1 /* 2 * drivers/input/touchscreen/tsc2007.c 3 * 4 * Copyright (c) 2008 MtekVision Co., Ltd. 5 * Kwangwoo Lee <kwlee@mtekvision.com> 6 * 7 * Using code from: 8 * - ads7846.c 9 * Copyright (c) 2005 David Brownell 10 * Copyright (c) 2006 Nokia Corporation 11 * - corgi_ts.c 12 * Copyright (C) 2004-2005 Richard Purdie 13 * - omap_ts.[hc], ads7846.h, ts_osk.c 14 * Copyright (C) 2002 MontaVista Software 15 * Copyright (C) 2004 Texas Instruments 16 * Copyright (C) 2005 Dirk Behme 17 * 18 * This program is free software; you can redistribute it and/or modify 19 * it under the terms of the GNU General Public License version 2 as 20 * published by the Free Software Foundation. 21 */ 22 23 #include <linux/module.h> 24 #include <linux/slab.h> 25 #include <linux/input.h> 26 #include <linux/interrupt.h> 27 #include <linux/i2c.h> 28 #include <linux/of_device.h> 29 #include <linux/of_gpio.h> 30 #include <linux/platform_data/tsc2007.h> 31 #include "tsc2007.h" 32 33 int tsc2007_xfer(struct tsc2007 *tsc, u8 cmd) 34 { 35 s32 data; 36 u16 val; 37 38 data = i2c_smbus_read_word_data(tsc->client, cmd); 39 if (data < 0) { 40 dev_err(&tsc->client->dev, "i2c io error: %d\n", data); 41 return data; 42 } 43 44 /* The protocol and raw data format from i2c interface: 45 * S Addr Wr [A] Comm [A] S Addr Rd [A] [DataLow] A [DataHigh] NA P 46 * Where DataLow has [D11-D4], DataHigh has [D3-D0 << 4 | Dummy 4bit]. 47 */ 48 val = swab16(data) >> 4; 49 50 dev_dbg(&tsc->client->dev, "data: 0x%x, val: 0x%x\n", data, val); 51 52 return val; 53 } 54 55 static void tsc2007_read_values(struct tsc2007 *tsc, struct ts_event *tc) 56 { 57 /* y- still on; turn on only y+ (and ADC) */ 58 tc->y = tsc2007_xfer(tsc, READ_Y); 59 60 /* turn y- off, x+ on, then leave in lowpower */ 61 tc->x = tsc2007_xfer(tsc, READ_X); 62 63 /* turn y+ off, x- on; we'll use formula #1 */ 64 tc->z1 = tsc2007_xfer(tsc, READ_Z1); 65 tc->z2 = tsc2007_xfer(tsc, READ_Z2); 66 67 /* Prepare for next touch reading - power down ADC, enable PENIRQ */ 68 tsc2007_xfer(tsc, PWRDOWN); 69 } 70 71 u32 tsc2007_calculate_resistance(struct tsc2007 *tsc, struct ts_event *tc) 72 { 73 u32 rt = 0; 74 75 /* range filtering */ 76 if (tc->x == MAX_12BIT) 77 tc->x = 0; 78 79 if (likely(tc->x && tc->z1)) { 80 /* compute touch resistance using equation #1 */ 81 rt = tc->z2 - tc->z1; 82 rt *= tc->x; 83 rt *= tsc->x_plate_ohms; 84 rt /= tc->z1; 85 rt = (rt + 2047) >> 12; 86 } 87 88 return rt; 89 } 90 91 bool tsc2007_is_pen_down(struct tsc2007 *ts) 92 { 93 /* 94 * NOTE: We can't rely on the pressure to determine the pen down 95 * state, even though this controller has a pressure sensor. 96 * The pressure value can fluctuate for quite a while after 97 * lifting the pen and in some cases may not even settle at the 98 * expected value. 99 * 100 * The only safe way to check for the pen up condition is in the 101 * work function by reading the pen signal state (it's a GPIO 102 * and IRQ). Unfortunately such callback is not always available, 103 * in that case we assume that the pen is down and expect caller 104 * to fall back on the pressure reading. 105 */ 106 107 if (!ts->get_pendown_state) 108 return true; 109 110 return ts->get_pendown_state(&ts->client->dev); 111 } 112 113 static irqreturn_t tsc2007_soft_irq(int irq, void *handle) 114 { 115 struct tsc2007 *ts = handle; 116 struct input_dev *input = ts->input; 117 struct ts_event tc; 118 u32 rt; 119 120 while (!ts->stopped && tsc2007_is_pen_down(ts)) { 121 122 /* pen is down, continue with the measurement */ 123 124 mutex_lock(&ts->mlock); 125 tsc2007_read_values(ts, &tc); 126 mutex_unlock(&ts->mlock); 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 