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/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 /* Read Z2 and power down ADC after A/D conversion, enable PENIRQ */ 64 tc->z2 = tsc2007_xfer(tsc, (TSC2007_POWER_OFF_IRQ_EN | TSC2007_MEASURE_Z2)); 65 } 66 67 u32 tsc2007_calculate_resistance(struct tsc2007 *tsc, struct ts_event *tc) 68 { 69 u64 rt = 0; 70 71 /* range filtering */ 72 if (tc->x == MAX_12BIT) 73 tc->x = 0; 74 75 if (likely(tc->x && tc->z1)) { 76 /* compute touch resistance using equation #1 */ 77 rt = tc->z2 - tc->z1; 78 rt *= tc->x; 79 rt *= tsc->x_plate_ohms; 80 rt = div_u64(rt, tc->z1); 81 rt = (rt + 2047) >> 12; 82 } 83 84 if (rt > U32_MAX) 85 return U32_MAX; 86 return (u32) 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 /* Serialize access between the ISR and IIO reads. */ 123 scoped_guard(mutex, &ts->mlock) { 124 tsc2007_read_values(ts, &tc); 125 } 126 127 rt = tsc2007_calculate_resistance(ts, &tc); 128 129 if (!rt && !ts->get_pendown_state) { 130 /* 131 * If pressure reported is 0 and we don't have 132 * callback to check pendown state, we have to 133 * assume that pen was lifted up. 134 */ 135 break; 136 } 137 138 if (rt <= ts->max_rt) { 139 dev_dbg(&ts->client->dev, 140 "DOWN point(%4d,%4d), resistance (%4u)\n", 141 tc.x, tc.y, rt); 142 143 rt = ts->max_rt - rt; 144 145 input_report_key(input, BTN_TOUCH, 1); 146 touchscreen_report_pos(input, &ts->prop, tc.x, tc.y, false); 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 if (ts->irq) 182 disable_irq(ts->irq); 183 } 184 185 static int tsc2007_open(struct input_dev *input_dev) 186 { 187 struct tsc2007 *ts = input_get_drvdata(input_dev); 188 int err; 189 190 ts->stopped = false; 191 mb(); 192 193 if (ts->irq) 194 enable_irq(ts->irq); 195 196 /* Prepare for touch readings - power down ADC and enable PENIRQ */ 197 err = tsc2007_xfer(ts, PWRDOWN); 198 if (err < 0) { 199 tsc2007_stop(ts); 200 return err; 201 } 202 203 return 0; 204 } 205 206 static void tsc2007_close(struct input_dev *input_dev) 207 { 208 struct tsc2007 *ts = input_get_drvdata(input_dev); 209 210 tsc2007_stop(ts); 211 } 212 213 static int tsc2007_get_pendown_state_gpio(struct device *dev) 214 { 215 struct i2c_client *client = to_i2c_client(dev); 216 struct tsc2007 *ts = i2c_get_clientdata(client); 217 218 return gpiod_get_value_cansleep(ts->gpiod); 219 } 220 221 static int tsc2007_probe_properties(struct device *dev, struct tsc2007 *ts) 222 { 223 u32 val32; 224 225 if (!device_property_read_u32(dev, "ti,max-rt", &val32)) 226 ts->max_rt = val32; 227 else 228 ts->max_rt = MAX_12BIT; 229 230 if (!device_property_read_u32(dev, "ti,fuzzx", &val32)) 231 ts->fuzzx = val32; 232 233 if (!device_property_read_u32(dev, "ti,fuzzy", &val32)) 234 ts->fuzzy = val32; 235 236 if (!device_property_read_u32(dev, "ti,fuzzz", &val32)) 237 ts->fuzzz = val32; 238 239 if (!device_property_read_u32(dev, "ti,poll-period", &val32)) 240 ts->poll_period = msecs_to_jiffies(val32); 241 else 242 ts->poll_period = msecs_to_jiffies(1); 243 244 if (!device_property_read_u32(dev, "ti,x-plate-ohms", &val32)) { 245 ts->x_plate_ohms = val32; 246 } else { 247 dev_err(dev, "Missing ti,x-plate-ohms device property\n"); 248 return -EINVAL; 249 } 250 251 ts->gpiod = devm_gpiod_get_optional(dev, NULL, GPIOD_IN); 252 if (IS_ERR(ts->gpiod)) 253 return PTR_ERR(ts->gpiod); 254 255 if (ts->gpiod) 256 ts->get_pendown_state = tsc2007_get_pendown_state_gpio; 257 else 258 dev_dbg(dev, "Pen down GPIO is not specified in properties\n"); 259 260 return 0; 261 } 262 263 static int tsc2007_probe_pdev(struct device *dev, struct tsc2007 *ts, 264 const struct tsc2007_platform_data *pdata, 265 const struct i2c_device_id *id) 266 { 267 ts->model = pdata->model; 268 ts->x_plate_ohms = pdata->x_plate_ohms; 269 ts->max_rt = pdata->max_rt ? : MAX_12BIT; 270 ts->poll_period = msecs_to_jiffies(pdata->poll_period ? : 1); 271 ts->get_pendown_state = pdata->get_pendown_state; 272 ts->clear_penirq = pdata->clear_penirq; 273 