drivers/input/touchscreen/ektf2127.c

   1 /*
   2  * Driver for ELAN eKTF2127 i2c touchscreen controller
   3  *
   4  * For this driver the layout of the Chipone icn8318 i2c
   5  * touchscreencontroller is used.
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation; either version 2 of the License, or
  10  * (at your option) any later version.
  11  *
  12  * Author:
  13  * Michel Verlaan <michel.verl@gmail.com>
  14  * Siebren Vroegindeweij <siebren.vroegindeweij@hotmail.com>
  15  *
  16  * Original chipone_icn8318 driver:
  17  * Hans de Goede <hdegoede@redhat.com>
  18  */
  19
  20 #include <linux/gpio/consumer.h>
  21 #include <linux/interrupt.h>
  22 #include <linux/i2c.h>
  23 #include <linux/input.h>
  24 #include <linux/input/mt.h>
  25 #include <linux/input/touchscreen.h>
  26 #include <linux/module.h>
  27 #include <linux/of.h>
  28 #include <linux/delay.h>
  29
  30 /* Packet header defines (first byte of data send / received) */
  31 #define EKTF2127_NOISE                  0x40
  32 #define EKTF2127_RESPONSE               0x52
  33 #define EKTF2127_REQUEST                0x53
  34 #define EKTF2127_HELLO                  0x55
  35 #define EKTF2127_REPORT                 0x5d
  36 #define EKTF2127_CALIB_DONE             0x66
  37
  38 /* Register defines (second byte of data send / received) */
  39 #define EKTF2127_ENV_NOISY              0x41
  40 #define EKTF2127_HEIGHT                 0x60
  41 #define EKTF2127_WIDTH                  0x63
  42
  43 /* 2 bytes header + 5 * 3 bytes coordinates + 3 bytes pressure info + footer */
  44 #define EKTF2127_TOUCH_REPORT_SIZE      21
  45 #define EKTF2127_MAX_TOUCHES            5
  46
  47 struct ektf2127_ts {
  48         struct i2c_client *client;
  49         struct input_dev *input;
  50         struct gpio_desc *power_gpios;
  51         struct touchscreen_properties prop;
  52 };
  53
  54 static void ektf2127_parse_coordinates(const u8* buf, unsigned int touch_count,
  55                                        struct input_mt_pos *touches)
  56 {
  57         int index = 0;
  58         int i;
  59
  60         for (i = 0; i < touch_count; i++) {
  61                 index = 2 + i * 3;
  62
  63                 touches[i].x = (buf[index] & 0x0f);
  64                 touches[i].x <<= 8;
  65                 touches[i].x |= buf[index + 2];
  66
  67                 touches[i].y = (buf[index] & 0xf0);
  68                 touches[i].y <<= 4;
  69                 touches[i].y |= buf[index + 1];
  70         }
  71 }
  72
  73 static void ektf2127_report_event(struct ektf2127_ts *ts, const u8 *buf)
  74 {
  75         struct input_mt_pos touches[EKTF2127_MAX_TOUCHES];
  76         int slots[EKTF2127_MAX_TOUCHES];
  77         unsigned int touch_count, i;
  78
  79         touch_count = buf[1] & 0x07;
  80         if (touch_count > EKTF2127_MAX_TOUCHES) {
  81                 dev_err(&ts->client->dev,
  82                         "Too many touches %d > %d\n",
  83                         touch_count, EKTF2127_MAX_TOUCHES);
  84                 touch_count = EKTF2127_MAX_TOUCHES;
  85         }
  86
  87         ektf2127_parse_coordinates(buf, touch_count, touches);
  88         input_mt_assign_slots(ts->input, slots, touches,
  89                               touch_count, 0);
  90
  91         for (i = 0; i < touch_count; i++) {
  92                 input_mt_slot(ts->input, slots[i]);
  93                 input_mt_report_slot_state(ts->input, MT_TOOL_FINGER, true);
  94                 touchscreen_report_pos(ts->input, &ts->prop,
  95                                        touches[i].x, touches[i].y, true);
  96         }
  97
  98         input_mt_sync_frame(ts->input);
  99         input_sync(ts->input);
 100 }
 101
 102 static irqreturn_t ektf2127_irq(int irq, void *dev_id)
 103 {
 104         struct ektf2127_ts *ts = dev_id;
 105         struct device *dev = &ts->client->dev;
 106         char buf[EKTF2127_TOUCH_REPORT_SIZE];
