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 __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 } 176 177 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 } 230 231 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 }; 257 258 static int __init max11801_ts_init(void) 259 { 260 return i2c_add_driver(&max11801_ts_driver); 261 } 262 263 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