linux/drivers/thermal/imx_thermal.c
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   1/*
   2 * Copyright 2013 Freescale Semiconductor, Inc.
   3 *
   4 * This program is free software; you can redistribute it and/or modify
   5 * it under the terms of the GNU General Public License version 2 as
   6 * published by the Free Software Foundation.
   7 *
   8 */
   9
  10#include <linux/clk.h>
  11#include <linux/cpu_cooling.h>
  12#include <linux/cpufreq.h>
  13#include <linux/delay.h>
  14#include <linux/device.h>
  15#include <linux/init.h>
  16#include <linux/interrupt.h>
  17#include <linux/io.h>
  18#include <linux/kernel.h>
  19#include <linux/mfd/syscon.h>
  20#include <linux/module.h>
  21#include <linux/of.h>
  22#include <linux/platform_device.h>
  23#include <linux/regmap.h>
  24#include <linux/slab.h>
  25#include <linux/thermal.h>
  26#include <linux/types.h>
  27
  28#define REG_SET         0x4
  29#define REG_CLR         0x8
  30#define REG_TOG         0xc
  31
  32#define MISC0                           0x0150
  33#define MISC0_REFTOP_SELBIASOFF         (1 << 3)
  34
  35#define TEMPSENSE0                      0x0180
  36#define TEMPSENSE0_ALARM_VALUE_SHIFT    20
  37#define TEMPSENSE0_ALARM_VALUE_MASK     (0xfff << TEMPSENSE0_ALARM_VALUE_SHIFT)
  38#define TEMPSENSE0_TEMP_CNT_SHIFT       8
  39#define TEMPSENSE0_TEMP_CNT_MASK        (0xfff << TEMPSENSE0_TEMP_CNT_SHIFT)
  40#define TEMPSENSE0_FINISHED             (1 << 2)
  41#define TEMPSENSE0_MEASURE_TEMP         (1 << 1)
  42#define TEMPSENSE0_POWER_DOWN           (1 << 0)
  43
  44#define TEMPSENSE1                      0x0190
  45#define TEMPSENSE1_MEASURE_FREQ         0xffff
  46
  47#define OCOTP_ANA1                      0x04e0
  48
  49/* The driver supports 1 passive trip point and 1 critical trip point */
  50enum imx_thermal_trip {
  51        IMX_TRIP_PASSIVE,
  52        IMX_TRIP_CRITICAL,
  53        IMX_TRIP_NUM,
  54};
  55
  56/*
  57 * It defines the temperature in millicelsius for passive trip point
  58 * that will trigger cooling action when crossed.
  59 */
  60#define IMX_TEMP_PASSIVE                85000
  61
  62#define IMX_POLLING_DELAY               2000 /* millisecond */
  63#define IMX_PASSIVE_DELAY               1000
  64
  65#define FACTOR0                         10000000
  66#define FACTOR1                         15976
  67#define FACTOR2                         4297157
  68
  69struct imx_thermal_data {
  70        struct thermal_zone_device *tz;
  71        struct thermal_cooling_device *cdev;
  72        enum thermal_device_mode mode;
  73        struct regmap *tempmon;
  74        u32 c1, c2; /* See formula in imx_get_sensor_data() */
  75        unsigned long temp_passive;
  76        unsigned long temp_critical;
  77        unsigned long alarm_temp;
  78        unsigned long last_temp;
  79        bool irq_enabled;
  80        int irq;
  81        struct clk *thermal_clk;
  82};
  83
  84static void imx_set_alarm_temp(struct imx_thermal_data *data,
  85                               signed long alarm_temp)
  86{
  87        struct regmap *map = data->tempmon;
  88        int alarm_value;
  89
  90        data->alarm_temp = alarm_temp;
  91        alarm_value = (data->c2 - alarm_temp) / data->c1;
  92        regmap_write(map, TEMPSENSE0 + REG_CLR, TEMPSENSE0_ALARM_VALUE_MASK);
  93        regmap_write(map, TEMPSENSE0 + REG_SET, alarm_value <<
  94                        TEMPSENSE0_ALARM_VALUE_SHIFT);
  95}
  96
  97static int imx_get_temp(struct thermal_zone_device *tz, unsigned long *temp)
  98{
  99        struct imx_thermal_data *data = tz->devdata;
 100        struct regmap *map = data->tempmon;
 101        unsigned int n_meas;
 102        bool wait;
 103        u32 val;
 104
 105        if (data->mode == THERMAL_DEVICE_ENABLED) {
 106                /* Check if a measurement is currently in progress */
 107                regmap_read(map, TEMPSENSE0, &val);
 108                wait = !(val & TEMPSENSE0_FINISHED);
 109        } else {
 110                /*
 111                 * Every time we measure the temperature, we will power on the
 112                 * temperature sensor, enable measurements, take a reading,
 113                 * disable measurements, power off the temperature sensor.
