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/init.h> 18 #include <linux/kernel.h> 19 #include <linux/err.h> 20 #include <linux/module.h> 21 #include <linux/input.h> 22 #include <linux/slab.h> 23 #include <linux/interrupt.h> 24 #include <linux/clk.h> 25 #include <linux/platform_device.h> 26 #include <linux/io.h> 27 #include <linux/delay.h> 28 #include <linux/of.h> 29 #include <linux/of_device.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 }; 56 57 static unsigned int titsc_readl(struct titsc *ts, unsigned int reg) 58 { 59 return readl(ts->mfd_tscadc->tscadc_base + reg); 60 } 61 62 static void titsc_writel(struct titsc *tsc, unsigned int reg, 63 unsigned int val) 64 { 65 writel(val, tsc->mfd_tscadc->tscadc_base + reg); 66 } 67 68 static int titsc_config_wires(struct titsc *ts_dev) 69 { 70 u32 analog_line[4]; 71 u32 wire_order[4]; 72 int i, bit_cfg; 73 74 for (i = 0; i < 4; i++) { 75 /* 76 * Get the order in which TSC wires are attached 77 * w.r.t. each of the analog input lines on the EVM. 78 */ 79 analog_line[i] = (ts_dev->config_inp[i] & 0xF0) >> 4; 80 wire_order[i] = ts_dev->config_inp[i] & 0x0F; 81 if (WARN_ON(analog_line[i] > 7)) 82 return -EINVAL; 83 if (WARN_ON(wire_order[i] > ARRAY_SIZE(config_pins))) 84 return -EINVAL; 85 } 86 87 for (i = 0; i < 4; i++) { 88 int an_line; 89 int wi_order; 90 91 an_line = analog_line[i]; 92 wi_order = wire_order[i]; 93 bit_cfg = config_pins[wi_order]; 94 if (bit_cfg == 0) 95 return -EINVAL; 96 switch (wi_order) { 97 case 0: 98 ts_dev->bit_xp = bit_cfg; 99 ts_dev->inp_xp = an_line; 100 break; 101 102 case 1: 103 ts_dev->bit_xn = bit_cfg; 104 ts_dev->inp_xn = an_line; 105 break; 106 107 case 2: 108 ts_dev->bit_yp = bit_cfg; 109 ts_dev->inp_yp = an_line; 110 break; 111 case 3: 112 ts_dev->bit_yn = bit_cfg; 113 ts_dev->inp_yn = an_line; 114 break; 115 } 116 } 117 return 0; 118 } 119 120 static void titsc_step_config(struct titsc *ts_dev) 121 { 122 unsigned int config; 123 int i; 124 int end_step; 125 u32 stepenable; 126 127 config = STEPCONFIG_MODE_HWSYNC | 128 STEPCONFIG_AVG_16 | ts_dev->bit_xp; 129 switch (ts_dev->wires) { 130 case 4: 131 config |= STEPCONFIG_INP(ts_dev->inp_yp) | ts_dev->bit_xn; 132 break; 133 case 5: 134 config |= ts_dev->bit_yn | 135 STEPCONFIG_INP_AN4 | ts_dev->bit_xn | 136 ts_dev->bit_yp; 137 break; 138 case 8: 139 config |= STEPCONFIG_INP(ts_dev->inp_yp) | ts_dev->bit_xn; 140 break; 141 } 142 143 /* 1 … coordinate_readouts is for X */ 144 end_step = ts_dev->coordinate_readouts; 145 for (i = 0; i < end_step; i++) { 146 titsc_writel(ts_dev, REG_STEPCONFIG(i), config); 147 titsc_writel(ts_dev, REG_STEPDELAY(i), STEPCONFIG_OPENDLY); 148 } 149 150 config = 0; 151 config = STEPCONFIG_MODE_HWSYNC | 152 STEPCONFIG_AVG_16 | ts_dev->bit_yn | 153 STEPCONFIG_INM_ADCREFM; 154 switch (ts_dev->wires) { 155 case 4: 156 config |= ts_dev->bit_yp | STEPCONFIG_INP(ts_dev->inp_xp); 157 break; 158 case 5: 159 config |= ts_dev->bit_xp | STEPCONFIG_INP_AN4 | 160 ts_dev->bit_xn | ts_dev->bit_yp; 161 break; 162 case 8: 163 config |= ts_dev->bit_yp | STEPCONFIG_INP(ts_dev->inp_xp); 164 break; 165 } 166 167 /* coordinate_readouts … coordinate_readouts * 2 is for Y */ 168 end_step = ts_dev->coordinate_readouts * 2; 169 for (i = ts_dev->coordinate_readouts; i < end_step; i++) { 170 titsc_writel(ts_dev, REG_STEPCONFIG(i), config); 171 titsc_writel(ts_dev, REG_STEPDELAY(i), STEPCONFIG_OPENDLY); 172 } 173 174 /* Charge step configuration */ 175 config = ts_dev->bit_xp | ts_dev->bit_yn | 176 STEPCHARGE_RFP_XPUL | STEPCHARGE_RFM_XNUR | 177 STEPCHARGE_INM_AN1 | STEPCHARGE_INP(ts_dev->inp_yp); 178 179 titsc_writel(ts_dev, REG_CHARGECONFIG, config); 180 titsc_writel(ts_dev, REG_CHARGEDELAY, CHARGEDLY_OPENDLY); 181 182 /* coordinate_readouts * 2 … coordinate_readouts * 2 + 2 is for Z */ 183 config = STEPCONFIG_MODE_HWSYNC | 184 STEPCONFIG_AVG_16 | ts_dev->bit_yp | 185 ts_dev->bit_xn | STEPCONFIG_INM_ADCREFM | 186 STEPCONFIG_INP(ts_dev->inp_xp); 187 titsc_writel(ts_dev, REG_STEPCONFIG(end_step), config); 188 titsc_writel(ts_dev, REG_STEPDELAY(end_step), 189 STEPCONFIG_OPENDLY); 190 191 end_step++; 192 config |= STEPCONFIG_INP(ts_dev->inp_yn); 193 titsc_writel(ts_dev, REG_STEPCONFIG(end_step), config); 194 titsc_writel(ts_dev, REG_STEPDELAY(end_step), 195 STEPCONFIG_OPENDLY); 196 197 /* The steps1 … end and bit 0 for TS_Charge */ 198 stepenable = (1 << (end_step + 2)) - 1; 199 am335x_tsc_se_set(ts_dev->mfd_tscadc, stepenable); 200 } 201 202 static void titsc_read_coordinates(struct titsc *ts_dev, 203 u32 *x, u32 *y, u32 *z1, u32 *z2) 204 { 205 unsigned int fifocount = titsc_readl(ts_dev, REG_FIFO0CNT); 206 unsigned int prev_val_x = ~0, prev_val_y = ~0; 207 unsigned int prev_diff_x = ~0, prev_diff_y = ~0; 208 unsigned int read, diff; 209 unsigned int i, channel; 210 unsigned int creads = ts_dev->coordinate_readouts; 211 212 *z1 = *z2 = 0; 213 if (fifocount % (creads * 2 + 2)) 214 fifocount -= fifocount % (creads * 2 + 2); 215 /* 216 * Delta filter is used to remove large variations in sampled 217 * values from ADC. The filter tries to predict where the next 218 * coordinate could be. This is done by taking a previous 219 * coordinate and subtracting it form current one. Further the 220 * algorithm compares the difference with that of a present value, 221 * if true the value is reported to the sub system. 222 */ 223 for (i = 0; i < fifocount; i++) { 224 read = titsc_readl(ts_dev, REG_FIFO0); 225 226 channel = (read & 0xf0000) >> 16; 227 read &= 0xfff; 228 if (channel < creads) { 229 diff = abs(read - prev_val_x); 230 if (diff < prev_diff_x) { 231 prev_diff_x = diff; 232 *x = read; 233 } 234 prev_val_x = read; 235 236 } else if (channel < creads * 2) { 237 diff = abs(read - prev_val_y); 238 if (diff < prev_diff_y) { 239 prev_diff_y = diff; 240 *y = read; 241 } 242 prev_val_y = read; 243 244 } else if (channel < creads * 2 + 1) { 245 *z1 = read; 246 247 } else if (channel < creads * 2 + 2) { 248 *z2 = read; 249 } 250 } 251 } 252 253 static irqreturn_t titsc_irq(int irq, void *dev) 254 { 255 struct titsc *ts_dev = dev; 256 struct input_dev *input_dev = ts_dev->input; 257 unsigned int status, irqclr = 0; 258 unsigned int x = 0, y = 0; 259 unsigned int z1, z2, z; 260 unsigned int fsm; 261 262 status = titsc_readl(ts_dev, REG_IRQSTATUS); 263 if (status & IRQENB_FIFO0THRES) { 264 265 titsc_read_coordinates(ts_dev, &x, &y, &z1, &z2); 266 267 if (ts_dev->pen_down && z1 != 0 && z2 != 0) { 268 /* 269 * Calculate pressure using formula 270 * Resistance(touch) = x plate