drivers/input/touchscreen/imx6ul_tsc.c

   1 /*
   2  * Freescale i.MX6UL touchscreen controller driver
   3  *
   4  * Copyright (C) 2015 Freescale Semiconductor, Inc.
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License version 2 as
   8  * published by the Free Software Foundation.
   9  */
  10
  11 #include <linux/errno.h>
  12 #include <linux/kernel.h>
  13 #include <linux/module.h>
  14 #include <linux/gpio/consumer.h>
  15 #include <linux/input.h>
  16 #include <linux/slab.h>
  17 #include <linux/completion.h>
  18 #include <linux/delay.h>
  19 #include <linux/of.h>
  20 #include <linux/interrupt.h>
  21 #include <linux/platform_device.h>
  22 #include <linux/clk.h>
  23 #include <linux/io.h>
  24 #include <linux/log2.h>
  25
  26 /* ADC configuration registers field define */
  27 #define ADC_AIEN                (0x1 << 7)
  28 #define ADC_CONV_DISABLE        0x1F
  29 #define ADC_AVGE                (0x1 << 5)
  30 #define ADC_CAL                 (0x1 << 7)
  31 #define ADC_CALF                0x2
  32 #define ADC_12BIT_MODE          (0x2 << 2)
  33 #define ADC_CONV_MODE_MASK      (0x3 << 2)
  34 #define ADC_IPG_CLK             0x00
  35 #define ADC_INPUT_CLK_MASK      0x3
  36 #define ADC_CLK_DIV_8           (0x03 << 5)
  37 #define ADC_CLK_DIV_MASK        (0x3 << 5)
  38 #define ADC_SHORT_SAMPLE_MODE   (0x0 << 4)
  39 #define ADC_SAMPLE_MODE_MASK    (0x1 << 4)
  40 #define ADC_HARDWARE_TRIGGER    (0x1 << 13)
  41 #define ADC_AVGS_SHIFT          14
  42 #define ADC_AVGS_MASK           (0x3 << 14)
  43 #define SELECT_CHANNEL_4        0x04
  44 #define SELECT_CHANNEL_1        0x01
  45 #define DISABLE_CONVERSION_INT  (0x0 << 7)
  46
  47 /* ADC registers */
  48 #define REG_ADC_HC0             0x00
  49 #define REG_ADC_HC1             0x04
  50 #define REG_ADC_HC2             0x08
  51 #define REG_ADC_HC3             0x0C
  52 #define REG_ADC_HC4             0x10
  53 #define REG_ADC_HS              0x14
  54 #define REG_ADC_R0              0x18
  55 #define REG_ADC_CFG             0x2C
  56 #define REG_ADC_GC              0x30
  57 #define REG_ADC_GS              0x34
  58
  59 #define ADC_TIMEOUT             msecs_to_jiffies(100)
  60
  61 /* TSC registers */
  62 #define REG_TSC_BASIC_SETING    0x00
  63 #define REG_TSC_PRE_CHARGE_TIME 0x10
  64 #define REG_TSC_FLOW_CONTROL    0x20
  65 #define REG_TSC_MEASURE_VALUE   0x30
  66 #define REG_TSC_INT_EN          0x40
  67 #define REG_TSC_INT_SIG_EN      0x50
  68 #define REG_TSC_INT_STATUS      0x60
  69 #define REG_TSC_DEBUG_MODE      0x70
  70 #define REG_TSC_DEBUG_MODE2     0x80
  71
  72 /* TSC configuration registers field define */
  73 #define DETECT_4_WIRE_MODE      (0x0 << 4)
  74 #define AUTO_MEASURE            0x1
  75 #define MEASURE_SIGNAL          0x1
  76 #define DETECT_SIGNAL           (0x1 << 4)
  77 #define VALID_SIGNAL            (0x1 << 8)
  78 #define MEASURE_INT_EN          0x1
  79 #define MEASURE_SIG_EN          0x1
  80 #define VALID_SIG_EN            (0x1 << 8)
  81 #define DE_GLITCH_2             (0x2 << 29)
  82 #define START_SENSE             (0x1 << 12)
  83 #define TSC_DISABLE             (0x1 << 16)
  84 #define DETECT_MODE             0x2
  85
  86 struct imx6ul_tsc {
  87         struct device *dev;
  88         struct input_dev *input;
  89         void __iomem *tsc_regs;
  90         void __iomem *adc_regs;
  91         struct clk *tsc_clk;
  92         struct clk *adc_clk;
  93         struct gpio_desc *xnur_gpio;
  94
  95         u32 measure_delay_time;
  96         u32 pre_charge_time;
  97         bool average_enable;
  98         u32 average_select;
  99
 100         struct completion completion;
 101 };
 102
 103 /*
 104  * TSC module need ADC to get the measure value. So
 105  * before config TSC, we should initialize ADC module.
