drivers/thermal/st/stm_thermal.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright (C) STMicroelectronics 2018 - All Rights Reserved
   4  * Author: David Hernandez Sanchez <david.hernandezsanchez@st.com> for
   5  * STMicroelectronics.
   6  */
   7
   8 #include <linux/clk.h>
   9 #include <linux/clk-provider.h>
  10 #include <linux/delay.h>
  11 #include <linux/err.h>
  12 #include <linux/interrupt.h>
  13 #include <linux/io.h>
  14 #include <linux/iopoll.h>
  15 #include <linux/module.h>
  16 #include <linux/of.h>
  17 #include <linux/platform_device.h>
  18 #include <linux/thermal.h>
  19
  20 #include "../thermal_hwmon.h"
  21
  22 /* DTS register offsets */
  23 #define DTS_CFGR1_OFFSET        0x0
  24 #define DTS_T0VALR1_OFFSET      0x8
  25 #define DTS_RAMPVALR_OFFSET     0X10
  26 #define DTS_ITR1_OFFSET         0x14
  27 #define DTS_DR_OFFSET           0x1C
  28 #define DTS_SR_OFFSET           0x20
  29 #define DTS_ITENR_OFFSET        0x24
  30 #define DTS_ICIFR_OFFSET        0x28
  31
  32 /* DTS_CFGR1 register mask definitions */
  33 #define HSREF_CLK_DIV_MASK      GENMASK(30, 24)
  34 #define TS1_SMP_TIME_MASK       GENMASK(19, 16)
  35 #define TS1_INTRIG_SEL_MASK     GENMASK(11, 8)
  36
  37 /* DTS_T0VALR1 register mask definitions */
  38 #define TS1_T0_MASK             GENMASK(17, 16)
  39 #define TS1_FMT0_MASK           GENMASK(15, 0)
  40
  41 /* DTS_RAMPVALR register mask definitions */
  42 #define TS1_RAMP_COEFF_MASK     GENMASK(15, 0)
  43
  44 /* DTS_ITR1 register mask definitions */
  45 #define TS1_HITTHD_MASK         GENMASK(31, 16)
  46 #define TS1_LITTHD_MASK         GENMASK(15, 0)
  47
  48 /* DTS_DR register mask definitions */
  49 #define TS1_MFREQ_MASK          GENMASK(15, 0)
  50
  51 /* DTS_ITENR register mask definitions */
  52 #define ITENR_MASK              (GENMASK(2, 0) | GENMASK(6, 4))
  53
  54 /* DTS_ICIFR register mask definitions */
  55 #define ICIFR_MASK              (GENMASK(2, 0) | GENMASK(6, 4))
  56
  57 /* Less significant bit position definitions */
  58 #define TS1_T0_POS              16
  59 #define TS1_HITTHD_POS          16
  60 #define TS1_LITTHD_POS          0
  61 #define HSREF_CLK_DIV_POS       24
  62
  63 /* DTS_CFGR1 bit definitions */
  64 #define TS1_EN                  BIT(0)
  65 #define TS1_START               BIT(4)
  66 #define REFCLK_SEL              BIT(20)
  67 #define REFCLK_LSE              REFCLK_SEL
  68 #define Q_MEAS_OPT              BIT(21)
  69 #define CALIBRATION_CONTROL     Q_MEAS_OPT
  70
  71 /* DTS_SR bit definitions */
  72 #define TS_RDY                  BIT(15)
  73 /* Bit definitions below are common for DTS_SR, DTS_ITENR and DTS_CIFR */
  74 #define HIGH_THRESHOLD          BIT(2)
