drivers/input/touchscreen/sis_i2c.c

   1 /*
   2  * Touch Screen driver for SiS 9200 family I2C Touch panels
   3  *
   4  * Copyright (C) 2015 SiS, Inc.
   5  * Copyright (C) 2016 Nextfour Group
   6  *
   7  * This software is licensed under the terms of the GNU General Public
   8  * License version 2, as published by the Free Software Foundation, and
   9  * may be copied, distributed, and modified under those terms.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  */
  16
  17 #include <linux/crc-itu-t.h>
  18 #include <linux/delay.h>
  19 #include <linux/i2c.h>
  20 #include <linux/input.h>
  21 #include <linux/input/mt.h>
  22 #include <linux/interrupt.h>
  23 #include <linux/gpio/consumer.h>
  24 #include <linux/module.h>
  25 #include <linux/slab.h>
  26 #include <asm/unaligned.h>
  27
  28 #define SIS_I2C_NAME            "sis_i2c_ts"
  29
  30 /*
  31  * The I2C packet format:
  32  * le16         byte count
  33  * u8           Report ID
  34  * <contact data - variable length>
  35  * u8           Number of contacts
  36  * le16         Scan Time (optional)
  37  * le16         CRC
  38  *
  39  * One touch point information consists of 6+ bytes, the order is:
  40  * u8           contact state
  41  * u8           finger id
  42  * le16         x axis
  43  * le16         y axis
  44  * u8           contact width (optional)
  45  * u8           contact height (optional)
  46  * u8           pressure (optional)
  47  *
  48  * Maximum amount of data transmitted in one shot is 64 bytes, if controller
  49  * needs to report more contacts than fit in one packet it will send true
  50  * number of contacts in first packet and 0 as number of contacts in second
  51  * packet.
  52  */
  53
  54 #define SIS_MAX_PACKET_SIZE             64
  55
  56 #define SIS_PKT_LEN_OFFSET              0
  57 #define SIS_PKT_REPORT_OFFSET           2 /* Report ID/type */
  58 #define SIS_PKT_CONTACT_OFFSET          3 /* First contact */
  59
  60 #define SIS_SCAN_TIME_LEN               2
  61
  62 /* Supported report types */
  63 #define SIS_ALL_IN_ONE_PACKAGE          0x10
  64 #define SIS_PKT_IS_TOUCH(x)             (((x) & 0x0f) == 0x01)
  65 #define SIS_PKT_IS_HIDI2C(x)            (((x) & 0x0f) == 0x06)
  66
  67 /* Contact properties within report */
  68 #define SIS_PKT_HAS_AREA(x)             ((x) & BIT(4))
  69 #define SIS_PKT_HAS_PRESSURE(x)         ((x) & BIT(5))
  70 #define SIS_PKT_HAS_SCANTIME(x)         ((x) & BIT(6))
  71
  72 /* Contact size */
  73 #define SIS_BASE_LEN_PER_CONTACT        6
  74 #define SIS_AREA_LEN_PER_CONTACT        2
  75 #define SIS_PRESSURE_LEN_PER_CONTACT    1
  76
  77 /* Offsets within contact data */
  78 #define SIS_CONTACT_STATUS_OFFSET       0
  79 #define SIS_CONTACT_ID_OFFSET           1 /* Contact ID */
  80 #define SIS_CONTACT_X_OFFSET            2
  81 #define SIS_CONTACT_Y_OFFSET            4
  82 #define SIS_CONTACT_WIDTH_OFFSET        6
  83 #define SIS_CONTACT_HEIGHT_OFFSET       7
  84 #define SIS_CONTACT_PRESSURE_OFFSET(id) (SIS_PKT_HAS_AREA(id) ? 8 : 6)
  85
  86 /* Individual contact state */
  87 #define SIS_STATUS_UP                   0x0
  88 #define SIS_STATUS_DOWN                 0x3
  89
  90 /* Touchscreen parameters */
  91 #define SIS_MAX_FINGERS                 10
  92 #define SIS_MAX_X                       4095
  93 #define SIS_MAX_Y                       4095
  94 #define SIS_MAX_PRESSURE                255
  95
  96 /* Resolution diagonal */
  97 #define SIS_AREA_LENGTH_LONGER          5792
  98 /*((SIS_MAX_X^2) + (SIS_MAX_Y^2))^0.5*/
  99 #define SIS_AREA_LENGTH_SHORT           5792
 100 #define SIS_AREA_UNIT                   (5792 / 32)
 101
 102 struct sis_ts_data {
 103         struct i2c_client *client;
 104         struct input_dev *input;
 105
 106         struct gpio_desc *attn_gpio;
 107         struct gpio_desc *reset_gpio;
 108
 109         u8 packet[SIS_MAX_PACKET_SIZE];
 110 };
 111
 112 static int sis_read_packet(struct i2c_client *client, u8 *buf,
