drivers/hwmon/lochnagar-hwmon.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Lochnagar hardware monitoring features
   4  *
   5  * Copyright (c) 2016-2019 Cirrus Logic, Inc. and
   6  *                         Cirrus Logic International Semiconductor Ltd.
   7  *
   8  * Author: Lucas Tanure <tanureal@opensource.cirrus.com>
   9  */
  10
  11 #include <linux/delay.h>
  12 #include <linux/hwmon.h>
  13 #include <linux/hwmon-sysfs.h>
  14 #include <linux/math64.h>
  15 #include <linux/mfd/lochnagar.h>
  16 #include <linux/mfd/lochnagar2_regs.h>
  17 #include <linux/module.h>
  18 #include <linux/of.h>
  19 #include <linux/platform_device.h>
  20 #include <linux/regmap.h>
  21
  22 #define LN2_MAX_NSAMPLE 1023
  23 #define LN2_SAMPLE_US   1670
  24
  25 #define LN2_CURR_UNITS  1000
  26 #define LN2_VOLT_UNITS  1000
  27 #define LN2_TEMP_UNITS  1000
  28 #define LN2_PWR_UNITS   1000000
  29
  30 static const char * const lochnagar_chan_names[] = {
  31         "DBVDD1",
  32         "1V8 DSP",
  33         "1V8 CDC",
  34         "VDDCORE DSP",
  35         "AVDD 1V8",
  36         "SYSVDD",
  37         "VDDCORE CDC",
  38         "MICVDD",
  39 };
  40
  41 struct lochnagar_hwmon {
  42         struct regmap *regmap;
  43
  44         long power_nsamples[ARRAY_SIZE(lochnagar_chan_names)];
  45
  46         /* Lock to ensure only a single sensor is read at a time */
  47         struct mutex sensor_lock;
  48 };
  49
  50 enum lochnagar_measure_mode {
  51         LN2_CURR = 0,
  52         LN2_VOLT,
  53         LN2_TEMP,
  54 };
  55
  56 /**
  57  * float_to_long - Convert ieee754 reading from hardware to an integer
  58  *
  59  * @data: Value read from the hardware
  60  * @precision: Units to multiply up to eg. 1000 = milli, 1000000 = micro
  61  *
  62  * Return: Converted integer reading
  63  *
  64  * Depending on the measurement type the hardware returns an ieee754
  65  * floating point value in either volts, amps or celsius. This function
  66  * will convert that into an integer in a smaller unit such as micro-amps
  67  * or milli-celsius. The hardware does not return NaN, so consideration of
  68  * that is not required.
  69  */
  70 static long float_to_long(u32 data, u32 precision)
  71 {
  72         u64 man = data & 0x007FFFFF;
  73         int exp = ((data & 0x7F800000) >> 23) - 127 - 23;
  74         bool negative = data & 0x80000000;
  75         long result;
  76
  77         man = (man + (1 << 23)) * precision;
  78
  79         if (fls64(man) + exp > (int)sizeof(long) * 8 - 1)
  80                 result = LONG_MAX;
  81         else if (exp < 0)
  82                 result = (man + (1ull << (-exp - 1))) >> -exp;
  83         else
  84                 result = man << exp;
  85
  86         return negative ? -result : result;
  87 }
  88
  89 static int do_measurement(struct regmap *regmap, int chan,
  90                           enum lochnagar_measure_mode mode, int nsamples)
  91 {
  92         unsigned int val;
  93         int ret;
  94
  95         chan = 1 << (chan + LOCHNAGAR2_IMON_MEASURED_CHANNELS_SHIFT);
  96
  97         ret = regmap_write(regmap, LOCHNAGAR2_IMON_CTRL1,
  98                            LOCHNAGAR2_IMON_ENA_MASK | chan | mode);
  99         if (ret < 0)
 100                 return ret;
 101
 102         ret = regmap_write(regmap, LOCHNAGAR2_IMON_CTRL2, nsamples);
 103         if (ret < 0)
 104                 return ret;
 105
 106         ret = regmap_write(regmap, LOCHNAGAR2_IMON_CTRL3,
 107                            LOCHNAGAR2_IMON_CONFIGURE_MASK);
 108         if (ret < 0)
 109                 return ret;
 110
 111         ret =  regmap_read_poll_timeout(regmap, LOCHNAGAR2_IMON_CTRL3, val,
 112                                         val & LOCHNAGAR2_IMON_DONE_MASK,
 113                                         1000, 10000);
 114         if (ret < 0)
 115                 return ret;
 116
 117         ret = regmap_write(regmap, LOCHNAGAR2_IMON_CTRL3,
 118                            LOCHNAGAR2_IMON_MEASURE_MASK);
 119         if (ret < 0)
 120                 return ret;
 121
 122         /*
 123          * Actual measurement time is ~1.67mS per sample, approximate this
 124          * with a 1.5mS per sample msleep and then poll for success up to
 125          * ~0.17mS * 1023 (LN2_MAX_NSAMPLES). Normally for smaller values
 126          * of nsamples the poll will complete on the first loop due to
 127          * other latency in the system.
