drivers/input/touchscreen/imx6ul_tsc.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 //
   3 // Freescale i.MX6UL touchscreen controller driver
   4 //
   5 // Copyright (C) 2015 Freescale Semiconductor, Inc.
   6
   7 #include <linux/errno.h>
   8 #include <linux/kernel.h>
   9 #include <linux/module.h>
  10 #include <linux/gpio/consumer.h>
  11 #include <linux/input.h>
  12 #include <linux/slab.h>
  13 #include <linux/completion.h>
  14 #include <linux/delay.h>
  15 #include <linux/of.h>
  16 #include <linux/interrupt.h>
  17 #include <linux/platform_device.h>
  18 #include <linux/clk.h>
  19 #include <linux/io.h>
  20 #include <linux/log2.h>
  21
  22 /* ADC configuration registers field define */
  23 #define ADC_AIEN                (0x1 << 7)
  24 #define ADC_CONV_DISABLE        0x1F
  25 #define ADC_AVGE                (0x1 << 5)
  26 #define ADC_CAL                 (0x1 << 7)
  27 #define ADC_CALF                0x2
  28 #define ADC_12BIT_MODE          (0x2 << 2)
  29 #define ADC_CONV_MODE_MASK      (0x3 << 2)
  30 #define ADC_IPG_CLK             0x00
  31 #define ADC_INPUT_CLK_MASK      0x3
  32 #define ADC_CLK_DIV_8           (0x03 << 5)
  33 #define ADC_CLK_DIV_MASK        (0x3 << 5)
  34 #define ADC_SHORT_SAMPLE_MODE   (0x0 << 4)
  35 #define ADC_SAMPLE_MODE_MASK    (0x1 << 4)
  36 #define ADC_HARDWARE_TRIGGER    (0x1 << 13)
  37 #define ADC_AVGS_SHIFT          14
  38 #define ADC_AVGS_MASK           (0x3 << 14)
  39 #define SELECT_CHANNEL_4        0x04
  40 #define SELECT_CHANNEL_1        0x01
  41 #define DISABLE_CONVERSION_INT  (0x0 << 7)
  42
  43 /* ADC registers */
  44 #define REG_ADC_HC0             0x00
  45 #define REG_ADC_HC1             0x04
  46 #define REG_ADC_HC2             0x08
  47 #define REG_ADC_HC3             0x0C
  48 #define REG_ADC_HC4             0x10
  49 #define REG_ADC_HS              0x14
  50 #define REG_ADC_R0              0x18
  51 #define REG_ADC_CFG             0x2C
  52 #define REG_ADC_GC              0x30
  53 #define REG_ADC_GS              0x34
  54
  55 #define ADC_TIMEOUT             msecs_to_jiffies(100)
  56
  57 /* TSC registers */
  58 #define REG_TSC_BASIC_SETING    0x00
  59 #define REG_TSC_PRE_CHARGE_TIME 0x10
  60 #define REG_TSC_FLOW_CONTROL    0x20
  61 #define REG_TSC_MEASURE_VALUE   0x30
  62 #define REG_TSC_INT_EN          0x40
  63 #define REG_TSC_INT_SIG_EN      0x50
  64 #define REG_TSC_INT_STATUS      0x60
  65 #define REG_TSC_DEBUG_MODE      0x70
  66 #define REG_TSC_DEBUG_MODE2     0x80
  67
  68 /* TSC configuration registers field define */
  69 #define DETECT_4_WIRE_MODE      (0x0 << 4)
  70 #define AUTO_MEASURE            0x1
  71 #define MEASURE_SIGNAL          0x1
  72 #define DETECT_SIGNAL           (0x1 << 4)
  73 #define VALID_SIGNAL            (0x1 << 8)
  74 #define MEASURE_INT_EN          0x1
  75 #define MEASURE_SIG_EN          0x1
  76 #define VALID_SIG_EN            (0x1 << 8)
  77 #define DE_GLITCH_2             (0x2 << 29)
  78 #define START_SENSE             (0x1 << 12)
  79 #define TSC_DISABLE             (0x1 << 16)
  80 #define DETECT_MODE             0x2
  81
  82 struct imx6ul_tsc {
  83         struct device *dev;
  84         struct input_dev *input;
  85         void __iomem *tsc_regs;
  86         void __iomem *adc_regs;
  87         struct clk *tsc_clk;
  88         struct clk *adc_clk;
  89         struct gpio_desc *xnur_gpio;
  90
  91         u32 measure_delay_time;
  92         u32 pre_charge_time;
  93         bool average_enable;
  94         u32 average_select;
  95
  96         struct completion completion;
  97 };
  98
  99 /*
 100  * TSC module need ADC to get the measure value. So
 101  * before config TSC, we should initialize ADC module.
