1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * Touch Screen driver for SiS 9200 family I2C Touch panels 4 * 5 * Copyright (C) 2015 SiS, Inc. 6 * Copyright (C) 2016 Nextfour Group 7 */ 8 9 #include <linux/crc-itu-t.h> 10 #include <linux/delay.h> 11 #include <linux/i2c.h> 12 #include <linux/input.h> 13 #include <linux/input/mt.h> 14 #include <linux/interrupt.h> 15 #include <linux/gpio/consumer.h> 16 #include <linux/module.h> 17 #include <linux/slab.h> 18 #include <asm/unaligned.h> 19 20 #define SIS_I2C_NAME "sis_i2c_ts" 21 22 /* 23 * The I2C packet format: 24 * le16 byte count 25 * u8 Report ID 26 * <contact data - variable length> 27 * u8 Number of contacts 28 * le16 Scan Time (optional) 29 * le16 CRC 30 * 31 * One touch point information consists of 6+ bytes, the order is: 32 * u8 contact state 33 * u8 finger id 34 * le16 x axis 35 * le16 y axis 36 * u8 contact width (optional) 37 * u8 contact height (optional) 38 * u8 pressure (optional) 39 * 40 * Maximum amount of data transmitted in one shot is 64 bytes, if controller 41 * needs to report more contacts than fit in one packet it will send true 42 * number of contacts in first packet and 0 as number of contacts in second 43 * packet. 44 */ 45 46 #define SIS_MAX_PACKET_SIZE 64 47 48 #define SIS_PKT_LEN_OFFSET 0 49 #define SIS_PKT_REPORT_OFFSET 2 /* Report ID/type */ 50 #define SIS_PKT_CONTACT_OFFSET 3 /* First contact */ 51 52 #define SIS_SCAN_TIME_LEN 2 53 54 /* Supported report types */ 55 #define SIS_ALL_IN_ONE_PACKAGE 0x10 56 #define SIS_PKT_IS_TOUCH(x) (((x) & 0x0f) == 0x01) 57 #define SIS_PKT_IS_HIDI2C(x) (((x) & 0x0f) == 0x06) 58 59 /* Contact properties within report */ 60 #define SIS_PKT_HAS_AREA(x) ((x) & BIT(4)) 61 #define SIS_PKT_HAS_PRESSURE(x) ((x) & BIT(5)) 62 #define SIS_PKT_HAS_SCANTIME(x) ((x) & BIT(6)) 63 64 /* Contact size */ 65 #define SIS_BASE_LEN_PER_CONTACT 6 66 #define SIS_AREA_LEN_PER_CONTACT 2 67 #define SIS_PRESSURE_LEN_PER_CONTACT 1 68 69 /* Offsets within contact data */ 70 #define SIS_CONTACT_STATUS_OFFSET 0 71 #define SIS_CONTACT_ID_OFFSET 1 /* Contact ID */ 72 #define SIS_CONTACT_X_OFFSET 2 73 #define SIS_CONTACT_Y_OFFSET 4 74 #define SIS_CONTACT_WIDTH_OFFSET 6 75 #define SIS_CONTACT_HEIGHT_OFFSET 7 76 #define SIS_CONTACT_PRESSURE_OFFSET(id) (SIS_PKT_HAS_AREA(id) ? 8 : 6) 77 78 /* Individual contact state */ 79 #define SIS_STATUS_UP 0x0 80 #define SIS_STATUS_DOWN 0x3 81 82 /* Touchscreen parameters */ 83 #define SIS_MAX_FINGERS 10 84 #define SIS_MAX_X 4095 85 #define SIS_MAX_Y 4095 86 #define SIS_MAX_PRESSURE 255 87 88 /* Resolution diagonal */ 89 #define SIS_AREA_LENGTH_LONGER 5792 90 /*((SIS_MAX_X^2) + (SIS_MAX_Y^2))^0.5*/ 91 #define SIS_AREA_LENGTH_SHORT 5792 92 #define