drivers/input/touchscreen/max11801_ts.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * Driver for MAXI MAX11801 - A Resistive touch screen controller with
   4  * i2c interface
   5  *
   6  * Copyright (C) 2011 Freescale Semiconductor, Inc.
   7  * Author: Zhang Jiejing <jiejing.zhang@freescale.com>
   8  *
   9  * Based on mcs5000_ts.c
  10  */
  11
  12 /*
  13  * This driver aims to support the series of MAXI touch chips max11801
  14  * through max11803. The main difference between these 4 chips can be
  15  * found in the table below:
  16  * -----------------------------------------------------
  17  * | CHIP     |  AUTO MODE SUPPORT(FIFO) | INTERFACE    |
  18  * |----------------------------------------------------|
  19  * | max11800 |  YES                     |   SPI        |
  20  * | max11801 |  YES                     |   I2C        |
  21  * | max11802 |  NO                      |   SPI        |
  22  * | max11803 |  NO                      |   I2C        |
  23  * ------------------------------------------------------
  24  *
  25  * Currently, this driver only supports max11801.
  26  *
  27  * Data Sheet:
  28  * http://www.maxim-ic.com/datasheet/index.mvp/id/5943
  29  */
  30
  31 #include <linux/module.h>
  32 #include <linux/i2c.h>
  33 #include <linux/interrupt.h>
  34 #include <linux/input.h>
  35 #include <linux/slab.h>
  36 #include <linux/bitops.h>
  37
  38 /* Register Address define */
  39 #define GENERNAL_STATUS_REG             0x00
  40 #define GENERNAL_CONF_REG               0x01
  41 #define MESURE_RES_CONF_REG             0x02
  42 #define MESURE_AVER_CONF_REG            0x03
  43 #define ADC_SAMPLE_TIME_CONF_REG        0x04
  44 #define PANEL_SETUPTIME_CONF_REG        0x05
  45 #define DELAY_CONVERSION_CONF_REG       0x06
  46 #define TOUCH_DETECT_PULLUP_CONF_REG    0x07
  47 #define AUTO_MODE_TIME_CONF_REG         0x08 /* only for max11800/max11801 */
  48 #define APERTURE_CONF_REG               0x09 /* only for max11800/max11801 */
  49 #define AUX_MESURE_CONF_REG             0x0a
  50 #define OP_MODE_CONF_REG                0x0b
  51
  52 /* FIFO is found only in max11800 and max11801 */
  53 #define FIFO_RD_CMD                     (0x50 << 1)
  54 #define MAX11801_FIFO_INT               (1 << 2)
  55 #define MAX11801_FIFO_OVERFLOW          (1 << 3)
  56
  57 #define XY_BUFSIZE                      4
  58 #define XY_BUF_OFFSET                   4
  59
  60 #define MAX11801_MAX_X                  0xfff
  61 #define MAX11801_MAX_Y                  0xfff
  62
  63 #define MEASURE_TAG_OFFSET              2
  64 #define MEASURE_TAG_MASK                (3 << MEASURE_TAG_OFFSET)
  65 #define EVENT_TAG_OFFSET                0
  66 #define EVENT_TAG_MASK                  (3 << EVENT_TAG_OFFSET)
  67 #define MEASURE_X_TAG                   (0 << MEASURE_TAG_OFFSET)
  68 #define MEASURE_Y_TAG                   (1 << MEASURE_TAG_OFFSET)
  69
  70 /* These are the state of touch event state machine */
  71 enum {
  72         EVENT_INIT,
  73         EVENT_MIDDLE,
  74         EVENT_RELEASE,
  75         EVENT_FIFO_END
  76 };
  77
  78 struct max11801_data {
  79         struct i2c_client               *client;
  80         struct input_dev                *input_dev;
  81 };
  82
  83 static u8 read_register(struct i2c_client *client, int addr)
  84 {
  85         /* XXX: The chip ignores LSB of register address */
  86         return i2c_smbus_read_byte_data(client, addr << 1);
  87 }
  88
  89 static int max11801_write_reg(struct i2c_client *client, int addr, int data)
  90 {
  91         /* XXX: The chip ignores LSB of register address */
  92         return i2c_smbus_write_byte_data(client, addr << 1, data);
  93 }
  94
  95 static irqreturn_t max11801_ts_interrupt(int irq, void *dev_id)
  96 {
  97         struct max11801_data *data = dev_id;
  98         struct i2c_client *client = data->client;
  99         int status, i, ret;
 100         u8 buf[XY_BUFSIZE];
 101         int x = -1;
 102         int y = -1;
 103
 104         status = read_register(data->client, GENERNAL_STATUS_REG);
 105
 106         if (status & (MAX11801_FIFO_INT | MAX11801_FIFO_OVERFLOW)) {
 107                 status = read_register(data->client, GENERNAL_STATUS_REG);
 108
 109                 ret = i2c_smbus_read_i2c_block_data(client, FIFO_RD_CMD,
 110                                                     XY_BUFSIZE, buf);
 111
 112                 /*
 113                  * We should get 4 bytes buffer that contains X,Y
 114                  * and event tag
 115                  */
 116                 if (ret < XY_BUFSIZE)
 117                         goto out;
 118
 119                 for (i = 0; i < XY_BUFSIZE; i += XY_BUFSIZE / 2) {
 120                         if ((buf[i + 1] & MEASURE_TAG_MASK) == MEASURE_X_TAG)
 121                                 x = (buf[i] << XY_BUF_OFFSET) +
