1 /* 2 * TI Touch Screen driver 3 * 4 * Copyright (C) 2011 Texas Instruments Incorporated - http://www.ti.com/ 5 * 6 * This program is free software; you can redistribute it and/or 7 * modify it under the terms of the GNU General Public License as 8 * published by the Free Software Foundation version 2. 9 * 10 * This program is distributed "as is" WITHOUT ANY WARRANTY of any 11 * kind, whether express or implied; without even the implied warranty 12 * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 13 * GNU General Public License for more details. 14 */ 15 16 17 #include <linux/kernel.h> 18 #include <linux/err.h> 19 #include <linux/module.h> 20 #include <linux/input.h> 21 #include <linux/slab.h> 22 #include <linux/interrupt.h> 23 #include <linux/clk.h> 24 #include <linux/platform_device.h> 25 #include <linux/io.h> 26 #include <linux/delay.h> 27 #include <linux/of.h> 28 #include <linux/of_device.h> 29 #include <linux/sort.h> 30 31 #include <linux/mfd/ti_am335x_tscadc.h> 32 33 #define ADCFSM_STEPID 0x10 34 #define SEQ_SETTLE 275 35 #define MAX_12BIT ((1 << 12) - 1) 36 37 static const int config_pins[] = { 38 STEPCONFIG_XPP, 39 STEPCONFIG_XNN, 40 STEPCONFIG_YPP, 41 STEPCONFIG_YNN, 42 }; 43 44 struct titsc { 45 struct input_dev *input; 46 struct ti_tscadc_dev *mfd_tscadc; 47 unsigned int irq; 48 unsigned int wires; 49 unsigned int x_plate_resistance; 50 bool pen_down; 51 int coordinate_readouts; 52 u32 config_inp[4]; 53 u32 bit_xp, bit_xn, bit_yp, bit_yn; 54 u32 inp_xp, inp_xn, inp_yp, inp_yn; 55 u32 step_mask; 56 u32 charge_delay; 57 }; 58 59 static unsigned int titsc_readl(struct titsc *ts, unsigned int reg) 60 { 61 return readl(ts->mfd_tscadc->tscadc_base + reg); 62 } 63 64 static void titsc_writel(struct titsc *tsc, unsigned int reg, 65 unsigned int val) 66 { 67 writel(val, tsc->mfd_tscadc->tscadc_base + reg); 68 } 69 70 static int titsc_config_wires(struct titsc *ts_dev) 71 { 72 u32 analog_line[4]; 73 u32 wire_order[4]; 74 int i, bit_cfg; 75 76 for (i = 0; i < 4; i++) { 77 /* 78 * Get the order in which TSC wires are attached 79 * w.r.t. each of the analog input lines on the EVM. 80 */ 81 analog_line[i] = (ts_dev->config_inp[i] & 0xF0) >> 4; 82 wire_order[i] = ts_dev->config_inp[i] & 0x0F; 83 if (WARN_ON(analog_line[i] > 7)) 84 return -EINVAL; 85 if (WARN_ON(wire_order[i] > ARRAY_SIZE(config_pins))) 86 return -EINVAL; 87 } 88 89 for (i = 0; i < 4; i++) { 90 int an_line; 91 int wi_order; 92 93 an_line = analog_line[i]; 94 wi_order = wire_order[i]; 95 bit_cfg = config_pins[wi_order]; 96 if (bit_cfg == 0) 97 return -EINVAL; 98 switch (wi_order) { 99 case 0: 100 ts_dev->bit_xp = bit_cfg; 101 ts_dev->inp_xp = an_line; 102 break; 103 104 case 1: 105 ts_dev->bit_xn = bit_cfg; 106 ts_dev->inp_xn = an_line; 107 break; 108 109 case 2: 110 ts_dev->bit_yp = bit_cfg; 111 ts_dev->inp_yp = an_line; 112 break; 113 case 3: 114 ts_dev->bit_yn = bit_cfg; 115 ts_dev->inp_yn = an_line; 116 break; 117 } 118 } 119 return 0; 120 } 121 122 static void titsc_step_config(struct