 107         int ret;
 108
 109         ret = i2c_master_recv(ts->client, buf, EKTF2127_TOUCH_REPORT_SIZE);
 110         if (ret != EKTF2127_TOUCH_REPORT_SIZE) {
 111                 dev_err(dev, "Error reading touch data: %d\n", ret);
 112                 goto out;
 113         }
 114
 115         switch (buf[0]) {
 116         case EKTF2127_REPORT:
 117                 ektf2127_report_event(ts, buf);
 118                 break;
 119
 120         case EKTF2127_NOISE:
 121                 if (buf[1] == EKTF2127_ENV_NOISY)
 122                         dev_dbg(dev, "Environment is electrically noisy\n");
 123                 break;
 124
 125         case EKTF2127_HELLO:
 126         case EKTF2127_CALIB_DONE:
 127                 break;
 128
 129         default:
 130                 dev_err(dev, "Unexpected packet header byte %#02x\n", buf[0]);
 131                 break;
 132         }
 133
 134 out:
 135         return IRQ_HANDLED;
 136 }
 137
 138 static int ektf2127_start(struct input_dev *dev)
 139 {
 140         struct ektf2127_ts *ts = input_get_drvdata(dev);
 141
 142         enable_irq(ts->client->irq);
 143         gpiod_set_value_cansleep(ts->power_gpios, 1);
 144
 145         return 0;
 146 }
 147
 148 static void ektf2127_stop(struct input_dev *dev)
 149 {
 150         struct ektf2127_ts *ts = input_get_drvdata(dev);
 151
 152         disable_irq(ts->client->irq);
 153         gpiod_set_value_cansleep(ts->power_gpios, 0);
 154 }
 155
 156 static int __maybe_unused ektf2127_suspend(struct device *dev)
 157 {
 158         struct ektf2127_ts *ts = i2c_get_clientdata(to_i2c_client(dev));
 159
 160         mutex_lock(&ts->input->mutex);
 161         if (ts->input->users)
 162                 ektf2127_stop(ts->input);
 163         mutex_unlock(&ts->input->mutex);
 164
 165         return 0;
 166 }
 167
 168 static int __maybe_unused ektf2127_resume(struct device *dev)
 169 {
 170         struct ektf2127_ts *ts = i2c_get_clientdata(to_i2c_client(dev));
 171
 172         mutex_lock(&ts->input->mutex);
 173         if (ts->input->users)
 174                 ektf2127_start(ts->input);
 175         mutex_unlock(&ts->input->mutex);
 176
 177         return 0;
 178 }
 179
 180 static SIMPLE_DEV_PM_OPS(ektf2127_pm_ops, ektf2127_suspend,
 181                          ektf2127_resume);
 182
 183 static int ektf2127_query_dimension(struct i2c_client *client, bool width)
 184 {
 185         struct device *dev = &client->dev;
 186         const char *what = width ? "width" : "height";
 187         u8 what_code = width ? EKTF2127_WIDTH : EKTF2127_HEIGHT;
 188         u8 buf[4];
 189         int ret;
 190         int error;
 191
 192         /* Request dimension */
 193         buf[0] = EKTF2127_REQUEST;
 194         buf[1] = width ? EKTF2127_WIDTH : EKTF2127_HEIGHT;
 195         buf[2] = 0x00;
 196         buf[3] = 0x00;
 197         ret = i2c_master_send(client, buf, sizeof(buf));
 198         if (ret != sizeof(buf)) {
 199                 error = ret < 0 ? ret : -EIO;
 200                 dev_err(dev, "Failed to request %s: %d\n", what, error);
 201                 return error;
 202         }
 203
 204         msleep(20);
 205
 206         /* Read response */
 207         ret = i2c_master_recv(client, buf, sizeof(buf));
 208         if (ret != sizeof(buf)) {
 209                 error = ret < 0 ? ret : -EIO;
 210                 dev_err(dev, "Failed to receive %s data: %d\n", what, error);
 211                 return error;
 212         }
 213
 214         if (buf[0] != EKTF2127_RESPONSE || buf[1] != what_code) {
 215                 dev_err(dev, "Unexpected %s data: %#02x %#02x\n",
 216                         what, buf[0], buf[1]);
 217                 return -EIO;
 218         }
 219
 220         return (((buf[3] & 0xf0) << 4) | buf[2]) - 1;
 221 }
 222
 223 static int ektf2127_probe(struct i2c_client *client,
 224                           const struct i2c_device_id *id)
 225 {