 114                 */
 115                regmap_write(map, TEMPSENSE0 + REG_CLR, TEMPSENSE0_POWER_DOWN);
 116                regmap_write(map, TEMPSENSE0 + REG_SET, TEMPSENSE0_MEASURE_TEMP);
 117
 118                wait = true;
 119        }
 120
 121        /*
 122         * According to the temp sensor designers, it may require up to ~17us
 123         * to complete a measurement.
 124         */
 125        if (wait)
 126                usleep_range(20, 50);
 127
 128        regmap_read(map, TEMPSENSE0, &val);
 129
 130        if (data->mode != THERMAL_DEVICE_ENABLED) {
 131                regmap_write(map, TEMPSENSE0 + REG_CLR, TEMPSENSE0_MEASURE_TEMP);
 132                regmap_write(map, TEMPSENSE0 + REG_SET, TEMPSENSE0_POWER_DOWN);
 133        }
 134
 135        if ((val & TEMPSENSE0_FINISHED) == 0) {
 136                dev_dbg(&tz->device, "temp measurement never finished\n");
 137                return -EAGAIN;
 138        }
 139
 140        n_meas = (val & TEMPSENSE0_TEMP_CNT_MASK) >> TEMPSENSE0_TEMP_CNT_SHIFT;
 141
 142        /* See imx_get_sensor_data() for formula derivation */
 143        *temp = data->c2 - n_meas * data->c1;
 144
 145        /* Update alarm value to next higher trip point */
 146        if (data->alarm_temp == data->temp_passive && *temp >= data->temp_passive)
 147                imx_set_alarm_temp(data, data->temp_critical);
 148        if (data->alarm_temp == data->temp_critical && *temp < data->temp_passive) {
 149                imx_set_alarm_temp(data, data->temp_passive);
 150                dev_dbg(&tz->device, "thermal alarm off: T < %lu\n",
 151                        data->alarm_temp / 1000);
 152        }
 153
 154        if (*temp != data->last_temp) {
 155                dev_dbg(&tz->device, "millicelsius: %ld\n", *temp);
 156                data->last_temp = *temp;
 157        }
 158
 159        /* Reenable alarm IRQ if temperature below alarm temperature */
 160        if (!data->irq_enabled && *temp < data->alarm_temp) {
 161                data->irq_enabled = true;
 162                enable_irq(data->irq);
 163        }
 164
 165        return 0;
 166}
 167
 168static int imx_get_mode(struct thermal_zone_device *tz,
 169                        enum thermal_device_mode *mode)
 170{
 171        struct imx_thermal_data *data = tz->devdata;
 172
 173        *mode = data->mode;
 174
 175        return 0;
 176}
 177
 178static int imx_set_mode(struct thermal_zone_device *tz,
 179                        enum thermal_device_mode mode)
 180{
 181        struct imx_thermal_data *data = tz->devdata;
 182        struct regmap *map = data->tempmon;
 183
 184        if (mode == THERMAL_DEVICE_ENABLED) {
 185                tz->polling_delay = IMX_POLLING_DELAY;
 186                tz->passive_delay = IMX_PASSIVE_DELAY;
 187
 188                regmap_write(map, TEMPSENSE0 + REG_CLR, TEMPSENSE0_POWER_DOWN);
 189                regmap_write(map, TEMPSENSE0 + REG_SET, TEMPSENSE0_MEASURE_TEMP);
 190
 191                if (!data->irq_enabled) {
 192                        data->irq_enabled = true;
 193                        enable_irq(data->irq);
 194                }