titsc *ts_dev) 123 { 124 unsigned int config; 125 int i; 126 int end_step, first_step, tsc_steps; 127 u32 stepenable; 128 129 config = STEPCONFIG_MODE_HWSYNC | 130 STEPCONFIG_AVG_16 | ts_dev->bit_xp; 131 switch (ts_dev->wires) { 132 case 4: 133 config |= STEPCONFIG_INP(ts_dev->inp_yp) | ts_dev->bit_xn; 134 break; 135 case 5: 136 config |= ts_dev->bit_yn | 137 STEPCONFIG_INP_AN4 | ts_dev->bit_xn | 138 ts_dev->bit_yp; 139 break; 140 case 8: 141 config |= STEPCONFIG_INP(ts_dev->inp_yp) | ts_dev->bit_xn; 142 break; 143 } 144 145 tsc_steps = ts_dev->coordinate_readouts * 2 + 2; 146 first_step = TOTAL_STEPS - tsc_steps; 147 /* Steps 16 to 16-coordinate_readouts is for X */ 148 end_step = first_step + tsc_steps; 149 for (i = end_step - ts_dev->coordinate_readouts; i < end_step; i++) { 150 titsc_writel(ts_dev, REG_STEPCONFIG(i), config); 151 titsc_writel(ts_dev, REG_STEPDELAY(i), STEPCONFIG_OPENDLY); 152 } 153 154 config = 0; 155 config = STEPCONFIG_MODE_HWSYNC | 156 STEPCONFIG_AVG_16 | ts_dev->bit_yn | 157 STEPCONFIG_INM_ADCREFM; 158 switch (ts_dev->wires) { 159 case 4: 160 config |= ts_dev->bit_yp | STEPCONFIG_INP(ts_dev->inp_xp); 161 break; 162 case 5: 163 config |= ts_dev->bit_xp | STEPCONFIG_INP_AN4 | 164 ts_dev->bit_xn | ts_dev->bit_yp; 165 break; 166 case 8: 167 config |= ts_dev->bit_yp | STEPCONFIG_INP(ts_dev->inp_xp); 168 break; 169 } 170 171 /* 1 ... coordinate_readouts is for Y */ 172 end_step = first_step + ts_dev->coordinate_readouts; 173 for (i = first_step; i < end_step; i++) { 174 titsc_writel(ts_dev, REG_STEPCONFIG(i), config); 175 titsc_writel(ts_dev, REG_STEPDELAY(i), STEPCONFIG_OPENDLY); 176 } 177 178 /* Make CHARGECONFIG same as IDLECONFIG */ 179 180 config = titsc_readl(ts_dev, REG_IDLECONFIG); 181 titsc_writel(ts_dev, REG_CHARGECONFIG, config); 182 titsc_writel(ts_dev, REG_CHARGEDELAY, ts_dev->charge_delay); 183 184 /* coordinate_readouts + 1 ... coordinate_readouts + 2 is for Z */ 185 config = STEPCONFIG_MODE_HWSYNC | 186 STEPCONFIG_AVG_16 | ts_dev->bit_yp | 187 ts_dev->bit_xn | STEPCONFIG_INM_ADCREFM | 188 STEPCONFIG_INP(ts_dev->inp_xp); 189 titsc_writel(ts_dev, REG_STEPCONFIG(end_step), config); 190 titsc_writel(ts_dev, REG_STEPDELAY(end_step), 191 STEPCONFIG_OPENDLY); 192 193 end_step++; 194 config |= STEPCONFIG_INP(ts_dev->inp_yn); 195 titsc_writel(ts_dev, REG_STEPCONFIG(end_step), config); 196 titsc_writel(ts_dev, REG_STEPDELAY(end_step), 197 STEPCONFIG_OPENDLY); 198 199 /* The steps end ... end - readouts * 2 + 2 and bit 0 for TS_Charge */ 200 stepenable = 1; 201 for (i = 0; i < tsc_steps; i++) 202 stepenable |= 1 << (first_step + i + 1); 203 204 ts_dev->step_mask = stepenable; 205 am335x_tsc_se_set_cache(ts_dev->mfd_tscadc, ts_dev->step_mask); 206 } 207 208 static int titsc_cmp_coord(const void *a, const void *b) 209 { 210 return *(int *)a - *(int *)b; 211 } 212 213 static void titsc_read_coordinates(struct titsc *ts_dev, 214 u32 *x, u32 *y, u32 *z1, u32 *z2) 215 { 216 unsigned int yvals[7], xvals[7]; 217 unsigned int i, xsum = 0, ysum = 