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/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 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 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 = devm_kzalloc(&client->dev, sizeof(*data), GFP_KERNEL);
 184         input_dev = devm_input_allocate_device(&client->dev);
 185         if (!data || !input_dev) {
 186                 dev_err(&client->dev, "Failed to allocate memory\n");
 187                 return -ENOMEM;
 188         }
 189
 190         data->client = client;
 191         data->input_dev = input_dev;
 192
 193         input_dev->name = "max11801_ts";
 194         input_dev->id.bustype = BUS_I2C;
 195         input_dev->dev.parent = &client->dev;
 196
 197         __set_bit(EV_ABS, input_dev->evbit);
 198         __set_bit(EV_KEY, input_dev->evbit);
 199         __set_bit(BTN_TOUCH, input_dev->keybit);
 200         input_set_abs_params(input_dev, ABS_X, 0, MAX11801_MAX_X, 0, 0);
 201         input_set_abs_params(input_dev, ABS_Y, 0, MAX11801_MAX_Y, 0, 0);
 202         input_set_drvdata(input_dev, data);
 203
 204         max11801_ts_phy_init(data);
 205
 206         error = devm_request_threaded_irq(&client->dev, client->irq, NULL,
 207                                           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                 return error;
 213         }
 214
 215         error = input_register_device(data->input_dev);
 216         if (error)
 217                 return error;
 218
 219         i2c_set_clientdata(client, data);
 220         return 0;
 221 }
 222
 223 static const struct i2c_device_id max11801_ts_id[] = {
 224         {"max11801", 0},
 225         { }
 226 };
 227 MODULE_DEVICE_TABLE(i2c, max11801_ts_id);
 228
 229 static struct i2c_driver max11801_ts_driver = {
 230         .driver = {
 231                 .name   = "max11801_ts",
 232         },
 233         .id_table       = max11801_ts_id,
 234         .probe          = max11801_ts_probe,
 235 };
 236
 237 module_i2c_driver(max11801_ts_driver);
 238
 239 MODULE_AUTHOR("Zhang Jiejing <jiejing.zhang@freescale.com>");
 240 MODULE_DESCRIPTION("Touchscreen driver for MAXI MAX11801 controller");
 241 MODULE_LICENSE("GPL");