 106  */
 107 static int imx6ul_adc_init(struct imx6ul_tsc *tsc)
 108 {
 109         u32 adc_hc = 0;
 110         u32 adc_gc;
 111         u32 adc_gs;
 112         u32 adc_cfg;
 113         unsigned long timeout;
 114
 115         reinit_completion(&tsc->completion);
 116
 117         adc_cfg = readl(tsc->adc_regs + REG_ADC_CFG);
 118         adc_cfg &= ~(ADC_CONV_MODE_MASK | ADC_INPUT_CLK_MASK);
 119         adc_cfg |= ADC_12BIT_MODE | ADC_IPG_CLK;
 120         adc_cfg &= ~(ADC_CLK_DIV_MASK | ADC_SAMPLE_MODE_MASK);
 121         adc_cfg |= ADC_CLK_DIV_8 | ADC_SHORT_SAMPLE_MODE;
 122         if (tsc->average_enable) {
 123                 adc_cfg &= ~ADC_AVGS_MASK;
 124                 adc_cfg |= (tsc->average_select) << ADC_AVGS_SHIFT;
 125         }
 126         adc_cfg &= ~ADC_HARDWARE_TRIGGER;
 127         writel(adc_cfg, tsc->adc_regs + REG_ADC_CFG);
 128
 129         /* enable calibration interrupt */
 130         adc_hc |= ADC_AIEN;
 131         adc_hc |= ADC_CONV_DISABLE;
 132         writel(adc_hc, tsc->adc_regs + REG_ADC_HC0);
 133
 134         /* start ADC calibration */
 135         adc_gc = readl(tsc->adc_regs + REG_ADC_GC);
 136         adc_gc |= ADC_CAL;
 137         if (tsc->average_enable)
 138                 adc_gc |= ADC_AVGE;
 139         writel(adc_gc, tsc->adc_regs + REG_ADC_GC);
 140
 141         timeout = wait_for_completion_timeout
 142                         (&tsc->completion, ADC_TIMEOUT);
 143         if (timeout == 0) {
 144                 dev_err(tsc->dev, "Timeout for adc calibration\n");
 145                 return -ETIMEDOUT;
 146         }
 147
 148         adc_gs = readl(tsc->adc_regs + REG_ADC_GS);
 149         if (adc_gs & ADC_CALF) {
 150                 dev_err(tsc->dev, "ADC calibration failed\n");
 151                 return -EINVAL;
 152         }
 153
 154         /* TSC need the ADC work in hardware trigger */
 155         adc_cfg = readl(tsc->adc_regs + REG_ADC_CFG);
 156         adc_cfg |= ADC_HARDWARE_TRIGGER;
 157         writel(adc_cfg, tsc->adc_regs + REG_ADC_CFG);
 158
 159         return 0;
 160 }
 161
 162 /*
 163  * This is a TSC workaround. Currently TSC misconnect two
 164  * ADC channels, this function remap channel configure for
 165  * hardware trigger.