 113                            unsigned int *num_contacts,
 114                            unsigned int *contact_size)
 115 {
 116         int count_idx;
 117         int ret;
 118         u16 len;
 119         u16 crc, pkg_crc;
 120         u8 report_id;
 121
 122         ret = i2c_master_recv(client, buf, SIS_MAX_PACKET_SIZE);
 123         if (ret <= 0)
 124                 return -EIO;
 125
 126         len = get_unaligned_le16(&buf[SIS_PKT_LEN_OFFSET]);
 127         if (len > SIS_MAX_PACKET_SIZE) {
 128                 dev_err(&client->dev,
 129                         "%s: invalid packet length (%d vs %d)\n",
 130                         __func__, len, SIS_MAX_PACKET_SIZE);
 131                 return -E2BIG;
 132         }
 133
 134         if (len < 10)
 135                 return -EINVAL;
 136
 137         report_id = buf[SIS_PKT_REPORT_OFFSET];
 138         count_idx  = len - 1;
 139         *contact_size = SIS_BASE_LEN_PER_CONTACT;
 140
 141         if (report_id != SIS_ALL_IN_ONE_PACKAGE) {
 142                 if (SIS_PKT_IS_TOUCH(report_id)) {
 143                         /*
 144                          * Calculate CRC ignoring packet length
 145                          * in the beginning and CRC transmitted
 146                          * at the end of the packet.
 147                          */
 148                         crc = crc_itu_t(0, buf + 2, len - 2 - 2);
 149                         pkg_crc = get_unaligned_le16(&buf[len - 2]);
 150
 151                         if (crc != pkg_crc) {
 152                                 dev_err(&client->dev,
 153                                         "%s: CRC Error (%d vs %d)\n",
 154                                         __func__, crc, pkg_crc);
 155                                 return -EINVAL;
 156                         }
 157
 158                         count_idx -= 2;
 159
 160                 } else if (!SIS_PKT_IS_HIDI2C(report_id)) {
 161                         dev_err(&client->dev,
 162                                 "%s: invalid packet ID %#02x\n",
 163                                 __func__, report_id);
 164                         return -EINVAL;
 165                 }
 166
 167                 if (SIS_PKT_HAS_SCANTIME(report_id))
 168                         count_idx -= SIS_SCAN_TIME_LEN;
 169
 170                 if (SIS_PKT_HAS_AREA(report_id))
 171                         *contact_size += SIS_AREA_LEN_PER_CONTACT;
 172                 if (SIS_PKT_HAS_PRESSURE(report_id))
 173                         *contact_size += SIS_PRESSURE_LEN_PER_CONTACT;
 174         }
 175
 176         *num_contacts = buf[count_idx];
 177         return 0;
 178 }
 179
 180 static int sis_ts_report_contact(struct sis_ts_data *ts, const u8 *data, u8 id)
 181 {
 182         struct input_dev *input = ts->input;
 183         int slot;
 184         u8 status = data[SIS_CONTACT_STATUS_OFFSET];
 185         u8 pressure;
 186         u8 height, width;
 187         u16 x, y;
 188
 189         if (status != SIS_STATUS_DOWN && status != SIS_STATUS_UP) {
 190                 dev_err(&ts->client->dev, "Unexpected touch status: %#02x\n",
 191                         data[SIS_CONTACT_STATUS_OFFSET]);
 192                 return -EINVAL;
 193         }
 194
 195         slot = input_mt_get_slot_by_key(input, data[SIS_CONTACT_ID_OFFSET]);
 196         if (slot < 0)
 197                 return -ENOENT;
 198
 199         input_mt_slot(input, slot);
 200         input_mt_report_slot_state(input, MT_TOOL_FINGER,
 201                                    status == SIS_STATUS_DOWN);
 202
 203         if (status == SIS_STATUS_DOWN) {
 204                 pressure = height = width = 1;
 205                 if (id != SIS_ALL_IN_ONE_PACKAGE) {
 206                         if (SIS_PKT_HAS_AREA(id)) {
 207                                 width = data[SIS_CONTACT_WIDTH_OFFSET];
 208                                 height = data[SIS_CONTACT_HEIGHT_OFFSET];