input_report_abs(input, ABS_X, tc.x); 148 input_report_abs(input, ABS_Y, tc.y); 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 irqreturn_t tsc2007_hard_irq(int irq, void *handle) 178 { 179 struct tsc2007 *ts = handle; 180 181 if (tsc2007_is_pen_down(ts)) 182 return IRQ_WAKE_THREAD; 183 184 if (ts->clear_penirq) 185 ts->clear_penirq(); 186 187 return IRQ_HANDLED; 188 } 189 190 static void tsc2007_stop(struct tsc2007 *ts) 191 { 192 ts->stopped = true; 193 mb(); 194 wake_up(&ts->wait); 195 196 disable_irq(ts->irq); 197 } 198 199 static int tsc2007_open(struct input_dev *input_dev) 200 { 201 struct tsc2007 *ts = input_get_drvdata(input_dev); 202 int err; 203 204 ts->stopped = false; 205 mb(); 206 207 enable_irq(ts->irq); 208 209 /* Prepare for touch readings - power down ADC and enable PENIRQ */ 210 err = tsc2007_xfer(ts, PWRDOWN); 211 if (err < 0) { 212 tsc2007_stop(ts); 213 return err; 214 } 215 216 return 0; 217 } 218 219 static void tsc2007_close(struct input_dev *input_dev) 220 { 221 struct tsc2007 *ts = input_get_drvdata(input_dev); 222 223 tsc2007_stop(ts); 224 } 225 226 #ifdef CONFIG_OF 227 static int tsc2007_get_pendown_state_gpio(struct device *dev) 228 { 229 struct i2c_client *client = to_i2c_client(dev); 230 struct tsc2007 *ts = i2c_get_clientdata(client); 231 232 return !gpio_get_value(ts->gpio); 233 } 234 235 static int tsc2007_probe_dt(struct i2c_client *client, struct tsc2007 *ts) 236 { 237 struct device_node *np = client->dev.of_node; 238 u32 val32; 239 u64 val64; 240 241 if (!np) { 242 dev_err(&client->dev, "missing device tree data\n"); 243 return -EINVAL; 244 } 245 246 if (!of_property_read_u32(np, "ti,max-rt", &val32)) 247 ts->max_rt = val32; 248 else 249 ts->max_rt = MAX_12BIT; 250 251 if (!of_property_read_u32(np, "ti,fuzzx", &val32)) 252 ts->fuzzx = val32; 253 254 if (!of_property_read_u32(np, "ti,fuzzy", &val32)) 255 ts->fuzzy = val32; 256 257 if (!of_property_read_u32(np, "ti,fuzzz", &val32)) 258 ts->fuzzz = val32; 259 260 if (!of_property_read_u64(np, "ti,poll-period", &val64)) 261 ts->poll_period = msecs_to_jiffies(val64); 262 else 263 ts->poll_period = msecs_to_jiffies(1); 264 265 if (!of_property_read_u32(np, "ti,x-plate-ohms", &val32)) { 266 ts->x_plate_ohms = val32; 267 } else { 268 dev_err(&client->dev, "missing ti,x-plate-ohms devicetree property."); 269 return -EINVAL; 270 } 271 272 ts->gpio = of_get_gpio(np, 0); 273 if (gpio_is_valid(ts->gpio)) 274 ts->get_pendown_state = tsc2007_get_pendown_state_gpio; 275 else 276 dev_warn(&client->dev, 277 "GPIO not specified in DT (of_get_gpio returned %d)\n", 278 ts->gpio); 279 280 return 0; 281 } 282 #else 283 static int tsc2007_probe_dt(struct i2c_client *client, struct tsc2007 *ts) 284 { 285 dev_err(&client->dev, "platform data is required!\n"); 286 return -EINVAL; 287 } 288 #endif 289 290 static int tsc2007_probe_pdev(struct i2c_client *client, struct tsc2007 *ts, 291 const struct tsc2007_platform_data *pdata, 292 const struct i2c_device_id *id) 293 { 294 ts->model = pdata->model; 295 ts->x_plate_ohms = pdata->x_plate_ohms; 296 ts->max_rt = pdata->max_rt ? : MAX_12BIT; 297 ts->poll_period = msecs_to_jiffies(pdata->poll_period ? : 1); 298 ts->get_pendown_state = pdata->get_pendown_state; 299 ts->clear_penirq = pdata->clear_penirq; 300 ts->fuzzx = pdata->fuzzx; 301 ts->fuzzy = pdata->fuzzy; 302 ts->fuzzz = pdata->fuzzz; 303 304 if (pdata->x_plate_ohms == 0) { 305 dev_err(&client->dev, "x_plate_ohms is not set up in platform data"); 306 return -EINVAL; 307 } 308 309 return 0; 310 } 311 312 static void tsc2007_call_exit_platform_hw(void *data) 313 { 314 struct device *dev = data; 315 