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/thermal.h>
  28
  29 #include "thermal_core.h"
  30
  31 /* Register offsets */
  32 #define REG_GEN3_IRQSTR         0x04
  33 #define REG_GEN3_IRQMSK         0x08
  34 #define REG_GEN3_IRQCTL         0x0C
  35 #define REG_GEN3_IRQEN          0x10
  36 #define REG_GEN3_IRQTEMP1       0x14
  37 #define REG_GEN3_IRQTEMP2       0x18
  38 #define REG_GEN3_IRQTEMP3       0x1C
  39 #define REG_GEN3_CTSR           0x20
  40 #define REG_GEN3_THCTR          0x20
  41 #define REG_GEN3_TEMP           0x28
  42 #define REG_GEN3_THCODE1        0x50
  43 #define REG_GEN3_THCODE2        0x54
  44 #define REG_GEN3_THCODE3        0x58
  45
  46 /* IRQ{STR,MSK,EN} bits */
  47 #define IRQ_TEMP1               BIT(0)
  48 #define IRQ_TEMP2               BIT(1)
  49 #define IRQ_TEMP3               BIT(2)
  50 #define IRQ_TEMPD1              BIT(3)
  51 #define IRQ_TEMPD2              BIT(4)
  52 #define IRQ_TEMPD3              BIT(5)
  53
  54 /* CTSR bits */
  55 #define CTSR_PONM       BIT(8)
  56 #define CTSR_AOUT       BIT(7)
  57 #define CTSR_THBGR      BIT(5)
  58 #define CTSR_VMEN       BIT(4)
  59 #define CTSR_VMST       BIT(1)
  60 #define CTSR_THSST      BIT(0)
  61
  62 /* THCTR bits */
  63 #define THCTR_PONM      BIT(6)
  64 #define THCTR_THSST     BIT(0)
  65
  66 #define CTEMP_MASK      0xFFF
  67
  68 #define MCELSIUS(temp)  ((temp) * 1000)
  69 #define GEN3_FUSE_MASK  0xFFF
  70
  71 #define TSC_MAX_NUM     3
  72
  73 /* Structure for thermal temperature calculation */
  74 struct equation_coefs {
  75         int a1;
  76         int b1;
  77         int a2;
  78         int b2;
  79 };
  80
  81 struct rcar_gen3_thermal_tsc {
  82         void __iomem *base;
  83         struct thermal_zone_device *zone;
  84         struct equation_coefs coef;
  85         int low;
  86         int high;
  87 };
  88
  89 struct rcar_gen3_thermal_priv {
  90         struct rcar_gen3_thermal_tsc *tscs[TSC_MAX_NUM];
  91         unsigned int num_tscs;
  92         spinlock_t lock; /* Protect interrupts on and off */
  93         const struct rcar_gen3_thermal_data *data;
  94 };
  95
  96 struct rcar_gen3_thermal_data {
  97         void (*thermal_init)(struct rcar_gen3_thermal_tsc *tsc);
  98 };
  99
 100 static inline u32 rcar_gen3_thermal_read(struct rcar_gen3_thermal_tsc *tsc,
 101                                          u32 reg)
 102 {
 103         return ioread32(tsc->base + reg);
 104 }
 105
 106 static inline void rcar_gen3_thermal_write(struct rcar_gen3_thermal_tsc *tsc,
 107                                            u32 reg, u32 data)
 108 {
 109         iowrite32(data, tsc->base + reg);
 110 }
 111
 112 /*
 113  * Linear approximation for temperature
 114  *
 115  * [reg] = [temp] * a + b => [temp] = ([reg] - b) / a
 116  *
 117  * The constants a and b are calculated using two triplets of int values PTAT
 118  * and THCODE. PTAT and THCODE can either be read from hardware or use hard
 119  * coded values from driver. The formula to calculate a and b are taken from
 120  * BSP and sparsely documented and understood.
 121  *
 122  * Examining the linear formula and the formula used to calculate constants a
 123  * and b while knowing that the span for PTAT and THCODE values are between
 124  * 0x000 and 0xfff the largest integer possible is 0xfff * 0xfff == 0xffe001.
 125  * Integer also needs to be signed so that leaves 7 bits for binary
 126  * fixed point scaling.