0; 218 unsigned int creads = ts_dev->coordinate_readouts; 219 220 for (i = 0; i < creads; i++) { 221 yvals[i] = titsc_readl(ts_dev, REG_FIFO0); 222 yvals[i] &= 0xfff; 223 } 224 225 *z1 = titsc_readl(ts_dev, REG_FIFO0); 226 *z1 &= 0xfff; 227 *z2 = titsc_readl(ts_dev, REG_FIFO0); 228 *z2 &= 0xfff; 229 230 for (i = 0; i < creads; i++) { 231 xvals[i] = titsc_readl(ts_dev, REG_FIFO0); 232 xvals[i] &= 0xfff; 233 } 234 235 /* 236 * If co-ordinates readouts is less than 4 then 237 * report the average. In case of 4 or more 238 * readouts, sort the co-ordinate samples, drop 239 * min and max values and report the average of 240 * remaining values. 241 */ 242 if (creads <= 3) { 243 for (i = 0; i < creads; i++) { 244 ysum += yvals[i]; 245 xsum += xvals[i]; 246 } 247 ysum /= creads; 248 xsum /= creads; 249 } else { 250 sort(yvals, creads, sizeof(unsigned int), 251 titsc_cmp_coord, NULL); 252 sort(xvals, creads, sizeof(unsigned int), 253 titsc_cmp_coord, NULL); 254 for (i = 1; i < creads - 1; i++) { 255 ysum += yvals[i]; 256 xsum += xvals[i]; 257 } 258 ysum /= creads - 2; 259 xsum /= creads - 2; 260 } 261 *y = ysum; 262 *x = xsum; 263 } 264 265 static irqreturn_t titsc_irq(int irq, void *dev) 266 { 267 struct titsc *ts_dev = dev; 268 struct input_dev *input_dev = ts_dev->input; 269 unsigned int fsm, status, irqclr = 0; 270 unsigned int x = 0, y = 0; 271 unsigned int z1, z2, z; 272 273 status = titsc_readl(ts_dev, REG_RAWIRQSTATUS); 274 if (status & IRQENB_HW_PEN) { 275 ts_dev->pen_down = true; 276 irqclr |= IRQENB_HW_PEN; 277 } 278 279 if (status & IRQENB_PENUP) { 280 fsm = titsc_readl(ts_dev, REG_ADCFSM); 281 if (fsm == ADCFSM_STEPID) { 282 ts_dev->pen_down = false; 283 input_report_key(input_dev, BTN_TOUCH, 0); 284 input_report_abs(input_dev, ABS_PRESSURE, 0); 285 input_sync(input_dev); 286 } else { 287 ts_dev->pen_down = true; 288 } 289 irqclr |= IRQENB_PENUP; 290 } 291 292 if (status & IRQENB_EOS) 293 irqclr |= IRQENB_EOS; 294 295 /* 296 * ADC and touchscreen share the IRQ line. 297 * FIFO1 interrupts are used by ADC. Handle FIFO0 IRQs here only 298 */ 299 if (status & IRQENB_FIFO0THRES) { 300 301 titsc_read_coordinates(ts_dev, &x, &y, &z1, &z2); 302 303 if (ts_dev->pen_down && z1 != 0 && z2 != 0) { 304 /* 305 * Calculate pressure using formula 306 * Resistance(touch) = x plate resistance * 307 * x postion/4096 * ((z2 / z1) - 1) 308 */ 309 z = z1 - z2; 310 z *= x; 311 z *= ts_dev->x_plate_resistance; 312 z /= z2; 313 z = (z + 2047) >> 12; 314 315 if (z <= MAX_12BIT) { 316 input_report_abs(input_dev, ABS_X, x); 317 input_report_abs(input_dev, ABS_Y, y); 318 input_report_abs(input_dev, ABS_PRESSURE, z); 319 input_report_key(input_dev, BTN_TOUCH, 1); 320 input_sync(input_dev); 321 } 322 } 323 irqclr |= IRQENB_FIFO0THRES; 324 } 325 if (irqclr) { 326 titsc_writel(ts_dev, REG_IRQSTATUS, irqclr); 327 if (status & IRQENB_EOS) 328 am335x_tsc_se_set_cache(ts_dev->mfd_tscadc, 329 ts_dev->step_mask); 330 return IRQ_HANDLED; 331 } 332 return IRQ_NONE; 333 } 334 335 static int