 195        } else {
 196                regmap_write(map, TEMPSENSE0 + REG_CLR, TEMPSENSE0_MEASURE_TEMP);
 197                regmap_write(map, TEMPSENSE0 + REG_SET, TEMPSENSE0_POWER_DOWN);
 198
 199                tz->polling_delay = 0;
 200                tz->passive_delay = 0;
 201
 202                if (data->irq_enabled) {
 203                        disable_irq(data->irq);
 204                        data->irq_enabled = false;
 205                }
 206        }
 207
 208        data->mode = mode;
 209        thermal_zone_device_update(tz);
 210
 211        return 0;
 212}
 213
 214static int imx_get_trip_type(struct thermal_zone_device *tz, int trip,
 215                             enum thermal_trip_type *type)
 216{
 217        *type = (trip == IMX_TRIP_PASSIVE) ? THERMAL_TRIP_PASSIVE :
 218                                             THERMAL_TRIP_CRITICAL;
 219        return 0;
 220}
 221
 222static int imx_get_crit_temp(struct thermal_zone_device *tz,
 223                             unsigned long *temp)
 224{
 225        struct imx_thermal_data *data = tz->devdata;
 226
 227        *temp = data->temp_critical;
 228        return 0;
 229}
 230
 231static int imx_get_trip_temp(struct thermal_zone_device *tz, int trip,
 232                             unsigned long *temp)
 233{
 234        struct imx_thermal_data *data = tz->devdata;
 235
 236        *temp = (trip == IMX_TRIP_PASSIVE) ? data->temp_passive :
 237                                             data->temp_critical;
 238        return 0;
 239}
 240
 241static int imx_set_trip_temp(struct thermal_zone_device *tz, int trip,
 242                             unsigned long temp)
 243{
 244        struct imx_thermal_data *data = tz->devdata;
 245
 246        if (trip == IMX_TRIP_CRITICAL)
 247                return -EPERM;
 248
 249        if (temp > IMX_TEMP_PASSIVE)
 250                return -EINVAL;
 251
 252        data->temp_passive = temp;
 253
 254        imx_set_alarm_temp(data, temp);
 255
 256        return 0;
 257}
 258
 259static int imx_bind(struct thermal_zone_device *tz,
 260                    struct thermal_cooling_device *cdev)
 261{
 262        int ret;
 263
 264        ret = thermal_zone_bind_cooling_device(tz, IMX_TRIP_PASSIVE, cdev,
 265                                               THERMAL_NO_LIMIT,
 266                                               THERMAL_NO_LIMIT);
 267        if (ret) {
 268                dev_err(&tz->device,
 269                        "binding zone %s with cdev %s failed:%d\n",
 270                        tz->type, cdev->type, ret);
 271                return ret;
 272        }
 273
 274        return 0;
 275}
 276
 277static int imx_unbind(struct thermal_zone_device *tz,
 278                      struct thermal_cooling_device *cdev)
 279{
 280        int ret;
 281
 282        ret = thermal_zone_unbind_cooling_device(tz, IMX_TRIP_PASSIVE, cdev);
 283        if (ret) {
 284                dev_err(&tz->device,
 285                        "unbinding zone %s with cdev %s failed:%d\n",
 286                        tz->type, cdev->type, ret);
 287                return ret;
 288        }
 289
