1/*
2 * Driver for MAXI MAX11801 - A Resistive touch screen controller with
3 * i2c interface
4 *
5 * Copyright (C) 2011 Freescale Semiconductor, Inc.
6 * Author: Zhang Jiejing <jiejing.zhang@freescale.com>
7 *
8 * Based on mcs5000_ts.c
9 *
10 * This program is free software; you can redistribute it and/or modify
11 * it under the terms of the GNU General Public License as published by
12 * the Free Software Foundation; either version 2 of the License, or
13 * (at your option) any later version.
14 */
15
16/*
17 * This driver aims to support the series of MAXI touch chips max11801
18 * through max11803. The main difference between these 4 chips can be
19 * found in the table below:
20 * -----------------------------------------------------
21 * | CHIP     |  AUTO MODE SUPPORT(FIFO) | INTERFACE    |
22 * |----------------------------------------------------|
23 * | max11800 |  YES                     |   SPI        |
24 * | max11801 |  YES                     |   I2C        |
25 * | max11802 |  NO                      |   SPI        |
26 * | max11803 |  NO                      |   I2C        |
27 * ------------------------------------------------------
28 *
29 * Currently, this driver only supports max11801.
30 *
31 * Data Sheet:
32 * http://www.maxim-ic.com/datasheet/index.mvp/id/5943
33 */
34
35#include <linux/module.h>
36#include <linux/i2c.h>
37#include <linux/interrupt.h>
38#include <linux/input.h>
39#include <linux/slab.h>
40#include <linux/bitops.h>
41
42/* Register Address define */
43#define GENERNAL_STATUS_REG		0x00
44#define GENERNAL_CONF_REG		0x01
45#define MESURE_RES_CONF_REG		0x02
46#define MESURE_AVER_CONF_REG		0x03
47#define ADC_SAMPLE_TIME_CONF_REG	0x04
48#define PANEL_SETUPTIME_CONF_REG	0x05
49#define DELAY_CONVERSION_CONF_REG	0x06
50#define TOUCH_DETECT_PULLUP_CONF_REG	0x07
51#define AUTO_MODE_TIME_CONF_REG		0x08 /* only for max11800/max11801 */
52#define APERTURE_CONF_REG		0x09 /* only for max11800/max11801 */
53#define AUX_MESURE_CONF_REG		0x0a
54#define OP_MODE_CONF_REG		0x0b
55
56/* FIFO is found only in max11800 and max11801 */
57#define FIFO_RD_CMD			(0x50 << 1)
58#define MAX11801_FIFO_INT		(1 << 2)
59#define MAX11801_FIFO_OVERFLOW		(1 << 3)
60
61#define XY_BUFSIZE			4
62#define XY_BUF_OFFSET			4
63
64#define MAX11801_MAX_X			0xfff
65#define MAX11801_MAX_Y			0xfff
66
67#define MEASURE_TAG_OFFSET		2
68#define MEASURE_TAG_MASK		(3 << MEASURE_TAG_OFFSET)
69#define EVENT_TAG_OFFSET		0
70#define EVENT_TAG_MASK			(3 << EVENT_TAG_OFFSET)
71#define MEASURE_X_TAG			(0 << MEASURE_TAG_OFFSET)
72#define MEASURE_Y_TAG			(1 << MEASURE_TAG_OFFSET)
73
74/* These are the state of touch event state machine */
75enum {
76	EVENT_INIT,
77	EVENT_MIDDLE,
78	EVENT_RELEASE,
79	EVENT_FIFO_END
80};
81
82struct max11801_data {
83	struct i2c_client		*client;
84	struct input_dev		*input_dev;
85};
86
87static u8 read_register(struct i2c_client *client, int addr)
88{
89	/* XXX: The chip ignores LSB of register address */
90	return i2c_smbus_read_byte_data(client, addr << 1);
91}
92
93static int max11801_write_reg(struct i2c_client *client, int addr, int data)
94{
95	/* XXX: The chip ignores LSB of register address */
96	return i2c_smbus_write_byte_data(client, addr << 1, data);
97}
98
99static irqreturn_t max11801_ts_interrupt(int irq, void *dev_id)
100{
101	struct max11801_data *data = dev_id;
102	struct i2c_client *client = data->client;
103	int status, i, ret;
104	u8 buf[XY_BUFSIZE];
105	int x = -1;
106	int y = -1;
107
108	status = read_register(data->client, GENERNAL_STATUS_REG);
109
110	if (status & (MAX11801_FIFO_INT | MAX11801_FIFO_OVERFLOW)) {
111		status = read_register(data->client, GENERNAL_STATUS_REG);
112
113		ret = i2c_smbus_read_i2c_block_data(client, FIFO_RD_CMD,
114						    XY_BUFSIZE, buf);
115
116		/*
117		 * We should get 4 bytes buffer that contains X,Y
