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. 13 */ 14 15 /* 16 * This driver aims to support the series of MAXI touch chips max11801 17 * through max11803. The main difference between these 4 chips can be 18 * found in the table below: 19 * ----------------------------------------------------- 20 * | CHIP | AUTO MODE SUPPORT(FIFO) | INTERFACE | 21 * |----------------------------------------------------| 22 * | max11800 | YES | SPI | 23 * | max11801 | YES | I2C | 24 * | max11802 | NO | SPI | 25 * | max11803 | NO | I2C | 26 * ------------------------------------------------------ 27 * 28 * Currently, this driver only supports max11801. 29 * 30 * Data Sheet: 31 * http://www.maxim-ic.com/datasheet/index.mvp/id/5943 32 */ 33 34 #include <linux/module.h> 35 #include <linux/init.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 */ 75 enum { 76 EVENT_INIT, 77 EVENT_MIDDLE, 78 EVENT_RELEASE, 79 EVENT_FIFO_END 80 }; 81 82 struct max11801_data { 83 struct i2c_client *client; 84 struct input_dev *input_dev; 85 }; 86 87 static 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 93 static 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 99 static 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 } 154 out: 155 return IRQ_HANDLED; 156 } 157 158 static void __devinit 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 } 175 176 static int __devinit 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 = kzalloc(sizeof(struct max11801_data), GFP_KERNEL); 184 input_dev = input_allocate_device(); 185 if (!data || !input_dev) { 186 dev_err(&client->dev, "Failed to allocate memory\n"); 187 error = -ENOMEM; 188 goto err_free_mem; 189 } 190 191 data->client = client; 192 data->input_dev = input_dev; 193 194 input_dev->name = "max11801_ts"; 195 input_dev->id.bustype = BUS_I2C; 196 input_dev->dev.parent = &client->dev; 197 198 __set_bit(EV_ABS, input_dev->evbit); 199 __set_bit(EV_KEY, input_dev->evbit); 200 __set_bit(BTN_TOUCH, input_dev->keybit); 201 input_set_abs_params(input_dev, ABS_X, 0, MAX11801_MAX_X, 0, 0); 202 input_set_abs_params(input_dev, ABS_Y, 0, MAX11801_MAX_Y, 0, 0); 203 input_set_drvdata(input_dev, data); 204 205 max11801_ts_phy_init(data); 206 207 error = request_threaded_irq(client->irq, NULL, 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 goto err_free_mem; 213 } 214 215 error = input_register_device(data->input_dev); 216 if (error) 217 goto err_free_irq; 218 219 i2c_set_clientdata(client, data); 220 return 0; 221 222 err_free_irq: 223 free_irq(client->irq, data); 224 err_free_mem: 225 input_free_device(input_dev); 226 kfree(data); 227 return error; 228 } 229 230 static __devexit int max11801_ts_remove(struct i2c_client *client) 231 { 232 struct max11801_data *data = i2c_get_clientdata(client); 233 234 free_irq(client->irq, data); 235 input_unregister_device(data->input_dev); 236 kfree(data); 237 238 return 0; 239 } 240 241 static const struct i2c_device_id max11801_ts_id[] = { 242 {"max11801", 0}, 243 { } 244 }; 245 MODULE_DEVICE_TABLE(i2c, max11801_ts_id); 246 247 static struct i2c_driver max11801_ts_driver = { 248 .driver = { 249 .name = "max11801_ts", 250 .owner = THIS_MODULE, 251 }, 252 .id_table = max11801_ts_id, 253 .probe = max11801_ts_probe, 254 .remove = __devexit_p(max11801_ts_remove), 255 }; 256 257 static int __init max11801_ts_init(void) 258 { 259 return i2c_add_driver(&max11801_ts_driver); 260 } 261 262 static void __exit max11801_ts_exit(void) 263 { 264 i2c_del_driver(&max11801_ts_driver); 265 } 266 267 module_init(max11801_ts_init); 268 module_exit(max11801_ts_exit); 269 270 MODULE_AUTHOR("Zhang Jiejing <jiejing.zhang@freescale.com>"); 271 MODULE_DESCRIPTION("Touchscreen driver for MAXI MAX11801 controller"); 272 MODULE_LICENSE("GPL"); 273