 290        return 0;
 291}
 292
 293static struct thermal_zone_device_ops imx_tz_ops = {
 294        .bind = imx_bind,
 295        .unbind = imx_unbind,
 296        .get_temp = imx_get_temp,
 297        .get_mode = imx_get_mode,
 298        .set_mode = imx_set_mode,
 299        .get_trip_type = imx_get_trip_type,
 300        .get_trip_temp = imx_get_trip_temp,
 301        .get_crit_temp = imx_get_crit_temp,
 302        .set_trip_temp = imx_set_trip_temp,
 303};
 304
 305static int imx_get_sensor_data(struct platform_device *pdev)
 306{
 307        struct imx_thermal_data *data = platform_get_drvdata(pdev);
 308        struct regmap *map;
 309        int t1, n1;
 310        int ret;
 311        u32 val;
 312        u64 temp64;
 313
 314        map = syscon_regmap_lookup_by_phandle(pdev->dev.of_node,
 315                                              "fsl,tempmon-data");
 316        if (IS_ERR(map)) {
 317                ret = PTR_ERR(map);
 318                dev_err(&pdev->dev, "failed to get sensor regmap: %d\n", ret);
 319                return ret;
 320        }
 321
 322        ret = regmap_read(map, OCOTP_ANA1, &val);
 323        if (ret) {
 324                dev_err(&pdev->dev, "failed to read sensor data: %d\n", ret);
 325                return ret;
 326        }
 327
 328        if (val == 0 || val == ~0) {
 329                dev_err(&pdev->dev, "invalid sensor calibration data\n");
 330                return -EINVAL;
 331        }
 332
 333        /*
 334         * Sensor data layout:
 335         *   [31:20] - sensor value @ 25C
 336         * Use universal formula now and only need sensor value @ 25C
 337         * slope = 0.4297157 - (0.0015976 * 25C fuse)
 338         */
 339        n1 = val >> 20;
 340        t1 = 25; /* t1 always 25C */
 341
 342        /*
 343         * Derived from linear interpolation:
 344         * slope = 0.4297157 - (0.0015976 * 25C fuse)
 345         * slope = (FACTOR2 - FACTOR1 * n1) / FACTOR0
 346         * (Nmeas - n1) / (Tmeas - t1) = slope
 347         * We want to reduce this down to the minimum computation necessary
 348         * for each temperature read.  Also, we want Tmeas in millicelsius
 349         * and we don't want to lose precision from integer division. So...
 350         * Tmeas = (Nmeas - n1) / slope + t1
 351         * milli_Tmeas = 1000 * (Nmeas - n1) / slope + 1000 * t1
 352         * milli_Tmeas = -1000 * (n1 - Nmeas) / slope + 1000 * t1
 353         * Let constant c1 = (-1000 / slope)
 354         * milli_Tmeas = (n1 - Nmeas) * c1 + 1000 * t1
 355         * Let constant c2 = n1 *c1 + 1000 * t1
 356         * milli_Tmeas = c2 - Nmeas * c1
 357         */
 358        temp64 = FACTOR0;
 359        temp64 *= 1000;
 360        do_div(temp64, FACTOR1 * n1 - FACTOR2);
 361        data->c1 = temp64;
 362        data->c2 = n1 * data->c1 + 1000 * t1;
 363
 364        /*
 365         * Set the default passive cooling trip point,
 366         * can be changed from userspace.
 367         */
 368        data->temp_passive = IMX_TEMP_PASSIVE;
 369
 370        /*
 371         * The maximum die temperature set to 20 C higher than
 372         * IMX_TEMP_PASSIVE.