titsc_parse_dt(struct platform_device *pdev, 336 struct titsc *ts_dev) 337 { 338 struct device_node *node = pdev->dev.of_node; 339 int err; 340 341 if (!node) 342 return -EINVAL; 343 344 err = of_property_read_u32(node, "ti,wires", &ts_dev->wires); 345 if (err < 0) 346 return err; 347 switch (ts_dev->wires) { 348 case 4: 349 case 5: 350 case 8: 351 break; 352 default: 353 return -EINVAL; 354 } 355 356 err = of_property_read_u32(node, "ti,x-plate-resistance", 357 &ts_dev->x_plate_resistance); 358 if (err < 0) 359 return err; 360 361 /* 362 * Try with the new binding first. If it fails, try again with 363 * bogus, miss-spelled version. 364 */ 365 err = of_property_read_u32(node, "ti,coordinate-readouts", 366 &ts_dev->coordinate_readouts); 367 if (err < 0) { 368 dev_warn(&pdev->dev, "please use 'ti,coordinate-readouts' instead\n"); 369 err = of_property_read_u32(node, "ti,coordiante-readouts", 370 &ts_dev->coordinate_readouts); 371 } 372 373 if (err < 0) 374 return err; 375 376 if (ts_dev->coordinate_readouts <= 0) { 377 dev_warn(&pdev->dev, 378 "invalid co-ordinate readouts, resetting it to 5\n"); 379 ts_dev->coordinate_readouts = 5; 380 } 381 382 err = of_property_read_u32(node, "ti,charge-delay", 383 &ts_dev->charge_delay); 384 /* 385 * If ti,charge-delay value is not specified, then use 386 * CHARGEDLY_OPENDLY as the default value. 387 */ 388 if (err < 0) { 389 ts_dev->charge_delay = CHARGEDLY_OPENDLY; 390 dev_warn(&pdev->dev, "ti,charge-delay not specified\n"); 391 } 392 393 return of_property_read_u32_array(node, "ti,wire-config", 394 ts_dev->config_inp, ARRAY_SIZE(ts_dev->config_inp)); 395 } 396 397 /* 398 * The functions for inserting/removing driver as a module. 399 */ 400 401 static int titsc_probe(struct platform_device *pdev) 402 { 403 struct titsc *ts_dev; 404 struct input_dev *input_dev; 405 struct ti_tscadc_dev *tscadc_dev = ti_tscadc_dev_get(pdev); 406 int err; 407 408 /* Allocate memory for device */ 409 ts_dev = kzalloc(sizeof(struct titsc), GFP_KERNEL); 410 input_dev = input_allocate_device(); 411 if (!ts_dev || !input_dev) { 412 dev_err(&pdev->dev, "failed to allocate memory.\n"); 413 err = -ENOMEM; 414 goto err_free_mem; 415 } 416 417 tscadc_dev->tsc = ts_dev; 418 ts_dev->mfd_tscadc = tscadc_dev; 419 ts_dev->input = input_dev; 420 ts_dev->irq = tscadc_dev->irq; 421 422 err = titsc_parse_dt(pdev, ts_dev); 423 if (err) { 424 dev_err(&pdev->dev, "Could not find valid DT data.\n"); 425 goto err_free_mem; 426 } 427 428 err = request_irq(ts_dev->irq, titsc_irq, 429 IRQF_SHARED, pdev->dev.driver->name, ts_dev); 430 if (err) { 431 dev_err(&pdev->dev, "failed to allocate irq.