drivers/hwmon/scmi-hwmon.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * System Control and Management Interface(SCMI) based hwmon sensor driver
   4  *
   5  * Copyright (C) 2018-2021 ARM Ltd.
   6  * Sudeep Holla <sudeep.holla@arm.com>
   7  */
   8
   9 #include <linux/hwmon.h>
  10 #include <linux/module.h>
  11 #include <linux/scmi_protocol.h>
  12 #include <linux/slab.h>
  13 #include <linux/sysfs.h>
  14 #include <linux/thermal.h>
  15
  16 static const struct scmi_sensor_proto_ops *sensor_ops;
  17
  18 struct scmi_sensors {
  19         const struct scmi_protocol_handle *ph;
  20         const struct scmi_sensor_info **info[hwmon_max];
  21 };
  22
  23 struct scmi_thermal_sensor {
  24         const struct scmi_protocol_handle *ph;
  25         const struct scmi_sensor_info *info;
  26 };
  27
  28 static inline u64 __pow10(u8 x)
  29 {
  30         u64 r = 1;
  31
  32         while (x--)
  33                 r *= 10;
  34
  35         return r;
  36 }
  37
  38 static int scmi_hwmon_scale(const struct scmi_sensor_info *sensor, u64 *value)
  39 {
  40         int scale = sensor->scale;
  41         u64 f;
  42
  43         switch (sensor->type) {
  44         case TEMPERATURE_C:
  45         case VOLTAGE:
  46         case CURRENT:
  47                 scale += 3;
  48                 break;
  49         case POWER:
  50         case ENERGY:
  51                 scale += 6;
  52                 break;
  53         default:
  54                 break;
  55         }
  56
  57         if (scale == 0)
  58                 return 0;
  59
  60         if (abs(scale) > 19)
  61                 return -E2BIG;
  62
  63         f = __pow10(abs(scale));
  64         if (scale > 0)
  65                 *value *= f;
  66         else
  67                 *value = div64_u64(*value, f);
  68
  69         return 0;
  70 }
  71
  72 static int scmi_hwmon_read_scaled_value(const struct scmi_protocol_handle *ph,
  73                                         const struct scmi_sensor_info *sensor,
  74                                         long *val)
  75 {
  76         int ret;
  77         u64 value;
  78
  79         ret = sensor_ops->reading_get(ph, sensor->id, &value);
  80         if (ret)
  81                 return ret;
  82
  83         ret = scmi_hwmon_scale(sensor, &value);
  84         if (!ret)
  85                 *val = value;
  86
  87         return ret;
  88 }
  89
  90 static int scmi_hwmon_read(struct device *dev, enum hwmon_sensor_types type,
  91                            u32 attr, int channel, long *val)
  92 {
  93         const struct scmi_sensor_info *sensor;
  94         struct scmi_sensors *scmi_sensors = dev_get_drvdata(dev);
  95
  96         sensor = *(scmi_sensors->info[type] + channel);
  97
  98         return scmi_hwmon_read_scaled_value(scmi_sensors->ph, sensor, val);
  99 }
 100
 101 static int
 102 scmi_hwmon_read_string(struct device *dev, enum hwmon_sensor_types type,
 103                        u32 attr, int channel, const char **str)
 104 {
 105         const struct scmi_sensor_info *sensor;
 106         struct scmi_sensors *scmi_sensors = dev_get_drvdata(dev);
 107
 108         sensor = *(scmi_sensors->info[type] + channel);
 109         *str = sensor->name;
 110
 111         return 0;
 112 }
 113
 114 static umode_t
 115 scmi_hwmon_is_visible(const void *drvdata, enum hwmon_sensor_types type,
 116                       u32 attr, int channel)
 117 {
 118         const struct scmi_sensor_info *sensor;
 119         const struct scmi_sensors *scmi_sensors = drvdata;
 120
 121         sensor = *(scmi_sensors->info[type] + channel);
 122         if (sensor)
 123                 return 0444;
 124
 125         return 0;
 126 }
 127
 128 static const struct hwmon_ops scmi_hwmon_ops = {
 129         .is_visible = scmi_hwmon_is_visible,
 130         .read = scmi_hwmon_read,
 131         .read_string = scmi_hwmon_read_string,
 132 };
 133
 134 static struct hwmon_chip_info scmi_chip_info = {
 135         .ops = &scmi_hwmon_ops,
 136         .info = NULL,
 137 };
 138
 139 static int scmi_hwmon_thermal_get_temp(struct thermal_zone_device *tz,
 140                                        int *temp)
 141 {
 142         int ret;
 143         long value;
 144         struct scmi_thermal_sensor *th_sensor = tz->devdata;
 145
 146         ret = scmi_hwmon_read_scaled_value(th_sensor->ph, th_sensor->info,