 102  */
 103 static int imx6ul_adc_init(struct imx6ul_tsc *tsc)
 104 {
 105         u32 adc_hc = 0;
 106         u32 adc_gc;
 107         u32 adc_gs;
 108         u32 adc_cfg;
 109         unsigned long timeout;
 110
 111         reinit_completion(&tsc->completion);
 112
 113         adc_cfg = readl(tsc->adc_regs + REG_ADC_CFG);
 114         adc_cfg &= ~(ADC_CONV_MODE_MASK | ADC_INPUT_CLK_MASK);
 115         adc_cfg |= ADC_12BIT_MODE | ADC_IPG_CLK;
 116         adc_cfg &= ~(ADC_CLK_DIV_MASK | ADC_SAMPLE_MODE_MASK);
 117         adc_cfg |= ADC_CLK_DIV_8 | ADC_SHORT_SAMPLE_MODE;
 118         if (tsc->average_enable) {
 119                 adc_cfg &= ~ADC_AVGS_MASK;
 120                 adc_cfg |= (tsc->average_select) << ADC_AVGS_SHIFT;
 121         }
 122         adc_cfg &= ~ADC_HARDWARE_TRIGGER;
 123         writel(adc_cfg, tsc->adc_regs + REG_ADC_CFG);
 124
 125         /* enable calibration interrupt */
 126         adc_hc |= ADC_AIEN;
 127         adc_hc |= ADC_CONV_DISABLE;
 128         writel(adc_hc, tsc->adc_regs + REG_ADC_HC0);
 129
 130         /* start ADC calibration */
 131         adc_gc = readl(tsc->adc_regs + REG_ADC_GC);
 132         adc_gc |= ADC_CAL;
 133         if (tsc->average_enable)
 134                 adc_gc |= ADC_AVGE;
 135         writel(adc_gc, tsc->adc_regs + REG_ADC_GC);
 136
 137         timeout = wait_for_completion_timeout
 138                         (&tsc->completion, ADC_TIMEOUT);
 139         if (timeout == 0) {
 140                 dev_err(tsc->dev, "Timeout for adc calibration\n");
 141                 return -ETIMEDOUT;
 142         }
 143
 144         adc_gs = readl(tsc->adc_regs + REG_ADC_GS);
 145         if (adc_gs & ADC_CALF) {
 146                 dev_err(tsc->dev, "ADC calibration failed\n");
 147                 return -EINVAL;
 148         }
 149
 150         /* TSC need the ADC work in hardware trigger */
 151         adc_cfg = readl(tsc->adc_regs + REG_ADC_CFG);
 152         adc_cfg |= ADC_HARDWARE_TRIGGER;
 153         writel(adc_cfg, tsc->adc_regs + REG_ADC_CFG);
 154
 155         return 0;
 156 }
 157
 158 /*
 159  * This is a TSC workaround. Currently TSC misconnect two
 160  * ADC channels, this function remap channel configure for
 161  * hardware trigger.
 162  */
 163 static void imx6ul_tsc_channel_config(struct imx6ul_tsc *tsc)
 164 {
 165         u32 adc_hc0, adc_hc1, adc_hc2, adc_hc3, adc_hc4;
 166
 167         adc_hc0 = DISABLE_CONVERSION_INT;
 168         writel(adc_hc0, tsc->adc_regs + REG_ADC_HC0);
 169
 170         adc_hc1 = DISABLE_CONVERSION_INT | SELECT_CHANNEL_4;
 171         writel(adc_hc1, tsc->adc_regs + REG_ADC_HC1);
 172
 173         adc_hc2 = DISABLE_CONVERSION_INT;
 174         writel(adc_hc2, tsc->adc_regs + REG_ADC_HC2);
 175
 176         adc_hc3 = DISABLE_CONVERSION_INT | SELECT_CHANNEL_1;
 177         writel(adc_hc3, tsc->adc_regs + REG_ADC_HC3);
 178
 179         adc_hc4 = DISABLE_CONVERSION_INT;
 180         writel(adc_hc4, tsc->adc_regs + REG_ADC_HC4);
 181 }
 182
 183 /*
 184  * TSC setting, confige the pre-charge time and measure delay time.