 122                                     (buf[i + 1] >> XY_BUF_OFFSET);
 123                         else if ((buf[i + 1] & MEASURE_TAG_MASK) == MEASURE_Y_TAG)
 124                                 y = (buf[i] << XY_BUF_OFFSET) +
 125                                     (buf[i + 1] >> XY_BUF_OFFSET);
 126                 }
 127
 128                 if ((buf[1] & EVENT_TAG_MASK) != (buf[3] & EVENT_TAG_MASK))
 129                         goto out;
 130
 131                 switch (buf[1] & EVENT_TAG_MASK) {
 132                 case EVENT_INIT:
 133                 case EVENT_MIDDLE:
 134                         input_report_abs(data->input_dev, ABS_X, x);
 135                         input_report_abs(data->input_dev, ABS_Y, y);
 136                         input_event(data->input_dev, EV_KEY, BTN_TOUCH, 1);
 137                         input_sync(data->input_dev);
 138                         break;
 139
 140                 case EVENT_RELEASE:
 141                         input_event(data->input_dev, EV_KEY, BTN_TOUCH, 0);
 142                         input_sync(data->input_dev);
 143                         break;
 144
 145                 case EVENT_FIFO_END:
 146                         break;
 147                 }
 148         }
 149 out:
 150         return IRQ_HANDLED;
 151 }
 152
 153 static void max11801_ts_phy_init(struct max11801_data *data)
 154 {
 155         struct i2c_client *client = data->client;
 156
 157         /* Average X,Y, take 16 samples, average eight media sample */
 158         max11801_write_reg(client, MESURE_AVER_CONF_REG, 0xff);
 159         /* X,Y panel setup time set to 20us */
 160         max11801_write_reg(client, PANEL_SETUPTIME_CONF_REG, 0x11);
 161         /* Rough pullup time (2uS), Fine pullup time (10us)  */
 162         max11801_write_reg(client, TOUCH_DETECT_PULLUP_CONF_REG, 0x10);
 163         /* Auto mode init period = 5ms , scan period = 5ms*/
 164         max11801_write_reg(client, AUTO_MODE_TIME_CONF_REG, 0xaa);
 165         /* Aperture X,Y set to +- 4LSB */
 166         max11801_write_reg(client, APERTURE_CONF_REG, 0x33);
 167         /* Enable Power, enable Automode, enable Aperture, enable Average X,Y */
 168         max11801_write_reg(client, OP_MODE_CONF_REG, 0x36);
 169 }
 170
 171 static int max11801_ts_probe(struct i2c_client *client)
 172 {
 173         struct max11801_data *data;
 174         struct input_dev *input_dev;
 175         int error;
 176
 177         data = devm_kzalloc(&client->dev, sizeof(*data), GFP_KERNEL);
 178         input_dev = devm_input_allocate_device(&client->dev);
 179         if (!data || !input_dev) {
 180                 dev_err(&client->dev, "Failed to allocate memory\n");
 181                 return -ENOMEM;
 182         }
 183
 184         data->client = client;
 185         data->input_dev = input_dev;
 186
 187         input_dev->name = "max11801_ts";
 188         input_dev->id.bustype = BUS_I2C;
 189         input_dev->dev.parent = &client->dev;
 190
 191         __set_bit(EV_ABS, input_dev->evbit);
 192         __set_bit(EV_KEY, input_dev->evbit);
 193         __set_bit(BTN_TOUCH, input_dev->keybit);
 194         input_set_abs_params(input_dev, ABS_X, 0, MAX11801_MAX_X, 0, 0);
 195         input_set_abs_params(input_dev, ABS_Y, 0, MAX11801_MAX_Y, 0, 0);
 196
 197         max11801_ts_phy_init(data);
 198
 199         error = devm_request_threaded_irq(&client->dev, client->irq, NULL,
 200                                           max11801_ts_interrupt,
 201                                           IRQF_TRIGGER_LOW | IRQF_ONESHOT,
 202                                           "max11801_ts", data);
 203         if (error) {
 204                 dev_err(&client->dev, "Failed to register interrupt\n");
 205                 return error;
 206         }
 207
 208         error = input_register_device(data->input_dev);
 209         if (error)
 210                 return error;
 211
 212         return 0;
 213 }
 214
 215 static const struct i2c_device_id max11801_ts_id[] = {
 216         { "max11801" },
 217         { }
 218 };
 219 MODULE_DEVICE_TABLE(i2c, max11801_ts_id);
 220
 221 static const struct of_device_id max11801_ts_dt_ids[] = {
 222         { .compatible = "maxim,max11801" },
 223         { /* sentinel */ }
 224 };
 225 MODULE_DEVICE_TABLE(of, max11801_ts_dt_ids);
 226
 227 static struct i2c_driver max11801_ts_driver = {
 228         .driver = {
 229                 .name   = "max11801_ts",
 230                 .of_match_table = max11801_ts_dt_ids,
 231         },
 232         .id_table       = max11801_ts_id,
 233         .probe          = max11801_ts_probe,
 234 };
 235
 236 module_i2c_driver(max11801_ts_driver);
 237
 238 MODULE_AUTHOR("Zhang Jiejing <jiejing.zhang@freescale.com>");
 239 MODULE_DESCRIPTION("Touchscreen driver for MAXI MAX11801 controller");
 240 MODULE_LICENSE("GPL");