 166  */
 167 static void imx6ul_tsc_channel_config(struct imx6ul_tsc *tsc)
 168 {
 169         u32 adc_hc0, adc_hc1, adc_hc2, adc_hc3, adc_hc4;
 170
 171         adc_hc0 = DISABLE_CONVERSION_INT;
 172         writel(adc_hc0, tsc->adc_regs + REG_ADC_HC0);
 173
 174         adc_hc1 = DISABLE_CONVERSION_INT | SELECT_CHANNEL_4;
 175         writel(adc_hc1, tsc->adc_regs + REG_ADC_HC1);
 176
 177         adc_hc2 = DISABLE_CONVERSION_INT;
 178         writel(adc_hc2, tsc->adc_regs + REG_ADC_HC2);
 179
 180         adc_hc3 = DISABLE_CONVERSION_INT | SELECT_CHANNEL_1;
 181         writel(adc_hc3, tsc->adc_regs + REG_ADC_HC3);
 182
 183         adc_hc4 = DISABLE_CONVERSION_INT;
 184         writel(adc_hc4, tsc->adc_regs + REG_ADC_HC4);
 185 }
 186
 187 /*
 188  * TSC setting, confige the pre-charge time and measure delay time.
 189  * different touch screen may need different pre-charge time and
 190  * measure delay time.
 191  */
 192 static void imx6ul_tsc_set(struct imx6ul_tsc *tsc)
 193 {
 194         u32 basic_setting = 0;
 195         u32 start;
 196
 197         basic_setting |= tsc->measure_delay_time << 8;
 198         basic_setting |= DETECT_4_WIRE_MODE | AUTO_MEASURE;
 199         writel(basic_setting, tsc->tsc_regs + REG_TSC_BASIC_SETING);
 200
 201         writel(DE_GLITCH_2, tsc->tsc_regs + REG_TSC_DEBUG_MODE2);
 202
 203         writel(tsc->pre_charge_time, tsc->tsc_regs + REG_TSC_PRE_CHARGE_TIME);
 204         writel(MEASURE_INT_EN, tsc->tsc_regs + REG_TSC_INT_EN);
 205         writel(MEASURE_SIG_EN | VALID_SIG_EN,
 206                 tsc->tsc_regs + REG_TSC_INT_SIG_EN);
 207
 208         /* start sense detection */
 209         start = readl(tsc->tsc_regs + REG_TSC_FLOW_CONTROL);
 210         start |= START_SENSE;
 211         start &= ~TSC_DISABLE;
 212         writel(start, tsc->tsc_regs + REG_TSC_FLOW_CONTROL);
 213 }
 214
 215 static int imx6ul_tsc_init(struct imx6ul_tsc *tsc)
 216 {
 217         int err;
 218
 219         err = imx6ul_adc_init(tsc);
 220         if (err)
 221                 return err;
 222         imx6ul_tsc_channel_config(tsc);
 223         imx6ul_tsc_set(tsc);
 224
 225         return 0;
 226 }
 227
 228 static void imx6ul_tsc_disable(struct imx6ul_tsc *tsc)
 229 {
 230         u32 tsc_flow;
 231         u32 adc_cfg;
 232
 233         /* TSC controller enters to idle status */
 234         tsc_flow = readl(tsc->tsc_regs + REG_TSC_FLOW_CONTROL);
 235         tsc_flow |= TSC_DISABLE;
 236         writel(tsc_flow, tsc->tsc_regs + REG_TSC_FLOW_CONTROL);
 237
 238         /* ADC controller enters to stop mode */
 239         adc_cfg = readl(tsc->adc_regs + REG_ADC_HC0);
 240         adc_cfg |= ADC_CONV_DISABLE;
 241         writel(adc_cfg, tsc->adc_regs + REG_ADC_HC0);
 242 }
 243
 244 /* Delay some time (max 2ms), wait the pre-charge done. */
 245 static bool tsc_wait_detect_mode(struct imx6ul_tsc *tsc)
 246 {
 247         unsigned long timeout = jiffies + msecs_to_jiffies(2);
 248         u32 state_machine;
 249         u32 debug_mode2;
 250
 251         do {
 252                 if (time_after(jiffies, timeout))
 253                         return false;
 254
 255                 usleep_range(200, 400);
 256                 debug_mode2 = readl(tsc->tsc_regs + REG_TSC_DEBUG_MODE2);
 257                 state_machine = (debug_mode2 >> 20) & 0x7;
 258         } while (state_machine != DETECT_MODE);
 259
 260         usleep_range(200, 400);
 261         return true;
 262 }
 263
 264 static irqreturn_t tsc_irq_fn(int irq, void *dev_id)
 265 {
 266         struct imx6ul_tsc *tsc = dev_id;
 267         u32 status;
 268         u32 value;
 269         u32 x, y;
 270         u32 start;
 271
 272         status = readl(tsc->tsc_regs + REG_TSC_INT_STATUS);
 273
 274         /* write 1 to clear the bit measure-signal */
 275         writel(MEASURE_SIGNAL | DETECT_SIGNAL,
 276                 tsc->tsc_regs + REG_TSC_INT_STATUS);
 277
 278         /* It's a HW self-clean bit. Set this bit and start sense detection */
 279         start = readl(tsc->tsc_regs + REG_TSC_FLOW_CONTROL);
 280         start |= START_SENSE;
 281         writel(start, tsc->tsc_regs + REG_TSC_FLOW_CONTROL);
 282
 283         if (status & MEASURE_SIGNAL) {
 284                 value = readl(tsc->tsc_regs + REG_TSC_MEASURE_VALUE);
 285                 x = (value >> 16) & 0x0fff;
 286                 y = value & 0x0fff;
 287
 288                 /*
 289                  * In detect mode, we can get the xnur gpio value,
 290                  * otherwise assume contact is stiull active.
