Mika Penttilä | a485cb0 | 2016-08-02 23:52:32 -0700 | [diff] [blame^] | 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>"); |