 185  * different touch screen may need different pre-charge time and
 186  * measure delay time.
 187  */
 188 static void imx6ul_tsc_set(struct imx6ul_tsc *tsc)
 189 {
 190         u32 basic_setting = 0;
 191         u32 start;
 192
 193         basic_setting |= tsc->measure_delay_time << 8;
 194         basic_setting |= DETECT_4_WIRE_MODE | AUTO_MEASURE;
 195         writel(basic_setting, tsc->tsc_regs + REG_TSC_BASIC_SETING);
 196
 197         writel(DE_GLITCH_2, tsc->tsc_regs + REG_TSC_DEBUG_MODE2);
 198
 199         writel(tsc->pre_charge_time, tsc->tsc_regs + REG_TSC_PRE_CHARGE_TIME);
 200         writel(MEASURE_INT_EN, tsc->tsc_regs + REG_TSC_INT_EN);
 201         writel(MEASURE_SIG_EN | VALID_SIG_EN,
 202                 tsc->tsc_regs + REG_TSC_INT_SIG_EN);
 203
 204         /* start sense detection */
 205         start = readl(tsc->tsc_regs + REG_TSC_FLOW_CONTROL);
 206         start |= START_SENSE;
 207         start &= ~TSC_DISABLE;
 208         writel(start, tsc->tsc_regs + REG_TSC_FLOW_CONTROL);
 209 }
 210
 211 static int imx6ul_tsc_init(struct imx6ul_tsc *tsc)
 212 {
 213         int err;
 214
 215         err = imx6ul_adc_init(tsc);
 216         if (err)
 217                 return err;
 218         imx6ul_tsc_channel_config(tsc);
 219         imx6ul_tsc_set(tsc);
 220
 221         return 0;
 222 }
 223
 224 static void imx6ul_tsc_disable(struct imx6ul_tsc *tsc)
 225 {
 226         u32 tsc_flow;
 227         u32 adc_cfg;
 228
 229         /* TSC controller enters to idle status */
 230         tsc_flow = readl(tsc->tsc_regs + REG_TSC_FLOW_CONTROL);
 231         tsc_flow |= TSC_DISABLE;
 232         writel(tsc_flow, tsc->tsc_regs + REG_TSC_FLOW_CONTROL);
 233
 234         /* ADC controller enters to stop mode */
 235         adc_cfg = readl(tsc->adc_regs + REG_ADC_HC0);
 236         adc_cfg |= ADC_CONV_DISABLE;
 237         writel(adc_cfg, tsc->adc_regs + REG_ADC_HC0);
 238 }
 239
 240 /* Delay some time (max 2ms), wait the pre-charge done. */
 241 static bool tsc_wait_detect_mode(struct imx6ul_tsc *tsc)
 242 {
 243         unsigned long timeout = jiffies + msecs_to_jiffies(2);
 244         u32 state_machine;
 245         u32 debug_mode2;
 246
 247         do {
 248                 if (time_after(jiffies, timeout))
 249                         return false;
 250
 251                 usleep_range(200, 400);
 252                 debug_mode2 = readl(tsc->tsc_regs + REG_TSC_DEBUG_MODE2);
 253                 state_machine = (debug_mode2 >> 20) & 0x7;
 254         } while (state_machine != DETECT_MODE);
 255
 256         usleep_range(200, 400);
 257         return true;
 258 }
 259
 260 static irqreturn_t tsc_irq_fn(int irq, void *dev_id)
 261 {
 262         struct imx6ul_tsc *tsc = dev_id;
 263         u32 status;
 264         u32 value;
 265         u32 x, y;
 266         u32 start;
 267
 268         status = readl(tsc->tsc_regs + REG_TSC_INT_STATUS);
 269
 270         /* write 1 to clear the bit measure-signal */
 271         writel(MEASURE_SIGNAL | DETECT_SIGNAL,
 272                 tsc->tsc_regs + REG_TSC_INT_STATUS);
 273
 274         /* It's a HW self-clean bit. Set this bit and start sense detection */
 275         start = readl(tsc->tsc_regs + REG_TSC_FLOW_CONTROL);
 276         start |= START_SENSE;
 277         writel(start, tsc->tsc_regs + REG_TSC_FLOW_CONTROL);
 278
 279         if (status & MEASURE_SIGNAL) {
 280                 value = readl(tsc->tsc_regs + REG_TSC_MEASURE_VALUE);
 281                 x = (value >> 16) & 0x0fff;
 282                 y = value & 0x0fff;
 283
 284                 /*
 285                  * In detect mode, we can get the xnur gpio value,
 286                  * otherwise assume contact is stiull active.