 291                  */
 292                 if (!tsc_wait_detect_mode(tsc) ||
 293                     gpiod_get_value_cansleep(tsc->xnur_gpio)) {
 294                         input_report_key(tsc->input, BTN_TOUCH, 1);
 295                         input_report_abs(tsc->input, ABS_X, x);
 296                         input_report_abs(tsc->input, ABS_Y, y);
 297                 } else {
 298                         input_report_key(tsc->input, BTN_TOUCH, 0);
 299                 }
 300
 301                 input_sync(tsc->input);
 302         }
 303
 304         return IRQ_HANDLED;
 305 }
 306
 307 static irqreturn_t adc_irq_fn(int irq, void *dev_id)
 308 {
 309         struct imx6ul_tsc *tsc = dev_id;
 310         u32 coco;
 311         u32 value;
 312
 313         coco = readl(tsc->adc_regs + REG_ADC_HS);
 314         if (coco & 0x01) {
 315                 value = readl(tsc->adc_regs + REG_ADC_R0);
 316                 complete(&tsc->completion);
 317         }
 318
 319         return IRQ_HANDLED;
 320 }
 321
 322 static int imx6ul_tsc_open(struct input_dev *input_dev)
 323 {
 324         struct imx6ul_tsc *tsc = input_get_drvdata(input_dev);
 325         int err;
 326
 327         err = clk_prepare_enable(tsc->adc_clk);
 328         if (err) {
 329                 dev_err(tsc->dev,
 330                         "Could not prepare or enable the adc clock: %d\n",
 331                         err);
 332                 return err;
 333         }
 334
 335         err = clk_prepare_enable(tsc->tsc_clk);
 336         if (err) {
 337                 dev_err(tsc->dev,
 338                         "Could not prepare or enable the tsc clock: %d\n",
 339                         err);
 340                 clk_disable_unprepare(tsc->adc_clk);
 341                 return err;
 342         }
 343
 344         return imx6ul_tsc_init(tsc);
 345 }
 346
 347 static void imx6ul_tsc_close(struct input_dev *input_dev)
 348 {
 349         struct imx6ul_tsc *tsc = input_get_drvdata(input_dev);
 350
 351         imx6ul_tsc_disable(tsc);
 352
 353         clk_disable_unprepare(tsc->tsc_clk);
 354         clk_disable_unprepare(tsc->adc_clk);
 355 }
 356
 357 static int imx6ul_tsc_probe(struct platform_device *pdev)
 358 {
 359         struct device_node *np = pdev->dev.of_node;
 360         struct imx6ul_tsc *tsc;
 361         struct input_dev *input_dev;
 362         struct resource *tsc_mem;
 363         struct resource *adc_mem;
 364         int err;
 365         int tsc_irq;
 366         int adc_irq;
 367         u32 average_samples;
 368
 369         tsc = devm_kzalloc(&pdev->dev, sizeof(*tsc), GFP_KERNEL);
 370         if (!tsc)
 371                 return -ENOMEM;
 372
 373         input_dev = devm_input_allocate_device(&pdev->dev);
 374         if (!input_dev)
 375                 return -ENOMEM;
 376
 377         input_dev->name = "iMX6UL Touchscreen Controller";
 378         input_dev->id.bustype = BUS_HOST;
 379
 380         input_dev->open = imx6ul_tsc_open;
 381         input_dev->close = imx6ul_tsc_close;
 382
 383         input_set_capability(input_dev, EV_KEY, BTN_TOUCH);
 384         input_set_abs_params(input_dev, ABS_X, 0, 0xFFF, 0, 0);
 385         input_set_abs_params(input_dev, ABS_Y, 0, 0xFFF, 0, 0);
 386
 387         input_set_drvdata(input_dev, tsc);
 388
 389         tsc->dev = &pdev->dev;
 390         tsc->input = input_dev;
 391         init_completion(&tsc->completion);
 392