 128          */
 129         msleep((nsamples * 3) / 2);
 130
 131         ret =  regmap_read_poll_timeout(regmap, LOCHNAGAR2_IMON_CTRL3, val,
 132                                         val & LOCHNAGAR2_IMON_DONE_MASK,
 133                                         5000, 200000);
 134         if (ret < 0)
 135                 return ret;
 136
 137         return regmap_write(regmap, LOCHNAGAR2_IMON_CTRL3, 0);
 138 }
 139
 140 static int request_data(struct regmap *regmap, int chan, u32 *data)
 141 {
 142         unsigned int val;
 143         int ret;
 144
 145         ret = regmap_write(regmap, LOCHNAGAR2_IMON_CTRL4,
 146                            LOCHNAGAR2_IMON_DATA_REQ_MASK |
 147                            chan << LOCHNAGAR2_IMON_CH_SEL_SHIFT);
 148         if (ret < 0)
 149                 return ret;
 150
 151         ret =  regmap_read_poll_timeout(regmap, LOCHNAGAR2_IMON_CTRL4, val,
 152                                         val & LOCHNAGAR2_IMON_DATA_RDY_MASK,
 153                                         1000, 10000);
 154         if (ret < 0)
 155                 return ret;
 156
 157         ret = regmap_read(regmap, LOCHNAGAR2_IMON_DATA1, &val);
 158         if (ret < 0)
 159                 return ret;
 160
 161         *data = val << 16;
 162
 163         ret = regmap_read(regmap, LOCHNAGAR2_IMON_DATA2, &val);
 164         if (ret < 0)
 165                 return ret;
 166
 167         *data |= val;
 168
 169         return regmap_write(regmap, LOCHNAGAR2_IMON_CTRL4, 0);
 170 }
 171
 172 static int read_sensor(struct device *dev, int chan,
 173                        enum lochnagar_measure_mode mode, int nsamples,
 174                        unsigned int precision, long *val)
 175 {
 176         struct lochnagar_hwmon *priv = dev_get_drvdata(dev);
 177         struct regmap *regmap = priv->regmap;
 178         u32 data;
 179         int ret;
 180
 181         mutex_lock(&priv->sensor_lock);
 182
 183         ret = do_measurement(regmap, chan, mode, nsamples);
 184         if (ret < 0) {
 185                 dev_err(dev, "Failed to perform measurement: %d\n", ret);
 186                 goto error;
 187         }
 188
 189         ret = request_data(regmap, chan, &data);
 190         if (ret < 0) {
 191                 dev_err(dev, "Failed to read measurement: %d\n", ret);
 192                 goto error;
 193         }
 194
 195         *val = float_to_long(data, precision);
 196
 197 error:
 198         mutex_unlock(&priv->sensor_lock);
 199
 200         return ret;
 201 }
 202
 203 static int read_power(struct device *dev, int chan, long *val)
 204 {
 205         struct lochnagar_hwmon *priv = dev_get_drvdata(dev);
 206         int nsamples = priv->power_nsamples[chan];
 207         u64 power;
 208         int ret;
 209
 210         if (!strcmp("SYSVDD", lochnagar_chan_names[chan])) {
 211                 power = 5 * LN2_PWR_UNITS;
 212         } else {
 213                 ret = read_sensor(dev, chan, LN2_VOLT, 1, LN2_PWR_UNITS, val);
 214                 if (ret < 0)
 215                         return ret;
 216
 217                 power = abs(*val);
 218         }
 219
 220         ret = read_sensor(dev, chan, LN2_CURR, nsamples, LN2_PWR_UNITS, val);
 221         if (ret < 0)
 222                 return ret;
 223
 224         power *= abs(*val);
 225         power = DIV_ROUND_CLOSEST_ULL(power, LN2_PWR_UNITS);
 226
 227         if (power > LONG_MAX)
 228                 *val = LONG_MAX;
 229         else
 230                 *val = power;
 231
 232         return 0;
 233 }
 234
 235 static umode_t lochnagar_is_visible(const void *drvdata,
 236                                     enum hwmon_sensor_types type,
