drivers/hwmon/scpi-hwmon.c

   1 /*
   2  * System Control and Power Interface(SCPI) based hwmon sensor driver
   3  *
   4  * Copyright (C) 2015 ARM Ltd.
   5  * Punit Agrawal <punit.agrawal@arm.com>
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License version 2 as
   9  * published by the Free Software Foundation.
  10  *
  11  * This program is distributed "as is" WITHOUT ANY WARRANTY of any
  12  * kind, whether express or implied; without even the implied warranty
  13  * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  14  * GNU General Public License for more details.
  15  */
  16
  17 #include <linux/hwmon.h>
  18 #include <linux/module.h>
  19 #include <linux/of_device.h>
  20 #include <linux/platform_device.h>
  21 #include <linux/scpi_protocol.h>
  22 #include <linux/slab.h>
  23 #include <linux/sysfs.h>
  24 #include <linux/thermal.h>
  25
  26 struct sensor_data {
  27         unsigned int scale;
  28         struct scpi_sensor_info info;
  29         struct device_attribute dev_attr_input;
  30         struct device_attribute dev_attr_label;
  31         char input[20];
  32         char label[20];
  33 };
  34
  35 struct scpi_thermal_zone {
  36         int sensor_id;
  37         struct scpi_sensors *scpi_sensors;
  38 };
  39
  40 struct scpi_sensors {
  41         struct scpi_ops *scpi_ops;
  42         struct sensor_data *data;
  43         struct list_head thermal_zones;
  44         struct attribute **attrs;
  45         struct attribute_group group;
  46         const struct attribute_group *groups[2];
  47 };
  48
  49 static const u32 gxbb_scpi_scale[] = {
  50         [TEMPERATURE]   = 1,            /* (celsius)            */
  51         [VOLTAGE]       = 1000,         /* (millivolts)         */
  52         [CURRENT]       = 1000,         /* (milliamperes)       */
  53         [POWER]         = 1000000,      /* (microwatts)         */
  54         [ENERGY]        = 1000000,      /* (microjoules)        */
  55 };
  56
  57 static const u32 scpi_scale[] = {
  58         [TEMPERATURE]   = 1000,         /* (millicelsius)       */
  59         [VOLTAGE]       = 1000,         /* (millivolts)         */
  60         [CURRENT]       = 1000,         /* (milliamperes)       */
  61         [POWER]         = 1000000,      /* (microwatts)         */
  62         [ENERGY]        = 1000000,      /* (microjoules)        */
  63 };
  64
  65 static void scpi_scale_reading(u64 *value, struct sensor_data *sensor)
  66 {
  67         if (scpi_scale[sensor->info.class] != sensor->scale) {
  68                 *value *= scpi_scale[sensor->info.class];
  69                 do_div(*value, sensor->scale);
  70         }
  71 }
  72
  73 static int scpi_read_temp(void *dev, int *temp)
  74 {
  75         struct scpi_thermal_zone *zone = dev;
  76         struct scpi_sensors *scpi_sensors = zone->scpi_sensors;
  77         struct scpi_ops *scpi_ops = scpi_sensors->scpi_ops;
  78         struct sensor_data *sensor = &scpi_sensors->data[zone->sensor_id];
  79         u64 value;
  80         int ret;
  81
  82         ret = scpi_ops->sensor_get_value(sensor->info.sensor_id, &value);
  83         if (ret)
  84                 return ret;
  85
  86         scpi_scale_reading(&value, sensor);
  87
  88         *temp = value;
  89         return 0;
  90 }
  91
  92 /* hwmon callback functions */
  93 static ssize_t
  94 scpi_show_sensor(struct device *dev, struct device_attribute *attr, char *buf)
  95 {
  96         struct scpi_sensors *scpi_sensors = dev_get_drvdata(dev);
  97         struct scpi_ops *scpi_ops = scpi_sensors->scpi_ops;
  98         struct sensor_data *sensor;
  99         u64 value;
 100         int ret;
 101
 102         sensor = container_of(attr, struct sensor_data, dev_attr_input);
 103
 104         ret = scpi_ops->sensor_get_value(sensor->info.sensor_id, &value);
 105         if (ret)
 106                 return ret;
 107
 108         scpi_scale_reading(&value, sensor);
 109
 110         /*
 111          * Temperature sensor values are treated as signed values based on
 112          * observation even though that is not explicitly specified, and
 113          * because an unsigned u64 temperature does not really make practical
 114          * sense especially when the temperature is below zero degrees Celsius.
