1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * drivers/input/touchscreen/tsc2007.c 4 * 5 * Copyright (c) 2008 MtekVision Co., Ltd. 6 * Kwangwoo Lee <kwlee@mtekvision.com> 7 * 8 * Using code from: 9 * - ads7846.c 10 * Copyright (c) 2005 David Brownell 11 * Copyright (c) 2006 Nokia Corporation 12 * - corgi_ts.c 13 * Copyright (C) 2004-2005 Richard Purdie 14 * - omap_ts.[hc], ads7846.h, ts_osk.c 15 * Copyright (C) 2002 MontaVista Software 16 * Copyright (C) 2004 Texas Instruments 17 * Copyright (C) 2005 Dirk Behme 18 */ 19 20 #include <linux/module.h> 21 #include <linux/slab.h> 22 #include <linux/input.h> 23 #include <linux/interrupt.h> 24 #include <linux/i2c.h> 25 #include <linux/of_device.h> 26 #include <linux/of_gpio.h> 27 #include <linux/platform_data/tsc2007.h> 28 #include "tsc2007.h" 29 30 int tsc2007_xfer(struct tsc2007 *tsc, u8 cmd) 31 { 32 s32 data; 33 u16 val; 34 35 data = i2c_smbus_read_word_data(tsc->client, cmd); 36 if (data < 0) { 37 dev_err(&tsc->client->dev, "i2c io error: %d\n", data); 38 return data; 39 } 40 41 /* The protocol and raw data format from i2c interface: 42 * S Addr Wr [A] Comm [A] S Addr Rd [A] [DataLow] A [DataHigh] NA P 43 * Where DataLow has [D11-D4], DataHigh has [D3-D0 << 4 | Dummy 4bit]. 44 */ 45 val = swab16(data) >> 4; 46 47 dev_dbg(&tsc->client->dev, "data: 0x%x, val: 0x%x\n", data, val); 48 49 return val; 50 } 51 52 static void tsc2007_read_values(struct tsc2007 *tsc, struct ts_event *tc) 53 { 54 /* y- still on; turn on only y+ (and ADC) */ 55 tc->y = tsc2007_xfer(tsc, READ_Y); 56 57 /* turn y- off, x+ on, then leave in lowpower */ 58 tc->x = tsc2007_xfer(tsc, READ_X); 59 60 /* turn y+ off, x- on; we'll use formula #1 */ 61 tc->z1 = tsc2007_xfer(tsc, READ_Z1); 62 tc->z2 = tsc2007_xfer(tsc, READ_Z2); 63 64 /* Prepare for next touch reading - power down ADC, enable PENIRQ */ 65 tsc2007_xfer(tsc, PWRDOWN); 66 } 67 68 u32 tsc2007_calculate_resistance(struct tsc2007 *tsc, struct ts_event *tc) 69 { 70 u32 rt = 0; 71 72 /* range filtering */ 73 if (tc->x == MAX_12BIT) 74 tc->x = 0; 75 76 if (likely(tc->x && tc->z1)) { 77 /* compute touch resistance using equation #1 */ 78 rt = tc->z2 - tc->z1; 79 rt *= tc->x; 80 rt *= tsc->x_plate_ohms; 81 rt /= tc->z1; 82 rt = (rt + 2047) >> 12; 83 } 84 85 return rt; 86 } 87 88 bool tsc2007_is_pen_down(struct tsc2007 *ts) 89 { 90 /* 91 * NOTE: We can't rely on the pressure to determine the pen down 92 * state, even though this controller has a pressure sensor. 93 * The pressure value can fluctuate for quite a while after 94 * lifting the pen and in some cases may not even settle at the 95 * expected value. 96 * 97 * The only safe way to check for the pen up condition is in the 98 * work function by reading the pen signal state (it's a GPIO 99 * and IRQ). Unfortunately such callback is not always available, 100 * in that case we assume that the pen is down and expect caller 101 * to fall back on the pressure reading. 