drivers/thermal/rcar_gen3_thermal.c

   1 /*
   2  *  R-Car Gen3 THS thermal sensor driver
   3  *  Based on rcar_thermal.c and work from Hien Dang and Khiem Nguyen.
   4  *
   5  * Copyright (C) 2016 Renesas Electronics Corporation.
   6  * Copyright (C) 2016 Sang Engineering
   7  *
   8  *  This program is free software; you can redistribute it and/or modify
   9  *  it under the terms of the GNU General Public License as published by
  10  *  the Free Software Foundation; version 2 of the License.
  11  *
  12  *  This program is distributed in the hope that it will be useful, but
  13  *  WITHOUT ANY WARRANTY; without even the implied warranty of
  14  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15  *  General Public License for more details.
  16  *
  17  */
  18 #include <linux/delay.h>
  19 #include <linux/err.h>
  20 #include <linux/interrupt.h>
  21 #include <linux/io.h>
  22 #include <linux/module.h>
  23 #include <linux/of_device.h>
  24 #include <linux/platform_device.h>
  25 #include <linux/pm_runtime.h>
  26 #include <linux/spinlock.h>
  27 #include <linux/sys_soc.h>
  28 #include <linux/thermal.h>
  29
  30 #include "thermal_core.h"
  31
  32 /* Register offsets */
  33 #define REG_GEN3_IRQSTR         0x04
  34 #define REG_GEN3_IRQMSK         0x08
  35 #define REG_GEN3_IRQCTL         0x0C
  36 #define REG_GEN3_IRQEN          0x10
  37 #define REG_GEN3_IRQTEMP1       0x14
  38 #define REG_GEN3_IRQTEMP2       0x18
  39 #define REG_GEN3_IRQTEMP3       0x1C
  40 #define REG_GEN3_CTSR           0x20
  41 #define REG_GEN3_THCTR          0x20
  42 #define REG_GEN3_TEMP           0x28
  43 #define REG_GEN3_THCODE1        0x50
  44 #define REG_GEN3_THCODE2        0x54
  45 #define REG_GEN3_THCODE3        0x58
  46
  47 /* IRQ{STR,MSK,EN} bits */
  48 #define IRQ_TEMP1               BIT(0)
  49 #define IRQ_TEMP2               BIT(1)
  50 #define IRQ_TEMP3               BIT(2)
  51 #define IRQ_TEMPD1              BIT(3)
  52 #define IRQ_TEMPD2              BIT(4)
  53 #define IRQ_TEMPD3              BIT(5)
  54
  55 /* CTSR bits */
  56 #define CTSR_PONM       BIT(8)
  57 #define CTSR_AOUT       BIT(7)
  58 #define CTSR_THBGR      BIT(5)
  59 #define CTSR_VMEN       BIT(4)
  60 #define CTSR_VMST       BIT(1)
  61 #define CTSR_THSST      BIT(0)
  62
  63 /* THCTR bits */
  64 #define THCTR_PONM      BIT(6)
  65 #define THCTR_THSST     BIT(0)
  66
  67 #define CTEMP_MASK      0xFFF
  68
  69 #define MCELSIUS(temp)  ((temp) * 1000)
  70 #define GEN3_FUSE_MASK  0xFFF
  71
  72 #define TSC_MAX_NUM     3
  73
  74 /* Structure for thermal temperature calculation */
  75 struct equation_coefs {
  76         int a1;
  77         int b1;
  78         int a2;
  79         int b2;
  80 };
  81
  82 struct rcar_gen3_thermal_tsc {
  83         void __iomem *base;
  84         struct thermal_zone_device *zone;
  85         struct equation_coefs coef;
  86         int low;
  87         int high;
  88 };
  89
  90 struct rcar_gen3_thermal_priv {
  91         struct rcar_gen3_thermal_tsc *tscs[TSC_MAX_NUM];
  92         unsigned int num_tscs;
  93         spinlock_t lock; /* Protect interrupts on and off */
  94         void (*thermal_init)(struct rcar_gen3_thermal_tsc *tsc);
  95 };
  96
  97 static inline u32 rcar_gen3_thermal_read(struct rcar_gen3_thermal_tsc *tsc,
  98                                          u32 reg)
  99 {
 100         return ioread32(tsc->base + reg);
 101 }
 102
 103 static inline void rcar_gen3_thermal_write(struct rcar_gen3_thermal_tsc *tsc,
 104                                            u32 reg, u32 data)
 105 {
 106         iowrite32(data, tsc->base + reg);
 107 }
 108
 109 /*
 110  * Linear approximation for temperature
 111  *
 112  * [reg] = [temp] * a + b => [temp] = ([reg] - b) / a
 113  *
 114  * The constants a and b are calculated using two triplets of int values PTAT
 115  * and THCODE. PTAT and THCODE can either be read from hardware or use hard
 116  * coded values from driver. The formula to calculate a and b are taken from
 117  * BSP and sparsely documented and understood.
