->input_dev, ABS_X, x);
+			input_report_abs(data->input_dev, ABS_Y, y);
+			input_event(data->input_dev, EV_KEY, BTN_TOUCH, 1);
+			input_sync(data->input_dev);
+			break;
+
+		case EVENT_RELEASE:
+			input_event(data->input_dev, EV_KEY, BTN_TOUCH, 0);
+			input_sync(data->input_dev);
+			break;
+
+		case EVENT_FIFO_END:
+			break;
+		}
+	}
+out:
+	return IRQ_HANDLED;
+}
+
+static void __devinit max11801_ts_phy_init(struct max11801_data *data)
+{
+	struct i2c_client *client = data->client;
+
+	/* Average X,Y, take 16 samples, average eight media sample */
+	max11801_write_reg(client, MESURE_AVER_CONF_REG, 0xff);
+	/* X,Y panel setup time set to 20us */
+	max11801_write_reg(client, PANEL_SETUPTIME_CONF_REG, 0x11);
+	/* Rough pullup time (2uS), Fine pullup time (10us)  */
+	max11801_write_reg(client, TOUCH_DETECT_PULLUP_CONF_REG, 0x10);
+	/* Auto mode init period = 5ms , scan period = 5ms*/
+	max11801_write_reg(client, AUTO_MODE_TIME_CONF_REG, 0xaa);
+	/* Aperture X,Y set to +- 4LSB */
+	max11801_write_reg(client, APERTURE_CONF_REG, 0x33);
+	/* Enable Power, enable Automode, enable Aperture, enable Average X,Y */
+	max11801_write_reg(client, OP_MODE_CONF_REG, 0x36);
+}
+
+static int __devinit max11801_ts_probe(struct i2c_client *client,
+				       const struct i2c_device_id *id)
+{
+	struct max11801_data *data;
+	struct input_dev *input_dev;
+	int error;
+
+	data = kzalloc(sizeof(struct max11801_data), 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;
+
+	input_dev->name = "max11801_ts";
+	input_dev->id.bustype = BUS_I2C;
+	input_dev->dev.parent = &client->dev;
+
+	__set_bit(EV_ABS, input_dev->evbit);
+	__set_bit(EV_KEY, input_dev->evbit);
+	__set_bit(BTN_TOUCH, input_dev->keybit);
+	input_set_abs_params(input_dev, ABS_X, 0, MAX11801_MAX_X, 0, 0);
+	input_set_abs_params(input_dev, ABS_Y, 0, MAX11801_MAX_Y, 0, 0);
+	input_set_drvdata(input_dev, data);
+
+	max11801_ts_phy_init(data);
+
+	error = request_threaded_irq(client->irq, NULL, max11801_ts_interrupt,
+				     IRQF_TRIGGER_LOW | IRQF_ONESHOT,
+				     "max11801_ts", data);
+	if (error) {
+		dev_err(&client->dev, "Failed to register interrupt\n");
+		goto err_free_mem;
+	}
+
+	error = input_register_device(data->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 __devexit int max11801_ts_remove(struct i2c_client *client)
+{
+	struct max11801_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 max11801_ts_id[] = {
+	{"max11801", 0},
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, max11801_ts_id);
+
+static struct i2c_driver max11801_ts_driver = {
+	.driver = {
+		.name	= "max11801_ts",
+		.owner	= THIS_MODULE,
+	},
+	.id_table	= max11801_ts_id,
+	.probe		= max11801_ts_probe,
+	.remove		= __devexit_p(max11801_ts_remove),
+};
+
+static int __init max11801_ts_init(void)
+{
+	return i2c_add_driver(&max11801_ts_driver);
+}
+
+static void __exit max11801_ts_exit(void)
+{
+	i2c_del_driver(&max11801_ts_driver);
+}
+
+module_init(max11801_ts_init);
+module_exit(max11801_ts_exit);
+
+MODULE_AUTHOR("Zhang Jiejing <jiejing.zhang@freescale.com>");
+MODULE_DESCRIPTION("Touchscreen driver for MAXI MAX11801 controller");
+MODULE_LICENSE("GPL");