 393         tsc->xnur_gpio = devm_gpiod_get(&pdev->dev, "xnur", GPIOD_IN);
 394         if (IS_ERR(tsc->xnur_gpio)) {
 395                 err = PTR_ERR(tsc->xnur_gpio);
 396                 dev_err(&pdev->dev,
 397                         "failed to request GPIO tsc_X- (xnur): %d\n", err);
 398                 return err;
 399         }
 400
 401         tsc_mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 402         tsc->tsc_regs = devm_ioremap_resource(&pdev->dev, tsc_mem);
 403         if (IS_ERR(tsc->tsc_regs)) {
 404                 err = PTR_ERR(tsc->tsc_regs);
 405                 dev_err(&pdev->dev, "failed to remap tsc memory: %d\n", err);
 406                 return err;
 407         }
 408
 409         adc_mem = platform_get_resource(pdev, IORESOURCE_MEM, 1);
 410         tsc->adc_regs = devm_ioremap_resource(&pdev->dev, adc_mem);
 411         if (IS_ERR(tsc->adc_regs)) {
 412                 err = PTR_ERR(tsc->adc_regs);
 413                 dev_err(&pdev->dev, "failed to remap adc memory: %d\n", err);
 414                 return err;
 415         }
 416
 417         tsc->tsc_clk = devm_clk_get(&pdev->dev, "tsc");
 418         if (IS_ERR(tsc->tsc_clk)) {
 419                 err = PTR_ERR(tsc->tsc_clk);
 420                 dev_err(&pdev->dev, "failed getting tsc clock: %d\n", err);
 421                 return err;
 422         }
 423
 424         tsc->adc_clk = devm_clk_get(&pdev->dev, "adc");
 425         if (IS_ERR(tsc->adc_clk)) {
 426                 err = PTR_ERR(tsc->adc_clk);
 427                 dev_err(&pdev->dev, "failed getting adc clock: %d\n", err);
 428                 return err;
 429         }
 430
 431         tsc_irq = platform_get_irq(pdev, 0);
 432         if (tsc_irq < 0) {
 433                 dev_err(&pdev->dev, "no tsc irq resource?\n");
 434                 return tsc_irq;
 435         }
 436
 437         adc_irq = platform_get_irq(pdev, 1);
 438         if (adc_irq < 0) {
 439                 dev_err(&pdev->dev, "no adc irq resource?\n");
 440                 return adc_irq;
 441         }
 442
 443         err = devm_request_threaded_irq(tsc->dev, tsc_irq,
 444                                         NULL, tsc_irq_fn, IRQF_ONESHOT,
 445                                         dev_name(&pdev->dev), tsc);
 446         if (err) {
 447                 dev_err(&pdev->dev,
 448                         "failed requesting tsc irq %d: %d\n",
 449                         tsc_irq, err);
 450                 return err;
 451         }
 452
 453         err = devm_request_irq(tsc->dev, adc_irq, adc_irq_fn, 0,
 454                                 dev_name(&pdev->dev), tsc);
 455         if (err) {
 456                 dev_err(&pdev->dev,
 457                         "failed requesting adc irq %d: %d\n",
 458                         adc_irq, err);
 459                 return err;
 460         }
 461
 462         err = of_property_read_u32(np, "measure-delay-time",
 463                                    &tsc->measure_delay_time);
 464         if (err)
 465                 tsc->measure_delay_time = 0xffff;
 466
 467         err = of_property_read_u32(np, "pre-charge-time",
 468                                    &tsc->pre_charge_time);
 469         if (err)
 470                 tsc->pre_charge_time = 0xfff;
 471
 472         err = of_property_read_u32(np, "touchscreen-average-samples",
 473                                    &average_samples);
 474         if (err)
 475                 average_samples = 1;