  75 #define LOW_THRESHOLD           BIT(1)
  76
  77 /* Constants */
  78 #define ADJUST                  100
  79 #define ONE_MHZ                 1000000
  80 #define POLL_TIMEOUT            5000
  81 #define STARTUP_TIME            40
  82 #define TS1_T0_VAL0             30000  /* 30 celsius */
  83 #define TS1_T0_VAL1             130000 /* 130 celsius */
  84 #define NO_HW_TRIG              0
  85 #define SAMPLING_TIME           15
  86
  87 struct stm_thermal_sensor {
  88         struct device *dev;
  89         struct thermal_zone_device *th_dev;
  90         enum thermal_device_mode mode;
  91         struct clk *clk;
  92         unsigned int low_temp_enabled;
  93         unsigned int high_temp_enabled;
  94         int irq;
  95         void __iomem *base;
  96         int t0, fmt0, ramp_coeff;
  97 };
  98
  99 static int stm_enable_irq(struct stm_thermal_sensor *sensor)
 100 {
 101         u32 value;
 102
 103         dev_dbg(sensor->dev, "low:%d high:%d\n", sensor->low_temp_enabled,
 104                 sensor->high_temp_enabled);
 105
 106         /* Disable IT generation for low and high thresholds */
 107         value = readl_relaxed(sensor->base + DTS_ITENR_OFFSET);
 108         value &= ~(LOW_THRESHOLD | HIGH_THRESHOLD);
 109
 110         if (sensor->low_temp_enabled)
 111                 value |= HIGH_THRESHOLD;
 112
 113         if (sensor->high_temp_enabled)
 114                 value |= LOW_THRESHOLD;
 115
 116         /* Enable interrupts */
 117         writel_relaxed(value, sensor->base + DTS_ITENR_OFFSET);
 118
 119         return 0;
 120 }
 121
 122 static irqreturn_t stm_thermal_irq_handler(int irq, void *sdata)
 123 {
 124         struct stm_thermal_sensor *sensor = sdata;
 125
 126         dev_dbg(sensor->dev, "sr:%d\n",
 127                 readl_relaxed(sensor->base + DTS_SR_OFFSET));
 128
 129         thermal_zone_device_update(sensor->th_dev, THERMAL_EVENT_UNSPECIFIED);
 130
 131         stm_enable_irq(sensor);
 132
 133         /* Acknoledge all DTS irqs */
 134         writel_relaxed(ICIFR_MASK, sensor->base + DTS_ICIFR_OFFSET);
 135
 136         return IRQ_HANDLED;
 137 }
 138
 139 static int stm_sensor_power_on(struct stm_thermal_sensor *sensor)
 140 {
 141         int ret;
 142         u32 value;
 143
 144         /* Enable sensor */
 145         value = readl_relaxed(sensor->base + DTS_CFGR1_OFFSET);
 146         value |= TS1_EN;
 147         writel_relaxed(value, sensor->base + DTS_CFGR1_OFFSET);
 148
 149         /*
 150          * The DTS block can be enabled by setting TSx_EN bit in
 151          * DTS_CFGRx register. It requires a startup time of
 152          * 40μs. Use 5 ms as arbitrary timeout.