102 */ 103 104 if (!ts->get_pendown_state) 105 return true; 106 107 return ts->get_pendown_state(&ts->client->dev); 108 } 109 110 static irqreturn_t tsc2007_soft_irq(int irq, void *handle) 111 { 112 struct tsc2007 *ts = handle; 113 struct input_dev *input = ts->input; 114 struct ts_event tc; 115 u32 rt; 116 117 while (!ts->stopped && tsc2007_is_pen_down(ts)) { 118 119 /* pen is down, continue with the measurement */ 120 121 mutex_lock(&ts->mlock); 122 tsc2007_read_values(ts, &tc); 123 mutex_unlock(&ts->mlock); 124 125 rt = tsc2007_calculate_resistance(ts, &tc); 126 127 if (!rt && !ts->get_pendown_state) { 128 /* 129 * If pressure reported is 0 and we don't have 130 * callback to check pendown state, we have to 131 * assume that pen was lifted up. 132 */ 133 break; 134 } 135 136 if (rt <= ts->max_rt) { 137 dev_dbg(&ts->client->dev, 138 "DOWN point(%4d,%4d), resistance (%4u)\n", 139 tc.x, tc.y, rt); 140 141 rt = ts->max_rt - rt; 142 143 input_report_key(input, BTN_TOUCH, 1); 144 input_report_abs(input, ABS_X, tc.x); 145 input_report_abs(input, ABS_Y, tc.y); 146 input_report_abs(input, ABS_PRESSURE, rt); 147 148 input_sync(input); 149 150 } else { 151 /* 152 * Sample found inconsistent by debouncing or pressure is 153 * beyond the maximum. Don't report it to user space, 154 * repeat at least once more the measurement. 155 */ 156 dev_dbg(&ts->client->dev, "ignored pressure %d\n", rt); 157 } 158 159 wait_event_timeout(ts->wait, ts->stopped, ts->poll_period); 160 } 161 162 dev_dbg(&ts->client->dev, "UP\n"); 163 164 input_report_key(input, BTN_TOUCH, 0); 165 input_report_abs(input, ABS_PRESSURE, 0); 166 input_sync(input); 167 168 if (ts->clear_penirq) 169 ts->clear_penirq(); 170 171 return IRQ_HANDLED; 172 } 173 174 static irqreturn_t tsc2007_hard_irq(int irq, void *handle) 175 { 176 struct tsc2007 *ts = handle; 177 178 if (tsc2007_is_pen_down(ts)) 179 return IRQ_WAKE_THREAD; 180 181 if (ts->clear_penirq) 182 ts->clear_penirq(); 183 184 return IRQ_HANDLED; 185 } 186 187 static void tsc2007_stop(struct tsc2007 *ts) 188 { 189 ts->stopped = true; 190 mb(); 191 wake_up(&ts->wait); 192 193 disable_irq(ts->irq); 194 } 195 196 static int tsc2007_open(struct input_dev *input_dev) 197 { 198 struct tsc2007 *ts = input_get_drvdata(input_dev); 199 int err; 200 201 ts->stopped = false; 202 mb(); 203 204 enable_irq(ts->irq); 205 206 /* Prepare for touch readings - power down ADC and enable PENIRQ */ 207 err = tsc2007_xfer(ts, PWRDOWN); 208 if (err < 0) { 209 tsc2007_stop(ts); 210 return err; 211 } 212 213 return 0; 214 } 215 216 static void tsc2007_close(struct input_dev *input_dev) 217 { 218 struct tsc2007 *ts = input_get_drvdata(input_dev); 219 220 tsc2007_stop(ts); 221 } 222 223 #ifdef CONFIG_OF 224 static int tsc2007_get_pendown_state_gpio(struct device *dev) 225 { 226 struct i2c_client *client = to_i2c_client(dev); 227 struct tsc2007 *ts = i2c_get_clientdata(client); 228 229 return !gpio_get_value(ts->gpio); 230 } 231 232 static int