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
read_register(struct i2c_client * client,int addr)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
max11801_write_reg(struct i2c_client * client,int addr,int data)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
max11801_ts_interrupt(int irq,void * dev_id)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
max11801_ts_phy_init(struct max11801_data * data)159 static void __devinit 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
max11801_ts_probe(struct i2c_client * client,const struct i2c_device_id * id)177 static int __devinit 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
max11801_ts_remove(struct i2c_client * client)231 static __devexit 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 = __devexit_p(max11801_ts_remove),
256 };
257
max11801_ts_init(void)258 static int __init max11801_ts_init(void)
259 {
260 return i2c_add_driver(&max11801_ts_driver);
261 }
262
max11801_ts_exit(void)263 static void __exit max11801_ts_exit(void)
264 {
265 i2c_del_driver(&max11801_ts_driver);
266 }
267
268 module_init(max11801_ts_init);
269 module_exit(max11801_ts_exit);
270
271 MODULE_AUTHOR("Zhang Jiejing <jiejing.zhang@freescale.com>");
272 MODULE_DESCRIPTION("Touchscreen driver for MAXI MAX11801 controller");
273 MODULE_LICENSE("GPL");
274