const struct tsc2007_platform_data *pdata = dev_get_platdata(dev); 316 317 pdata->exit_platform_hw(); 318 } 319 320 static int tsc2007_probe(struct i2c_client *client, 321 const struct i2c_device_id *id) 322 { 323 const struct tsc2007_platform_data *pdata = 324 dev_get_platdata(&client->dev); 325 struct tsc2007 *ts; 326 struct input_dev *input_dev; 327 int err; 328 329 if (!i2c_check_functionality(client->adapter, 330 I2C_FUNC_SMBUS_READ_WORD_DATA)) 331 return -EIO; 332 333 ts = devm_kzalloc(&client->dev, sizeof(struct tsc2007), GFP_KERNEL); 334 if (!ts) 335 return -ENOMEM; 336 337 if (pdata) 338 err = tsc2007_probe_pdev(client, ts, pdata, id); 339 else 340 err = tsc2007_probe_dt(client, ts); 341 if (err) 342 return err; 343 344 input_dev = devm_input_allocate_device(&client->dev); 345 if (!input_dev) 346 return -ENOMEM; 347 348 i2c_set_clientdata(client, ts); 349 350 ts->client = client; 351 ts->irq = client->irq; 352 ts->input = input_dev; 353 354 init_waitqueue_head(&ts->wait); 355 mutex_init(&ts->mlock); 356 357 snprintf(ts->phys, sizeof(ts->phys), 358 "%s/input0", dev_name(&client->dev)); 359 360 input_dev->name = "TSC2007 Touchscreen"; 361 input_dev->phys = ts->phys; 362 input_dev->id.bustype = BUS_I2C; 363 364 input_dev->open = tsc2007_open; 365 input_dev->close = tsc2007_close; 366 367 input_set_drvdata(input_dev, ts); 368 369 input_set_capability(input_dev, EV_KEY, BTN_TOUCH); 370 371 input_set_abs_params(input_dev, ABS_X, 0, MAX_12BIT, ts->fuzzx, 0); 372 input_set_abs_params(input_dev, ABS_Y, 0, MAX_12BIT, ts->fuzzy, 0); 373 input_set_abs_params(input_dev, ABS_PRESSURE, 0, MAX_12BIT, 374 ts->fuzzz, 0); 375 376 if (pdata) { 377 if (pdata->exit_platform_hw) { 378 err = devm_add_action(&client->dev, 379 tsc2007_call_exit_platform_hw, 380 &client->dev); 381 if (err) { 382 dev_err(&client->dev, 383 "Failed to register exit_platform_hw action, %d\n", 384 err); 385 return err; 386 } 387 } 388 389 if (pdata->init_platform_hw) 390 pdata->init_platform_hw(); 391 } 392 393 err = devm_request_threaded_irq(&client->dev, ts->irq, 394 tsc2007_hard_irq, tsc2007_soft_irq, 395 IRQF_ONESHOT, 396 client->dev.driver->name, ts); 397 if (err) { 398 dev_err(&client->dev, "Failed to request irq %d: %d\n", 399 ts->irq, err); 400 return err; 401 } 402 403 tsc2007_stop(ts); 404 405 /* power down the chip (TSC2007_SETUP does not ACK on I2C) */ 406 err = tsc2007_xfer(ts, PWRDOWN); 407 if (err < 0) { 408 dev_err(&client->dev, 409 "Failed to setup chip: %d\n", err); 410 return err; /* chip does not respond */ 411 } 412 413 err = input_register_device(input_dev); 414 if (err) { 415 dev_err(&client->dev, 416 "Failed to register input device: %d\n", err); 417 return err; 418 } 419 420 err = tsc2007_iio_configure(ts); 421 if (err) { 422 dev_err(&client->dev, 423 "Failed to register with IIO: %d\n", err); 424 return err; 425 } 426 427 return 0; 428 } 429 430 static const struct i2c_device_id tsc2007_idtable[] = { 431 { "tsc2007", 0 }, 432 { } 433 }; 434 435 MODULE_DEVICE_TABLE(i2c, tsc2007_idtable); 436 437 #ifdef CONFIG_OF 438 static const struct of_device_id tsc2007_of_match[] = { 439 { .compatible = "ti,tsc2007" }, 440 { /* sentinel */ } 441 }; 442 MODULE_DEVICE_TABLE(of, tsc2007_of_match); 443 #endif 444 445 static struct i2c_driver tsc2007_driver = { 446 .driver = { 447 .name = "tsc2007", 448 .of_match_table = of_match_ptr(tsc2007_of_match), 449 }, 450 .id_table = tsc2007_idtable, 451 .probe = tsc2007_probe, 452 }; 453 454 module_i2c_driver(tsc2007_driver); 455 456 MODULE_AUTHOR("Kwangwoo Lee <kwlee@mtekvision.com>"); 457 MODULE_DESCRIPTION("TSC2007 TouchScreen Driver"); 458 MODULE_LICENSE("GPL"); 459