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 /* Read Z2 and power down ADC after A/D conversion, enable PENIRQ */ 65 tc->z2 = tsc2007_xfer(tsc, (TSC2007_POWER_OFF_IRQ_EN | TSC2007_MEASURE_Z2)); 66 } 67 68 u32 tsc2007_calculate_resistance(struct tsc2007 *tsc, struct ts_event *tc) 69 { 70 u64 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 = div_u64(rt, tc->z1); 82 rt = (rt + 2047) >> 12; 83 } 84 85 if (rt > U32_MAX) 86 return U32_MAX; 87 return (u32) rt; 88 } 89 90 bool tsc2007_is_pen_down(struct tsc2007 *ts) 91 { 92 /* 93 * NOTE: We can't rely on the pressure to determine the pen down 94 * state, even though this controller has a pressure sensor. 95 * The pressure value can fluctuate for quite a while after 96 * lifting the pen and in some cases may not even settle at the 97 * expected value. 98 * 99 * The only safe way to check for the pen up condition is in the 100 * work function by reading the pen signal state (it's a GPIO 101 * and IRQ). Unfortunately such callback is not always available, 102 * in that case we assume that the pen is down and expect caller 103 * to fall back on the pressure reading. 104 */ 105 106 if (!ts->get_pendown_state) 107 return true; 108 109 return ts->get_pendown_state(&ts->client->dev); 110 } 111 112 static irqreturn_t tsc2007_soft_irq(int irq, void *handle) 113 { 114 struct tsc2007 *ts = handle; 115 struct input_dev *input = ts->input; 116 struct ts_event tc; 117 u32 rt; 118 119 while (!ts->stopped && tsc2007_is_pen_down(ts)) { 120 121 /* pen is down, continue with the measurement */ 122 123 /* Serialize access between the ISR and IIO reads. */ 124 scoped_guard(mutex, &ts->mlock) { 125 tsc2007_read_values(ts, &tc); 126 } 127 128 rt = tsc2007_calculate_resistance(ts, &tc); 129 130 if (!rt && !ts->get_pendown_state) { 131 /* 132 * If pressure reported is 0 and we don't have 133 * callback to check pendown state, we have to 134 * assume that pen was lifted up. 135 */ 136 break; 137 } 138 139 if (rt <= ts->max_rt) { 140 dev_dbg(&ts->client->dev, 141 "DOWN point(%4d,%4d), resistance (%4u)\n", 142 tc.x, tc.y, rt); 143 144 rt = ts->max_rt - rt; 145 146 input_report_key(input, BTN_TOUCH, 1); 147 touchscreen_report_pos(input, &ts->prop, tc.x, tc.y, false); 148 input_report_abs(input, ABS_PRESSURE, rt); 149 150 input_sync(input); 151 152 } else { 153 /* 154 * Sample found inconsistent by debouncing or pressure is 155 * beyond the maximum. Don't report it to user space, 156 * repeat at least once more the measurement. 157 */ 158 dev_dbg(&ts->client->dev, "ignored pressure %d\n", rt); 159 } 160 161 wait_event_timeout(ts->wait, ts->stopped, ts->poll_period); 162 } 163 164 dev_dbg(&ts->client->dev, "UP\n"); 165 166 input_report_key(input, BTN_TOUCH, 0); 167 input_report_abs(input, ABS_PRESSURE, 0); 168 input_sync(input); 169 170 if (ts->clear_penirq) 171 ts->clear_penirq(); 172 173 return IRQ_HANDLED; 174 } 175 176 static void tsc2007_stop(struct tsc2007 *ts) 177 { 178 ts->stopped = true; 179 mb(); 180 wake_up(&ts->wait); 181 182 if (ts->irq) 183 disable_irq(ts->irq); 184 } 185 186 static int tsc2007_open(struct input_dev *input_dev) 187 { 188 struct tsc2007 *ts = input_get_drvdata(input_dev); 189 int err; 