 147                                            &value);
 148         if (!ret)
 149                 *temp = value;
 150
 151         return ret;
 152 }
 153
 154 static const struct thermal_zone_device_ops scmi_hwmon_thermal_ops = {
 155         .get_temp = scmi_hwmon_thermal_get_temp,
 156 };
 157
 158 static int scmi_hwmon_add_chan_info(struct hwmon_channel_info *scmi_hwmon_chan,
 159                                     struct device *dev, int num,
 160                                     enum hwmon_sensor_types type, u32 config)
 161 {
 162         int i;
 163         u32 *cfg = devm_kcalloc(dev, num + 1, sizeof(*cfg), GFP_KERNEL);
 164
 165         if (!cfg)
 166                 return -ENOMEM;
 167
 168         scmi_hwmon_chan->type = type;
 169         scmi_hwmon_chan->config = cfg;
 170         for (i = 0; i < num; i++, cfg++)
 171                 *cfg = config;
 172
 173         return 0;
 174 }
 175
 176 static enum hwmon_sensor_types scmi_types[] = {
 177         [TEMPERATURE_C] = hwmon_temp,
 178         [VOLTAGE] = hwmon_in,
 179         [CURRENT] = hwmon_curr,
 180         [POWER] = hwmon_power,
 181         [ENERGY] = hwmon_energy,
 182 };
 183
 184 static u32 hwmon_attributes[hwmon_max] = {
 185         [hwmon_temp] = HWMON_T_INPUT | HWMON_T_LABEL,
 186         [hwmon_in] = HWMON_I_INPUT | HWMON_I_LABEL,
 187         [hwmon_curr] = HWMON_C_INPUT | HWMON_C_LABEL,
 188         [hwmon_power] = HWMON_P_INPUT | HWMON_P_LABEL,
 189         [hwmon_energy] = HWMON_E_INPUT | HWMON_E_LABEL,
 190 };
 191
 192 static int scmi_thermal_sensor_register(struct device *dev,
 193                                         const struct scmi_protocol_handle *ph,
 194                                         const struct scmi_sensor_info *sensor)
 195 {
 196         struct scmi_thermal_sensor *th_sensor;
 197         struct thermal_zone_device *tzd;
 198
 199         th_sensor = devm_kzalloc(dev, sizeof(*th_sensor), GFP_KERNEL);
 200         if (!th_sensor)
 201                 return -ENOMEM;
 202
 203         th_sensor->ph = ph;
 204         th_sensor->info = sensor;
 205
 206         /*
 207          * Try to register a temperature sensor with the Thermal Framework:
 208          * skip sensors not defined as part of any thermal zone (-ENODEV) but
 209          * report any other errors related to misconfigured zones/sensors.
 210          */
 211         tzd = devm_thermal_of_zone_register(dev, th_sensor->info->id, th_sensor,
 212                                             &scmi_hwmon_thermal_ops);
 213         if (IS_ERR(tzd)) {
 214                 devm_kfree(dev, th_sensor);
 215
 216                 if (PTR_ERR(tzd) != -ENODEV)
 217                         return PTR_ERR(tzd);
 218
 219                 dev_dbg(dev, "Sensor '%s' not attached to any thermal zone.\n",
 220                         sensor->name);
 221         } else {
 222                 dev_dbg(dev, "Sensor '%s' attached to thermal zone ID:%d\n",
 223                         sensor->name, tzd->id);
 224         }
 225
 226         return 0;
 227 }
 228
 229 static int scmi_hwmon_probe(struct scmi_device *sdev)
 230 {
 231         int i, idx;
 232         u16 nr_sensors;
 233         enum hwmon_sensor_types type;
 234         struct scmi_sensors *scmi_sensors;
 235         const struct scmi_sensor_info *sensor;
 236         int nr_count[hwmon_max] = {0}, nr_types = 0, nr_count_temp = 0;
 237         const struct hwmon_chip_info *chip_info;
 238         struct device *hwdev, *dev = &sdev->dev;
 239         struct hwmon_channel_info *scmi_hwmon_chan;
 240         const struct hwmon_channel_info **ptr_scmi_ci;
 241         const struct scmi_handle *handle = sdev->handle;
 242         struct scmi_protocol_handle *ph;
 243
 244         if (!handle)
 245                 return -ENODEV;
 246
 247         sensor_ops = handle->devm_protocol_get(sdev, SCMI_PROTOCOL_SENSOR, &ph);
 248         if (IS_ERR(sensor_ops))
 249                 return PTR_ERR(sensor_ops);
 250
 251         nr_sensors = sensor_ops->count_get(ph);
 252         if (!nr_sensors)
 253                 return -EIO;
 254
 255         scmi_sensors = devm_kzalloc(dev, sizeof(*scmi_sensors), GFP_KERNEL);
 256         if (!scmi_sensors)
 257                 return -ENOMEM;
 258
 259         scmi_sensors->ph = ph;
 260
 261         for (i = 0; i < nr_sensors; i++) {