resistance * 271 * x postion/4096 * ((z2 / z1) - 1) 272 */ 273 z = z1 - z2; 274 z *= x; 275 z *= ts_dev->x_plate_resistance; 276 z /= z2; 277 z = (z + 2047) >> 12; 278 279 if (z <= MAX_12BIT) { 280 input_report_abs(input_dev, ABS_X, x); 281 input_report_abs(input_dev, ABS_Y, y); 282 input_report_abs(input_dev, ABS_PRESSURE, z); 283 input_report_key(input_dev, BTN_TOUCH, 1); 284 input_sync(input_dev); 285 } 286 } 287 irqclr |= IRQENB_FIFO0THRES; 288 } 289 290 /* 291 * Time for sequencer to settle, to read 292 * correct state of the sequencer. 293 */ 294 udelay(SEQ_SETTLE); 295 296 status = titsc_readl(ts_dev, REG_RAWIRQSTATUS); 297 if (status & IRQENB_PENUP) { 298 /* Pen up event */ 299 fsm = titsc_readl(ts_dev, REG_ADCFSM); 300 if (fsm == ADCFSM_STEPID) { 301 ts_dev->pen_down = false; 302 input_report_key(input_dev, BTN_TOUCH, 0); 303 input_report_abs(input_dev, ABS_PRESSURE, 0); 304 input_sync(input_dev); 305 } else { 306 ts_dev->pen_down = true; 307 } 308 irqclr |= IRQENB_PENUP; 309 } 310 311 if (status & IRQENB_HW_PEN) { 312 313 titsc_writel(ts_dev, REG_IRQWAKEUP, 0x00); 314 titsc_writel(ts_dev, REG_IRQCLR, IRQENB_HW_PEN); 315 } 316 317 if (irqclr) { 318 titsc_writel(ts_dev, REG_IRQSTATUS, irqclr); 319 am335x_tsc_se_update(ts_dev->mfd_tscadc); 320 return IRQ_HANDLED; 321 } 322 return IRQ_NONE; 323 } 324 325 static int titsc_parse_dt(struct platform_device *pdev, 326 struct titsc *ts_dev) 327 { 328 struct device_node *node = pdev->dev.of_node; 329 int err; 330 331 if (!node) 332 return -EINVAL; 333 334 err = of_property_read_u32(node, "ti,wires", &ts_dev->wires); 335 if (err < 0) 336 return err; 337 switch (ts_dev->wires) { 338 case 4: 339 case 5: 340 case 8: 341 break; 342 default: 343 return -EINVAL; 344 } 345 346 err = of_property_read_u32(node, "ti,x-plate-resistance", 347 &ts_dev->x_plate_resistance); 348 if (err < 0) 349 return err; 350 351 err = of_property_read_u32(node, "ti,coordiante-readouts", 352 &ts_dev->coordinate_readouts); 353 if (err < 0) 354 return err; 355 356 return of_property_read_u32_array(node, "ti,wire-config", 357 ts_dev->config_inp, ARRAY_SIZE(ts_dev->config_inp)); 358 } 359 360 /* 361 * The functions for inserting/removing driver as a module. 362 */ 363 364 static int titsc_probe(struct platform_device *pdev) 365 { 366 struct titsc *ts_dev; 367 struct input_dev *input_dev; 368 struct ti_tscadc_dev *tscadc_dev = ti_tscadc_dev_get(pdev); 369 int err; 370 371 /* Allocate memory for device */ 372 ts_dev = kzalloc(sizeof(struct titsc), GFP_KERNEL); 373 input_dev = input_allocate_device(); 374 if (!ts_dev || !input_dev) { 375 dev_err(&pdev->dev, "failed to allocate memory.\n"); 376 err = -ENOMEM; 377 goto err_free_mem; 378 } 379 380 tscadc_dev->tsc = ts_dev; 381 ts_dev->mfd_tscadc = tscadc_dev; 382 ts_dev->input = input_dev; 383 ts_dev->irq = tscadc_dev->irq; 384 385 err = titsc_parse_dt(pdev, ts_dev); 386 if (err) { 387 dev_err(&pdev->dev, "Could not find valid DT data.\n"); 388 goto err_free_mem; 389 } 390 391 err = request_irq(ts_dev->irq, titsc_irq, 392 0, pdev->dev.driver->name, ts_dev); 393 if (err) { 394 dev_err(&pdev->dev, "failed to allocate irq.