 209                         }
 210
 211                         if (SIS_PKT_HAS_PRESSURE(id))
 212                                 pressure =
 213                                         data[SIS_CONTACT_PRESSURE_OFFSET(id)];
 214                 }
 215
 216                 x = get_unaligned_le16(&data[SIS_CONTACT_X_OFFSET]);
 217                 y = get_unaligned_le16(&data[SIS_CONTACT_Y_OFFSET]);
 218
 219                 input_report_abs(input, ABS_MT_TOUCH_MAJOR,
 220                                  width * SIS_AREA_UNIT);
 221                 input_report_abs(input, ABS_MT_TOUCH_MINOR,
 222                                  height * SIS_AREA_UNIT);
 223                 input_report_abs(input, ABS_MT_PRESSURE, pressure);
 224                 input_report_abs(input, ABS_MT_POSITION_X, x);
 225                 input_report_abs(input, ABS_MT_POSITION_Y, y);
 226         }
 227
 228         return 0;
 229 }
 230
 231 static void sis_ts_handle_packet(struct sis_ts_data *ts)
 232 {
 233         const u8 *contact;
 234         unsigned int num_to_report = 0;
 235         unsigned int num_contacts;
 236         unsigned int num_reported;
 237         unsigned int contact_size;
 238         int error;
 239         u8 report_id;
 240
 241         do {
 242                 error = sis_read_packet(ts->client, ts->packet,
 243                                         &num_contacts, &contact_size);
 244                 if (error)
 245                         break;
 246
 247                 if (num_to_report == 0) {
 248                         num_to_report = num_contacts;
 249                 } else if (num_contacts != 0) {
 250                         dev_err(&ts->client->dev,
 251                                 "%s: nonzero (%d) point count in tail packet\n",
 252                                 __func__, num_contacts);
 253                         break;
 254                 }
 255
 256                 report_id = ts->packet[SIS_PKT_REPORT_OFFSET];
 257                 contact = &ts->packet[SIS_PKT_CONTACT_OFFSET];
 258                 num_reported = 0;
 259
 260                 while (num_to_report > 0) {
 261                         error = sis_ts_report_contact(ts, contact, report_id);
 262                         if (error)
 263                                 break;
 264
 265                         contact += contact_size;
 266                         num_to_report--;
 267                         num_reported++;
 268
 269                         if (report_id != SIS_ALL_IN_ONE_PACKAGE &&
 270                             num_reported >= 5) {
 271                                 /*
 272                                  * The remainder of contacts is sent
 273                                  * in the 2nd packet.
 274                                  */
 275                                 break;
 276                         }
 277                 }
 278         } while (num_to_report > 0);
 279
 280         input_mt_sync_frame(ts->input);
 281         input_sync(ts->input);
 282 }
 283
 284 static irqreturn_t sis_ts_irq_handler(int irq, void *dev_id)
 285 {
 286         struct sis_ts_data *ts = dev_id;
 287
 288         do {
 289                 sis_ts_handle_packet(ts);
 290         } while (ts->attn_gpio && gpiod_get_value_cansleep(ts->attn_gpio));
 291
 292         return IRQ_HANDLED;
 293 }
 294
 295 static void sis_ts_reset(struct sis_ts_data *ts)
 296 {
 297         if (ts->reset_gpio) {
 298                 /* Get out of reset */
 299                 usleep_range(1000, 2000);
 300                 gpiod_set_value(ts->reset_gpio, 1);
 301                 usleep_range(1000, 2000);
 302                 gpiod_set_value(ts->reset_gpio, 0);
 303                 msleep(100);
 304         }
 305 }
 306
 307 static int sis_ts_probe(struct i2c_client *client,
 308                         const struct i2c_device_id *id)
 309 {
 310         struct sis_ts_data *ts;
 311         struct input_dev *input;
 312         int error;
 313