 262                 sensor = sensor_ops->info_get(ph, i);
 263                 if (!sensor)
 264                         return -EINVAL;
 265
 266                 switch (sensor->type) {
 267                 case TEMPERATURE_C:
 268                 case VOLTAGE:
 269                 case CURRENT:
 270                 case POWER:
 271                 case ENERGY:
 272                         type = scmi_types[sensor->type];
 273                         if (!nr_count[type])
 274                                 nr_types++;
 275                         nr_count[type]++;
 276                         break;
 277                 }
 278         }
 279
 280         if (nr_count[hwmon_temp])
 281                 nr_count_temp = nr_count[hwmon_temp];
 282
 283         scmi_hwmon_chan = devm_kcalloc(dev, nr_types, sizeof(*scmi_hwmon_chan),
 284                                        GFP_KERNEL);
 285         if (!scmi_hwmon_chan)
 286                 return -ENOMEM;
 287
 288         ptr_scmi_ci = devm_kcalloc(dev, nr_types + 1, sizeof(*ptr_scmi_ci),
 289                                    GFP_KERNEL);
 290         if (!ptr_scmi_ci)
 291                 return -ENOMEM;
 292
 293         scmi_chip_info.info = ptr_scmi_ci;
 294         chip_info = &scmi_chip_info;
 295
 296         for (type = 0; type < hwmon_max; type++) {
 297                 if (!nr_count[type])
 298                         continue;
 299
 300                 scmi_hwmon_add_chan_info(scmi_hwmon_chan, dev, nr_count[type],
 301                                          type, hwmon_attributes[type]);
 302                 *ptr_scmi_ci++ = scmi_hwmon_chan++;
 303
 304                 scmi_sensors->info[type] =
 305                         devm_kcalloc(dev, nr_count[type],
 306                                      sizeof(*scmi_sensors->info), GFP_KERNEL);
 307                 if (!scmi_sensors->info[type])
 308                         return -ENOMEM;
 309         }
 310
 311         for (i = nr_sensors - 1; i >= 0 ; i--) {
 312                 sensor = sensor_ops->info_get(ph, i);
 313                 if (!sensor)
 314                         continue;
 315
 316                 switch (sensor->type) {
 317                 case TEMPERATURE_C:
 318                 case VOLTAGE:
 319                 case CURRENT:
 320                 case POWER:
 321                 case ENERGY:
 322                         type = scmi_types[sensor->type];
 323                         idx = --nr_count[type];
 324                         *(scmi_sensors->info[type] + idx) = sensor;
 325                         break;
 326                 }
 327         }
 328
 329         hwdev = devm_hwmon_device_register_with_info(dev, "scmi_sensors",
 330                                                      scmi_sensors, chip_info,
 331                                                      NULL);
 332         if (IS_ERR(hwdev))
 333                 return PTR_ERR(hwdev);
 334
 335         for (i = 0; i < nr_count_temp; i++) {
 336                 int ret;
 337
 338                 sensor = *(scmi_sensors->info[hwmon_temp] + i);
 339                 if (!sensor)
 340                         continue;
 341
 342                 /*
 343                  * Warn on any misconfiguration related to thermal zones but
 344                  * bail out of probing only on memory errors.
 345                  */
 346                 ret = scmi_thermal_sensor_register(dev, ph, sensor);
 347                 if (ret) {
 348                         if (ret == -ENOMEM)
 349                                 return ret;
 350                         dev_warn(dev,
 351                                  "Thermal zone misconfigured for %s. err=%d\n",
 352                                  sensor->name, ret);
 353                 }
 354         }
 355
 356         return 0;
 357 }
 358
 359 static const struct scmi_device_id scmi_id_table[] = {
 360         { SCMI_PROTOCOL_SENSOR, "hwmon" },
 361         { },
 362 };
 363 MODULE_DEVICE_TABLE(scmi, scmi_id_table);
 364
 365 static struct scmi_driver scmi_hwmon_drv = {
 366         .name           = "scmi-hwmon",
 367         .probe          = scmi_hwmon_probe,
 368         .id_table       = scmi_id_table,
 369 };
 370 module_scmi_driver(scmi_hwmon_drv);
 371
 372 MODULE_AUTHOR("Sudeep Holla <sudeep.holla@arm.com>");
 373 MODULE_DESCRIPTION("ARM SCMI HWMON interface driver");
 374 MODULE_LICENSE("GPL v2");