SIS_AREA_UNIT (5792 / 32) 93 94 struct sis_ts_data { 95 struct i2c_client *client; 96 struct input_dev *input; 97 98 struct gpio_desc *attn_gpio; 99 struct gpio_desc *reset_gpio; 100 101 u8 packet[SIS_MAX_PACKET_SIZE]; 102 }; 103 104 static int sis_read_packet(struct i2c_client *client, u8 *buf, 105 unsigned int *num_contacts, 106 unsigned int *contact_size) 107 { 108 int count_idx; 109 int ret; 110 u16 len; 111 u16 crc, pkg_crc; 112 u8 report_id; 113 114 ret = i2c_master_recv(client, buf, SIS_MAX_PACKET_SIZE); 115 if (ret <= 0) 116 return -EIO; 117 118 len = get_unaligned_le16(&buf[SIS_PKT_LEN_OFFSET]); 119 if (len > SIS_MAX_PACKET_SIZE) { 120 dev_err(&client->dev, 121 "%s: invalid packet length (%d vs %d)\n", 122 __func__, len, SIS_MAX_PACKET_SIZE); 123 return -E2BIG; 124 } 125 126 if (len < 10) 127 return -EINVAL; 128 129 report_id = buf[SIS_PKT_REPORT_OFFSET]; 130 count_idx = len - 1; 131 *contact_size = SIS_BASE_LEN_PER_CONTACT; 132 133 if (report_id != SIS_ALL_IN_ONE_PACKAGE) { 134 if (SIS_PKT_IS_TOUCH(report_id)) { 135 /* 136 * Calculate CRC ignoring packet length 137 * in the beginning and CRC transmitted 138 * at the end of the packet. 139 */ 140 crc = crc_itu_t(0, buf + 2, len - 2 - 2); 141 pkg_crc = get_unaligned_le16(&buf[len - 2]); 142 143 if (crc != pkg_crc) { 144 dev_err(&client->dev, 145 "%s: CRC Error (%d vs %d)\n", 146 __func__, crc, pkg_crc); 147 return -EINVAL; 148 } 149 150 count_idx -= 2; 151 152 } else if (!SIS_PKT_IS_HIDI2C(report_id)) { 153 dev_err(&client->dev, 154 "%s: invalid packet ID %#02x\n", 155 __func__, report_id); 156 return -EINVAL; 157 } 158 159 if (SIS_PKT_HAS_SCANTIME(report_id)) 160 count_idx -= SIS_SCAN_TIME_LEN; 161 162 if (SIS_PKT_HAS_AREA(report_id)) 163 *contact_size += SIS_AREA_LEN_PER_CONTACT; 164 if (SIS_PKT_HAS_PRESSURE(report_id)) 165 *contact_size += SIS_PRESSURE_LEN_PER_CONTACT; 166 } 167 168 *num_contacts = buf[count_idx]; 169 return 0; 170 } 171 172 static int sis_ts_report_contact(struct sis_ts_data *ts, const u8 *data, u8 id) 173 { 174 struct input_dev *input = ts->input; 175 int slot; 176 u8 status = data[SIS_CONTACT_STATUS_OFFSET]; 177 u8 pressure; 178 u8 height, width; 179 u16 x, y; 180 181 if (status != SIS_STATUS_DOWN && status != SIS_STATUS_UP) { 182 dev_err(&ts->client->dev, "Unexpected touch status: %#02x\n", 183 data[SIS_CONTACT_STATUS_OFFSET]); 184 return -EINVAL; 185 } 186 187 slot = input_mt_get_slot_by_key(input, data[SIS_CONTACT_ID_OFFSET]); 188 if (slot < 0) 189 return -ENOENT; 190 191 input_mt_slot(input, slot); 192 input_mt_report_slot_state(input, MT_TOOL_FINGER, 193 status == SIS_STATUS_DOWN); 194 195 if (status == SIS_STATUS_DOWN) { 196 pressure = height = width = 1; 197 if (id != SIS_ALL_IN_ONE_PACKAGE) { 