 153          */
 154         ret = readl_poll_timeout(sensor->base + DTS_SR_OFFSET,
 155                                  value, (value & TS_RDY),
 156                                  STARTUP_TIME, POLL_TIMEOUT);
 157         if (ret)
 158                 return ret;
 159
 160         /* Start continuous measuring */
 161         value = readl_relaxed(sensor->base +
 162                               DTS_CFGR1_OFFSET);
 163         value |= TS1_START;
 164         writel_relaxed(value, sensor->base +
 165                        DTS_CFGR1_OFFSET);
 166
 167         sensor->mode = THERMAL_DEVICE_ENABLED;
 168
 169         return 0;
 170 }
 171
 172 static int stm_sensor_power_off(struct stm_thermal_sensor *sensor)
 173 {
 174         u32 value;
 175
 176         sensor->mode = THERMAL_DEVICE_DISABLED;
 177
 178         /* Stop measuring */
 179         value = readl_relaxed(sensor->base + DTS_CFGR1_OFFSET);
 180         value &= ~TS1_START;
 181         writel_relaxed(value, sensor->base + DTS_CFGR1_OFFSET);
 182
 183         /* Ensure stop is taken into account */
 184         usleep_range(STARTUP_TIME, POLL_TIMEOUT);
 185
 186         /* Disable sensor */
 187         value = readl_relaxed(sensor->base + DTS_CFGR1_OFFSET);
 188         value &= ~TS1_EN;
 189         writel_relaxed(value, sensor->base + DTS_CFGR1_OFFSET);
 190
 191         /* Ensure disable is taken into account */
 192         return readl_poll_timeout(sensor->base + DTS_SR_OFFSET, value,
 193                                   !(value & TS_RDY),
 194                                   STARTUP_TIME, POLL_TIMEOUT);
 195 }
 196
 197 static int stm_thermal_calibration(struct stm_thermal_sensor *sensor)
 198 {
 199         u32 value, clk_freq;
 200         u32 prescaler;
 201
 202         /* Figure out prescaler value for PCLK during calibration */
 203         clk_freq = clk_get_rate(sensor->clk);
 204         if (!clk_freq)
 205                 return -EINVAL;
 206
 207         prescaler = 0;
 208         clk_freq /= ONE_MHZ;
 209         if (clk_freq) {
 210                 while (prescaler <= clk_freq)
 211                         prescaler++;
 212         }
 213
 214         value = readl_relaxed(sensor->base + DTS_CFGR1_OFFSET);
 215
 216         /* Clear prescaler */
 217         value &= ~HSREF_CLK_DIV_MASK;
 218
 219         /* Set prescaler. pclk_freq/prescaler < 1MHz */
 220         value |= (prescaler << HSREF_CLK_DIV_POS);
 221
 222         /* Select PCLK as reference clock */
 223         value &= ~REFCLK_SEL;
 224
 225         /* Set maximal sampling time for better precision */
 226         value |= TS1_SMP_TIME_MASK;
 227
 228         /* Measure with calibration */
 229         value &= ~CALIBRATION_CONTROL;
 230
 231         /* select trigger */
 232         value &= ~TS1_INTRIG_SEL_MASK;
 233         value |= NO_HW_TRIG;
 234
 235         writel_relaxed(value, sensor->base + DTS_CFGR1_OFFSET);
 236
 237         return 0;
 238 }
 239
 240 /* Fill in DTS structure with factory sensor values */
 241 static int stm_thermal_read_factory_settings(struct stm_thermal_sensor *sensor)
 242 {
 243         /* Retrieve engineering calibration temperature */
 244         sensor->t0 = readl_relaxed(sensor->base + DTS_T0VALR1_OFFSET) &
 245                                         TS1_T0_MASK;
 246         if (!sensor->t0)
 247                 sensor->t0 = TS1_T0_VAL0;
 248         else
 249                 sensor->t0 = TS1_T0_VAL1;
 250
 251         /* Retrieve fmt0 and put it on Hz */
 252         sensor->fmt0 = ADJUST * (readl_relaxed(sensor->base +
 253                                  DTS_T0VALR1_OFFSET) & TS1_FMT0_MASK);
 254
 255         /* Retrieve ramp coefficient */
 256         sensor->ramp_coeff = readl_relaxed(sensor->base + DTS_RAMPVALR_OFFSET) &