 118  *
 119  * Examining the linear formula and the formula used to calculate constants a
 120  * and b while knowing that the span for PTAT and THCODE values are between
 121  * 0x000 and 0xfff the largest integer possible is 0xfff * 0xfff == 0xffe001.
 122  * Integer also needs to be signed so that leaves 7 bits for binary
 123  * fixed point scaling.
 124  */
 125
 126 #define FIXPT_SHIFT 7
 127 #define FIXPT_INT(_x) ((_x) << FIXPT_SHIFT)
 128 #define INT_FIXPT(_x) ((_x) >> FIXPT_SHIFT)
 129 #define FIXPT_DIV(_a, _b) DIV_ROUND_CLOSEST(((_a) << FIXPT_SHIFT), (_b))
 130 #define FIXPT_TO_MCELSIUS(_x) ((_x) * 1000 >> FIXPT_SHIFT)
 131
 132 #define RCAR3_THERMAL_GRAN 500 /* mili Celsius */
 133
 134 /* no idea where these constants come from */
 135 #define TJ_1 96
 136 #define TJ_3 -41
 137
 138 static void rcar_gen3_thermal_calc_coefs(struct equation_coefs *coef,
 139                                          int *ptat, int *thcode)
 140 {
 141         int tj_2;
 142
 143         /* TODO: Find documentation and document constant calculation formula */
 144
 145         /*
 146          * Division is not scaled in BSP and if scaled it might overflow
 147          * the dividend (4095 * 4095 << 14 > INT_MAX) so keep it unscaled
 148          */
 149         tj_2 = (FIXPT_INT((ptat[1] - ptat[2]) * 137)
 150                 / (ptat[0] - ptat[2])) - FIXPT_INT(41);
 151
 152         coef->a1 = FIXPT_DIV(FIXPT_INT(thcode[1] - thcode[2]),
 153                              tj_2 - FIXPT_INT(TJ_3));
 154         coef->b1 = FIXPT_INT(thcode[2]) - coef->a1 * TJ_3;
 155
 156         coef->a2 = FIXPT_DIV(FIXPT_INT(thcode[1] - thcode[0]),
 157                              tj_2 - FIXPT_INT(TJ_1));
 158         coef->b2 = FIXPT_INT(thcode[0]) - coef->a2 * TJ_1;
 159 }
 160
 161 static int rcar_gen3_thermal_round(int temp)
 162 {
 163         int result, round_offs;
 164
 165         round_offs = temp >= 0 ? RCAR3_THERMAL_GRAN / 2 :
 166                 -RCAR3_THERMAL_GRAN / 2;
 167         result = (temp + round_offs) / RCAR3_THERMAL_GRAN;
 168         return result * RCAR3_THERMAL_GRAN;
 169 }
 170
 171 static int rcar_gen3_thermal_get_temp(void *devdata, int *temp)
 172 {
 173         struct rcar_gen3_thermal_tsc *tsc = devdata;
 174         int mcelsius, val1, val2;
 175         u32 reg;
 176
 177         /* Read register and convert to mili Celsius */
 178         reg = rcar_gen3_thermal_read(tsc, REG_GEN3_TEMP) & CTEMP_MASK;
 179
 180         val1 = FIXPT_DIV(FIXPT_INT(reg) - tsc->coef.b1, tsc->coef.a1);
 181         val2 = FIXPT_DIV(FIXPT_INT(reg) - tsc->coef.b2, tsc->coef.a2);
 182         mcelsius = FIXPT_TO_MCELSIUS((val1 + val2) / 2);
 183
 184         /* Make sure we are inside specifications */
 185         if ((mcelsius < MCELSIUS(-40)) || (mcelsius > MCELSIUS(125)))
 186                 return -EIO;
 187
 188         /* Round value to device granularity setting */
 189         *temp = rcar_gen3_thermal_round(mcelsius);
 190
 191         return 0;
 192 }
 193
 194 static int rcar_gen3_thermal_mcelsius_to_temp(struct rcar_gen3_thermal_tsc *tsc,
 195                                               int mcelsius)
 196 {
 197         int celsius, val1, val2;
 198
 199         celsius = DIV_ROUND_CLOSEST(mcelsius, 1000);