tsc2007_probe_dt(struct i2c_client *client, struct tsc2007 *ts) 233 { 234 struct device_node *np = client->dev.of_node; 235 u32 val32; 236 u64 val64; 237 238 if (!np) { 239 dev_err(&client->dev, "missing device tree data\n"); 240 return -EINVAL; 241 } 242 243 if (!of_property_read_u32(np, "ti,max-rt", &val32)) 244 ts->max_rt = val32; 245 else 246 ts->max_rt = MAX_12BIT; 247 248 if (!of_property_read_u32(np, "ti,fuzzx", &val32)) 249 ts->fuzzx = val32; 250 251 if (!of_property_read_u32(np, "ti,fuzzy", &val32)) 252 ts->fuzzy = val32; 253 254 if (!of_property_read_u32(np, "ti,fuzzz", &val32)) 255 ts->fuzzz = val32; 256 257 if (!of_property_read_u64(np, "ti,poll-period", &val64)) 258 ts->poll_period = msecs_to_jiffies(val64); 259 else 260 ts->poll_period = msecs_to_jiffies(1); 261 262 if (!of_property_read_u32(np, "ti,x-plate-ohms", &val32)) { 263 ts->x_plate_ohms = val32; 264 } else { 265 dev_err(&client->dev, "missing ti,x-plate-ohms devicetree property."); 266 return -EINVAL; 267 } 268 269 ts->gpio = of_get_gpio(np, 0); 270 if (gpio_is_valid(ts->gpio)) 271 ts->get_pendown_state = tsc2007_get_pendown_state_gpio; 272 else 273 dev_warn(&client->dev, 274 "GPIO not specified in DT (of_get_gpio returned %d)\n", 275 ts->gpio); 276 277 return 0; 278 } 279 #else 280 static int tsc2007_probe_dt(struct i2c_client *client, struct tsc2007 *ts) 281 { 282 dev_err(&client->dev, "platform data is required!\n"); 283 return -EINVAL; 284 } 285 #endif 286 287 static int tsc2007_probe_pdev(struct i2c_client *client, struct tsc2007 *ts, 288 const struct tsc2007_platform_data *pdata, 289 const struct i2c_device_id *id) 290 { 291 ts->model = pdata->model; 292 ts->x_plate_ohms = pdata->x_plate_ohms; 293 ts->max_rt = pdata->max_rt ? : MAX_12BIT; 294 ts->poll_period = msecs_to_jiffies(pdata->poll_period ? : 1); 295 ts->get_pendown_state = pdata->get_pendown_state; 296 ts->clear_penirq = pdata->clear_penirq; 297 ts->fuzzx = pdata->fuzzx; 298 ts->fuzzy = pdata->fuzzy; 299 ts->fuzzz = pdata->fuzzz; 300 301 if (pdata->x_plate_ohms == 0) { 302 dev_err(&client->dev, "x_plate_ohms is not set up in platform data"); 303 return -EINVAL; 304 } 305 306 return 0; 307 } 308 309 static void tsc2007_call_exit_platform_hw(void *data) 310 { 311 struct device *dev = data; 312 const struct tsc2007_platform_data *pdata = dev_get_platdata(dev); 313 314 pdata->exit_platform_hw(); 315 } 316 317 static int tsc2007_probe(struct i2c_client *client, 318 const struct i2c_device_id *id) 319 { 320 const struct tsc2007_platform_data *pdata = 321 dev_get_platdata(&client->dev); 322 struct tsc2007 *ts; 323 struct input_dev *input_dev; 324 int err; 325 326 if (!i2c_check_functionality(client->adapter, 327 I2C_FUNC_SMBUS_READ_WORD_DATA)) 328 return -EIO; 329 330 ts = devm_kzalloc(&client->dev, sizeof(struct tsc2007), GFP_KERNEL); 331 if (!ts) 332 return -ENOMEM; 333 334 if (pdata) 335 err = tsc2007_probe_pdev(client, ts, pdata, id); 336 else 337 err = tsc2007_probe_dt(client, ts); 