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