 200         val1 = celsius * tsc->coef.a1 + tsc->coef.b1;
 201         val2 = celsius * tsc->coef.a2 + tsc->coef.b2;
 202
 203         return INT_FIXPT((val1 + val2) / 2);
 204 }
 205
 206 static int rcar_gen3_thermal_set_trips(void *devdata, int low, int high)
 207 {
 208         struct rcar_gen3_thermal_tsc *tsc = devdata;
 209
 210         low = clamp_val(low, -40000, 125000);
 211         high = clamp_val(high, -40000, 125000);
 212
 213         rcar_gen3_thermal_write(tsc, REG_GEN3_IRQTEMP1,
 214                                 rcar_gen3_thermal_mcelsius_to_temp(tsc, low));
 215
 216         rcar_gen3_thermal_write(tsc, REG_GEN3_IRQTEMP2,
 217                                 rcar_gen3_thermal_mcelsius_to_temp(tsc, high));
 218
 219         tsc->low = low;
 220         tsc->high = high;
 221
 222         return 0;
 223 }
 224
 225 static const struct thermal_zone_of_device_ops rcar_gen3_tz_of_ops = {
 226         .get_temp       = rcar_gen3_thermal_get_temp,
 227         .set_trips      = rcar_gen3_thermal_set_trips,
 228 };
 229
 230 static void rcar_thermal_irq_set(struct rcar_gen3_thermal_priv *priv, bool on)
 231 {
 232         unsigned int i;
 233         u32 val = on ? IRQ_TEMPD1 | IRQ_TEMP2 : 0;
 234
 235         for (i = 0; i < priv->num_tscs; i++)
 236                 rcar_gen3_thermal_write(priv->tscs[i], REG_GEN3_IRQMSK, val);
 237 }
 238
 239 static irqreturn_t rcar_gen3_thermal_irq(int irq, void *data)
 240 {
 241         struct rcar_gen3_thermal_priv *priv = data;
 242         u32 status;
 243         int i, ret = IRQ_HANDLED;
 244
 245         spin_lock(&priv->lock);
 246         for (i = 0; i < priv->num_tscs; i++) {
 247                 status = rcar_gen3_thermal_read(priv->tscs[i], REG_GEN3_IRQSTR);
 248                 rcar_gen3_thermal_write(priv->tscs[i], REG_GEN3_IRQSTR, 0);
 249                 if (status)
 250                         ret = IRQ_WAKE_THREAD;
 251         }
 252
 253         if (ret == IRQ_WAKE_THREAD)
 254                 rcar_thermal_irq_set(priv, false);
 255
 256         spin_unlock(&priv->lock);
 257
 258         return ret;
 259 }
 260
 261 static irqreturn_t rcar_gen3_thermal_irq_thread(int irq, void *data)
 262 {
 263         struct rcar_gen3_thermal_priv *priv = data;
 264         unsigned long flags;
 265         int i;
 266
 267         for (i = 0; i < priv->num_tscs; i++)
 268                 thermal_zone_device_update(priv->tscs[i]->zone,
 269                                            THERMAL_EVENT_UNSPECIFIED);
 270
 271         spin_lock_irqsave(&priv->lock, flags);
 272         rcar_thermal_irq_set(priv, true);
 273         spin_unlock_irqrestore(&priv->lock, flags);
 274
 275         return IRQ_HANDLED;
 276 }
 277
 278 static const struct soc_device_attribute r8a7795es1[] = {
 279         { .soc_id = "r8a7795", .revision = "ES1.*" },
 280         { /* sentinel */ }
 281 };
 282
 283 static void rcar_gen3_thermal_init_r8a7795es1(struct rcar_gen3_thermal_tsc *tsc)
 284 {
 285         rcar_gen3_thermal_write(tsc, REG_GEN3_CTSR,  CTSR_THBGR);
 286         rcar_gen3_thermal_write(tsc, REG_GEN3_CTSR,  0x0);
 287
 288         usleep_range(1000, 2000);
 289
 290         rcar_gen3_thermal_write(tsc, REG_GEN3_CTSR, CTSR_PONM);
 291