 115          */
 116         if (sensor->info.class == TEMPERATURE)
 117                 return sprintf(buf, "%lld\n", (s64)value);
 118
 119         return sprintf(buf, "%llu\n", value);
 120 }
 121
 122 static ssize_t
 123 scpi_show_label(struct device *dev, struct device_attribute *attr, char *buf)
 124 {
 125         struct sensor_data *sensor;
 126
 127         sensor = container_of(attr, struct sensor_data, dev_attr_label);
 128
 129         return sprintf(buf, "%s\n", sensor->info.name);
 130 }
 131
 132 static const struct thermal_zone_of_device_ops scpi_sensor_ops = {
 133         .get_temp = scpi_read_temp,
 134 };
 135
 136 static const struct of_device_id scpi_of_match[] = {
 137         {.compatible = "arm,scpi-sensors", .data = &scpi_scale},
 138         {.compatible = "amlogic,meson-gxbb-scpi-sensors", .data = &gxbb_scpi_scale},
 139         {},
 140 };
 141 MODULE_DEVICE_TABLE(of, scpi_of_match);
 142
 143 static int scpi_hwmon_probe(struct platform_device *pdev)
 144 {
 145         u16 nr_sensors, i;
 146         const u32 *scale;
 147         int num_temp = 0, num_volt = 0, num_current = 0, num_power = 0;
 148         int num_energy = 0;
 149         struct scpi_ops *scpi_ops;
 150         struct device *hwdev, *dev = &pdev->dev;
 151         struct scpi_sensors *scpi_sensors;
 152         const struct of_device_id *of_id;
 153         int idx, ret;
 154
 155         scpi_ops = get_scpi_ops();
 156         if (!scpi_ops)
 157                 return -EPROBE_DEFER;
 158
 159         ret = scpi_ops->sensor_get_capability(&nr_sensors);
 160         if (ret)
 161                 return ret;
 162
 163         if (!nr_sensors)
 164                 return -ENODEV;
 165
 166         scpi_sensors = devm_kzalloc(dev, sizeof(*scpi_sensors), GFP_KERNEL);
 167         if (!scpi_sensors)
 168                 return -ENOMEM;
 169
 170         scpi_sensors->data = devm_kcalloc(dev, nr_sensors,
 171                                    sizeof(*scpi_sensors->data), GFP_KERNEL);
 172         if (!scpi_sensors->data)
 173                 return -ENOMEM;
 174
 175         scpi_sensors->attrs = devm_kcalloc(dev, (nr_sensors * 2) + 1,
 176                                    sizeof(*scpi_sensors->attrs), GFP_KERNEL);
 177         if (!scpi_sensors->attrs)
 178                 return -ENOMEM;
 179
 180         scpi_sensors->scpi_ops = scpi_ops;
 181
 182         of_id = of_match_device(scpi_of_match, &pdev->dev);
 183         if (!of_id) {
 184                 dev_err(&pdev->dev, "Unable to initialize scpi-hwmon data\n");
 185                 return -ENODEV;
 186         }
 187         scale = of_id->data;
 188
 189         for (i = 0, idx = 0; i < nr_sensors; i++) {
 190                 struct sensor_data *sensor = &scpi_sensors->data[idx];
 191
 192                 ret = scpi_ops->sensor_get_info(i, &sensor->info);
 193                 if (ret)
 194                         return ret;
 195
 196                 switch (sensor->info.class) {
 197                 case TEMPERATURE:
 198                         snprintf(sensor->input, sizeof(sensor->input),
 199                                  "temp%d_input", num_temp + 1);
 200                         snprintf(sensor->label, sizeof(sensor->input),
 201                                  "temp%d_label", num_temp + 1);
 202                         num_temp++;
 203                         break;
 204                 case VOLTAGE:
 205                         snprintf(sensor->input, sizeof(sensor->input),
 206                                  "in%d_input", num_volt);
 207                         snprintf(sensor->label, sizeof(sensor->input),
 208                                  "in%d_label", num_volt);
 209                         num_volt++;
 210                         break;
 211                 case CURRENT:
 212                         snprintf(sensor->input, sizeof(sensor->input),
 213                                  "curr%d_input", num_current + 1);
 214                         snprintf(sensor->label, sizeof(sensor->input),
 215                                  "curr%d_label", num_current + 1);
 216                         num_current++;
 217                         break;
 218                 case POWER:
 219                         snprintf(sensor->input, sizeof(sensor->input),
