drivers/input/touchscreen/max11801_ts.c

   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");