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/gpio/consumer.h> 23 #include <linux/input.h> 24 #include <linux/interrupt.h> 25 #include <linux/i2c.h> 26 #include <linux/math64.h> 27 #include <linux/mod_devicetable.h> 28 #include <linux/property.h> 29 #include <linux/platform_data/tsc2007.h> 30 #include "tsc2007.h" 31 32 int tsc2007_xfer(struct tsc2007 *tsc, u8 cmd) 33 { 34 s32 data; 35 u16 val; 36 37 data = i2c_smbus_read_word_data(tsc->client, cmd); 38 if (data < 0) { 39 dev_err(&tsc->client->dev, "i2c io error: %d\n", data); 40 return data; 41 } 42 43 /* The protocol and raw data format from i2c interface: 44 * S Addr Wr [A] Comm [A] S Addr Rd [A] [DataLow] A [DataHigh] NA P 45 * Where DataLow has [D11-D4], DataHigh has [D3-D0 << 4 | Dummy 4bit]. 46 */ 47 val = swab16(data) >> 4; 48 49 dev_dbg(&tsc->client->dev, "data: 0x%x, val: 0x%x\n", data, val); 50 51 return val; 52 } 53 54 static void tsc2007_read_values(struct tsc2007 *tsc, struct ts_event *tc) 55 { 56 /* y- still on; turn on only y+ (and ADC) */ 57 tc->y = tsc2007_xfer(tsc, READ_Y); 58 59 /* turn y- off, x+ on, then leave in lowpower */ 60 tc->x = tsc2007_xfer(tsc, READ_X); 61 62 /* turn y+ off, x- on; we'll use formula #1 */ 63 tc->z1 = tsc2007_xfer(tsc, READ_Z1); 64 tc->z2 = tsc2007_xfer(tsc, READ_Z2); 65 66 /* Prepare for next touch reading - power down ADC, enable PENIRQ */ 67 tsc2007_xfer(tsc, PWRDOWN); 68 } 69 70 u32 tsc2007_calculate_resistance(struct tsc2007 *tsc, struct ts_event *tc) 71 { 72 u64 rt = 0; 73 74 /* range filtering */ 75 if (tc->x == MAX_12BIT) 76 tc->x = 0; 77 78 if (likely(tc->x && tc->z1)) { 79 /* compute touch resistance using equation #1 */ 80 rt = tc->z2 - tc->z1; 81 rt *= tc->x; 82 rt *= tsc->x_plate_ohms; 83 rt = div_u64(rt, tc->z1); 84 rt = (rt + 2047) >> 12; 85 } 86 87 if (rt > U32_MAX) 88 return U32_MAX; 89 return (u32) rt; 90 } 91 92 bool tsc2007_is_pen_down(struct tsc2007 *ts) 93 { 94 /* 95 * NOTE: We can't rely on the pressure to determine the pen down 96 * state, even though this controller has a pressure sensor. 97 * The pressure value can fluctuate for quite a while after 98 * lifting the pen and in some cases may not even settle at the 99 * expected value. 100 * 101 * The only safe way to check for the pen up condition is in the 102 * work function by reading the pen signal state (it's a GPIO 103 * and IRQ). Unfortunately such callback is not always available, 104 * in that case we assume that the pen is down and expect caller 105 * to fall back on the pressure reading. 106 */ 107 108 if (!ts->get_pendown_state) 109 return true; 110 111 return ts->get_pendown_state(&ts->client->dev); 112 } 113 114 static irqreturn_t tsc2007_soft_irq(int irq, void *handle) 115 { 116 struct tsc2007 *ts = handle; 117 struct input_dev *input = ts->input; 118 struct ts_event tc; 119 u32 rt; 120 121 while (!ts->stopped && tsc2007_is_pen_down(ts)) { 122 123 /* pen is down, continue with the measurement */ 124 125 /* Serialize access between the ISR and IIO reads. */ 126 scoped_guard(mutex, &ts->mlock) { 127 tsc2007_read_values(ts, &tc); 128 } 129 130 rt = tsc2007_calculate_resistance(ts, &tc); 131 132 if (!rt && !ts->get_pendown_state) { 133 /* 134 * If pressure reported is 0 and we don't have 135 * callback to check pendown state, we have to 136 * assume that pen was lifted up. 137 */ 138 break; 139 } 140 141 if (rt <= ts->max_rt) { 142 dev_dbg(&ts->client->dev, 143 "DOWN point(%4d,%4d), resistance (%4u)\n", 144 tc.x, tc.y, rt); 145 146 rt = ts->max_rt - rt; 147 148 input_report_key(input, BTN_TOUCH, 1); 149 touchscreen_report_pos(input, &ts->prop, tc.x, tc.y, false); 150 input_report_abs(input, ABS_PRESSURE, rt); 151 152 input_sync(input); 153 154 } else { 155 /* 156 * Sample found inconsistent by debouncing or pressure is 157 * beyond the maximum. Don't report it to user space, 158 * repeat at least once more the measurement. 