 257                                            TS1_RAMP_COEFF_MASK;
 258
 259         if (!sensor->fmt0 || !sensor->ramp_coeff) {
 260                 dev_err(sensor->dev, "%s: wrong setting\n", __func__);
 261                 return -EINVAL;
 262         }
 263
 264         dev_dbg(sensor->dev, "%s: T0 = %doC, FMT0 = %dHz, RAMP_COEFF = %dHz/oC",
 265                 __func__, sensor->t0, sensor->fmt0, sensor->ramp_coeff);
 266
 267         return 0;
 268 }
 269
 270 static int stm_thermal_calculate_threshold(struct stm_thermal_sensor *sensor,
 271                                            int temp, u32 *th)
 272 {
 273         int freqM;
 274
 275         /* Figure out the CLK_PTAT frequency for a given temperature */
 276         freqM = ((temp - sensor->t0) * sensor->ramp_coeff) / 1000 +
 277                 sensor->fmt0;
 278
 279         /* Figure out the threshold sample number */
 280         *th = clk_get_rate(sensor->clk) * SAMPLING_TIME / freqM;
 281         if (!*th)
 282                 return -EINVAL;
 283
 284         dev_dbg(sensor->dev, "freqM=%d Hz, threshold=0x%x", freqM, *th);
 285
 286         return 0;
 287 }
 288
 289 /* Disable temperature interrupt */
 290 static int stm_disable_irq(struct stm_thermal_sensor *sensor)
 291 {
 292         u32 value;
 293
 294         /* Disable IT generation */
 295         value = readl_relaxed(sensor->base + DTS_ITENR_OFFSET);
 296         value &= ~ITENR_MASK;
 297         writel_relaxed(value, sensor->base + DTS_ITENR_OFFSET);
 298
 299         return 0;
 300 }
 301
 302 static int stm_thermal_set_trips(struct thermal_zone_device *tz, int low, int high)
 303 {
 304         struct stm_thermal_sensor *sensor = thermal_zone_device_priv(tz);
 305         u32 itr1, th;
 306         int ret;
 307
 308         dev_dbg(sensor->dev, "set trips %d <--> %d\n", low, high);
 309
 310         /* Erase threshold content */
 311         itr1 = readl_relaxed(sensor->base + DTS_ITR1_OFFSET);
 312         itr1 &= ~(TS1_LITTHD_MASK | TS1_HITTHD_MASK);
 313
 314         /*
 315          * Disable low-temp if "low" is too small. As per thermal framework
 316          * API, we use -INT_MAX rather than INT_MIN.
 317          */
 318
 319         if (low > -INT_MAX) {
 320                 sensor->low_temp_enabled = 1;
 321                 /* add 0.5 of hysteresis due to measurement error */
 322                 ret = stm_thermal_calculate_threshold(sensor, low - 500, &th);
 323                 if (ret)
 324                         return ret;
 325
 326                 itr1 |= (TS1_HITTHD_MASK  & (th << TS1_HITTHD_POS));
 327         } else {
 328                 sensor->low_temp_enabled = 0;
 329         }
 330
 331         /* Disable high-temp if "high" is too big. */
 332         if (high < INT_MAX) {
 333                 sensor->high_temp_enabled = 1;
 334                 ret = stm_thermal_calculate_threshold(sensor, high, &th);
 335                 if (ret)
 336                         return ret;
 337
 338                 itr1 |= (TS1_LITTHD_MASK  & (th << TS1_LITTHD_POS));
 339         } else {
 340                 sensor->high_temp_enabled = 0;
 341         }
 342
 343         /* Write new threshod values*/
 344         writel_relaxed(itr1, sensor->base + DTS_ITR1_OFFSET);
 345
 346         return 0;
 347 }
 348
 349 /* Callback to get temperature from HW */
 350 static int stm_thermal_get_temp(struct thermal_zone_device *tz, int *temp)
 351 {
 352         struct stm_thermal_sensor *sensor = thermal_zone_device_priv(tz);
 353         u32 periods;
 354         int freqM, ret;
 355
 356         if (sensor->mode != THERMAL_DEVICE_ENABLED)
 357                 return -EAGAIN;
 358
 359         /* Retrieve the number of periods sampled */
 360         ret = readl_relaxed_poll_timeout(sensor->base + DTS_DR_OFFSET, periods,