 287                  */
 288                 if (!tsc_wait_detect_mode(tsc) ||
 289                     gpiod_get_value_cansleep(tsc->xnur_gpio)) {
 290                         input_report_key(tsc->input, BTN_TOUCH, 1);
 291                         input_report_abs(tsc->input, ABS_X, x);
 292                         input_report_abs(tsc->input, ABS_Y, y);
 293                 } else {
 294                         input_report_key(tsc->input, BTN_TOUCH, 0);
 295                 }
 296
 297                 input_sync(tsc->input);
 298         }
 299
 300         return IRQ_HANDLED;
 301 }
 302
 303 static irqreturn_t adc_irq_fn(int irq, void *dev_id)
 304 {
 305         struct imx6ul_tsc *tsc = dev_id;
 306         u32 coco;
 307         u32 value;
 308
 309         coco = readl(tsc->adc_regs + REG_ADC_HS);
 310         if (coco & 0x01) {
 311                 value = readl(tsc->adc_regs + REG_ADC_R0);
 312                 complete(&tsc->completion);
 313         }
 314
 315         return IRQ_HANDLED;
 316 }
 317
 318 static int imx6ul_tsc_start(struct imx6ul_tsc *tsc)
 319 {
 320         int err;
 321
 322         err = clk_prepare_enable(tsc->adc_clk);
 323         if (err) {
 324                 dev_err(tsc->dev,
 325                         "Could not prepare or enable the adc clock: %d\n",
 326                         err);
 327                 return err;
 328         }
 329
 330         err = clk_prepare_enable(tsc->tsc_clk);
 331         if (err) {
 332                 dev_err(tsc->dev,
 333                         "Could not prepare or enable the tsc clock: %d\n",
 334                         err);
 335                 goto disable_adc_clk;
 336         }
 337
 338         err = imx6ul_tsc_init(tsc);
 339         if (err)
 340                 goto disable_tsc_clk;
 341
 342         return 0;
 343
 344 disable_tsc_clk:
 345         clk_disable_unprepare(tsc->tsc_clk);
 346 disable_adc_clk:
 347         clk_disable_unprepare(tsc->adc_clk);
 348         return err;
 349 }
 350
 351 static void imx6ul_tsc_stop(struct imx6ul_tsc *tsc)
 352 {
 353         imx6ul_tsc_disable(tsc);
 354
 355         clk_disable_unprepare(tsc->tsc_clk);
 356         clk_disable_unprepare(tsc->adc_clk);
 357 }
 358
 359
 360 static int imx6ul_tsc_open(struct input_dev *input_dev)
 361 {
 362         struct imx6ul_tsc *tsc = input_get_drvdata(input_dev);
 363
 364         return imx6ul_tsc_start(tsc);
 365 }
 366
 367 static void imx6ul_tsc_close(struct input_dev *input_dev)
 368 {
 369         struct imx6ul_tsc *tsc = input_get_drvdata(input_dev);
 370
 371         imx6ul_tsc_stop(tsc);
 372 }
 373
 374 static int imx6ul_tsc_probe(struct platform_device *pdev)
 375 {
 376         struct device_node *np = pdev->dev.of_node;
 377         struct imx6ul_tsc *tsc;
 378         struct input_dev *input_dev;
 379         int err;
 380         int tsc_irq;
 381         int adc_irq;
 382         u32 average_samples;
 383
 384         tsc = devm_kzalloc(&pdev->dev, sizeof(*tsc), GFP_KERNEL);
 385         if (!tsc)
 386                 return -ENOMEM;
 387
 388         input_dev = devm_input_allocate_device(&pdev->dev);
 389         if (!input_dev)
 390                 return -ENOMEM;
 391
 392         input_dev->name = "iMX6UL Touchscreen Controller";
 393         input_dev->id.bustype = BUS_HOST;
 394
 395         input_dev->open = imx6ul_tsc_open;
 396         input_dev->close = imx6ul_tsc_close;
 397
 398         input_set_capability(input_dev, EV_KEY, BTN_TOUCH);
 399         input_set_abs_params(input_dev, ABS_X, 0, 0xFFF, 0, 0);