198 if (SIS_PKT_HAS_AREA(id)) { 199 width = data[SIS_CONTACT_WIDTH_OFFSET]; 200 height = data[SIS_CONTACT_HEIGHT_OFFSET]; 201 } 202 203 if (SIS_PKT_HAS_PRESSURE(id)) 204 pressure = 205 data[SIS_CONTACT_PRESSURE_OFFSET(id)]; 206 } 207 208 x = get_unaligned_le16(&data[SIS_CONTACT_X_OFFSET]); 209 y = get_unaligned_le16(&data[SIS_CONTACT_Y_OFFSET]); 210 211 input_report_abs(input, ABS_MT_TOUCH_MAJOR, 212 width * SIS_AREA_UNIT); 213 input_report_abs(input, ABS_MT_TOUCH_MINOR, 214 height * SIS_AREA_UNIT); 215 input_report_abs(input, ABS_MT_PRESSURE, pressure); 216 input_report_abs(input, ABS_MT_POSITION_X, x); 217 input_report_abs(input, ABS_MT_POSITION_Y, y); 218 } 219 220 return 0; 221 } 222 223 static void sis_ts_handle_packet(struct sis_ts_data *ts) 224 { 225 const u8 *contact; 226 unsigned int num_to_report = 0; 227 unsigned int num_contacts; 228 unsigned int num_reported; 229 unsigned int contact_size; 230 int error; 231 u8 report_id; 232 233 do { 234 error = sis_read_packet(ts->client, ts->packet, 235 &num_contacts, &contact_size); 236 if (error) 237 break; 238 239 if (num_to_report == 0) { 240 num_to_report = num_contacts; 241 } else if (num_contacts != 0) { 242 dev_err(&ts->client->dev, 243 "%s: nonzero (%d) point count in tail packet\n", 244 __func__, num_contacts); 245 break; 246 } 247 248 report_id = ts->packet[SIS_PKT_REPORT_OFFSET]; 249 contact = &ts->packet[SIS_PKT_CONTACT_OFFSET]; 250 num_reported = 0; 251 252 while (num_to_report > 0) { 253 error = sis_ts_report_contact(ts, contact, report_id); 254 if (error) 255 break; 256 257 contact += contact_size; 258 num_to_report--; 259 num_reported++; 260 261 if (report_id != SIS_ALL_IN_ONE_PACKAGE && 262 num_reported >= 5) { 263 /* 264 * The remainder of contacts is sent 265 * in the 2nd packet. 266 */ 267 break; 268 } 269 } 270 } while (num_to_report > 0); 271 272 input_mt_sync_frame(ts->input); 273 input_sync(ts->input); 274 } 275 276 static irqreturn_t sis_ts_irq_handler(int irq, void *dev_id) 277 { 278 struct sis_ts_data *ts = dev_id; 279 280 do { 281 sis_ts_handle_packet(ts); 282 } while (ts->attn_gpio && gpiod_get_value_cansleep(ts->attn_gpio)); 283 284 return IRQ_HANDLED; 285 } 286 287 static void sis_ts_reset(struct sis_ts_data *ts) 288 { 289 if (ts->reset_gpio) { 290 /* Get out of reset */ 291 usleep_range(1000, 2000); 292 gpiod_set_value(ts->reset_gpio, 1); 293 usleep_range(1000, 2000); 294 gpiod_set_value(ts->reset_gpio, 0); 295 msleep(100); 296 } 297 } 298 299 static int sis_ts_probe(struct i2c_client *client) 300 { 301 struct sis_ts_data *ts; 302 struct input_dev *input; 303 int error; 304 305 ts = devm_kzalloc(&client->dev, sizeof(*ts), GFP_KERNEL); 306 if (!ts) 307 return -ENOMEM; 308 