 226         struct device *dev = &client->dev;
 227         struct ektf2127_ts *ts;
 228         struct input_dev *input;
 229         u8 buf[4];
 230         int max_x, max_y;
 231         int error;
 232
 233         if (!client->irq) {
 234                 dev_err(dev, "Error no irq specified\n");
 235                 return -EINVAL;
 236         }
 237
 238         ts = devm_kzalloc(dev, sizeof(*ts), GFP_KERNEL);
 239         if (!ts)
 240                 return -ENOMEM;
 241
 242         /* This requests the gpio *and* turns on the touchscreen controller */
 243         ts->power_gpios = devm_gpiod_get(dev, "power", GPIOD_OUT_HIGH);
 244         if (IS_ERR(ts->power_gpios)) {
 245                 error = PTR_ERR(ts->power_gpios);
 246                 if (error != -EPROBE_DEFER)
 247                         dev_err(dev, "Error getting power gpio: %d\n", error);
 248                 return error;
 249         }
 250
 251         input = devm_input_allocate_device(dev);
 252         if (!input)
 253                 return -ENOMEM;
 254
 255         input->name = client->name;
 256         input->id.bustype = BUS_I2C;
 257         input->open = ektf2127_start;
 258         input->close = ektf2127_stop;
 259
 260         ts->client = client;
 261
 262         /* Read hello (ignore result, depends on initial power state) */
 263         msleep(20);
 264         i2c_master_recv(ts->client, buf, sizeof(buf));
 265
 266         /* Read resolution from chip */
 267         max_x = ektf2127_query_dimension(client, true);
 268         if (max_x < 0)
 269                 return max_x;
 270
 271         max_y = ektf2127_query_dimension(client, false);
 272         if (max_y < 0)
 273                 return max_y;
 274
 275         input_set_abs_params(input, ABS_MT_POSITION_X, 0, max_x, 0, 0);
 276         input_set_abs_params(input, ABS_MT_POSITION_Y, 0, max_y, 0, 0);
 277         touchscreen_parse_properties(input, true, &ts->prop);
 278
 279         error = input_mt_init_slots(input, EKTF2127_MAX_TOUCHES,
 280                                     INPUT_MT_DIRECT |
 281                                         INPUT_MT_DROP_UNUSED |
 282                                         INPUT_MT_TRACK);
 283         if (error)
 284                 return error;
 285
 286         ts->input = input;
 287         input_set_drvdata(input, ts);
 288
 289         error = devm_request_threaded_irq(dev, client->irq,
 290                                           NULL, ektf2127_irq,
 291                                           IRQF_ONESHOT, client->name, ts);
 292         if (error) {
 293                 dev_err(dev, "Error requesting irq: %d\n", error);
 294                 return error;
 295         }
 296
 297         /* Stop device till opened */
 298         ektf2127_stop(ts->input);
 299
 300         error = input_register_device(input);
 301         if (error)
 302                 return error;
 303
 304         i2c_set_clientdata(client, ts);
 305
 306         return 0;
 307 }
 308
 309 #ifdef CONFIG_OF
 310 static const struct of_device_id ektf2127_of_match[] = {
 311         { .compatible = "elan,ektf2127" },
 312         {}
 313 };
 314 MODULE_DEVICE_TABLE(of, ektf2127_of_match);
 315 #endif
 316
 317 static const struct i2c_device_id ektf2127_i2c_id[] = {
 318         { "ektf2127", 0 },
 319         {}
 320 };
 321 MODULE_DEVICE_TABLE(i2c, ektf2127_i2c_id);
 322
 323 static struct i2c_driver ektf2127_driver = {
 324         .driver = {
 325                 .name   = "elan_ektf2127",
 326                 .pm     = &ektf2127_pm_ops,
 327                 .of_match_table = of_match_ptr(ektf2127_of_match),
 328         },
 329         .probe = ektf2127_probe,
 330         .id_table = ektf2127_i2c_id,
 331 };
 332 module_i2c_driver(ektf2127_driver);
 333
 334 MODULE_DESCRIPTION("ELAN eKTF2127 I2C Touchscreen Driver");
 335 MODULE_AUTHOR("Michel Verlaan, Siebren Vroegindeweij");
 336 MODULE_LICENSE("GPL");