 476
 477         switch (average_samples) {
 478         case 1:
 479                 tsc->average_enable = false;
 480                 tsc->average_select = 0; /* value unused; initialize anyway */
 481                 break;
 482         case 4:
 483         case 8:
 484         case 16:
 485         case 32:
 486                 tsc->average_enable = true;
 487                 tsc->average_select = ilog2(average_samples) - 2;
 488                 break;
 489         default:
 490                 dev_err(&pdev->dev,
 491                         "touchscreen-average-samples (%u) must be 1, 4, 8, 16 or 32\n",
 492                         average_samples);
 493                 return -EINVAL;
 494         }
 495
 496         err = input_register_device(tsc->input);
 497         if (err) {
 498                 dev_err(&pdev->dev,
 499                         "failed to register input device: %d\n", err);
 500                 return err;
 501         }
 502
 503         platform_set_drvdata(pdev, tsc);
 504         return 0;
 505 }
 506
 507 static int __maybe_unused imx6ul_tsc_suspend(struct device *dev)
 508 {
 509         struct platform_device *pdev = to_platform_device(dev);
 510         struct imx6ul_tsc *tsc = platform_get_drvdata(pdev);
 511         struct input_dev *input_dev = tsc->input;
 512
 513         mutex_lock(&input_dev->mutex);
 514
 515         if (input_dev->users) {
 516                 imx6ul_tsc_disable(tsc);
 517
 518                 clk_disable_unprepare(tsc->tsc_clk);
 519                 clk_disable_unprepare(tsc->adc_clk);
 520         }
 521
 522         mutex_unlock(&input_dev->mutex);
 523
 524         return 0;
 525 }
 526
 527 static int __maybe_unused imx6ul_tsc_resume(struct device *dev)
 528 {
 529         struct platform_device *pdev = to_platform_device(dev);
 530         struct imx6ul_tsc *tsc = platform_get_drvdata(pdev);
 531         struct input_dev *input_dev = tsc->input;
 532         int retval = 0;
 533
 534         mutex_lock(&input_dev->mutex);
 535
 536         if (input_dev->users) {
 537                 retval = clk_prepare_enable(tsc->adc_clk);
 538                 if (retval)
 539                         goto out;
 540
 541                 retval = clk_prepare_enable(tsc->tsc_clk);
 542                 if (retval) {
 543                         clk_disable_unprepare(tsc->adc_clk);
 544                         goto out;
 545                 }
 546
 547                 retval = imx6ul_tsc_init(tsc);
 548         }
 549
 550 out:
 551         mutex_unlock(&input_dev->mutex);
 552         return retval;
 553 }
 554
 555 static SIMPLE_DEV_PM_OPS(imx6ul_tsc_pm_ops,
 556                          imx6ul_tsc_suspend, imx6ul_tsc_resume);
 557
 558 static const struct of_device_id imx6ul_tsc_match[] = {
 559         { .compatible = "fsl,imx6ul-tsc", },
 560         { /* sentinel */ }
 561 };
 562 MODULE_DEVICE_TABLE(of, imx6ul_tsc_match);
 563
 564 static struct platform_driver imx6ul_tsc_driver = {
 565         .driver         = {
 566                 .name   = "imx6ul-tsc",
 567                 .of_match_table = imx6ul_tsc_match,
 568                 .pm     = &imx6ul_tsc_pm_ops,
 569         },
 570         .probe          = imx6ul_tsc_probe,
 571 };
 572 module_platform_driver(imx6ul_tsc_driver);
 573
 574 MODULE_AUTHOR("Haibo Chen <haibo.chen@freescale.com>");
 575 MODULE_DESCRIPTION("Freescale i.MX6UL Touchscreen controller driver");
 576 MODULE_LICENSE("GPL v2");