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                 goto disable_adc_clk;
 341         }
 342
 343         err = imx6ul_tsc_init(tsc);
 344         if (err)
 345                 goto disable_tsc_clk;
 346
 347         return 0;
 348
 349 disable_tsc_clk:
 350         clk_disable_unprepare(tsc->tsc_clk);
 351 disable_adc_clk:
 352         clk_disable_unprepare(tsc->adc_clk);
 353         return err;
 354 }
 355
 356 static void imx6ul_tsc_close(struct input_dev *input_dev)
 357 {
 358         struct imx6ul_tsc *tsc = input_get_drvdata(input_dev);
 359
 360         imx6ul_tsc_disable(tsc);
 361
 362         clk_disable_unprepare(tsc->tsc_clk);
 363         clk_disable_unprepare(tsc->adc_clk);
 364 }
 365
 366 static int imx6ul_tsc_probe(struct platform_device *pdev)
 367 {
 368         struct device_node *np = pdev->dev.of_node;
 369         struct imx6ul_tsc *tsc;
 370         struct input_dev *input_dev;
 371         struct resource *tsc_mem;
 372         struct resource *adc_mem;
 373         int err;
 374         int tsc_irq;
 375         int adc_irq;
 376         u32 average_samples;
 377
 378         tsc = devm_kzalloc(&pdev->dev, sizeof(*tsc), GFP_KERNEL);
 379         if (!tsc)
 380                 return -ENOMEM;
 381
 382         input_dev = devm_input_allocate_device(&pdev->dev);
 383         if (!input_dev)
 384                 return -ENOMEM;
 385
 386         input_dev->name = "iMX6UL Touchscreen Controller";
 387         input_dev->id.bustype = BUS_HOST;
 388
 389         input_dev->open = imx6ul_tsc_open;
 390         input_dev->close = imx6ul_tsc_close;
 391
 392         input_set_capability(input_dev, EV_KEY, BTN_TOUCH);
 393         input_set_abs_params(input_dev, ABS_X, 0, 0xFFF, 0, 0);
 394         input_set_abs_params(input_dev, ABS_Y, 0, 0xFFF, 0, 0);
 395
 396         input_set_drvdata(input_dev, tsc);
 397
 398         tsc->dev = &pdev->dev;
 399         tsc->input = input_dev;
 400         init_completion(&tsc->completion);
 401
 402         tsc->xnur_gpio = devm_gpiod_get(&pdev->dev, "xnur", GPIOD_IN);
 403         if (IS_ERR(tsc->xnur_gpio)) {
 404                 err = PTR_ERR(tsc->xnur_gpio);
 405                 dev_err(&pdev->dev,
 406                         "failed to request GPIO tsc_X- (xnur): %d\n", err);
 407                 return err;
 408         }
 409
 410         tsc_mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 411         tsc->tsc_regs = devm_ioremap_resource(&pdev->dev, tsc_mem);
 412         if (IS_ERR(tsc->tsc_regs)) {
 413                 err = PTR_ERR(tsc->tsc_regs);
 414                 dev_err(&pdev->dev, "failed to remap tsc memory: %d\n", err);
 415                 return err;
 416         }
 417
 418         adc_mem = platform_get_resource(pdev, IORESOURCE_MEM, 1);
 419         tsc->adc_regs = devm_ioremap_resource(&pdev->dev, adc_mem);
 420         if (IS_ERR(tsc->adc_regs)) {
 421                 err = PTR_ERR(tsc->adc_regs);
 422                 dev_err(&pdev->dev, "failed to remap adc memory: %d\n", err);
 423                 return err;
 424         }
 425
 426         tsc->tsc_clk = devm_clk_get(&pdev->dev, "tsc");
 427         if (IS_ERR(tsc->tsc_clk)) {
 428                 err = PTR_ERR(tsc->tsc_clk);
 429                 dev_err(&pdev->dev, "failed getting tsc clock: %d\n", err);
 430                 return err;
 431         }
 432
 433         tsc->adc_clk = devm_clk_get(&pdev->dev, "adc");
 434         if (IS_ERR(tsc->adc_clk)) {
 435                 err = PTR_ERR(tsc->adc_clk);
 436                 dev_err(&pdev->dev, "failed getting adc clock: %d\n", err);
 437                 return err;
 438         }
 439
 440         tsc_irq = platform_get_irq(pdev, 0);
 441         if (tsc_irq < 0) {
 442                 dev_err(&pdev->dev, "no tsc irq resource?\n");
 443                 return tsc_irq;
 444         }
 445
 446         adc_irq = platform_get_irq(pdev, 1);
 447         if (adc_irq < 0) {
 448                 dev_err(&pdev->dev, "no adc irq resource?\n");
 449                 return adc_irq;
 450         }
 451
 452         err = devm_request_threaded_irq(tsc->dev, tsc_irq,
 453                                         NULL, tsc_irq_fn, IRQF_ONESHOT,
 454                                         dev_name(&pdev->dev), tsc);
 455         if (err) {
 456                 dev_err(&pdev->dev,
 457                         "failed requesting tsc irq %d: %d\n",
 458                         tsc_irq, err);
 459                 return err;