 361                                          (periods & TS1_MFREQ_MASK),
 362                                          STARTUP_TIME, POLL_TIMEOUT);
 363         if (ret)
 364                 return ret;
 365
 366         /* Figure out the CLK_PTAT frequency */
 367         freqM = (clk_get_rate(sensor->clk) * SAMPLING_TIME) / periods;
 368         if (!freqM)
 369                 return -EINVAL;
 370
 371         /* Figure out the temperature in mili celsius */
 372         *temp = (freqM - sensor->fmt0) * 1000 / sensor->ramp_coeff + sensor->t0;
 373
 374         return 0;
 375 }
 376
 377 /* Registers DTS irq to be visible by GIC */
 378 static int stm_register_irq(struct stm_thermal_sensor *sensor)
 379 {
 380         struct device *dev = sensor->dev;
 381         struct platform_device *pdev = to_platform_device(dev);
 382         int ret;
 383
 384         sensor->irq = platform_get_irq(pdev, 0);
 385         if (sensor->irq < 0)
 386                 return sensor->irq;
 387
 388         ret = devm_request_threaded_irq(dev, sensor->irq,
 389                                         NULL,
 390                                         stm_thermal_irq_handler,
 391                                         IRQF_ONESHOT,
 392                                         dev->driver->name, sensor);
 393         if (ret) {
 394                 dev_err(dev, "%s: Failed to register IRQ %d\n", __func__,
 395                         sensor->irq);
 396                 return ret;
 397         }
 398
 399         dev_dbg(dev, "%s: thermal IRQ registered", __func__);
 400
 401         return 0;
 402 }
 403
 404 static int stm_thermal_sensor_off(struct stm_thermal_sensor *sensor)
 405 {
 406         int ret;
 407
 408         stm_disable_irq(sensor);
 409
 410         ret = stm_sensor_power_off(sensor);
 411         if (ret)
 412                 return ret;
 413
 414         clk_disable_unprepare(sensor->clk);
 415
 416         return 0;
 417 }
 418
 419 static int stm_thermal_prepare(struct stm_thermal_sensor *sensor)
 420 {
 421         int ret;
 422
 423         ret = clk_prepare_enable(sensor->clk);
 424         if (ret)
 425                 return ret;
 426
 427         ret = stm_thermal_read_factory_settings(sensor);
 428         if (ret)
 429                 goto thermal_unprepare;
 430
 431         ret = stm_thermal_calibration(sensor);
 432         if (ret)
 433                 goto thermal_unprepare;
 434
 435         return 0;
 436
 437 thermal_unprepare:
 438         clk_disable_unprepare(sensor->clk);
 439
 440         return ret;
 441 }
 442
 443 static int stm_thermal_suspend(struct device *dev)
 444 {
 445         struct stm_thermal_sensor *sensor = dev_get_drvdata(dev);
 446
 447         return stm_thermal_sensor_off(sensor);
 448 }
 449
 450 static int stm_thermal_resume(struct device *dev)
 451 {
 452         int ret;
 453         struct stm_thermal_sensor *sensor = dev_get_drvdata(dev);
 454
 455         ret = stm_thermal_prepare(sensor);
 456         if (ret)
 457                 return ret;
 458
 459         ret = stm_sensor_power_on(sensor);
 460         if (ret)
 461                 return ret;
 462
 463         thermal_zone_device_update(sensor->th_dev, THERMAL_EVENT_UNSPECIFIED);
 464         stm_enable_irq(sensor);
 465
 466         return 0;
 467 }
 468
 469 static DEFINE_SIMPLE_DEV_PM_OPS(stm_thermal_pm_ops,
 470                                 stm_thermal_suspend, stm_thermal_resume);
 471
 472 static const struct thermal_zone_device_ops stm_tz_ops = {
 473         .get_temp       = stm_thermal_get_temp,
 474         .set_trips      = stm_thermal_set_trips,
 475 };
 476
 477 static const struct of_device_id stm_thermal_of_match[] = {
 478                 { .compatible = "st,stm32-thermal"},
 479         { /* sentinel */ }
 480 };
 481 MODULE_DEVICE_TABLE(of, stm_thermal_of_match);