 292         rcar_gen3_thermal_write(tsc, REG_GEN3_IRQCTL, 0x3F);
 293         rcar_gen3_thermal_write(tsc, REG_GEN3_IRQMSK, 0);
 294         rcar_gen3_thermal_write(tsc, REG_GEN3_IRQEN, IRQ_TEMPD1 | IRQ_TEMP2);
 295
 296         rcar_gen3_thermal_write(tsc, REG_GEN3_CTSR,
 297                                 CTSR_PONM | CTSR_AOUT | CTSR_THBGR | CTSR_VMEN);
 298
 299         usleep_range(100, 200);
 300
 301         rcar_gen3_thermal_write(tsc, REG_GEN3_CTSR,
 302                                 CTSR_PONM | CTSR_AOUT | CTSR_THBGR | CTSR_VMEN |
 303                                 CTSR_VMST | CTSR_THSST);
 304
 305         usleep_range(1000, 2000);
 306 }
 307
 308 static void rcar_gen3_thermal_init(struct rcar_gen3_thermal_tsc *tsc)
 309 {
 310         u32 reg_val;
 311
 312         reg_val = rcar_gen3_thermal_read(tsc, REG_GEN3_THCTR);
 313         reg_val &= ~THCTR_PONM;
 314         rcar_gen3_thermal_write(tsc, REG_GEN3_THCTR, reg_val);
 315
 316         usleep_range(1000, 2000);
 317
 318         rcar_gen3_thermal_write(tsc, REG_GEN3_IRQCTL, 0x3F);
 319         rcar_gen3_thermal_write(tsc, REG_GEN3_IRQMSK, 0);
 320         rcar_gen3_thermal_write(tsc, REG_GEN3_IRQEN, IRQ_TEMPD1 | IRQ_TEMP2);
 321
 322         reg_val = rcar_gen3_thermal_read(tsc, REG_GEN3_THCTR);
 323         reg_val |= THCTR_THSST;
 324         rcar_gen3_thermal_write(tsc, REG_GEN3_THCTR, reg_val);
 325
 326         usleep_range(1000, 2000);
 327 }
 328
 329 static const struct of_device_id rcar_gen3_thermal_dt_ids[] = {
 330         { .compatible = "renesas,r8a7795-thermal", },
 331         { .compatible = "renesas,r8a7796-thermal", },
 332         {},
 333 };
 334 MODULE_DEVICE_TABLE(of, rcar_gen3_thermal_dt_ids);
 335
 336 static int rcar_gen3_thermal_remove(struct platform_device *pdev)
 337 {
 338         struct device *dev = &pdev->dev;
 339
 340         pm_runtime_put(dev);
 341         pm_runtime_disable(dev);
 342
 343         return 0;
 344 }
 345
 346 static int rcar_gen3_thermal_probe(struct platform_device *pdev)
 347 {
 348         struct rcar_gen3_thermal_priv *priv;
 349         struct device *dev = &pdev->dev;
 350         struct resource *res;
 351         struct thermal_zone_device *zone;
 352         int ret, irq, i;
 353         char *irqname;
 354
 355         /* default values if FUSEs are missing */
 356         /* TODO: Read values from hardware on supported platforms */
 357         int ptat[3] = { 2351, 1509, 435 };
 358         int thcode[TSC_MAX_NUM][3] = {
 359                 { 3248, 2800, 2221 },
 360                 { 3245, 2795, 2216 },
 361                 { 3250, 2805, 2237 },
 362         };
 363
 364         priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
 365         if (!priv)
 366                 return -ENOMEM;
 367
 368         priv->thermal_init = rcar_gen3_thermal_init;
 369         if (soc_device_match(r8a7795es1))
 370                 priv->thermal_init = rcar_gen3_thermal_init_r8a7795es1;
 371
 372         spin_lock_init(&priv->lock);
 373
 374         platform_set_drvdata(pdev, priv);
 375
 376         /*
 377          * Request 2 (of the 3 possible) IRQs, the driver only needs to
 378          * to trigger on the low and high trip points of the current
 379          * temp window at this point.