\n"); 432 goto err_free_mem; 433 } 434 435 titsc_writel(ts_dev, REG_IRQENABLE, IRQENB_FIFO0THRES); 436 titsc_writel(ts_dev, REG_IRQENABLE, IRQENB_EOS); 437 err = titsc_config_wires(ts_dev); 438 if (err) { 439 dev_err(&pdev->dev, "wrong i/p wire configuration\n"); 440 goto err_free_irq; 441 } 442 titsc_step_config(ts_dev); 443 titsc_writel(ts_dev, REG_FIFO0THR, 444 ts_dev->coordinate_readouts * 2 + 2 - 1); 445 446 input_dev->name = "ti-tsc"; 447 input_dev->dev.parent = &pdev->dev; 448 449 input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS); 450 input_dev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH); 451 452 input_set_abs_params(input_dev, ABS_X, 0, MAX_12BIT, 0, 0); 453 input_set_abs_params(input_dev, ABS_Y, 0, MAX_12BIT, 0, 0); 454 input_set_abs_params(input_dev, ABS_PRESSURE, 0, MAX_12BIT, 0, 0); 455 456 /* register to the input system */ 457 err = input_register_device(input_dev); 458 if (err) 459 goto err_free_irq; 460 461 platform_set_drvdata(pdev, ts_dev); 462 return 0; 463 464 err_free_irq: 465 free_irq(ts_dev->irq, ts_dev); 466 err_free_mem: 467 input_free_device(input_dev); 468 kfree(ts_dev); 469 return err; 470 } 471 472 static int titsc_remove(struct platform_device *pdev) 473 { 474 struct titsc *ts_dev = platform_get_drvdata(pdev); 475 u32 steps; 476 477 free_irq(ts_dev->irq, ts_dev); 478 479 /* total steps followed by the enable mask */ 480 steps = 2 * ts_dev->coordinate_readouts + 2; 481 steps = (1 << steps) - 1; 482 am335x_tsc_se_clr(ts_dev->mfd_tscadc, steps); 483 484 input_unregister_device(ts_dev->input); 485 486 kfree(ts_dev); 487 return 0; 488 } 489 490 #ifdef CONFIG_PM 491 static int titsc_suspend(struct device *dev) 492 { 493 struct titsc *ts_dev = dev_get_drvdata(dev); 494 struct ti_tscadc_dev *tscadc_dev; 495 unsigned int idle; 496 497 tscadc_dev = ti_tscadc_dev_get(to_platform_device(dev)); 498 if (device_may_wakeup(tscadc_dev->dev)) { 499 idle = titsc_readl(ts_dev, REG_IRQENABLE); 500 titsc_writel(ts_dev, REG_IRQENABLE, 501 (idle | IRQENB_HW_PEN)); 502 titsc_writel(ts_dev, REG_IRQWAKEUP, IRQWKUP_ENB); 503 } 504 return 0; 505 } 506 507 static int titsc_resume(struct device *dev) 508 { 509 struct titsc *ts_dev = dev_get_drvdata(dev); 510 struct ti_tscadc_dev *tscadc_dev; 511 512 tscadc_dev = ti_tscadc_dev_get(to_platform_device(dev)); 513 if (device_may_wakeup(tscadc_dev->dev)) { 514 titsc_writel(ts_dev, REG_IRQWAKEUP, 515 0x00); 516 titsc_writel(ts_dev, REG_IRQCLR, IRQENB_HW_PEN); 517 } 518 titsc_step_config(ts_dev); 519 titsc_writel(ts_dev, REG_FIFO0THR, 520 ts_dev->coordinate_readouts * 2 + 2 - 1); 521 return 0; 522 } 523 524 static const struct dev_pm_ops titsc_pm_ops = { 525 .suspend = titsc_suspend, 526 .resume = titsc_resume, 527 }; 528 #define TITSC_PM_OPS (&titsc_pm_ops) 529 #else 530 #define TITSC_PM_OPS NULL 531 #endif 532 533 static const struct of_device_id ti_tsc_dt_ids[] = { 534 { .compatible = "ti,am3359-tsc", }, 535 { } 536 }; 537 MODULE_DEVICE_TABLE(of, ti_tsc_dt_ids); 538 539 static struct platform_driver ti_tsc_driver = { 540 .probe = titsc_probe, 541 .remove = titsc_remove, 542 .driver = { 543 .name = "TI-am335x-tsc", 544 .pm = TITSC_PM_OPS, 545 .of_match_table = ti_tsc_dt_ids, 546 }, 547 }; 548 module_platform_driver(ti_tsc_driver); 549 550 MODULE_DESCRIPTION("TI touchscreen controller driver"); 551 MODULE_AUTHOR("Rachna Patil <rachna@ti.com>"); 552 MODULE_LICENSE("GPL"); 553