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 mutex_lock(&ts->mlock); 126 tsc2007_read_values(ts, &tc); 127 mutex_unlock(&ts->mlock); 128 129 rt = tsc2007_calculate_resistance(ts, &tc); 130 131 if (!rt && !ts->get_pendown_state) { 132 /* 133 * If pressure reported is 0 and we don't have 134 * callback to check pendown state, we have to 135 * assume that pen was lifted up. 136 */ 137 break; 138 } 139 140 if (rt <= ts->max_rt) { 141 dev_dbg(&ts->client->dev, 142 "DOWN point(%4d,%4d), resistance (%4u)\n", 143 tc.x, tc.y, rt); 144 145 rt = ts->max_rt - rt; 146 147 input_report_key(input, BTN_TOUCH, 1); 148 touchscreen_report_pos(input, &ts->prop, tc.x, tc.y, false); 149 input_report_abs(input, ABS_PRESSURE, rt); 150 151 input_sync(input); 152 153 } else { 154 /* 155 * Sample found inconsistent by debouncing or pressure is 156 * beyond the maximum. Don't report it to user space, 157 * repeat at least once more the measurement. 158 */ 159 dev_dbg(&ts->client->dev, "ignored pressure %d\n", rt); 160 } 161 162 wait_event_timeout(ts->wait, ts->stopped, ts->poll_period); 163 } 164 165 dev_dbg(&ts->client->dev, "UP\n"); 166 167 input_report_key(input, BTN_TOUCH, 0); 168 input_report_abs(input, ABS_PRESSURE, 0); 169 input_sync(input); 170 171 if (ts->clear_penirq) 172 ts->clear_penirq(); 173 174 return IRQ_HANDLED; 175 } 176 177 static void tsc2007_stop(struct tsc2007 *ts) 178 { 179 ts->stopped = true; 180 mb(); 181 wake_up(&ts->wait); 182 183 if (ts->irq) 184 disable_irq(ts->irq); 185 } 186 187 static int tsc2007_open(struct input_dev *input_dev) 188 { 189 struct tsc2007 *ts = input_get_drvdata(input_dev); 190 int err; 191 192 ts->stopped = false; 193 mb(); 194 195 if (ts->irq) 196 enable_irq(ts->irq); 197 198 /* Prepare for touch readings - power down ADC and enable PENIRQ */ 199 err = tsc2007_xfer(ts, PWRDOWN); 200 if (err < 0) { 201 tsc2007_stop(ts); 202 return err; 203 } 204 205 return 0; 206 } 207 208 static void tsc2007_close(struct input_dev *input_dev) 209 { 210 struct tsc2007 *ts = input_get_drvdata(input_dev); 211 212 tsc2007_stop(ts); 213 } 214 215 static int tsc2007_get_pendown_state_gpio(struct device *dev) 216 { 217 struct i2c_client *client = to_i2c_client(dev); 218 struct tsc2007 *ts = i2c_get_clientdata(client); 219 220 return gpiod_get_value_cansleep(ts->gpiod); 221 } 222 223 static int tsc2007_probe_properties(struct device *dev, struct tsc2007 *ts) 224 { 225 u32 val32; 226 u64 val64; 227 228 if (!device_property_read_u32(dev, "ti,max-rt", &val32)) 229 ts->max_rt = val32; 230 else 231 ts->max_rt = MAX_12BIT; 232 233 if (!device_property_read_u32(dev, "ti,fuzzx", &val32)) 234 ts->fuzzx = val32; 235 236 if (!device_property_read_u32(dev, "ti,fuzzy", &val32)) 237 ts->fuzzy = val32; 238 239 if (!device_property_read_u32(dev, "ti,fuzzz", &val32)) 240 ts->fuzzz = val32; 241 242 if (!device_property_read_u64(dev, "ti,poll-period", &val64)) 243 ts->poll_period = msecs_to_jiffies(val64); 244 else 245 ts->poll_period = msecs_to_jiffies(1); 246 247 if (!device_property_read_u32(dev, "ti,x-plate-ohms", &val32)) { 248 ts->x_plate_ohms = val32; 249 } else { 250 dev_err(dev, "Missing ti,x-plate-ohms device property\n"); 251 return -EINVAL; 252 } 253 254 ts->gpiod = devm_gpiod_get_optional(dev, NULL, GPIOD_IN); 255 if (IS_ERR(ts->gpiod)) 256 return PTR_ERR(ts->gpiod); 257 258 if (ts->gpiod) 259 ts->get_pendown_state = tsc2007_get_pendown_state_gpio; 260 else 261 dev_dbg(dev, "Pen down GPIO is not specified in properties\n"); 262 263 return 0; 264 } 265 266 static int tsc2007_probe_pdev(struct device *dev, struct tsc2007 *ts, 267 const struct tsc2007_platform_data *pdata, 268 const struct i2c_device_id *id) 269 { 270 ts->model = pdata->model; 271 ts->x_plate_ohms = pdata->x_plate_ohms; 272 ts->max_rt = pdata->max_rt ? : MAX_12BIT; 273 ts->poll_period = msecs_to_jiffies(pdata->poll_period ? : 1); 274 ts->get_pendown_state = pdata->get_pendown_state; 275 ts->clear_penirq = pdata->clear_penirq; 276 ts->fuzzx = pdata->fuzzx; 277 ts->fuzzy = pdata->fuzzy; 