ts->fuzzx = pdata->fuzzx; 274 ts->fuzzy = pdata->fuzzy; 275 ts->fuzzz = pdata->fuzzz; 276 277 if (pdata->x_plate_ohms == 0) { 278 dev_err(dev, "x_plate_ohms is not set up in platform data\n"); 279 return -EINVAL; 280 } 281 282 return 0; 283 } 284 285 static void tsc2007_call_exit_platform_hw(void *data) 286 { 287 struct device *dev = data; 288 const struct tsc2007_platform_data *pdata = dev_get_platdata(dev); 289 290 pdata->exit_platform_hw(); 291 } 292 293 static int tsc2007_probe(struct i2c_client *client) 294 { 295 const struct i2c_device_id *id = i2c_client_get_device_id(client); 296 const struct tsc2007_platform_data *pdata = 297 dev_get_platdata(&client->dev); 298 struct tsc2007 *ts; 299 struct input_dev *input_dev; 300 int err; 301 302 if (!i2c_check_functionality(client->adapter, 303 I2C_FUNC_SMBUS_READ_WORD_DATA)) 304 return -EIO; 305 306 ts = devm_kzalloc(&client->dev, sizeof(struct tsc2007), GFP_KERNEL); 307 if (!ts) 308 return -ENOMEM; 309 310 if (pdata) 311 err = tsc2007_probe_pdev(&client->dev, ts, pdata, id); 312 else 313 err = tsc2007_probe_properties(&client->dev, ts); 314 if (err) 315 return err; 316 317 input_dev = devm_input_allocate_device(&client->dev); 318 if (!input_dev) 319 return -ENOMEM; 320 321 i2c_set_clientdata(client, ts); 322 323 ts->client = client; 324 ts->irq = client->irq; 325 ts->input = input_dev; 326 327 init_waitqueue_head(&ts->wait); 328 mutex_init(&ts->mlock); 329 330 snprintf(ts->phys, sizeof(ts->phys), 331 "%s/input0", dev_name(&client->dev)); 332 333 input_dev->name = "TSC2007 Touchscreen"; 334 input_dev->phys = ts->phys; 335 input_dev->id.bustype = BUS_I2C; 336 337 input_dev->open = tsc2007_open; 338 input_dev->close = tsc2007_close; 339 340 input_set_drvdata(input_dev, ts); 341 342 input_set_capability(input_dev, EV_KEY, BTN_TOUCH); 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 touchscreen_parse_properties(input_dev, false, &ts->prop); 346 input_set_abs_params(input_dev, ABS_PRESSURE, 0, MAX_12BIT, 347 ts->fuzzz, 0); 348 349 if (pdata) { 350 if (pdata->exit_platform_hw) { 351 err = devm_add_action(&client->dev, 352 tsc2007_call_exit_platform_hw, 353 &client->dev); 354 if (err) { 355 dev_err(&client->dev, 356 "Failed to register exit_platform_hw action, %d\n", 357 err); 358 return err; 359 } 360 } 361 362 if (pdata->init_platform_hw) 363 pdata->init_platform_hw(); 364 } 365 366 if (ts->irq) { 367 err = devm_request_threaded_irq(&client->dev, ts->irq, 368 NULL, tsc2007_soft_irq, 369 IRQF_ONESHOT, 370 client->dev.driver->name, ts); 371 if (err) { 372 dev_err(&client->dev, "Failed to request irq %d: %d\n", 373 ts->irq, err); 374 return err; 375 } 376 377 tsc2007_stop(ts); 378 } 379 380 /* power down the chip (TSC2007_SETUP does not ACK on I2C) */ 381 err = tsc2007_xfer(ts, PWRDOWN); 382 if (err < 0) { 383 dev_err(&client->dev, 384 "Failed to setup chip: %d\n", err); 385 return err; /* chip does not respond */ 386 } 387 388 err = input_register_device(input_dev); 389 if (err) { 390 dev_err(&client->dev, 391 "Failed to register input device: %d\n", err); 392 return err; 393 } 394 395 err = tsc2007_iio_configure(ts); 396 if (err) { 397 dev_err(&client->dev, 398 "Failed to register with IIO: %d\n", err); 399 return err; 400 } 401 402 return 0; 403 } 404 405 static const struct i2c_device_id tsc2007_idtable[] = { 406 { .name = "tsc2007" }, 407 { } 408 }; 409 410 MODULE_DEVICE_TABLE(i2c, tsc2007_idtable); 411 412 static const struct of_device_id tsc2007_of_match[] = { 413 { .compatible = "ti,tsc2007" }, 414 { /* sentinel */ } 415 }; 416 MODULE_DEVICE_TABLE(of, tsc2007_of_match); 417 418 static struct i2c_driver tsc2007_driver = { 419 .driver = { 420 .name = "tsc2007", 421 .of_match_table = tsc2007_of_match, 422 }, 423 .id_table = tsc2007_idtable, 424 .probe = tsc2007_probe, 425 }; 426 427 module_i2c_driver(tsc2007_driver); 428 429 MODULE_AUTHOR("Kwangwoo Lee <kwlee@mtekvision.com>"); 430 MODULE_DESCRIPTION("TSC2007 TouchScreen Driver"); 431 MODULE_LICENSE("GPL"); 432