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/mutex.h>
  24 #include <linux/of_device.h>
  25 #include <linux/platform_device.h>
  26 #include <linux/pm_runtime.h>
  27 #include <linux/thermal.h>
  28
  29 /* Register offsets */
  30 #define REG_GEN3_IRQSTR         0x04
  31 #define REG_GEN3_IRQMSK         0x08
  32 #define REG_GEN3_IRQCTL         0x0C
  33 #define REG_GEN3_IRQEN          0x10
  34 #define REG_GEN3_IRQTEMP1       0x14
  35 #define REG_GEN3_IRQTEMP2       0x18
  36 #define REG_GEN3_IRQTEMP3       0x1C
  37 #define REG_GEN3_CTSR           0x20
  38 #define REG_GEN3_THCTR          0x20
  39 #define REG_GEN3_TEMP           0x28
  40 #define REG_GEN3_THCODE1        0x50
  41 #define REG_GEN3_THCODE2        0x54
  42 #define REG_GEN3_THCODE3        0x58
  43
  44 /* CTSR bits */
  45 #define CTSR_PONM       BIT(8)
  46 #define CTSR_AOUT       BIT(7)
  47 #define CTSR_THBGR      BIT(5)
  48 #define CTSR_VMEN       BIT(4)
  49 #define CTSR_VMST       BIT(1)
  50 #define CTSR_THSST      BIT(0)
  51
  52 /* THCTR bits */
  53 #define THCTR_PONM      BIT(6)
  54 #define THCTR_THSST     BIT(0)
  55
  56 #define CTEMP_MASK      0xFFF
  57
  58 #define MCELSIUS(temp)  ((temp) * 1000)
  59 #define GEN3_FUSE_MASK  0xFFF
  60
  61 #define TSC_MAX_NUM     3
  62
  63 /* Structure for thermal temperature calculation */
  64 struct equation_coefs {
  65         int a1;
  66         int b1;
  67         int a2;
  68         int b2;
  69 };
  70
  71 struct rcar_gen3_thermal_tsc {
  72         void __iomem *base;
  73         struct thermal_zone_device *zone;
  74         struct equation_coefs coef;
  75         struct mutex lock;
  76 };
  77
  78 struct rcar_gen3_thermal_priv {
  79         struct rcar_gen3_thermal_tsc *tscs[TSC_MAX_NUM];
  80 };
  81
  82 struct rcar_gen3_thermal_data {
  83         void (*thermal_init)(struct rcar_gen3_thermal_tsc *tsc);
  84 };
  85
  86 static inline u32 rcar_gen3_thermal_read(struct rcar_gen3_thermal_tsc *tsc,
  87                                          u32 reg)
  88 {
  89         return ioread32(tsc->base + reg);
  90 }
  91
  92 static inline void rcar_gen3_thermal_write(struct rcar_gen3_thermal_tsc *tsc,
  93                                            u32 reg, u32 data)
  94 {
  95         iowrite32(data, tsc->base + reg);
  96 }
  97
  98 /*
  99  * Linear approximation for temperature
 100  *
 101  * [reg] = [temp] * a + b => [temp] = ([reg] - b) / a
 102  *
 103  * The constants a and b are calculated using two triplets of int values PTAT
 104  * and THCODE. PTAT and THCODE can either be read from hardware or use hard
 105  * coded values from driver. The formula to calculate a and b are taken from
 106  * BSP and sparsely documented and understood.
 107  *
 108  * Examining the linear formula and the formula used to calculate constants a
 109  * and b while knowing that the span for PTAT and THCODE values are between
 110  * 0x000 and 0xfff the largest integer possible is 0xfff * 0xfff == 0xffe001.
 111  * Integer also needs to be signed so that leaves 7 bits for binary
 112  * fixed point scaling.