 237                                     u32 attr, int chan)
 238 {
 239         switch (type) {
 240         case hwmon_in:
 241                 if (!strcmp("SYSVDD", lochnagar_chan_names[chan]))
 242                         return 0;
 243                 break;
 244         case hwmon_power:
 245                 if (attr == hwmon_power_average_interval)
 246                         return 0644;
 247                 break;
 248         default:
 249                 break;
 250         }
 251
 252         return 0444;
 253 }
 254
 255 static int lochnagar_read(struct device *dev, enum hwmon_sensor_types type,
 256                           u32 attr, int chan, long *val)
 257 {
 258         struct lochnagar_hwmon *priv = dev_get_drvdata(dev);
 259         int interval;
 260
 261         switch (type) {
 262         case hwmon_in:
 263                 return read_sensor(dev, chan, LN2_VOLT, 1, LN2_VOLT_UNITS, val);
 264         case hwmon_curr:
 265                 return read_sensor(dev, chan, LN2_CURR, 1, LN2_CURR_UNITS, val);
 266         case hwmon_temp:
 267                 return read_sensor(dev, chan, LN2_TEMP, 1, LN2_TEMP_UNITS, val);
 268         case hwmon_power:
 269                 switch (attr) {
 270                 case hwmon_power_average:
 271                         return read_power(dev, chan, val);
 272                 case hwmon_power_average_interval:
 273                         interval = priv->power_nsamples[chan] * LN2_SAMPLE_US;
 274                         *val = DIV_ROUND_CLOSEST(interval, 1000);
 275                         return 0;
 276                 default:
 277                         return -EOPNOTSUPP;
 278                 }
 279         default:
 280                 return -EOPNOTSUPP;
 281         }
 282 }
 283
 284 static int lochnagar_read_string(struct device *dev,
 285                                  enum hwmon_sensor_types type, u32 attr,
 286                                  int chan, const char **str)
 287 {
 288         switch (type) {
 289         case hwmon_in:
 290         case hwmon_curr:
 291         case hwmon_power:
 292                 *str = lochnagar_chan_names[chan];
 293                 return 0;
 294         default:
 295                 return -EOPNOTSUPP;
 296         }
 297 }
 298
 299 static int lochnagar_write(struct device *dev, enum hwmon_sensor_types type,
 300                            u32 attr, int chan, long val)
 301 {
 302         struct lochnagar_hwmon *priv = dev_get_drvdata(dev);
 303
 304         if (type != hwmon_power || attr != hwmon_power_average_interval)
 305                 return -EOPNOTSUPP;
 306
 307         val = clamp_t(long, val, 1, (LN2_MAX_NSAMPLE * LN2_SAMPLE_US) / 1000);
 308         val = DIV_ROUND_CLOSEST(val * 1000, LN2_SAMPLE_US);
 309
 310         priv->power_nsamples[chan] = val;
 311
 312         return 0;
 313 }
 314
 315 static const struct hwmon_ops lochnagar_ops = {
 316         .is_visible = lochnagar_is_visible,
 317         .read = lochnagar_read,
 318         .read_string = lochnagar_read_string,
 319         .write = lochnagar_write,
 320 };
 321
 322 static const struct hwmon_channel_info * const lochnagar_info[] = {
 323         HWMON_CHANNEL_INFO(temp,  HWMON_T_INPUT),
 324         HWMON_CHANNEL_INFO(in,    HWMON_I_INPUT | HWMON_I_LABEL,
 325                                   HWMON_I_INPUT | HWMON_I_LABEL,
 326                                   HWMON_I_INPUT | HWMON_I_LABEL,
 327                                   HWMON_I_INPUT | HWMON_I_LABEL,
 328                                   HWMON_I_INPUT | HWMON_I_LABEL,
 329                                   HWMON_I_INPUT | HWMON_I_LABEL,