118		 * and event tag
119		 */
120		if (ret < XY_BUFSIZE)
121			goto out;
122
123		for (i = 0; i < XY_BUFSIZE; i += XY_BUFSIZE / 2) {
124			if ((buf[i + 1] & MEASURE_TAG_MASK) == MEASURE_X_TAG)
125				x = (buf[i] << XY_BUF_OFFSET) +
126				    (buf[i + 1] >> XY_BUF_OFFSET);
127			else if ((buf[i + 1] & MEASURE_TAG_MASK) == MEASURE_Y_TAG)
128				y = (buf[i] << XY_BUF_OFFSET) +
129				    (buf[i + 1] >> XY_BUF_OFFSET);
130		}
131
132		if ((buf[1] & EVENT_TAG_MASK) != (buf[3] & EVENT_TAG_MASK))
133			goto out;
134
135		switch (buf[1] & EVENT_TAG_MASK) {
136		case EVENT_INIT:
137			/* fall through */
138		case EVENT_MIDDLE:
139			input_report_abs(data->input_dev, ABS_X, x);
140			input_report_abs(data->input_dev, ABS_Y, y);
141			input_event(data->input_dev, EV_KEY, BTN_TOUCH, 1);
142			input_sync(data->input_dev);
143			break;
144
145		case EVENT_RELEASE:
146			input_event(data->input_dev, EV_KEY, BTN_TOUCH, 0);
147			input_sync(data->input_dev);
148			break;
149
150		case EVENT_FIFO_END:
151			break;
152		}
153	}
154out:
155	return IRQ_HANDLED;
156}
157
158static void max11801_ts_phy_init(struct max11801_data *data)
159{
160	struct i2c_client *client = data->client;
161
162	/* Average X,Y, take 16 samples, average eight media sample */
163	max11801_write_reg(client, MESURE_AVER_CONF_REG, 0xff);
164	/* X,Y panel setup time set to 20us */
165	max11801_write_reg(client, PANEL_SETUPTIME_CONF_REG, 0x11);
166	/* Rough pullup time (2uS), Fine pullup time (10us)  */
167	max11801_write_reg(client, TOUCH_DETECT_PULLUP_CONF_REG, 0x10);
168	/* Auto mode init period = 5ms , scan period = 5ms*/
169	max11801_write_reg(client, AUTO_MODE_TIME_CONF_REG, 0xaa);
170	/* Aperture X,Y set to +- 4LSB */
171	max11801_write_reg(client, APERTURE_CONF_REG, 0x33);
172	/* Enable Power, enable Automode, enable Aperture, enable Average X,Y */
173	max11801_write_reg(client, OP_MODE_CONF_REG, 0x36);
174}
175
176static int max11801_ts_probe(struct i2c_client *client,
177				       const struct i2c_device_id *id)
178{
179	struct max11801_data *data;
180	struct input_dev *input_dev;
181	int error;
182
183	data = devm_kzalloc(&client->dev, sizeof(*data), GFP_KERNEL);
184	input_dev = devm_input_allocate_device(&client->dev);
185	if (!data || !input_dev) {
186		dev_err(&client->dev, "Failed to allocate memory\n");
187		return -ENOMEM;
188	}
189
190	data->client = client;
191	data->input_dev = input_dev;
192
193	input_dev->name = "max11801_ts";
194	input_dev->id.bustype = BUS_I2C;
195	input_dev->dev.parent = &client->dev;
196
197	__set_bit(EV_ABS, input_dev->evbit);
198	__set_bit(EV_KEY, input_dev->evbit);
199	__set_bit(BTN_TOUCH, input_dev->keybit);
200	input_set_abs_params(input_dev, ABS_X, 0, MAX11801_MAX_X, 0, 0);
201	input_set_abs_params(input_dev, ABS_Y, 0, MAX11801_MAX_Y, 0, 0);
202	input_set_drvdata(input_dev, data);
203
204	max11801_ts_phy_init(data);
205
206	error = devm_request_threaded_irq(&client->dev, client->irq, NULL,
207					  max11801_ts_interrupt,
208					  IRQF_TRIGGER_LOW | IRQF_ONESHOT,
209					  "max11801_ts", data);
210	if (error) {
211		dev_err(&client->dev, "Failed to register interrupt\n");
212		return error;
213	}
214
215	error = input_register_device(data->input_dev);
216	if (error)
217		return error;
218
219	i2c_set_clientdata(client, data);
220	return 0;
221}
222
223static const struct i2c_device_id max11801_ts_id[] = {
224	{"max11801", 0},
225	{ }
226};
227MODULE_DEVICE_TABLE(i2c, max11801_ts_id);
228
229static struct i2c_driver max11801_ts_driver = {
230	.driver = {
231		.name	= "max11801_ts",
232	},
233	.id_table	= max11801_ts_id,
234	.probe		= max11801_ts_probe,
235};
236
237module_i2c_driver(max11801_ts_driver);
238
239MODULE_AUTHOR("Zhang Jiejing <jiejing.zhang@freescale.com>");
240MODULE_DESCRIPTION("Touchscreen driver for MAXI MAX11801 controller");
241MODULE_LICENSE("GPL");
242