159 */ 160 dev_dbg(&ts->client->dev, "ignored pressure %d\n", rt); 161 } 162 163 wait_event_timeout(ts->wait, ts->stopped, ts->poll_period); 164 } 165 166 dev_dbg(&ts->client->dev, "UP\n"); 167 168 input_report_key(input, BTN_TOUCH, 0); 169 input_report_abs(input, ABS_PRESSURE, 0); 170 input_sync(input); 171 172 if (ts->clear_penirq) 173 ts->clear_penirq(); 174 175 return IRQ_HANDLED; 176 } 177 178 static void tsc2007_stop(struct tsc2007 *ts) 179 { 180 ts->stopped = true; 181 mb(); 182 wake_up(&ts->wait); 183 184 if (ts->irq) 185 disable_irq(ts->irq); 186 } 187 188 static int tsc2007_open(struct input_dev *input_dev) 189 { 190 struct tsc2007 *ts = input_get_drvdata(input_dev); 191 int err; 192 193 ts->stopped = false; 194 mb(); 195 196 if (ts->irq) 197 enable_irq(ts->irq); 198 199 /* Prepare for touch readings - power down ADC and enable PENIRQ */ 200 err = tsc2007_xfer(ts, PWRDOWN); 201 if (err < 0) { 202 tsc2007_stop(ts); 203 return err; 204 } 205 206 return 0; 207 } 208 209 static void tsc2007_close(struct input_dev *input_dev) 210 { 211 struct tsc2007 *ts = input_get_drvdata(input_dev); 212 213 tsc2007_stop(ts); 214 } 215 216 static int tsc2007_get_pendown_state_gpio(struct device *dev) 217 { 218 struct i2c_client *client = to_i2c_client(dev); 219 struct tsc2007 *ts = i2c_get_clientdata(client); 220 221 return gpiod_get_value_cansleep(ts->gpiod); 222 } 223 224 static int tsc2007_probe_properties(struct device *dev, struct tsc2007 *ts) 225 { 226 u32 val32; 227 u64 val64; 228 229 if (!device_property_read_u32(dev, "ti,max-rt", &val32)) 230 ts->max_rt = val32; 231 else 232 ts->max_rt = MAX_12BIT; 233 234 if (!device_property_read_u32(dev, "ti,fuzzx", &val32)) 235 ts->fuzzx = val32; 236 237 if (!device_property_read_u32(dev, "ti,fuzzy", &val32)) 238 ts->fuzzy = val32; 239 240 if (!device_property_read_u32(dev, "ti,fuzzz", &val32)) 241 ts->fuzzz = val32; 242 243 if (!device_property_read_u64(dev, "ti,poll-period", &val64)) 244 ts->poll_period = msecs_to_jiffies(val64); 245 else 246 ts->poll_period = msecs_to_jiffies(1); 247 248 if (!device_property_read_u32(dev, "ti,x-plate-ohms", &val32)) { 249 ts->x_plate_ohms = val32; 250 } else { 251 dev_err(dev, "Missing ti,x-plate-ohms device property\n"); 252 return -EINVAL; 253 } 254 255 ts->gpiod = devm_gpiod_get_optional(dev, NULL, GPIOD_IN); 256 if (IS_ERR(ts->gpiod)) 257 return PTR_ERR(ts->gpiod); 258 259 if (ts->gpiod) 260 ts->get_pendown_state = tsc2007_get_pendown_state_gpio; 261 else 262 dev_dbg(dev, "Pen down GPIO is not specified in properties\n"); 263 264 return 0; 265 } 266 267 static int tsc2007_probe_pdev(struct device *dev, struct tsc2007 *ts, 268 const struct tsc2007_platform_data *pdata, 269 const struct i2c_device_id *id) 270 { 271 ts->model = pdata->model; 272 ts->x_plate_ohms = pdata->x_plate_ohms; 273 ts->max_rt = pdata->max_rt ? : MAX_12BIT; 274 ts->poll_period = msecs_to_jiffies(pdata->poll_period ? : 1); 275 ts->get_pendown_state = pdata->get_pendown_state; 276 ts->clear_penirq = pdata->clear_penirq; 277 ts->fuzzx = pdata->fuzzx; 278 ts->fuzzy = pdata->fuzzy; 279 ts->fuzzz = pdata->fuzzz; 280 281 if (pdata->x_plate_ohms == 0) { 282 dev_err(dev, "x_plate_ohms is not set up in platform data\n"); 283 return -EINVAL; 284 } 285 286 return 0; 287 } 288 289 static void tsc2007_call_exit_platform_hw(void *data) 290 { 291 struct device *dev = data; 292 const struct tsc2007_platform_data *pdata = dev_get_platdata(dev); 