 220                                  "power%d_input", num_power + 1);
 221                         snprintf(sensor->label, sizeof(sensor->input),
 222                                  "power%d_label", num_power + 1);
 223                         num_power++;
 224                         break;
 225                 case ENERGY:
 226                         snprintf(sensor->input, sizeof(sensor->input),
 227                                  "energy%d_input", num_energy + 1);
 228                         snprintf(sensor->label, sizeof(sensor->input),
 229                                  "energy%d_label", num_energy + 1);
 230                         num_energy++;
 231                         break;
 232                 default:
 233                         continue;
 234                 }
 235
 236                 sensor->scale = scale[sensor->info.class];
 237
 238                 sensor->dev_attr_input.attr.mode = S_IRUGO;
 239                 sensor->dev_attr_input.show = scpi_show_sensor;
 240                 sensor->dev_attr_input.attr.name = sensor->input;
 241
 242                 sensor->dev_attr_label.attr.mode = S_IRUGO;
 243                 sensor->dev_attr_label.show = scpi_show_label;
 244                 sensor->dev_attr_label.attr.name = sensor->label;
 245
 246                 scpi_sensors->attrs[idx << 1] = &sensor->dev_attr_input.attr;
 247                 scpi_sensors->attrs[(idx << 1) + 1] = &sensor->dev_attr_label.attr;
 248
 249                 sysfs_attr_init(scpi_sensors->attrs[idx << 1]);
 250                 sysfs_attr_init(scpi_sensors->attrs[(idx << 1) + 1]);
 251                 idx++;
 252         }
 253
 254         scpi_sensors->group.attrs = scpi_sensors->attrs;
 255         scpi_sensors->groups[0] = &scpi_sensors->group;
 256
 257         platform_set_drvdata(pdev, scpi_sensors);
 258
 259         hwdev = devm_hwmon_device_register_with_groups(dev,
 260                         "scpi_sensors", scpi_sensors, scpi_sensors->groups);
 261
 262         if (IS_ERR(hwdev))
 263                 return PTR_ERR(hwdev);
 264
 265         /*
 266          * Register the temperature sensors with the thermal framework
 267          * to allow their usage in setting up the thermal zones from
 268          * device tree.
 269          *
 270          * NOTE: Not all temperature sensors maybe used for thermal
 271          * control
 272          */
 273         INIT_LIST_HEAD(&scpi_sensors->thermal_zones);
 274         for (i = 0; i < nr_sensors; i++) {
 275                 struct sensor_data *sensor = &scpi_sensors->data[i];
 276                 struct thermal_zone_device *z;
 277                 struct scpi_thermal_zone *zone;
 278
 279                 if (sensor->info.class != TEMPERATURE)
 280                         continue;
 281
 282                 zone = devm_kzalloc(dev, sizeof(*zone), GFP_KERNEL);
 283                 if (!zone)
 284                         return -ENOMEM;
 285
 286                 zone->sensor_id = i;
 287                 zone->scpi_sensors = scpi_sensors;
 288                 z = devm_thermal_zone_of_sensor_register(dev,
 289                                                          sensor->info.sensor_id,
 290                                                          zone,
 291                                                          &scpi_sensor_ops);
 292                 /*
 293                  * The call to thermal_zone_of_sensor_register returns
 294                  * an error for sensors that are not associated with
 295                  * any thermal zones or if the thermal subsystem is
 296                  * not configured.
 297                  */
 298                 if (IS_ERR(z)) {
 299                         devm_kfree(dev, zone);
 300                         continue;
 301                 }
 302         }
 303
 304         return 0;
 305 }
 306
 307 static struct platform_driver scpi_hwmon_platdrv = {
 308         .driver = {
 309                 .name   = "scpi-hwmon",
 310                 .of_match_table = scpi_of_match,
 311         },
 312         .probe          = scpi_hwmon_probe,
 313 };
 314 module_platform_driver(scpi_hwmon_platdrv);
 315
 316 MODULE_AUTHOR("Punit Agrawal <punit.agrawal@arm.com>");
 317 MODULE_DESCRIPTION("ARM SCPI HWMON interface driver");
 318 MODULE_LICENSE("GPL v2");