 482
 483 static int stm_thermal_probe(struct platform_device *pdev)
 484 {
 485         struct stm_thermal_sensor *sensor;
 486         void __iomem *base;
 487         int ret;
 488
 489         if (!pdev->dev.of_node) {
 490                 dev_err(&pdev->dev, "%s: device tree node not found\n",
 491                         __func__);
 492                 return -EINVAL;
 493         }
 494
 495         sensor = devm_kzalloc(&pdev->dev, sizeof(*sensor), GFP_KERNEL);
 496         if (!sensor)
 497                 return -ENOMEM;
 498
 499         platform_set_drvdata(pdev, sensor);
 500
 501         sensor->dev = &pdev->dev;
 502
 503         base = devm_platform_get_and_ioremap_resource(pdev, 0, NULL);
 504         if (IS_ERR(base))
 505                 return PTR_ERR(base);
 506
 507         /* Populate sensor */
 508         sensor->base = base;
 509
 510         sensor->clk = devm_clk_get(&pdev->dev, "pclk");
 511         if (IS_ERR(sensor->clk)) {
 512                 dev_err(&pdev->dev, "%s: failed to fetch PCLK clock\n",
 513                         __func__);
 514                 return PTR_ERR(sensor->clk);
 515         }
 516
 517         stm_disable_irq(sensor);
 518
 519         /* Clear irq flags */
 520         writel_relaxed(ICIFR_MASK, sensor->base + DTS_ICIFR_OFFSET);
 521
 522         /* Configure and enable HW sensor */
 523         ret = stm_thermal_prepare(sensor);
 524         if (ret) {
 525                 dev_err(&pdev->dev, "Error prepare sensor: %d\n", ret);
 526                 return ret;
 527         }
 528
 529         ret = stm_sensor_power_on(sensor);
 530         if (ret) {
 531                 dev_err(&pdev->dev, "Error power on sensor: %d\n", ret);
 532                 return ret;
 533         }
 534
 535         sensor->th_dev = devm_thermal_of_zone_register(&pdev->dev, 0,
 536                                                        sensor,
 537                                                        &stm_tz_ops);
 538
 539         if (IS_ERR(sensor->th_dev)) {
 540                 dev_err(&pdev->dev, "%s: thermal zone sensor registering KO\n",
 541                         __func__);
 542                 ret = PTR_ERR(sensor->th_dev);
 543                 return ret;
 544         }
 545
 546         /* Register IRQ into GIC */
 547         ret = stm_register_irq(sensor);
 548         if (ret)
 549                 goto err_tz;
 550
 551         stm_enable_irq(sensor);
 552
 553         /*
 554          * Thermal_zone doesn't enable hwmon as default,
 555          * enable it here
 556          */
 557         ret = thermal_add_hwmon_sysfs(sensor->th_dev);
 558         if (ret)
 559                 goto err_tz;
 560
 561         dev_info(&pdev->dev, "%s: Driver initialized successfully\n",
 562                  __func__);
 563
 564         return 0;
 565
 566 err_tz:
 567         return ret;
 568 }
 569
 570 static void stm_thermal_remove(struct platform_device *pdev)
 571 {
 572         struct stm_thermal_sensor *sensor = platform_get_drvdata(pdev);
 573
 574         stm_thermal_sensor_off(sensor);
 575         thermal_remove_hwmon_sysfs(sensor->th_dev);
 576 }
 577
 578 static struct platform_driver stm_thermal_driver = {
 579         .driver = {
 580                 .name   = "stm_thermal",
 581                 .pm     = pm_sleep_ptr(&stm_thermal_pm_ops),
 582                 .of_match_table = stm_thermal_of_match,
 583         },
 584         .probe          = stm_thermal_probe,
 585         .remove         = stm_thermal_remove,
 586 };
 587 module_platform_driver(stm_thermal_driver);
 588
 589 MODULE_DESCRIPTION("STMicroelectronics STM32 Thermal Sensor Driver");
 590 MODULE_AUTHOR("David Hernandez Sanchez <david.hernandezsanchez@st.com>");
 591 MODULE_LICENSE("GPL v2");
 592 MODULE_ALIAS("platform:stm_thermal");