 460         }
 461
 462         err = devm_request_irq(tsc->dev, adc_irq, adc_irq_fn, 0,
 463                                 dev_name(&pdev->dev), tsc);
 464         if (err) {
 465                 dev_err(&pdev->dev,
 466                         "failed requesting adc irq %d: %d\n",
 467                         adc_irq, err);
 468                 return err;
 469         }
 470
 471         err = of_property_read_u32(np, "measure-delay-time",
 472                                    &tsc->measure_delay_time);
 473         if (err)
 474                 tsc->measure_delay_time = 0xffff;
 475
 476         err = of_property_read_u32(np, "pre-charge-time",
 477                                    &tsc->pre_charge_time);
 478         if (err)
 479                 tsc->pre_charge_time = 0xfff;
 480
 481         err = of_property_read_u32(np, "touchscreen-average-samples",
 482                                    &average_samples);
 483         if (err)
 484                 average_samples = 1;
 485
 486         switch (average_samples) {
 487         case 1:
 488                 tsc->average_enable = false;
 489                 tsc->average_select = 0; /* value unused; initialize anyway */
 490                 break;
 491         case 4:
 492         case 8:
 493         case 16:
 494         case 32:
 495                 tsc->average_enable = true;
 496                 tsc->average_select = ilog2(average_samples) - 2;
 497                 break;
 498         default:
 499                 dev_err(&pdev->dev,
 500                         "touchscreen-average-samples (%u) must be 1, 4, 8, 16 or 32\n",
 501                         average_samples);
 502                 return -EINVAL;
 503         }
 504
 505         err = input_register_device(tsc->input);
 506         if (err) {
 507                 dev_err(&pdev->dev,
 508                         "failed to register input device: %d\n", err);
 509                 return err;
 510         }
 511
 512         platform_set_drvdata(pdev, tsc);
 513         return 0;
 514 }
 515
 516 static int __maybe_unused imx6ul_tsc_suspend(struct device *dev)
 517 {
 518         struct platform_device *pdev = to_platform_device(dev);
 519         struct imx6ul_tsc *tsc = platform_get_drvdata(pdev);
 520         struct input_dev *input_dev = tsc->input;
 521
 522         mutex_lock(&input_dev->mutex);
 523
 524         if (input_dev->users) {
 525                 imx6ul_tsc_disable(tsc);
 526
 527                 clk_disable_unprepare(tsc->tsc_clk);
 528                 clk_disable_unprepare(tsc->adc_clk);
 529         }
 530
 531         mutex_unlock(&input_dev->mutex);
 532
 533         return 0;
 534 }
 535
 536 static int __maybe_unused imx6ul_tsc_resume(struct device *dev)
 537 {
 538         struct platform_device *pdev = to_platform_device(dev);
 539         struct imx6ul_tsc *tsc = platform_get_drvdata(pdev);
 540         struct input_dev *input_dev = tsc->input;
 541         int retval = 0;
 542
 543         mutex_lock(&input_dev->mutex);
 544
 545         if (input_dev->users) {
 546                 retval = clk_prepare_enable(tsc->adc_clk);
 547                 if (retval)
 548                         goto out;
 549
 550                 retval = clk_prepare_enable(tsc->tsc_clk);
 551                 if (retval) {
 552                         clk_disable_unprepare(tsc->adc_clk);
 553                         goto out;
 554                 }
 555
 556                 retval = imx6ul_tsc_init(tsc);
 557         }
 558
 559 out:
 560         mutex_unlock(&input_dev->mutex);
 561         return retval;
 562 }
 563
 564 static SIMPLE_DEV_PM_OPS(imx6ul_tsc_pm_ops,
 565                          imx6ul_tsc_suspend, imx6ul_tsc_resume);
 566
 567 static const struct of_device_id imx6ul_tsc_match[] = {
 568         { .compatible = "fsl,imx6ul-tsc", },
 569         { /* sentinel */ }
 570 };
 571 MODULE_DEVICE_TABLE(of, imx6ul_tsc_match);
 572
 573 static struct platform_driver imx6ul_tsc_driver = {
 574         .driver         = {
 575                 .name   = "imx6ul-tsc",
 576                 .of_match_table = imx6ul_tsc_match,
 577                 .pm     = &imx6ul_tsc_pm_ops,
 578         },
 579         .probe          = imx6ul_tsc_probe,
 580 };
 581 module_platform_driver(imx6ul_tsc_driver);
 582
 583 MODULE_AUTHOR("Haibo Chen <haibo.chen@freescale.com>");
 584 MODULE_DESCRIPTION("Freescale i.MX6UL Touchscreen controller driver");
 585 MODULE_LICENSE("GPL v2");