293 294 pdata->exit_platform_hw(); 295 } 296 297 static int tsc2007_probe(struct i2c_client *client) 298 { 299 const struct i2c_device_id *id = i2c_client_get_device_id(client); 300 const struct tsc2007_platform_data *pdata = 301 dev_get_platdata(&client->dev); 302 struct tsc2007 *ts; 303 struct input_dev *input_dev; 304 int err; 305 306 if (!i2c_check_functionality(client->adapter, 307 I2C_FUNC_SMBUS_READ_WORD_DATA)) 308 return -EIO; 309 310 ts = devm_kzalloc(&client->dev, sizeof(struct tsc2007), GFP_KERNEL); 311 if (!ts) 312 return -ENOMEM; 313 314 if (pdata) 315 err = tsc2007_probe_pdev(&client->dev, ts, pdata, id); 316 else 317 err = tsc2007_probe_properties(&client->dev, ts); 318 if (err) 319 return err; 320 321 input_dev = devm_input_allocate_device(&client->dev); 322 if (!input_dev) 323 return -ENOMEM; 324 325 i2c_set_clientdata(client, ts); 326 327 ts->client = client; 328 ts->irq = client->irq; 329 ts->input = input_dev; 330 331 init_waitqueue_head(&ts->wait); 332 mutex_init(&ts->mlock); 333 334 snprintf(ts->phys, sizeof(ts->phys), 335 "%s/input0", dev_name(&client->dev)); 336 337 input_dev->name = "TSC2007 Touchscreen"; 338 input_dev->phys = ts->phys; 339 input_dev->id.bustype = BUS_I2C; 340 341 input_dev->open = tsc2007_open; 342 input_dev->close = tsc2007_close; 343 344 input_set_drvdata(input_dev, ts); 345 346 input_set_capability(input_dev, EV_KEY, BTN_TOUCH); 347 input_set_abs_params(input_dev, ABS_X, 0, MAX_12BIT, ts->fuzzx, 0); 348 input_set_abs_params(input_dev, ABS_Y, 0, MAX_12BIT, ts->fuzzy, 0); 349 touchscreen_parse_properties(input_dev, false, &ts->prop); 350 input_set_abs_params(input_dev, ABS_PRESSURE, 0, MAX_12BIT, 351 ts->fuzzz, 0); 352 353 if (pdata) { 354 if (pdata->exit_platform_hw) { 355 err = devm_add_action(&client->dev, 356 tsc2007_call_exit_platform_hw, 357 &client->dev); 358 if (err) { 359 dev_err(&client->dev, 360 "Failed to register exit_platform_hw action, %d\n", 361 err); 362 return err; 363 } 364 } 365 366 if (pdata->init_platform_hw) 367 pdata->init_platform_hw(); 368 } 369 370 if (ts->irq) { 371 err = devm_request_threaded_irq(&client->dev, ts->irq, 372 NULL, tsc2007_soft_irq, 373 IRQF_ONESHOT, 374 client->dev.driver->name, ts); 375 if (err) { 376 dev_err(&client->dev, "Failed to request irq %d: %d\n", 377 ts->irq, err); 378 return err; 379 } 380 381 tsc2007_stop(ts); 382 } 383 384 /* power down the chip (TSC2007_SETUP does not ACK on I2C) */ 385 err = tsc2007_xfer(ts, PWRDOWN); 386 if (err < 0) { 387 dev_err(&client->dev, 388 "Failed to setup chip: %d\n", err); 389 return err; /* chip does not respond */ 390 } 391 392 err = input_register_device(input_dev); 393 if (err) { 394 dev_err(&client->dev, 395 "Failed to register input device: %d\n", err); 396 return err; 397 } 398 399 err = tsc2007_iio_configure(ts); 400 if (err) { 401 dev_err(&client->dev, 402 "Failed to register with IIO: %d\n", err); 403 return err; 404 } 405 406 return 0; 407 } 408 409 static const struct i2c_device_id tsc2007_idtable[] = { 410 { "tsc2007" }, 411 { } 412 }; 413 414 MODULE_DEVICE_TABLE(i2c, tsc2007_idtable); 415 416 static const struct of_device_id tsc2007_of_match[] = { 417 { .compatible = "ti,tsc2007" }, 418 { /* sentinel */ } 419 }; 420 MODULE_DEVICE_TABLE(of, tsc2007_of_match); 421 422 static struct i2c_driver tsc2007_driver = { 423 .driver = { 424 .name = "tsc2007", 425 .of_match_table = tsc2007_of_match, 426 }, 427 .id_table = tsc2007_idtable, 428 .probe = tsc2007_probe, 429 }; 430 431 module_i2c_driver(tsc2007_driver); 432 433 MODULE_AUTHOR("Kwangwoo Lee <kwlee@mtekvision.com>"); 434 MODULE_DESCRIPTION("TSC2007 TouchScreen Driver"); 435 MODULE_LICENSE("GPL"); 436