 380          */
 381         for (i = 0; i < 2; i++) {
 382                 irq = platform_get_irq(pdev, i);
 383                 if (irq < 0)
 384                         return irq;
 385
 386                 irqname = devm_kasprintf(dev, GFP_KERNEL, "%s:ch%d",
 387                                          dev_name(dev), i);
 388                 if (!irqname)
 389                         return -ENOMEM;
 390
 391                 ret = devm_request_threaded_irq(dev, irq, rcar_gen3_thermal_irq,
 392                                                 rcar_gen3_thermal_irq_thread,
 393                                                 IRQF_SHARED, irqname, priv);
 394                 if (ret)
 395                         return ret;
 396         }
 397
 398         pm_runtime_enable(dev);
 399         pm_runtime_get_sync(dev);
 400
 401         for (i = 0; i < TSC_MAX_NUM; i++) {
 402                 struct rcar_gen3_thermal_tsc *tsc;
 403
 404                 res = platform_get_resource(pdev, IORESOURCE_MEM, i);
 405                 if (!res)
 406                         break;
 407
 408                 tsc = devm_kzalloc(dev, sizeof(*tsc), GFP_KERNEL);
 409                 if (!tsc) {
 410                         ret = -ENOMEM;
 411                         goto error_unregister;
 412                 }
 413
 414                 tsc->base = devm_ioremap_resource(dev, res);
 415                 if (IS_ERR(tsc->base)) {
 416                         ret = PTR_ERR(tsc->base);
 417                         goto error_unregister;
 418                 }
 419
 420                 priv->tscs[i] = tsc;
 421
 422                 priv->thermal_init(tsc);
 423                 rcar_gen3_thermal_calc_coefs(&tsc->coef, ptat, thcode[i]);
 424
 425                 zone = devm_thermal_zone_of_sensor_register(dev, i, tsc,
 426                                                             &rcar_gen3_tz_of_ops);
 427                 if (IS_ERR(zone)) {
 428                         dev_err(dev, "Can't register thermal zone\n");
 429                         ret = PTR_ERR(zone);
 430                         goto error_unregister;
 431                 }
 432                 tsc->zone = zone;
 433
 434                 ret = of_thermal_get_ntrips(tsc->zone);
 435                 if (ret < 0)
 436                         goto error_unregister;
 437
 438                 dev_info(dev, "TSC%d: Loaded %d trip points\n", i, ret);
 439         }
 440
 441         priv->num_tscs = i;
 442
 443         if (!priv->num_tscs) {
 444                 ret = -ENODEV;
 445                 goto error_unregister;
 446         }
 447
 448         rcar_thermal_irq_set(priv, true);
 449
 450         return 0;
 451
 452 error_unregister:
 453         rcar_gen3_thermal_remove(pdev);
 454
 455         return ret;
 456 }
 457
 458 static int __maybe_unused rcar_gen3_thermal_suspend(struct device *dev)
 459 {
 460         struct rcar_gen3_thermal_priv *priv = dev_get_drvdata(dev);
 461
 462         rcar_thermal_irq_set(priv, false);
 463
 464         return 0;
 465 }
 466
 467 static int __maybe_unused rcar_gen3_thermal_resume(struct device *dev)
 468 {
 469         struct rcar_gen3_thermal_priv *priv = dev_get_drvdata(dev);
 470         unsigned int i;
 471
 472         for (i = 0; i < priv->num_tscs; i++) {
 473                 struct rcar_gen3_thermal_tsc *tsc = priv->tscs[i];
 474
 475                 priv->thermal_init(tsc);
 476                 rcar_gen3_thermal_set_trips(tsc, tsc->low, tsc->high);
 477         }
 478
 479         rcar_thermal_irq_set(priv, true);
 480
 481         return 0;
 482 }
 483
 484 static SIMPLE_DEV_PM_OPS(rcar_gen3_thermal_pm_ops, rcar_gen3_thermal_suspend,
 485                          rcar_gen3_thermal_resume);
 486
 487 static struct platform_driver rcar_gen3_thermal_driver = {
 488         .driver = {
 489                 .name   = "rcar_gen3_thermal",
 490                 .pm = &rcar_gen3_thermal_pm_ops,
 491                 .of_match_table = rcar_gen3_thermal_dt_ids,
 492         },
 493         .probe          = rcar_gen3_thermal_probe,
 494         .remove         = rcar_gen3_thermal_remove,
 495 };
 496 module_platform_driver(rcar_gen3_thermal_driver);
 497
 498 MODULE_LICENSE("GPL v2");
 499 MODULE_DESCRIPTION("R-Car Gen3 THS thermal sensor driver");
 500 MODULE_AUTHOR("Wolfram Sang <wsa+renesas@sang-engineering.com>");