338 if (err) 339 return err; 340 341 input_dev = devm_input_allocate_device(&client->dev); 342 if (!input_dev) 343 return -ENOMEM; 344 345 i2c_set_clientdata(client, ts); 346 347 ts->client = client; 348 ts->irq = client->irq; 349 ts->input = input_dev; 350 351 init_waitqueue_head(&ts->wait); 352 mutex_init(&ts->mlock); 353 354 snprintf(ts->phys, sizeof(ts->phys), 355 "%s/input0", dev_name(&client->dev)); 356 357 input_dev->name = "TSC2007 Touchscreen"; 358 input_dev->phys = ts->phys; 359 input_dev->id.bustype = BUS_I2C; 360 361 input_dev->open = tsc2007_open; 362 input_dev->close = tsc2007_close; 363 364 input_set_drvdata(input_dev, ts); 365 366 input_set_capability(input_dev, EV_KEY, BTN_TOUCH); 367 368 input_set_abs_params(input_dev, ABS_X, 0, MAX_12BIT, ts->fuzzx, 0); 369 input_set_abs_params(input_dev, ABS_Y, 0, MAX_12BIT, ts->fuzzy, 0); 370 input_set_abs_params(input_dev, ABS_PRESSURE, 0, MAX_12BIT, 371 ts->fuzzz, 0); 372 373 if (pdata) { 374 if (pdata->exit_platform_hw) { 375 err = devm_add_action(&client->dev, 376 tsc2007_call_exit_platform_hw, 377 &client->dev); 378 if (err) { 379 dev_err(&client->dev, 380 "Failed to register exit_platform_hw action, %d\n", 381 err); 382 return err; 383 } 384 } 385 386 if (pdata->init_platform_hw) 387 pdata->init_platform_hw(); 388 } 389 390 err = devm_request_threaded_irq(&client->dev, ts->irq, 391 tsc2007_hard_irq, tsc2007_soft_irq, 392 IRQF_ONESHOT, 393 client->dev.driver->name, ts); 394 if (err) { 395 dev_err(&client->dev, "Failed to request irq %d: %d\n", 396 ts->irq, err); 397 return err; 398 } 399 400 tsc2007_stop(ts); 401 402 /* power down the chip (TSC2007_SETUP does not ACK on I2C) */ 403 err = tsc2007_xfer(ts, PWRDOWN); 404 if (err < 0) { 405 dev_err(&client->dev, 406 "Failed to setup chip: %d\n", err); 407 return err; /* chip does not respond */ 408 } 409 410 err = input_register_device(input_dev); 411 if (err) { 412 dev_err(&client->dev, 413 "Failed to register input device: %d\n", err); 414 return err; 415 } 416 417 err = tsc2007_iio_configure(ts); 418 if (err) { 419 dev_err(&client->dev, 420 "Failed to register with IIO: %d\n", err); 421 return err; 422 } 423 424 return 0; 425 } 426 427 static const struct i2c_device_id tsc2007_idtable[] = { 428 { "tsc2007", 0 }, 429 { } 430 }; 431 432 MODULE_DEVICE_TABLE(i2c, tsc2007_idtable); 433 434 #ifdef CONFIG_OF 435 static const struct of_device_id tsc2007_of_match[] = { 436 { .compatible = "ti,tsc2007" }, 437 { /* sentinel */ } 438 }; 439 MODULE_DEVICE_TABLE(of, tsc2007_of_match); 440 #endif 441 442 static struct i2c_driver tsc2007_driver = { 443 .driver = { 444 .name = "tsc2007", 445 .of_match_table = of_match_ptr(tsc2007_of_match), 446 }, 447 .id_table = tsc2007_idtable, 448 .probe = tsc2007_probe, 449 }; 450 451 module_i2c_driver(tsc2007_driver); 452 453 MODULE_AUTHOR("Kwangwoo Lee <kwlee@mtekvision.com>"); 454 MODULE_DESCRIPTION("TSC2007 TouchScreen Driver"); 455 MODULE_LICENSE("GPL"); 456