 400         input_set_abs_params(input_dev, ABS_Y, 0, 0xFFF, 0, 0);
 401
 402         input_set_drvdata(input_dev, tsc);
 403
 404         tsc->dev = &pdev->dev;
 405         tsc->input = input_dev;
 406         init_completion(&tsc->completion);
 407
 408         tsc->xnur_gpio = devm_gpiod_get(&pdev->dev, "xnur", GPIOD_IN);
 409         if (IS_ERR(tsc->xnur_gpio)) {
 410                 err = PTR_ERR(tsc->xnur_gpio);
 411                 dev_err(&pdev->dev,
 412                         "failed to request GPIO tsc_X- (xnur): %d\n", err);
 413                 return err;
 414         }
 415
 416         tsc->tsc_regs = devm_platform_ioremap_resource(pdev, 0);
 417         if (IS_ERR(tsc->tsc_regs)) {
 418                 err = PTR_ERR(tsc->tsc_regs);
 419                 dev_err(&pdev->dev, "failed to remap tsc memory: %d\n", err);
 420                 return err;
 421         }
 422
 423         tsc->adc_regs = devm_platform_ioremap_resource(pdev, 1);
 424         if (IS_ERR(tsc->adc_regs)) {
 425                 err = PTR_ERR(tsc->adc_regs);
 426                 dev_err(&pdev->dev, "failed to remap adc memory: %d\n", err);
 427                 return err;
 428         }
 429
 430         tsc->tsc_clk = devm_clk_get(&pdev->dev, "tsc");
 431         if (IS_ERR(tsc->tsc_clk)) {
 432                 err = PTR_ERR(tsc->tsc_clk);
 433                 dev_err(&pdev->dev, "failed getting tsc clock: %d\n", err);
 434                 return err;
 435         }
 436
 437         tsc->adc_clk = devm_clk_get(&pdev->dev, "adc");
 438         if (IS_ERR(tsc->adc_clk)) {
 439                 err = PTR_ERR(tsc->adc_clk);
 440                 dev_err(&pdev->dev, "failed getting adc clock: %d\n", err);
 441                 return err;
 442         }
 443
 444         tsc_irq = platform_get_irq(pdev, 0);
 445         if (tsc_irq < 0)
 446                 return tsc_irq;
 447
 448         adc_irq = platform_get_irq(pdev, 1);
 449         if (adc_irq < 0)
 450                 return adc_irq;
 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_stop(tsc);
 526
 527         mutex_unlock(&input_dev->mutex);
 528
 529         return 0;
 530 }
 531
 532 static int __maybe_unused imx6ul_tsc_resume(struct device *dev)
 533 {
 534         struct platform_device *pdev = to_platform_device(dev);
 535         struct imx6ul_tsc *tsc = platform_get_drvdata(pdev);
 536         struct input_dev *input_dev = tsc->input;
 537         int retval = 0;
 538
 539         mutex_lock(&input_dev->mutex);
 540
 541         if (input_dev->users)
 542                 retval = imx6ul_tsc_start(tsc);
 543
 544         mutex_unlock(&input_dev->mutex);
 545
 546         return retval;
 547 }
 548
 549 static SIMPLE_DEV_PM_OPS(imx6ul_tsc_pm_ops,
 550                          imx6ul_tsc_suspend, imx6ul_tsc_resume);
 551
 552 static const struct of_device_id imx6ul_tsc_match[] = {
 553         { .compatible = "fsl,imx6ul-tsc", },
 554         { /* sentinel */ }
 555 };
 556 MODULE_DEVICE_TABLE(of, imx6ul_tsc_match);
 557
 558 static struct platform_driver imx6ul_tsc_driver = {
 559         .driver         = {
 560                 .name   = "imx6ul-tsc",
 561                 .of_match_table = imx6ul_tsc_match,
 562                 .pm     = &imx6ul_tsc_pm_ops,
 563         },
 564         .probe          = imx6ul_tsc_probe,
 565 };
 566 module_platform_driver(imx6ul_tsc_driver);
 567
 568 MODULE_AUTHOR("Haibo Chen <haibo.chen@freescale.com>");
 569 MODULE_DESCRIPTION("Freescale i.MX6UL Touchscreen controller driver");
 570 MODULE_LICENSE("GPL v2");