 314         ts = devm_kzalloc(&client->dev, sizeof(*ts), GFP_KERNEL);
 315         if (!ts)
 316                 return -ENOMEM;
 317
 318         ts->client = client;
 319         i2c_set_clientdata(client, ts);
 320
 321         ts->attn_gpio = devm_gpiod_get_optional(&client->dev,
 322                                                 "attn", GPIOD_IN);
 323         if (IS_ERR(ts->attn_gpio)) {
 324                 error = PTR_ERR(ts->attn_gpio);
 325                 if (error != -EPROBE_DEFER)
 326                         dev_err(&client->dev,
 327                                 "Failed to get attention GPIO: %d\n", error);
 328                 return error;
 329         }
 330
 331         ts->reset_gpio = devm_gpiod_get_optional(&client->dev,
 332                                                  "reset", GPIOD_OUT_LOW);
 333         if (IS_ERR(ts->reset_gpio)) {
 334                 error = PTR_ERR(ts->reset_gpio);
 335                 if (error != -EPROBE_DEFER)
 336                         dev_err(&client->dev,
 337                                 "Failed to get reset GPIO: %d\n", error);
 338                 return error;
 339         }
 340
 341         sis_ts_reset(ts);
 342
 343         ts->input = input = devm_input_allocate_device(&client->dev);
 344         if (!input) {
 345                 dev_err(&client->dev, "Failed to allocate input device\n");
 346                 return -ENOMEM;
 347         }
 348
 349         input->name = "SiS Touchscreen";
 350         input->id.bustype = BUS_I2C;
 351
 352         input_set_abs_params(input, ABS_MT_POSITION_X, 0, SIS_MAX_X, 0, 0);
 353         input_set_abs_params(input, ABS_MT_POSITION_Y, 0, SIS_MAX_Y, 0, 0);
 354         input_set_abs_params(input, ABS_MT_PRESSURE, 0, SIS_MAX_PRESSURE, 0, 0);
 355         input_set_abs_params(input, ABS_MT_TOUCH_MAJOR,
 356                              0, SIS_AREA_LENGTH_LONGER, 0, 0);
 357         input_set_abs_params(input, ABS_MT_TOUCH_MINOR,
 358                              0, SIS_AREA_LENGTH_SHORT, 0, 0);
 359
 360         error = input_mt_init_slots(input, SIS_MAX_FINGERS, INPUT_MT_DIRECT);
 361         if (error) {
 362                 dev_err(&client->dev,
 363                         "Failed to initialize MT slots: %d\n", error);
 364                 return error;
 365         }
 366
 367         error = devm_request_threaded_irq(&client->dev, client->irq,
 368                                           NULL, sis_ts_irq_handler,
 369                                           IRQF_ONESHOT,
 370                                           client->name, ts);
 371         if (error) {
 372                 dev_err(&client->dev, "Failed to request IRQ: %d\n", error);
 373                 return error;
 374         }
 375
 376         error = input_register_device(ts->input);
 377         if (error) {
 378                 dev_err(&client->dev,
 379                         "Failed to register input device: %d\n", error);
 380                 return error;
 381         }
 382
 383         return 0;
 384 }
 385
 386 #ifdef CONFIG_OF
 387 static const struct of_device_id sis_ts_dt_ids[] = {
 388         { .compatible = "sis,9200-ts" },
 389         { /* sentinel */ }
 390 };
 391 MODULE_DEVICE_TABLE(of, sis_ts_dt_ids);
 392 #endif
 393
 394 static const struct i2c_device_id sis_ts_id[] = {
 395         { SIS_I2C_NAME, 0 },
 396         { "9200-ts",    0 },
 397         { /* sentinel */  }
 398 };
 399 MODULE_DEVICE_TABLE(i2c, sis_ts_id);
 400
 401 static struct i2c_driver sis_ts_driver = {
 402         .driver = {
 403                 .name   = SIS_I2C_NAME,
 404                 .of_match_table = of_match_ptr(sis_ts_dt_ids),
 405         },
 406         .probe          = sis_ts_probe,
 407         .id_table       = sis_ts_id,
 408 };
 409 module_i2c_driver(sis_ts_driver);
 410
 411 MODULE_DESCRIPTION("SiS 9200 Family Touchscreen Driver");
 412 MODULE_LICENSE("GPL v2");
 413 MODULE_AUTHOR("Mika Penttilä <mika.penttila@nextfour.com>");