 127  */
 128
 129 #define FIXPT_SHIFT 7
 130 #define FIXPT_INT(_x) ((_x) << FIXPT_SHIFT)
 131 #define INT_FIXPT(_x) ((_x) >> FIXPT_SHIFT)
 132 #define FIXPT_DIV(_a, _b) DIV_ROUND_CLOSEST(((_a) << FIXPT_SHIFT), (_b))
 133 #define FIXPT_TO_MCELSIUS(_x) ((_x) * 1000 >> FIXPT_SHIFT)
 134
 135 #define RCAR3_THERMAL_GRAN 500 /* mili Celsius */
 136
 137 /* no idea where these constants come from */
 138 #define TJ_1 96
 139 #define TJ_3 -41
 140
 141 static void rcar_gen3_thermal_calc_coefs(struct equation_coefs *coef,
 142                                          int *ptat, int *thcode)
 143 {
 144         int tj_2;
 145
 146         /* TODO: Find documentation and document constant calculation formula */
 147
 148         /*
 149          * Division is not scaled in BSP and if scaled it might overflow
 150          * the dividend (4095 * 4095 << 14 > INT_MAX) so keep it unscaled
 151          */
 152         tj_2 = (FIXPT_INT((ptat[1] - ptat[2]) * 137)
 153                 / (ptat[0] - ptat[2])) - FIXPT_INT(41);
 154
 155         coef->a1 = FIXPT_DIV(FIXPT_INT(thcode[1] - thcode[2]),
 156                              tj_2 - FIXPT_INT(TJ_3));
 157         coef->b1 = FIXPT_INT(thcode[2]) - coef->a1 * TJ_3;
 158
 159         coef->a2 = FIXPT_DIV(FIXPT_INT(thcode[1] - thcode[0]),
 160                              tj_2 - FIXPT_INT(TJ_1));
 161         coef->b2 = FIXPT_INT(thcode[0]) - coef->a2 * TJ_1;
 162 }
 163
 164 static int rcar_gen3_thermal_round(int temp)
 165 {
 166         int result, round_offs;
 167
 168         round_offs = temp >= 0 ? RCAR3_THERMAL_GRAN / 2 :
 169                 -RCAR3_THERMAL_GRAN / 2;
 170         result = (temp + round_offs) / RCAR3_THERMAL_GRAN;
 171         return result * RCAR3_THERMAL_GRAN;
 172 }
 173
 174 static int rcar_gen3_thermal_get_temp(void *devdata, int *temp)
 175 {
 176         struct rcar_gen3_thermal_tsc *tsc = devdata;
 177         int mcelsius, val1, val2;
 178         u32 reg;
 179
 180         /* Read register and convert to mili Celsius */
 181         reg = rcar_gen3_thermal_read(tsc, REG_GEN3_TEMP) & CTEMP_MASK;
 182
 183         val1 = FIXPT_DIV(FIXPT_INT(reg) - tsc->coef.b1, tsc->coef.a1);
 184         val2 = FIXPT_DIV(FIXPT_INT(reg) - tsc->coef.b2, tsc->coef.a2);
 185         mcelsius = FIXPT_TO_MCELSIUS((val1 + val2) / 2);
 186
 187         /* Make sure we are inside specifications */
 188         if ((mcelsius < MCELSIUS(-40)) || (mcelsius > MCELSIUS(125)))
 189                 return -EIO;
 190
 191         /* Round value to device granularity setting */
 192         *temp = rcar_gen3_thermal_round(mcelsius);
 193
 194         return 0;
 195 }
 196
 197 static int rcar_gen3_thermal_mcelsius_to_temp(struct rcar_gen3_thermal_tsc *tsc,
 198                                               int mcelsius)
 199 {
 200         int celsius, val1, val2;
 201
 202         celsius = DIV_ROUND_CLOSEST(mcelsius, 1000);
 203         val1 = celsius * tsc->coef.a1 + tsc->coef.b1;
 204         val2 = celsius * tsc->coef.a2 + tsc->coef.b2;
 205
 206         return INT_FIXPT((val1 + val2) / 2);
 207 }
 208
 209 static int rcar_gen3_thermal_set_trips(void *devdata, int low, int high)