309 ts->client = client; 310 311 ts->attn_gpio = devm_gpiod_get_optional(&client->dev, 312 "attn", GPIOD_IN); 313 if (IS_ERR(ts->attn_gpio)) { 314 error = PTR_ERR(ts->attn_gpio); 315 if (error != -EPROBE_DEFER) 316 dev_err(&client->dev, 317 "Failed to get attention GPIO: %d\n", error); 318 return error; 319 } 320 321 ts->reset_gpio = devm_gpiod_get_optional(&client->dev, 322 "reset", GPIOD_OUT_LOW); 323 if (IS_ERR(ts->reset_gpio)) { 324 error = PTR_ERR(ts->reset_gpio); 325 if (error != -EPROBE_DEFER) 326 dev_err(&client->dev, 327 "Failed to get reset GPIO: %d\n", error); 328 return error; 329 } 330 331 sis_ts_reset(ts); 332 333 ts->input = input = devm_input_allocate_device(&client->dev); 334 if (!input) { 335 dev_err(&client->dev, "Failed to allocate input device\n"); 336 return -ENOMEM; 337 } 338 339 input->name = "SiS Touchscreen"; 340 input->id.bustype = BUS_I2C; 341 342 input_set_abs_params(input, ABS_MT_POSITION_X, 0, SIS_MAX_X, 0, 0); 343 input_set_abs_params(input, ABS_MT_POSITION_Y, 0, SIS_MAX_Y, 0, 0); 344 input_set_abs_params(input, ABS_MT_PRESSURE, 0, SIS_MAX_PRESSURE, 0, 0); 345 input_set_abs_params(input, ABS_MT_TOUCH_MAJOR, 346 0, SIS_AREA_LENGTH_LONGER, 0, 0); 347 input_set_abs_params(input, ABS_MT_TOUCH_MINOR, 348 0, SIS_AREA_LENGTH_SHORT, 0, 0); 349 350 error = input_mt_init_slots(input, SIS_MAX_FINGERS, INPUT_MT_DIRECT); 351 if (error) { 352 dev_err(&client->dev, 353 "Failed to initialize MT slots: %d\n", error); 354 return error; 355 } 356 357 error = devm_request_threaded_irq(&client->dev, client->irq, 358 NULL, sis_ts_irq_handler, 359 IRQF_ONESHOT, 360 client->name, ts); 361 if (error) { 362 dev_err(&client->dev, "Failed to request IRQ: %d\n", error); 363 return error; 364 } 365 366 error = input_register_device(ts->input); 367 if (error) { 368 dev_err(&client->dev, 369 "Failed to register input device: %d\n", error); 370 return error; 371 } 372 373 return 0; 374 } 375 376 #ifdef CONFIG_OF 377 static const struct of_device_id sis_ts_dt_ids[] = { 378 { .compatible = "sis,9200-ts" }, 379 { /* sentinel */ } 380 }; 381 MODULE_DEVICE_TABLE(of, sis_ts_dt_ids); 382 #endif 383 384 static const struct i2c_device_id sis_ts_id[] = { 385 { SIS_I2C_NAME, 0 }, 386 { "9200-ts", 0 }, 387 { /* sentinel */ } 388 }; 389 MODULE_DEVICE_TABLE(i2c, sis_ts_id); 390 391 static struct i2c_driver sis_ts_driver = { 392 .driver = { 393 .name = SIS_I2C_NAME, 394 .of_match_table = of_match_ptr(sis_ts_dt_ids), 395 }, 396 .probe = sis_ts_probe, 397 .id_table = sis_ts_id, 398 }; 399 module_i2c_driver(sis_ts_driver); 400 401 MODULE_DESCRIPTION("SiS 9200 Family Touchscreen Driver"); 402 MODULE_LICENSE("GPL v2"); 403 MODULE_AUTHOR("Mika Penttilä <mika.penttila@nextfour.com>"); 404