 330                                   HWMON_I_INPUT | HWMON_I_LABEL,
 331                                   HWMON_I_INPUT | HWMON_I_LABEL),
 332         HWMON_CHANNEL_INFO(curr,  HWMON_C_INPUT | HWMON_C_LABEL,
 333                                   HWMON_C_INPUT | HWMON_C_LABEL,
 334                                   HWMON_C_INPUT | HWMON_C_LABEL,
 335                                   HWMON_C_INPUT | HWMON_C_LABEL,
 336                                   HWMON_C_INPUT | HWMON_C_LABEL,
 337                                   HWMON_C_INPUT | HWMON_C_LABEL,
 338                                   HWMON_C_INPUT | HWMON_C_LABEL,
 339                                   HWMON_C_INPUT | HWMON_C_LABEL),
 340         HWMON_CHANNEL_INFO(power, HWMON_P_AVERAGE | HWMON_P_AVERAGE_INTERVAL |
 341                                   HWMON_P_LABEL,
 342                                   HWMON_P_AVERAGE | HWMON_P_AVERAGE_INTERVAL |
 343                                   HWMON_P_LABEL,
 344                                   HWMON_P_AVERAGE | HWMON_P_AVERAGE_INTERVAL |
 345                                   HWMON_P_LABEL,
 346                                   HWMON_P_AVERAGE | HWMON_P_AVERAGE_INTERVAL |
 347                                   HWMON_P_LABEL,
 348                                   HWMON_P_AVERAGE | HWMON_P_AVERAGE_INTERVAL |
 349                                   HWMON_P_LABEL,
 350                                   HWMON_P_AVERAGE | HWMON_P_AVERAGE_INTERVAL |
 351                                   HWMON_P_LABEL,
 352                                   HWMON_P_AVERAGE | HWMON_P_AVERAGE_INTERVAL |
 353                                   HWMON_P_LABEL,
 354                                   HWMON_P_AVERAGE | HWMON_P_AVERAGE_INTERVAL |
 355                                   HWMON_P_LABEL),
 356         NULL
 357 };
 358
 359 static const struct hwmon_chip_info lochnagar_chip_info = {
 360         .ops = &lochnagar_ops,
 361         .info = lochnagar_info,
 362 };
 363
 364 static const struct of_device_id lochnagar_of_match[] = {
 365         { .compatible = "cirrus,lochnagar2-hwmon" },
 366         {}
 367 };
 368 MODULE_DEVICE_TABLE(of, lochnagar_of_match);
 369
 370 static int lochnagar_hwmon_probe(struct platform_device *pdev)
 371 {
 372         struct device *dev = &pdev->dev;
 373         struct device *hwmon_dev;
 374         struct lochnagar_hwmon *priv;
 375         int i;
 376
 377         priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
 378         if (!priv)
 379                 return -ENOMEM;
 380
 381         mutex_init(&priv->sensor_lock);
 382
 383         priv->regmap = dev_get_regmap(dev->parent, NULL);
 384         if (!priv->regmap) {
 385                 dev_err(dev, "No register map found\n");
 386                 return -EINVAL;
 387         }
 388
 389         for (i = 0; i < ARRAY_SIZE(priv->power_nsamples); i++)
 390                 priv->power_nsamples[i] = 96;
 391
 392         hwmon_dev = devm_hwmon_device_register_with_info(dev, "Lochnagar", priv,
 393                                                          &lochnagar_chip_info,
 394                                                          NULL);
 395
 396         return PTR_ERR_OR_ZERO(hwmon_dev);
 397 }
 398
 399 static struct platform_driver lochnagar_hwmon_driver = {
 400         .driver = {
 401                 .name = "lochnagar-hwmon",
 402                 .of_match_table = lochnagar_of_match,
 403         },
 404         .probe = lochnagar_hwmon_probe,
 405 };
 406 module_platform_driver(lochnagar_hwmon_driver);
 407
 408 MODULE_AUTHOR("Lucas Tanure <tanureal@opensource.cirrus.com>");
 409 MODULE_DESCRIPTION("Lochnagar hardware monitoring features");
 410 MODULE_LICENSE("GPL");