 373         */
 374        data->temp_critical = 1000 * 20 + data->temp_passive;
 375
 376        return 0;
 377}
 378
 379static irqreturn_t imx_thermal_alarm_irq(int irq, void *dev)
 380{
 381        struct imx_thermal_data *data = dev;
 382
 383        disable_irq_nosync(irq);
 384        data->irq_enabled = false;
 385
 386        return IRQ_WAKE_THREAD;
 387}
 388
 389static irqreturn_t imx_thermal_alarm_irq_thread(int irq, void *dev)
 390{
 391        struct imx_thermal_data *data = dev;
 392
 393        dev_dbg(&data->tz->device, "THERMAL ALARM: T > %lu\n",
 394                data->alarm_temp / 1000);
 395
 396        thermal_zone_device_update(data->tz);
 397
 398        return IRQ_HANDLED;
 399}
 400
 401static int imx_thermal_probe(struct platform_device *pdev)
 402{
 403        struct imx_thermal_data *data;
 404        struct cpumask clip_cpus;
 405        struct regmap *map;
 406        int measure_freq;
 407        int ret;
 408
 409        data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
 410        if (!data)
 411                return -ENOMEM;
 412
 413        map = syscon_regmap_lookup_by_phandle(pdev->dev.of_node, "fsl,tempmon");
 414        if (IS_ERR(map)) {
 415                ret = PTR_ERR(map);
 416                dev_err(&pdev->dev, "failed to get tempmon regmap: %d\n", ret);
 417                return ret;
 418        }
 419        data->tempmon = map;
 420
 421        data->irq = platform_get_irq(pdev, 0);
 422        if (data->irq < 0)
 423                return data->irq;
 424
 425        ret = devm_request_threaded_irq(&pdev->dev, data->irq,
 426                        imx_thermal_alarm_irq, imx_thermal_alarm_irq_thread,
 427                        0, "imx_thermal", data);
 428        if (ret < 0) {
 429                dev_err(&pdev->dev, "failed to request alarm irq: %d\n", ret);
 430                return ret;
 431        }
 432
 433        platform_set_drvdata(pdev, data);
 434
 435        ret = imx_get_sensor_data(pdev);
 436        if (ret) {
 437                dev_err(&pdev->dev, "failed to get sensor data\n");
 438                return ret;
 439        }
 440
 441        /* Make sure sensor is in known good state for measurements */
 442        regmap_write(map, TEMPSENSE0 + REG_CLR, TEMPSENSE0_POWER_DOWN);
 443        regmap_write(map, TEMPSENSE0 + REG_CLR, TEMPSENSE0_MEASURE_TEMP);
 444        regmap_write(map, TEMPSENSE1 + REG_CLR, TEMPSENSE1_MEASURE_FREQ);
 445        regmap_write(map, MISC0 + REG_SET, MISC0_REFTOP_SELBIASOFF);
 446        regmap_write(map, TEMPSENSE0 + REG_SET, TEMPSENSE0_POWER_DOWN);
 447
 448        cpumask_set_cpu(0, &clip_cpus);
 449        data->cdev = cpufreq_cooling_register(&clip_cpus);
 450        if (IS_ERR(data->cdev)) {
 451                ret = PTR_ERR(data->cdev);
 452                dev_err(&pdev->dev,
 453                        "failed to register cpufreq cooling device: %d\n", ret);
 454                return ret;
 455        }
 456
 457        data->tz = thermal_zone_device_register("imx_thermal_zone",
 458                                                IMX_TRIP_NUM,
 459                                                BIT(IMX_TRIP_PASSIVE), data,
 460                                                &imx_tz_ops, NULL,
 461                                                IMX_PASSIVE_DELAY,
 462                                                IMX_POLLING_DELAY);
 463        if (IS_ERR(data->tz)) {
 464                ret = PTR_ERR(data->tz);
 465                dev_err(&pdev->dev,
 466                        "failed to register thermal zone device %d\n", ret);
 467                cpufreq_cooling_unregister(data->cdev);
 468                return ret;
 469        }
 470
 471        data->thermal_clk = devm_clk_get(&pdev->dev, NULL);
 472        if (IS_ERR(data->thermal_clk)) {
 473                dev_warn(&pdev->dev, "failed to get thermal clk!\n");
 474        } else {
 475                /*
 476                 * Thermal sensor needs clk on to get correct value, normally
 477                 * we should enable its clk before taking measurement and disable
 478                 * clk after measurement is done, but if alarm function is enabled,
 479                 * hardware will auto measure the temperature periodically, so we
 480                 * need to keep the clk always on for alarm function.
