aboutsummaryrefslogtreecommitdiffstats
path: root/drivers/input/touchscreen/max11801_ts.c
blob: a68ec142ee9a5bceea5674397c8b5bfc573c9fc3 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
/*
 * 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, or
 * (at your option) any later version.
 */

/*
 * 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/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 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 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 = devm_kzalloc(&client->dev, sizeof(*data), GFP_KERNEL);
	input_dev = devm_input_allocate_device(&client->dev);
	if (!data || !input_dev) {
		dev_err(&client->dev, "Failed to allocate memory\n");
		return -ENOMEM;
	}

	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 = devm_request_threaded_irq(&client->dev, 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");
		return error;
	}

	error = input_register_device(data->input_dev);
	if (error)
		return error;

	i2c_set_clientdata(client, 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,
};

module_i2c_driver(max11801_ts_driver);

MODULE_AUTHOR("Zhang Jiejing <jiejing.zhang@freescale.com>");
MODULE_DESCRIPTION("Touchscreen driver for MAXI MAX11801 controller");
MODULE_LICENSE("GPL");