 210 {
 211         struct rcar_gen3_thermal_tsc *tsc = devdata;
 212
 213         low = clamp_val(low, -40000, 125000);
 214         high = clamp_val(high, -40000, 125000);
 215
 216         rcar_gen3_thermal_write(tsc, REG_GEN3_IRQTEMP1,
 217                                 rcar_gen3_thermal_mcelsius_to_temp(tsc, low));
 218
 219         rcar_gen3_thermal_write(tsc, REG_GEN3_IRQTEMP2,
 220                                 rcar_gen3_thermal_mcelsius_to_temp(tsc, high));
 221
 222         tsc->low = low;
 223         tsc->high = high;
 224
 225         return 0;
 226 }
 227
 228 static const struct thermal_zone_of_device_ops rcar_gen3_tz_of_ops = {
 229         .get_temp       = rcar_gen3_thermal_get_temp,
 230         .set_trips      = rcar_gen3_thermal_set_trips,
 231 };
 232
 233 static void rcar_thermal_irq_set(struct rcar_gen3_thermal_priv *priv, bool on)
 234 {
 235         unsigned int i;
 236         u32 val = on ? IRQ_TEMPD1 | IRQ_TEMP2 : 0;
 237
 238         for (i = 0; i < priv->num_tscs; i++)
 239                 rcar_gen3_thermal_write(priv->tscs[i], REG_GEN3_IRQMSK, val);
 240 }
 241
 242 static irqreturn_t rcar_gen3_thermal_irq(int irq, void *data)
 243 {
 244         struct rcar_gen3_thermal_priv *priv = data;
 245         u32 status;
 246         int i, ret = IRQ_HANDLED;
 247
 248         spin_lock(&priv->lock);
 249         for (i = 0; i < priv->num_tscs; i++) {
 250                 status = rcar_gen3_thermal_read(priv->tscs[i], REG_GEN3_IRQSTR);
 251                 rcar_gen3_thermal_write(priv->tscs[i], REG_GEN3_IRQSTR, 0);
 252                 if (status)
 253                         ret = IRQ_WAKE_THREAD;
 254         }
 255
 256         if (ret == IRQ_WAKE_THREAD)
 257                 rcar_thermal_irq_set(priv, false);
 258
 259         spin_unlock(&priv->lock);
 260
 261         return ret;
 262 }
 263
 264 static irqreturn_t rcar_gen3_thermal_irq_thread(int irq, void *data)
 265 {
 266         struct rcar_gen3_thermal_priv *priv = data;
 267         unsigned long flags;
 268         int i;
 269
 270         for (i = 0; i < priv->num_tscs; i++)
 271                 thermal_zone_device_update(priv->tscs[i]->zone,
 272                                            THERMAL_EVENT_UNSPECIFIED);
 273
 274         spin_lock_irqsave(&priv->lock, flags);
 275         rcar_thermal_irq_set(priv, true);
 276         spin_unlock_irqrestore(&priv->lock, flags);
 277
 278         return IRQ_HANDLED;
 279 }
 280
 281 static void r8a7795_thermal_init(struct rcar_gen3_thermal_tsc *tsc)
 282 {
 283         rcar_gen3_thermal_write(tsc, REG_GEN3_CTSR,  CTSR_THBGR);
 284         rcar_gen3_thermal_write(tsc, REG_GEN3_CTSR,  0x0);
 285
 286         usleep_range(1000, 2000);
 287
 288         rcar_gen3_thermal_write(tsc, REG_GEN3_CTSR, CTSR_PONM);
 289
 290         rcar_gen3_thermal_write(tsc, REG_GEN3_IRQCTL, 0x3F);
 291         rcar_gen3_thermal_write(tsc, REG_GEN3_IRQMSK, 0);
 292         rcar_gen3_thermal_write(tsc, REG_GEN3_IRQEN, IRQ_TEMPD1 | IRQ_TEMP2);
 293
 294         rcar_gen3_thermal_write(tsc, REG_GEN3_CTSR,