278 ts->fuzzz = pdata->fuzzz; 279 280 if (pdata->x_plate_ohms == 0) { 281 dev_err(dev, "x_plate_ohms is not set up in platform data\n"); 282 return -EINVAL; 283 } 284 285 return 0; 286 } 287 288 static void tsc2007_call_exit_platform_hw(void *data) 289 { 290 struct device *dev = data; 291 const struct tsc2007_platform_data *pdata = dev_get_platdata(dev); 292 293 pdata->exit_platform_hw(); 294 } 295 296 static int tsc2007_probe(struct i2c_client *client) 297 { 298 const struct i2c_device_id *id = i2c_client_get_device_id(client); 299 const struct tsc2007_platform_data *pdata = 300 dev_get_platdata(&client->dev); 301 struct tsc2007 *ts; 302 struct input_dev *input_dev; 303 int err; 304 305 if (!i2c_check_functionality(client->adapter, 306 I2C_FUNC_SMBUS_READ_WORD_DATA)) 307 return -EIO; 308 309 ts = devm_kzalloc(&client->dev, sizeof(struct tsc2007), GFP_KERNEL); 310 if (!ts) 311 return -ENOMEM; 312 313 if (pdata) 314 err = tsc2007_probe_pdev(&client->dev, ts, pdata, id); 315 else 316 err = tsc2007_probe_properties(&client->dev, ts); 317 if (err) 318 return err; 319 320 input_dev = devm_input_allocate_device(&client->dev); 321 if (!input_dev) 322 return -ENOMEM; 323 324 i2c_set_clientdata(client, ts); 325 326 ts->client = client; 327 ts->irq = client->irq; 328 ts->input = input_dev; 329 330 init_waitqueue_head(&ts->wait); 331 mutex_init(&ts->mlock); 332 333 snprintf(ts->phys, sizeof(ts->phys), 334 "%s/input0", dev_name(&client->dev)); 335 336 input_dev->name = "TSC2007 Touchscreen"; 337 input_dev->phys = ts->phys; 338 input_dev->id.bustype = BUS_I2C; 339 340 input_dev->open = tsc2007_open; 341 input_dev->close = tsc2007_close; 342 343 input_set_drvdata(input_dev, ts); 344 345 input_set_capability(input_dev, EV_KEY, BTN_TOUCH); 346 input_set_abs_params(input_dev, ABS_X, 0, MAX_12BIT, ts->fuzzx, 0); 347 input_set_abs_params(input_dev, ABS_Y, 0, MAX_12BIT, ts->fuzzy, 0); 348 touchscreen_parse_properties(input_dev, false, &ts->prop); 349 input_set_abs_params(input_dev, ABS_PRESSURE, 0, MAX_12BIT, 350 ts->fuzzz, 0); 351 352 if (pdata) { 353 if (pdata->exit_platform_hw) { 354 err = devm_add_action(&client->dev, 355 tsc2007_call_exit_platform_hw, 356 &client->dev); 357 if (err) { 358 dev_err(&client->dev, 359 "Failed to register exit_platform_hw action, %d\n", 360 err); 361 return err; 362 } 363 } 364 365 if (pdata->init_platform_hw) 366 pdata->init_platform_hw(); 367 } 368 369 if (ts->irq) { 370 err = devm_request_threaded_irq(&client->dev, ts->irq, 371 NULL, tsc2007_soft_irq, 372 IRQF_ONESHOT, 373 client->dev.driver->name, ts); 374 if (err) { 375 dev_err(&client->dev, "Failed to request irq %d: %d\n", 376 ts->irq, err); 377 return err; 378 } 379 380 tsc2007_stop(ts); 381 } 382 383 /* power down the chip (TSC2007_SETUP does not ACK on I2C) */ 384 err = tsc2007_xfer(ts, PWRDOWN); 385 if (err < 0) { 386 dev_err(&client->dev, 387 "Failed to setup chip: %d\n", err); 388 return err; /* chip does not respond */ 389 } 390 391 err = input_register_device(input_dev); 392 if (err) { 393 dev_err(&client->dev, 394 "Failed to register input device: %d\n", err); 395 return err; 396 } 397 398 err = tsc2007_iio_configure(ts); 399 if (err) { 400 dev_err(&client->dev, 401 "Failed to register with IIO: %d\n", err); 402 return err; 403 } 404 405 return 0; 406 } 407 408 static const struct i2c_device_id tsc2007_idtable[] = { 409 { "tsc2007" }, 410 { } 411 }; 412 413 MODULE_DEVICE_TABLE(i2c, tsc2007_idtable); 414 415 static const struct of_device_id tsc2007_of_match[] = { 416 { .compatible = "ti,tsc2007" }, 417 { /* sentinel */ } 418 }; 419 MODULE_DEVICE_TABLE(of, tsc2007_of_match); 420 421 static struct i2c_driver tsc2007_driver = { 422 .driver = { 423 .name = "tsc2007", 424 .of_match_table = tsc2007_of_match, 425 }, 426 .id_table = tsc2007_idtable, 427 .probe = tsc2007_probe, 428 }; 429 430 module_i2c_driver(tsc2007_driver); 431 432 MODULE_AUTHOR("Kwangwoo Lee <kwlee@mtekvision.com>"); 433 MODULE_DESCRIPTION("TSC2007 TouchScreen Driver"); 434 MODULE_LICENSE("GPL"); 435