190 191 ts->stopped = false; 192 mb(); 193 194 if (ts->irq) 195 enable_irq(ts->irq); 196 197 /* Prepare for touch readings - power down ADC and enable PENIRQ */ 198 err = tsc2007_xfer(ts, PWRDOWN); 199 if (err < 0) { 200 tsc2007_stop(ts); 201 return err; 202 } 203 204 return 0; 205 } 206 207 static void tsc2007_close(struct input_dev *input_dev) 208 { 209 struct tsc2007 *ts = input_get_drvdata(input_dev); 210 211 tsc2007_stop(ts); 212 } 213 214 static int tsc2007_get_pendown_state_gpio(struct device *dev) 215 { 216 struct i2c_client *client = to_i2c_client(dev); 217 struct tsc2007 *ts = i2c_get_clientdata(client); 218 219 return gpiod_get_value_cansleep(ts->gpiod); 220 } 221 222 static int tsc2007_probe_properties(struct device *dev, struct tsc2007 *ts) 223 { 224 u32 val32; 225 u64 val64; 226 227 if (!device_property_read_u32(dev, "ti,max-rt", &val32)) 228 ts->max_rt = val32; 229 else 230 ts->max_rt = MAX_12BIT; 231 232 if (!device_property_read_u32(dev, "ti,fuzzx", &val32)) 233 ts->fuzzx = val32; 234 235 if (!device_property_read_u32(dev, "ti,fuzzy", &val32)) 236 ts->fuzzy = val32; 237 238 if (!device_property_read_u32(dev, "ti,fuzzz", &val32)) 239 ts->fuzzz = val32; 240 241 if (!device_property_read_u64(dev, "ti,poll-period", &val64)) 242 ts->poll_period = msecs_to_jiffies(val64); 243 else 244 ts->poll_period = msecs_to_jiffies(1); 245 246 if (!device_property_read_u32(dev, "ti,x-plate-ohms", &val32)) { 247 ts->x_plate_ohms = val32; 248 } else { 249 dev_err(dev, "Missing ti,x-plate-ohms device property\n"); 250 return -EINVAL; 251 } 252 253 ts->gpiod = devm_gpiod_get_optional(dev, NULL, GPIOD_IN); 254 if (IS_ERR(ts->gpiod)) 255 return PTR_ERR(ts->gpiod); 256 257 if (ts->gpiod) 258 ts->get_pendown_state = tsc2007_get_pendown_state_gpio; 259 else 260 dev_dbg(dev, "Pen down GPIO is not specified in properties\n"); 261 262 return 0; 263 } 264 265 static int tsc2007_probe_pdev(struct device *dev, struct tsc2007 *ts, 266 const struct tsc2007_platform_data *pdata, 267 const struct i2c_device_id *id) 268 { 269 ts->model = pdata->model; 270 ts->x_plate_ohms = pdata->x_plate_ohms; 271 ts->max_rt = pdata->max_rt ? : MAX_12BIT; 272 ts->poll_period = msecs_to_jiffies(pdata->poll_period ? : 1); 273 ts->get_pendown_state = pdata->get_pendown_state; 274 ts->clear_penirq = pdata->clear_penirq; 275 ts->fuzzx = pdata->fuzzx; 276 ts->fuzzy = pdata->fuzzy; 277 ts->fuzzz = pdata->fuzzz; 278 279 if (pdata->x_plate_ohms == 0) { 280 dev_err(dev, "x_plate_ohms is not set up in platform data\n"); 281 return -EINVAL; 282 } 283 284 return 0; 285 } 286 287 static void tsc2007_call_exit_platform_hw(void *data) 288 { 289 struct device *dev = data; 290 const struct tsc2007_platform_data *pdata = dev_get_platdata(dev); 291 292 pdata->exit_platform_hw(); 293 } 294 295 static int tsc2007_probe(struct i2c_client *client) 296 { 297 const struct i2c_device_id *id = i2c_client_get_device_id(client); 298 const struct tsc2007_platform_data *pdata = 299 dev_get_platdata(&client->dev); 300 struct tsc2007 *ts; 301 struct input_dev *input_dev; 302 int err; 303 304 if (!i2c_check_functionality(client->adapter, 305 I2C_FUNC_SMBUS_READ_WORD_DATA)) 306 return -EIO; 307 308 ts = devm_kzalloc(&client->dev, sizeof(struct tsc2007), GFP_KERNEL); 309 if (!ts) 310 return -ENOMEM; 311 312 if (pdata) 313 err = tsc2007_probe_pdev(&client->dev, ts, pdata, id); 314 else 315 err = tsc2007_probe_properties(&client->dev, ts); 316 if (err) 317 return err; 318 319 input_dev = devm_input_allocate_device(&client->dev); 320 if (!input_dev) 321 return -ENOMEM; 322 323 i2c_set_clientdata(client, ts); 324 325 ts->client = client; 326 ts->irq = client->irq; 327 ts->input = input_dev; 328 329 init_waitqueue_head(&ts->wait); 330 mutex_init(&ts->mlock); 331 332 snprintf(ts->phys, sizeof(ts->phys), 333 "%s/input0", dev_name(&client->dev)); 334 335 input_dev->name = "TSC2007 Touchscreen"; 336 input_dev->phys = ts->phys; 337 input_dev->id.bustype = BUS_I2C; 338 339 input_dev->open = tsc2007_open; 340 input_dev->close = tsc2007_close; 341 342 input_set_drvdata(input_dev, ts); 343 344 input_set_capability(input_dev, EV_KEY, BTN_TOUCH); 345 input_set_abs_params(input_dev, ABS_X, 0, MAX_12BIT, ts->fuzzx, 0); 346 input_set_abs_params(input_dev, ABS_Y, 0, MAX_12BIT, ts->fuzzy, 0); 347 touchscreen_parse_properties(input_dev, false, &ts->prop); 348 input_set_abs_params(input_dev, ABS_PRESSURE, 0, MAX_12BIT, 349 ts->fuzzz, 0); 350 351 if (pdata) { 352 if (pdata->exit_platform_hw) { 353 err = devm_add_action(&client->dev, 354 tsc2007_call_exit_platform_hw, 355 &client->dev); 356 if (err) { 357 dev_err(&client->dev, 358 "Failed to register exit_platform_hw action, %d\n", 359 err); 360 return err; 361 } 362 } 363 364 if (pdata->init_platform_hw) 365 pdata->init_platform_hw(); 366 } 367 368 if (ts->irq) { 369 err = devm_request_threaded_irq(&client->dev, ts->irq, 370 NULL, tsc2007_soft_irq, 371 IRQF_ONESHOT, 372 client->dev.driver->name, ts); 373 if (err) { 374 dev_err(&client->dev, "Failed to request irq %d: %d\n", 375 ts->irq, err); 376 return err; 377 } 378 379 tsc2007_stop(ts); 380 } 381 382 /* power down the chip (TSC2007_SETUP does not ACK on I2C) */ 383 err = tsc2007_xfer(ts, PWRDOWN); 384 if (err < 0) { 385 dev_err(&client->dev, 386 "Failed to setup chip: %d\n", err); 387 return err; /* chip does not respond */ 388 } 389 390 err = input_register_device(input_dev); 391 if (err) { 392 dev_err(&client->dev, 393 "Failed to register input device: %d\n", err); 394 return err; 395 } 396 397 err = tsc2007_iio_configure(ts); 398 if (err) { 399 dev_err(&client->dev, 400 "Failed to register with IIO: %d\n", err); 401 return err; 402 } 403 404 return 0; 405 } 406 407 static const struct i2c_device_id tsc2007_idtable[] = { 408 { .name = "tsc2007" }, 409 { } 410 }; 411 412 MODULE_DEVICE_TABLE(i2c, tsc2007_idtable); 413 414 static const struct of_device_id tsc2007_of_match[] = { 415 { .compatible = "ti,tsc2007" }, 416 { /* sentinel */ } 417 }; 418 MODULE_DEVICE_TABLE(of, tsc2007_of_match); 419 420 static struct i2c_driver tsc2007_driver = { 421 .driver = { 422 .name = "tsc2007", 423 .of_match_table = tsc2007_of_match, 424 }, 425 .id_table = tsc2007_idtable, 426 .probe = tsc2007_probe, 427 }; 428 429 module_i2c_driver(tsc2007_driver); 430 431 MODULE_AUTHOR("Kwangwoo Lee <kwlee@mtekvision.com>"); 432 MODULE_DESCRIPTION("TSC2007 TouchScreen Driver"); 433 MODULE_LICENSE("GPL"); 434