 295                                 CTSR_PONM | CTSR_AOUT | CTSR_THBGR | CTSR_VMEN);
 296
 297         usleep_range(100, 200);
 298
 299         rcar_gen3_thermal_write(tsc, REG_GEN3_CTSR,
 300                                 CTSR_PONM | CTSR_AOUT | CTSR_THBGR | CTSR_VMEN |
 301                                 CTSR_VMST | CTSR_THSST);
 302
 303         usleep_range(1000, 2000);
 304 }
 305
 306 static void r8a7796_thermal_init(struct rcar_gen3_thermal_tsc *tsc)
 307 {
 308         u32 reg_val;
 309
 310         reg_val = rcar_gen3_thermal_read(tsc, REG_GEN3_THCTR);
 311         reg_val &= ~THCTR_PONM;
 312         rcar_gen3_thermal_write(tsc, REG_GEN3_THCTR, reg_val);
 313
 314         usleep_range(1000, 2000);
 315
 316         rcar_gen3_thermal_write(tsc, REG_GEN3_IRQCTL, 0x3F);
 317         rcar_gen3_thermal_write(tsc, REG_GEN3_IRQMSK, 0);
 318         rcar_gen3_thermal_write(tsc, REG_GEN3_IRQEN, IRQ_TEMPD1 | IRQ_TEMP2);
 319
 320         reg_val = rcar_gen3_thermal_read(tsc, REG_GEN3_THCTR);
 321         reg_val |= THCTR_THSST;
 322         rcar_gen3_thermal_write(tsc, REG_GEN3_THCTR, reg_val);
 323
 324         usleep_range(1000, 2000);
 325 }
 326
 327 static const struct rcar_gen3_thermal_data r8a7795_data = {
 328         .thermal_init = r8a7795_thermal_init,
 329 };
 330
 331 static const struct rcar_gen3_thermal_data r8a7796_data = {
 332         .thermal_init = r8a7796_thermal_init,
 333 };
 334
 335 static const struct of_device_id rcar_gen3_thermal_dt_ids[] = {
 336         { .compatible = "renesas,r8a7795-thermal", .data = &r8a7795_data},
 337         { .compatible = "renesas,r8a7796-thermal", .data = &r8a7796_data},
 338         {},
 339 };
 340 MODULE_DEVICE_TABLE(of, rcar_gen3_thermal_dt_ids);
 341
 342 static int rcar_gen3_thermal_remove(struct platform_device *pdev)
 343 {
 344         struct device *dev = &pdev->dev;
 345
 346         pm_runtime_put(dev);
 347         pm_runtime_disable(dev);
 348
 349         return 0;
 350 }
 351
 352 static int rcar_gen3_thermal_probe(struct platform_device *pdev)
 353 {
 354         struct rcar_gen3_thermal_priv *priv;
 355         struct device *dev = &pdev->dev;
 356         struct resource *res;
 357         struct thermal_zone_device *zone;
 358         int ret, irq, i;
 359         char *irqname;
 360
 361         /* default values if FUSEs are missing */
 362         /* TODO: Read values from hardware on supported platforms */
 363         int ptat[3] = { 2351, 1509, 435 };
 364         int thcode[TSC_MAX_NUM][3] = {
 365                 { 3248, 2800, 2221 },
 366                 { 3245, 2795, 2216 },
 367                 { 3250, 2805, 2237 },
 368         };
 369
 370         priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
 371         if (!priv)
 372                 return -ENOMEM;
 373
 374         priv->data = of_device_get_match_data(dev);
 375
 376         spin_lock_init(&priv->lock);
 377
 378         platform_set_drvdata(pdev, priv);
 379
 380         /*
 381          * Request 2 (of the 3 possible) IRQs, the driver only needs to
 382          * to trigger on the low and high trip points of the current
 383          * temp window at this point.
