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/init.h>
37 #include <linux/i2c.h>
38 #include <linux/interrupt.h>
39 #include <linux/input.h>
40 #include <linux/slab.h>
41 #include <linux/bitops.h>
42 
43 /* Register Address define */
44 #define GENERNAL_STATUS_REG		0x00
45 #define GENERNAL_CONF_REG		0x01
46 #define MESURE_RES_CONF_REG		0x02
47 #define MESURE_AVER_CONF_REG		0x03
48 #define ADC_SAMPLE_TIME_CONF_REG	0x04
49 #define PANEL_SETUPTIME_CONF_REG	0x05
50 #define DELAY_CONVERSION_CONF_REG	0x06
51 #define TOUCH_DETECT_PULLUP_CONF_REG	0x07
52 #define AUTO_MODE_TIME_CONF_REG		0x08 /* only for max11800/max11801 */
53 #define APERTURE_CONF_REG		0x09 /* only for max11800/max11801 */
54 #define AUX_MESURE_CONF_REG		0x0a
55 #define OP_MODE_CONF_REG		0x0b
56 
57 /* FIFO is found only in max11800 and max11801 */
58 #define FIFO_RD_CMD			(0x50 << 1)
59 #define MAX11801_FIFO_INT		(1 << 2)
60 #define MAX11801_FIFO_OVERFLOW		(1 << 3)
61 
62 #define XY_BUFSIZE			4
63 #define XY_BUF_OFFSET			4
64 
65 #define MAX11801_MAX_X			0xfff
66 #define MAX11801_MAX_Y			0xfff
67 
68 #define MEASURE_TAG_OFFSET		2
69 #define MEASURE_TAG_MASK		(3 << MEASURE_TAG_OFFSET)
70 #define EVENT_TAG_OFFSET		0
71 #define EVENT_TAG_MASK			(3 << EVENT_TAG_OFFSET)
72 #define MEASURE_X_TAG			(0 << MEASURE_TAG_OFFSET)
73 #define MEASURE_Y_TAG			(1 << MEASURE_TAG_OFFSET)
74 
75 /* These are the state of touch event state machine */
76 enum {
77 	EVENT_INIT,
78 	EVENT_MIDDLE,
79 	EVENT_RELEASE,
80 	EVENT_FIFO_END
81 };
82 
83 struct max11801_data {
84 	struct i2c_client		*client;
85 	struct input_dev		*input_dev;
86 };
87 
88 static u8 read_register(struct i2c_client *client, int addr)
89 {
90 	/* XXX: The chip ignores LSB of register address */
91 	return i2c_smbus_read_byte_data(client, addr << 1);
92 }
93 
94 static int max11801_write_reg(struct i2c_client *client, int addr, int data)
95 {
96 	/* XXX: The chip ignores LSB of register address */
97 	return i2c_smbus_write_byte_data(client, addr << 1, data);
98 }
99 
100 static irqreturn_t max11801_ts_interrupt(int irq, void *dev_id)
101 {
102 	struct max11801_data *data = dev_id;
103 	struct i2c_client *client = data->client;
104 	int status, i, ret;
105 	u8 buf[XY_BUFSIZE];
106 	int x = -1;
107 	int y = -1;
108 
109 	status = read_register(data->client, GENERNAL_STATUS_REG);
110 
111 	if (status & (MAX11801_FIFO_INT | MAX11801_FIFO_OVERFLOW)) {
112 		status = read_register(data->client, GENERNAL_STATUS_REG);
113 
114 		ret = i2c_smbus_read_i2c_block_data(client, FIFO_RD_CMD,
115 						    XY_BUFSIZE, buf);
116 
117 		/*
118 		 * We should get 4 bytes buffer that contains X,Y
119 		 * and event tag
120 		 */
121 		if (ret < XY_BUFSIZE)
122 			goto out;
123 
124 		for (i = 0; i < XY_BUFSIZE; i += XY_BUFSIZE / 2) {
125 			if ((buf[i + 1] & MEASURE_TAG_MASK) == MEASURE_X_TAG)
126 				x = (buf[i] << XY_BUF_OFFSET) +
127 				    (buf[i + 1] >> XY_BUF_OFFSET);
128 			else if ((buf[i + 1] & MEASURE_TAG_MASK) == MEASURE_Y_TAG)
129 				y = (buf[i] << XY_BUF_OFFSET) +
130 				    (buf[i + 1] >> XY_BUF_OFFSET);
131 		}
132 
133 		if ((buf[1] & EVENT_TAG_MASK) != (buf[3] & EVENT_TAG_MASK))
134 			goto out;
135 
136 		switch (buf[1] & EVENT_TAG_MASK) {
137 		case EVENT_INIT:
138 			/* fall through */
139 		case EVENT_MIDDLE:
140 			input_report_abs(data->input_dev, ABS_X, x);
141 			input_report_abs(data->input_dev, ABS_Y, y);
142 			input_event(data->input_dev, EV_KEY, BTN_TOUCH, 1);
143 			input_sync(data->input_dev);
144 			break;
145 
146 		case EVENT_RELEASE:
147 			input_event(data->input_dev, EV_KEY, BTN_TOUCH, 0);
148 			input_sync(data->input_dev);
149 			break;
150 
151 		case EVENT_FIFO_END:
152 			break;
153 		}
154 	}
155 out:
156 	return IRQ_HANDLED;
157 }
158 
159 static void max11801_ts_phy_init(struct max11801_data *data)
160 {
161 	struct i2c_client *client = data->client;
162 
163 	/* Average X,Y, take 16 samples, average eight media sample */
164 	max11801_write_reg(client, MESURE_AVER_CONF_REG, 0xff);
165 	/* X,Y panel setup time set to 20us */
166 	max11801_write_reg(client, PANEL_SETUPTIME_CONF_REG, 0x11);
167 	/* Rough pullup time (2uS), Fine pullup time (10us)  */
168 	max11801_write_reg(client, TOUCH_DETECT_PULLUP_CONF_REG, 0x10);
169 	/* Auto mode init period = 5ms , scan period = 5ms*/
170 	max11801_write_reg(client, AUTO_MODE_TIME_CONF_REG, 0xaa);
171 	/* Aperture X,Y set to +- 4LSB */
172 	max11801_write_reg(client, APERTURE_CONF_REG, 0x33);
173 	/* Enable Power, enable Automode, enable Aperture, enable Average X,Y */
174 	max11801_write_reg(client, OP_MODE_CONF_REG, 0x36);
175 }
176 
177 static int max11801_ts_probe(struct i2c_client *client,
178 				       const struct i2c_device_id *id)
179 {
180 	struct max11801_data *data;
181 	struct input_dev *input_dev;
182 	int error;
183 
184 	data = kzalloc(sizeof(struct max11801_data), GFP_KERNEL);
185 	input_dev = input_allocate_device();
186 	if (!data || !input_dev) {
187 		dev_err(&client->dev, "Failed to allocate memory\n");
188 		error = -ENOMEM;
189 		goto err_free_mem;
190 	}
191 
192 	data->client = client;
193 	data->input_dev = input_dev;
194 
195 	input_dev->name = "max11801_ts";
196 	input_dev->id.bustype = BUS_I2C;
197 	input_dev->dev.parent = &client->dev;
198 
199 	__set_bit(EV_ABS, input_dev->evbit);
200 	__set_bit(EV_KEY, input_dev->evbit);
201 	__set_bit(BTN_TOUCH, input_dev->keybit);
202 	input_set_abs_params(input_dev, ABS_X, 0, MAX11801_MAX_X, 0, 0);
203 	input_set_abs_params(input_dev, ABS_Y, 0, MAX11801_MAX_Y, 0, 0);
204 	input_set_drvdata(input_dev, data);
205 
206 	max11801_ts_phy_init(data);
207 
208 	error = request_threaded_irq(client->irq, NULL, max11801_ts_interrupt,
209 				     IRQF_TRIGGER_LOW | IRQF_ONESHOT,
210 				     "max11801_ts", data);
211 	if (error) {
212 		dev_err(&client->dev, "Failed to register interrupt\n");
213 		goto err_free_mem;
214 	}
215 
216 	error = input_register_device(data->input_dev);
217 	if (error)
218 		goto err_free_irq;
219 
220 	i2c_set_clientdata(client, data);
221 	return 0;
222 
223 err_free_irq:
224 	free_irq(client->irq, data);
225 err_free_mem:
226 	input_free_device(input_dev);
227 	kfree(data);
228 	return error;
229 }
230 
231 static int max11801_ts_remove(struct i2c_client *client)
232 {
233 	struct max11801_data *data = i2c_get_clientdata(client);
234 
235 	free_irq(client->irq, data);
236 	input_unregister_device(data->input_dev);
237 	kfree(data);
238 
239 	return 0;
240 }
241 
242 static const struct i2c_device_id max11801_ts_id[] = {
243 	{"max11801", 0},
244 	{ }
245 };
246 MODULE_DEVICE_TABLE(i2c, max11801_ts_id);
247 
248 static struct i2c_driver max11801_ts_driver = {
249 	.driver = {
250 		.name	= "max11801_ts",
251 		.owner	= THIS_MODULE,
252 	},
253 	.id_table	= max11801_ts_id,
254 	.probe		= max11801_ts_probe,
255 	.remove		= max11801_ts_remove,
256 };
257 
258 module_i2c_driver(max11801_ts_driver);
259 
260 MODULE_AUTHOR("Zhang Jiejing <jiejing.zhang@freescale.com>");
261 MODULE_DESCRIPTION("Touchscreen driver for MAXI MAX11801 controller");
262 MODULE_LICENSE("GPL");
263