 113  */
 114
 115 #define FIXPT_SHIFT 7
 116 #define FIXPT_INT(_x) ((_x) << FIXPT_SHIFT)
 117 #define FIXPT_DIV(_a, _b) DIV_ROUND_CLOSEST(((_a) << FIXPT_SHIFT), (_b))
 118 #define FIXPT_TO_MCELSIUS(_x) ((_x) * 1000 >> FIXPT_SHIFT)
 119
 120 #define RCAR3_THERMAL_GRAN 500 /* mili Celsius */
 121
 122 /* no idea where these constants come from */
 123 #define TJ_1 96
 124 #define TJ_3 -41
 125
 126 static void rcar_gen3_thermal_calc_coefs(struct equation_coefs *coef,
 127                                          int *ptat, int *thcode)
 128 {
 129         int tj_2;
 130
 131         /* TODO: Find documentation and document constant calculation formula */
 132
 133         /*
 134          * Division is not scaled in BSP and if scaled it might overflow
 135          * the dividend (4095 * 4095 << 14 > INT_MAX) so keep it unscaled
 136          */
 137         tj_2 = (FIXPT_INT((ptat[1] - ptat[2]) * 137)
 138                 / (ptat[0] - ptat[2])) - FIXPT_INT(41);
 139
 140         coef->a1 = FIXPT_DIV(FIXPT_INT(thcode[1] - thcode[2]),
 141                              tj_2 - FIXPT_INT(TJ_3));
 142         coef->b1 = FIXPT_INT(thcode[2]) - coef->a1 * TJ_3;
 143
 144         coef->a2 = FIXPT_DIV(FIXPT_INT(thcode[1] - thcode[0]),
 145                              tj_2 - FIXPT_INT(TJ_1));
 146         coef->b2 = FIXPT_INT(thcode[0]) - coef->a2 * TJ_1;
 147 }
 148
 149 static int rcar_gen3_thermal_round(int temp)
 150 {
 151         int result, round_offs;
 152
 153         round_offs = temp >= 0 ? RCAR3_THERMAL_GRAN / 2 :
 154                 -RCAR3_THERMAL_GRAN / 2;
 155         result = (temp + round_offs) / RCAR3_THERMAL_GRAN;
 156         return result * RCAR3_THERMAL_GRAN;
 157 }
 158
 159 static int rcar_gen3_thermal_get_temp(void *devdata, int *temp)
 160 {
 161         struct rcar_gen3_thermal_tsc *tsc = devdata;
 162         int mcelsius, val1, val2;
 163         u32 reg;
 164
 165         /* Read register and convert to mili Celsius */
 166         mutex_lock(&tsc->lock);
 167
 168         reg = rcar_gen3_thermal_read(tsc, REG_GEN3_TEMP) & CTEMP_MASK;
 169
 170         val1 = FIXPT_DIV(FIXPT_INT(reg) - tsc->coef.b1, tsc->coef.a1);
 171         val2 = FIXPT_DIV(FIXPT_INT(reg) - tsc->coef.b2, tsc->coef.a2);
 172         mcelsius = FIXPT_TO_MCELSIUS((val1 + val2) / 2);
 173
 174         mutex_unlock(&tsc->lock);
 175
 176         /* Make sure we are inside specifications */
 177         if ((mcelsius < MCELSIUS(-40)) || (mcelsius > MCELSIUS(125)))
 178                 return -EIO;
 179
 180         /* Round value to device granularity setting */
 181         *temp = rcar_gen3_thermal_round(mcelsius);
 182
 183         return 0;
 184 }
 185
 186 static struct thermal_zone_of_device_ops rcar_gen3_tz_of_ops = {
 187         .get_temp       = rcar_gen3_thermal_get_temp,
 188 };
 189
 190 static void r8a7795_thermal_init(struct rcar_gen3_thermal_tsc *tsc)
 191 {
 192         rcar_gen3_thermal_write(tsc, REG_GEN3_CTSR,  CTSR_THBGR);
 193         rcar_gen3_thermal_write(tsc, REG_GEN3_CTSR,  0x0);
 194
 195         usleep_range(1000, 2000);
 196
 197         rcar_gen3_thermal_write(tsc, REG_GEN3_CTSR, CTSR_PONM);
 198         rcar_gen3_thermal_write(tsc, REG_GEN3_IRQCTL, 0x3F);
 199         rcar_gen3_thermal_write(tsc, REG_GEN3_CTSR,
 200                                 CTSR_PONM | CTSR_AOUT | CTSR_THBGR | CTSR_VMEN);
 201
 202         usleep_range(100, 200);
 203
 204         rcar_gen3_thermal_write(tsc, REG_GEN3_CTSR,
 205                                 CTSR_PONM | CTSR_AOUT | CTSR_THBGR | CTSR_VMEN |
 206                                 CTSR_VMST | CTSR_THSST);
 207
 208         usleep_range(1000, 2000);
 209 }
 210
 211 static void r8a7796_thermal_init(struct rcar_gen3_thermal_tsc *tsc)
 212 {
 213         u32 reg_val;
 214
 215         reg_val = rcar_gen3_thermal_read(tsc, REG_GEN3_THCTR);
 216         reg_val &= ~THCTR_PONM;
 217         rcar_gen3_thermal_write(tsc, REG_GEN3_THCTR, reg_val);
 218
 219         usleep_range(1000, 2000);
 220
 221         rcar_gen3_thermal_write(tsc, REG_GEN3_IRQCTL, 0x3F);
 222         reg_val = rcar_gen3_thermal_read(tsc, REG_GEN3_THCTR);