\n"); 395 goto err_free_mem; 396 } 397 398 titsc_writel(ts_dev, REG_IRQENABLE, IRQENB_FIFO0THRES); 399 err = titsc_config_wires(ts_dev); 400 if (err) { 401 dev_err(&pdev->dev, "wrong i/p wire configuration\n"); 402 goto err_free_irq; 403 } 404 titsc_step_config(ts_dev); 405 titsc_writel(ts_dev, REG_FIFO0THR, 406 ts_dev->coordinate_readouts * 2 + 2 - 1); 407 408 input_dev->name = "ti-tsc"; 409 input_dev->dev.parent = &pdev->dev; 410 411 input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS); 412 input_dev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH); 413 414 input_set_abs_params(input_dev, ABS_X, 0, MAX_12BIT, 0, 0); 415 input_set_abs_params(input_dev, ABS_Y, 0, MAX_12BIT, 0, 0); 416 input_set_abs_params(input_dev, ABS_PRESSURE, 0, MAX_12BIT, 0, 0); 417 418 /* register to the input system */ 419 err = input_register_device(input_dev); 420 if (err) 421 goto err_free_irq; 422 423 platform_set_drvdata(pdev, ts_dev); 424 return 0; 425 426 err_free_irq: 427 free_irq(ts_dev->irq, ts_dev); 428 err_free_mem: 429 input_free_device(input_dev); 430 kfree(ts_dev); 431 return err; 432 } 433 434 static int titsc_remove(struct platform_device *pdev) 435 { 436 struct titsc *ts_dev = platform_get_drvdata(pdev); 437 u32 steps; 438 439 free_irq(ts_dev->irq, ts_dev); 440 441 /* total steps followed by the enable mask */ 442 steps = 2 * ts_dev->coordinate_readouts + 2; 443 steps = (1 << steps) - 1; 444 am335x_tsc_se_clr(ts_dev->mfd_tscadc, steps); 445 446 input_unregister_device(ts_dev->input); 447 448 kfree(ts_dev); 449 return 0; 450 } 451 452 #ifdef CONFIG_PM 453 static int titsc_suspend(struct device *dev) 454 { 455 struct titsc *ts_dev = dev_get_drvdata(dev); 456 struct ti_tscadc_dev *tscadc_dev; 457 unsigned int idle; 458 459 tscadc_dev = ti_tscadc_dev_get(to_platform_device(dev)); 460 if (device_may_wakeup(tscadc_dev->dev)) { 461 idle = titsc_readl(ts_dev, REG_IRQENABLE); 462 titsc_writel(ts_dev, REG_IRQENABLE, 463 (idle | IRQENB_HW_PEN)); 464 titsc_writel(ts_dev, REG_IRQWAKEUP, IRQWKUP_ENB); 465 } 466 return 0; 467 } 468 469 static int titsc_resume(struct device *dev) 470 { 471 struct titsc *ts_dev = dev_get_drvdata(dev); 472 struct ti_tscadc_dev *tscadc_dev; 473 474 tscadc_dev = ti_tscadc_dev_get(to_platform_device(dev)); 475 if (device_may_wakeup(tscadc_dev->dev)) { 476 titsc_writel(ts_dev, REG_IRQWAKEUP, 477 0x00); 478 titsc_writel(ts_dev, REG_IRQCLR, IRQENB_HW_PEN); 479 } 480 titsc_step_config(ts_dev); 481 titsc_writel(ts_dev, REG_FIFO0THR, 482 ts_dev->coordinate_readouts * 2 + 2 - 1); 483 return 0; 484 } 485 486 static const struct dev_pm_ops titsc_pm_ops = { 487 .suspend = titsc_suspend, 488 .resume = titsc_resume, 489 }; 490 #define TITSC_PM_OPS (&titsc_pm_ops) 491 #else 492 #define TITSC_PM_OPS NULL 493 #endif 494 495 static const struct of_device_id ti_tsc_dt_ids[] = { 496 { .compatible = "ti,am3359-tsc", }, 497 { } 498 }; 499 MODULE_DEVICE_TABLE(of, ti_tsc_dt_ids); 500 501 static struct platform_driver ti_tsc_driver = { 502 .probe = titsc_probe, 503 .remove = titsc_remove, 504 .driver = { 505 .name = "TI-am335x-tsc", 506 .owner = THIS_MODULE, 507 .pm = TITSC_PM_OPS, 508 .of_match_table = of_match_ptr(ti_tsc_dt_ids), 509 }, 510 }; 511 module_platform_driver(ti_tsc_driver); 512 513 MODULE_DESCRIPTION("TI touchscreen controller driver"); 514 MODULE_AUTHOR("Rachna Patil <rachna@ti.com>"); 515 MODULE_LICENSE("GPL"); 516