 384          */
 385         for (i = 0; i < 2; i++) {
 386                 irq = platform_get_irq(pdev, i);
 387                 if (irq < 0)
 388                         return irq;
 389
 390                 irqname = devm_kasprintf(dev, GFP_KERNEL, "%s:ch%d",
 391                                          dev_name(dev), i);
 392                 if (!irqname)
 393                         return -ENOMEM;
 394
 395                 ret = devm_request_threaded_irq(dev, irq, rcar_gen3_thermal_irq,
 396                                                 rcar_gen3_thermal_irq_thread,
 397                                                 IRQF_SHARED, irqname, priv);
 398                 if (ret)
 399                         return ret;
 400         }
 401
 402         pm_runtime_enable(dev);
 403         pm_runtime_get_sync(dev);
 404
 405         for (i = 0; i < TSC_MAX_NUM; i++) {
 406                 struct rcar_gen3_thermal_tsc *tsc;
 407
 408                 res = platform_get_resource(pdev, IORESOURCE_MEM, i);
 409                 if (!res)
 410                         break;
 411
 412                 tsc = devm_kzalloc(dev, sizeof(*tsc), GFP_KERNEL);
 413                 if (!tsc) {
 414                         ret = -ENOMEM;
 415                         goto error_unregister;
 416                 }
 417
 418                 tsc->base = devm_ioremap_resource(dev, res);
 419                 if (IS_ERR(tsc->base)) {
 420                         ret = PTR_ERR(tsc->base);
 421                         goto error_unregister;
 422                 }
 423
 424                 priv->tscs[i] = tsc;
 425
 426                 priv->data->thermal_init(tsc);
 427                 rcar_gen3_thermal_calc_coefs(&tsc->coef, ptat, thcode[i]);
 428
 429                 zone = devm_thermal_zone_of_sensor_register(dev, i, tsc,
 430                                                             &rcar_gen3_tz_of_ops);
 431                 if (IS_ERR(zone)) {
 432                         dev_err(dev, "Can't register thermal zone\n");
 433                         ret = PTR_ERR(zone);
 434                         goto error_unregister;
 435                 }
 436                 tsc->zone = zone;
 437
 438                 ret = of_thermal_get_ntrips(tsc->zone);
 439                 if (ret < 0)
 440                         goto error_unregister;
 441
 442                 dev_info(dev, "TSC%d: Loaded %d trip points\n", i, ret);
 443         }
 444
 445         priv->num_tscs = i;
 446
 447         if (!priv->num_tscs) {
 448                 ret = -ENODEV;
 449                 goto error_unregister;
 450         }
 451
 452         rcar_thermal_irq_set(priv, true);
 453
 454         return 0;
 455
 456 error_unregister:
 457         rcar_gen3_thermal_remove(pdev);
 458
 459         return ret;
 460 }
 461
 462 static int __maybe_unused rcar_gen3_thermal_suspend(struct device *dev)
 463 {
 464         struct rcar_gen3_thermal_priv *priv = dev_get_drvdata(dev);
 465
 466         rcar_thermal_irq_set(priv, false);
 467
 468         return 0;
 469 }
 470
 471 static int __maybe_unused rcar_gen3_thermal_resume(struct device *dev)
 472 {
 473         struct rcar_gen3_thermal_priv *priv = dev_get_drvdata(dev);
 474         unsigned int i;
 475
 476         for (i = 0; i < priv->num_tscs; i++) {
 477                 struct rcar_gen3_thermal_tsc *tsc = priv->tscs[i];
 478
 479                 priv->data->thermal_init(tsc);
 480                 rcar_gen3_thermal_set_trips(tsc, tsc->low, tsc->high);
 481         }
 482
 483         rcar_thermal_irq_set(priv, true);
 484
 485         return 0;
 486 }
 487
 488 static SIMPLE_DEV_PM_OPS(rcar_gen3_thermal_pm_ops, rcar_gen3_thermal_suspend,
 489                          rcar_gen3_thermal_resume);
 490
 491 static struct platform_driver rcar_gen3_thermal_driver = {
 492         .driver = {
 493                 .name   = "rcar_gen3_thermal",
 494                 .pm = &rcar_gen3_thermal_pm_ops,
 495                 .of_match_table = rcar_gen3_thermal_dt_ids,
 496         },
 497         .probe          = rcar_gen3_thermal_probe,
 498         .remove         = rcar_gen3_thermal_remove,
 499 };
 500 module_platform_driver(rcar_gen3_thermal_driver);
 501
 502 MODULE_LICENSE("GPL v2");
 503 MODULE_DESCRIPTION("R-Car Gen3 THS thermal sensor driver");
 504 MODULE_AUTHOR("Wolfram Sang <wsa+renesas@sang-engineering.com>");