 481                 */
 482                ret = clk_prepare_enable(data->thermal_clk);
 483                if (ret)
 484                        dev_warn(&pdev->dev, "failed to enable thermal clk: %d\n", ret);
 485        }
 486
 487        /* Enable measurements at ~ 10 Hz */
 488        regmap_write(map, TEMPSENSE1 + REG_CLR, TEMPSENSE1_MEASURE_FREQ);
 489        measure_freq = DIV_ROUND_UP(32768, 10); /* 10 Hz */
 490        regmap_write(map, TEMPSENSE1 + REG_SET, measure_freq);
 491        imx_set_alarm_temp(data, data->temp_passive);
 492        regmap_write(map, TEMPSENSE0 + REG_CLR, TEMPSENSE0_POWER_DOWN);
 493        regmap_write(map, TEMPSENSE0 + REG_SET, TEMPSENSE0_MEASURE_TEMP);
 494
 495        data->irq_enabled = true;
 496        data->mode = THERMAL_DEVICE_ENABLED;
 497
 498        return 0;
 499}
 500
 501static int imx_thermal_remove(struct platform_device *pdev)
 502{
 503        struct imx_thermal_data *data = platform_get_drvdata(pdev);
 504        struct regmap *map = data->tempmon;
 505
 506        /* Disable measurements */
 507        regmap_write(map, TEMPSENSE0 + REG_SET, TEMPSENSE0_POWER_DOWN);
 508        if (!IS_ERR(data->thermal_clk))
 509                clk_disable_unprepare(data->thermal_clk);
 510
 511        thermal_zone_device_unregister(data->tz);
 512        cpufreq_cooling_unregister(data->cdev);
 513
 514        return 0;
 515}
 516
 517#ifdef CONFIG_PM_SLEEP
 518static int imx_thermal_suspend(struct device *dev)
 519{
 520        struct imx_thermal_data *data = dev_get_drvdata(dev);
 521        struct regmap *map = data->tempmon;
 522
 523        /*
 524         * Need to disable thermal sensor, otherwise, when thermal core
 525         * try to get temperature before thermal sensor resume, a wrong
 526         * temperature will be read as the thermal sensor is powered
 527         * down.
 528         */
 529        regmap_write(map, TEMPSENSE0 + REG_CLR, TEMPSENSE0_MEASURE_TEMP);
 530        regmap_write(map, TEMPSENSE0 + REG_SET, TEMPSENSE0_POWER_DOWN);
 531        data->mode = THERMAL_DEVICE_DISABLED;
 532
 533        return 0;
 534}
 535
 536static int imx_thermal_resume(struct device *dev)
 537{
 538        struct imx_thermal_data *data = dev_get_drvdata(dev);
 539        struct regmap *map = data->tempmon;
 540
 541        /* Enabled thermal sensor after resume */
 542        regmap_write(map, TEMPSENSE0 + REG_CLR, TEMPSENSE0_POWER_DOWN);
 543        regmap_write(map, TEMPSENSE0 + REG_SET, TEMPSENSE0_MEASURE_TEMP);
 544        data->mode = THERMAL_DEVICE_ENABLED;
 545
 546        return 0;
 547}
 548#endif
 549
 550static SIMPLE_DEV_PM_OPS(imx_thermal_pm_ops,
 551                         imx_thermal_suspend, imx_thermal_resume);
 552
 553static const struct of_device_id of_imx_thermal_match[] = {
 554        { .compatible = "fsl,imx6q-tempmon", },
 555        { /* end */ }
 556};
 557MODULE_DEVICE_TABLE(of, of_imx_thermal_match);
 558
 559static struct platform_driver imx_thermal = {
 560        .driver = {
 561                .name   = "imx_thermal",
 562                .owner  = THIS_MODULE,
 563                .pm     = &imx_thermal_pm_ops,
 564                .of_match_table = of_imx_thermal_match,
 565        },
 566        .probe          = imx_thermal_probe,
 567        .remove         = imx_thermal_remove,
 568};
 569module_platform_driver(imx_thermal);
 570
 571MODULE_AUTHOR("Freescale Semiconductor, Inc.");
 572MODULE_DESCRIPTION("Thermal driver for Freescale i.MX SoCs");
 573MODULE_LICENSE("GPL v2");
 574MODULE_ALIAS("platform:imx-thermal");
 575
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