 223         reg_val |= THCTR_THSST;
 224         rcar_gen3_thermal_write(tsc, REG_GEN3_THCTR, reg_val);
 225 }
 226
 227 static const struct rcar_gen3_thermal_data r8a7795_data = {
 228         .thermal_init = r8a7795_thermal_init,
 229 };
 230
 231 static const struct rcar_gen3_thermal_data r8a7796_data = {
 232         .thermal_init = r8a7796_thermal_init,
 233 };
 234
 235 static const struct of_device_id rcar_gen3_thermal_dt_ids[] = {
 236         { .compatible = "renesas,r8a7795-thermal", .data = &r8a7795_data},
 237         { .compatible = "renesas,r8a7796-thermal", .data = &r8a7796_data},
 238         {},
 239 };
 240 MODULE_DEVICE_TABLE(of, rcar_gen3_thermal_dt_ids);
 241
 242 static int rcar_gen3_thermal_remove(struct platform_device *pdev)
 243 {
 244         struct device *dev = &pdev->dev;
 245
 246         pm_runtime_put(dev);
 247         pm_runtime_disable(dev);
 248
 249         return 0;
 250 }
 251
 252 static int rcar_gen3_thermal_probe(struct platform_device *pdev)
 253 {
 254         struct rcar_gen3_thermal_priv *priv;
 255         struct device *dev = &pdev->dev;
 256         struct resource *res;
 257         struct thermal_zone_device *zone;
 258         int ret, i;
 259         const struct rcar_gen3_thermal_data *match_data =
 260                 of_device_get_match_data(dev);
 261
 262         /* default values if FUSEs are missing */
 263         /* TODO: Read values from hardware on supported platforms */
 264         int ptat[3] = { 2351, 1509, 435 };
 265         int thcode[TSC_MAX_NUM][3] = {
 266                 { 3248, 2800, 2221 },
 267                 { 3245, 2795, 2216 },
 268                 { 3250, 2805, 2237 },
 269         };
 270
 271         priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
 272         if (!priv)
 273                 return -ENOMEM;
 274
 275         platform_set_drvdata(pdev, priv);
 276
 277         pm_runtime_enable(dev);
 278         pm_runtime_get_sync(dev);
 279
 280         for (i = 0; i < TSC_MAX_NUM; i++) {
 281                 struct rcar_gen3_thermal_tsc *tsc;
 282
 283                 tsc = devm_kzalloc(dev, sizeof(*tsc), GFP_KERNEL);
 284                 if (!tsc) {
 285                         ret = -ENOMEM;
 286                         goto error_unregister;
 287                 }
 288
 289                 res = platform_get_resource(pdev, IORESOURCE_MEM, i);
 290                 if (!res)
 291                         break;
 292
 293                 tsc->base = devm_ioremap_resource(dev, res);
 294                 if (IS_ERR(tsc->base)) {
 295                         ret = PTR_ERR(tsc->base);
 296                         goto error_unregister;
 297                 }
 298
 299                 priv->tscs[i] = tsc;
 300                 mutex_init(&tsc->lock);
 301
 302                 match_data->thermal_init(tsc);
 303                 rcar_gen3_thermal_calc_coefs(&tsc->coef, ptat, thcode[i]);
 304
 305                 zone = devm_thermal_zone_of_sensor_register(dev, i, tsc,
 306                                                             &rcar_gen3_tz_of_ops);
 307                 if (IS_ERR(zone)) {
 308                         dev_err(dev, "Can't register thermal zone\n");
 309                         ret = PTR_ERR(zone);
 310                         goto error_unregister;
 311                 }
 312                 tsc->zone = zone;
 313         }
 314
 315         return 0;
 316
 317 error_unregister:
 318         rcar_gen3_thermal_remove(pdev);
 319
 320         return ret;
 321 }
 322
 323 static struct platform_driver rcar_gen3_thermal_driver = {
 324         .driver = {
 325                 .name   = "rcar_gen3_thermal",
 326                 .of_match_table = rcar_gen3_thermal_dt_ids,
 327         },
 328         .probe          = rcar_gen3_thermal_probe,
 329         .remove         = rcar_gen3_thermal_remove,
 330 };
 331 module_platform_driver(rcar_gen3_thermal_driver);
 332
 333 MODULE_LICENSE("GPL v2");
 334 MODULE_DESCRIPTION("R-Car Gen3 THS thermal sensor driver");
 335 MODULE_AUTHOR("Wolfram Sang <wsa+renesas@sang-engineering.com>");