kernel/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/platform_device.h>
  20 #include <linux/scpi_protocol.h>
  21 #include <linux/slab.h>
  22 #include <linux/sysfs.h>
  23 #include <linux/thermal.h>
  24
  25 struct sensor_data {
  26         struct scpi_sensor_info info;
  27         struct device_attribute dev_attr_input;
  28         struct device_attribute dev_attr_label;
  29         char input[20];
  30         char label[20];
  31 };
  32
  33 struct scpi_thermal_zone {
  34         struct list_head list;
  35         int sensor_id;
  36         struct scpi_sensors *scpi_sensors;
  37         struct thermal_zone_device *tzd;
  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 int scpi_read_temp(void *dev, int *temp)
  50 {
  51         struct scpi_thermal_zone *zone = dev;
  52         struct scpi_sensors *scpi_sensors = zone->scpi_sensors;
  53         struct scpi_ops *scpi_ops = scpi_sensors->scpi_ops;
  54         struct sensor_data *sensor = &scpi_sensors->data[zone->sensor_id];
  55         u32 value;
  56         int ret;
  57
  58         ret = scpi_ops->sensor_get_value(sensor->info.sensor_id, &value);
  59         if (ret)
  60                 return ret;
  61
  62         *temp = value;
  63         return 0;
  64 }
  65
  66 /* hwmon callback functions */
  67 static ssize_t
  68 scpi_show_sensor(struct device *dev, struct device_attribute *attr, char *buf)
  69 {
  70         struct scpi_sensors *scpi_sensors = dev_get_drvdata(dev);
  71         struct scpi_ops *scpi_ops = scpi_sensors->scpi_ops;
  72         struct sensor_data *sensor;
  73         u32 value;
  74         int ret;
  75
  76         sensor = container_of(attr, struct sensor_data, dev_attr_input);
  77
  78         ret = scpi_ops->sensor_get_value(sensor->info.sensor_id, &value);
  79         if (ret)
  80                 return ret;
  81
  82         return sprintf(buf, "%u\n", value);
  83 }
  84
  85 static ssize_t
  86 scpi_show_label(struct device *dev, struct device_attribute *attr, char *buf)
  87 {
  88         struct sensor_data *sensor;
  89
  90         sensor = container_of(attr, struct sensor_data, dev_attr_label);
  91
  92         return sprintf(buf, "%s\n", sensor->info.name);
  93 }
  94
  95 static void
  96 unregister_thermal_zones(struct platform_device *pdev,
  97                          struct scpi_sensors *scpi_sensors)
  98 {
  99         struct list_head *pos;
 100
 101         list_for_each(pos, &scpi_sensors->thermal_zones) {
 102                 struct scpi_thermal_zone *zone;
 103
 104                 zone = list_entry(pos, struct scpi_thermal_zone, list);
 105                 thermal_zone_of_sensor_unregister(&pdev->dev, zone->tzd);
 106         }
 107 }
 108
 109 static struct thermal_zone_of_device_ops scpi_sensor_ops = {
 110         .get_temp = scpi_read_temp,
 111 };
 112
 113 static int scpi_hwmon_probe(struct platform_device *pdev)
 114 {
 115         u16 nr_sensors, i;
 116         int num_temp = 0, num_volt = 0, num_current = 0, num_power = 0;
 117         struct scpi_ops *scpi_ops;
 118         struct device *hwdev, *dev = &pdev->dev;
 119         struct scpi_sensors *scpi_sensors;
 120         int ret, idx;
 121
 122         scpi_ops = get_scpi_ops();
 123         if (!scpi_ops)
 124                 return -EPROBE_DEFER;
 125
 126         ret = scpi_ops->sensor_get_capability(&nr_sensors);
 127         if (ret)
 128                 return ret;
 129
 130         if (!nr_sensors)
 131                 return -ENODEV;
 132
 133         scpi_sensors = devm_kzalloc(dev, sizeof(*scpi_sensors), GFP_KERNEL);
 134         if (!scpi_sensors)
 135                 return -ENOMEM;
 136
 137         scpi_sensors->data = devm_kcalloc(dev, nr_sensors,
 138                                    sizeof(*scpi_sensors->data), GFP_KERNEL);
 139         if (!scpi_sensors->data)
 140                 return -ENOMEM;
 141
 142         scpi_sensors->attrs = devm_kcalloc(dev, (nr_sensors * 2) + 1,
 143                                    sizeof(*scpi_sensors->attrs), GFP_KERNEL);
 144         if (!scpi_sensors->attrs)
 145                 return -ENOMEM;
 146
 147         scpi_sensors->scpi_ops = scpi_ops;
 148
 149         for (i = 0, idx = 0; i < nr_sensors; i++) {
 150                 struct sensor_data *sensor = &scpi_sensors->data[idx];
 151
 152                 ret = scpi_ops->sensor_get_info(i, &sensor->info);
 153                 if (ret)
 154                         return ret;
 155
 156                 switch (sensor->info.class) {
 157                 case TEMPERATURE:
 158                         snprintf(sensor->input, sizeof(sensor->input),
 159                                  "temp%d_input", num_temp + 1);
 160                         snprintf(sensor->label, sizeof(sensor->input),
 161                                  "temp%d_label", num_temp + 1);
 162                         num_temp++;
 163                         break;
 164                 case VOLTAGE:
 165                         snprintf(sensor->input, sizeof(sensor->input),
 166                                  "in%d_input", num_volt);
 167                         snprintf(sensor->label, sizeof(sensor->input),
 168                                  "in%d_label", num_volt);
 169                         num_volt++;
 170                         break;
 171                 case CURRENT:
 172                         snprintf(sensor->input, sizeof(sensor->input),
 173                                  "curr%d_input", num_current + 1);
 174                         snprintf(sensor->label, sizeof(sensor->input),
 175                                  "curr%d_label", num_current + 1);
 176                         num_current++;
 177                         break;
 178                 case POWER:
 179                         snprintf(sensor->input, sizeof(sensor->input),
 180                                  "power%d_input", num_power + 1);
 181                         snprintf(sensor->label, sizeof(sensor->input),
 182                                  "power%d_label", num_power + 1);
 183                         num_power++;
 184                         break;
 185                 default:
 186                         continue;
 187                 }
 188
 189                 sensor->dev_attr_input.attr.mode = S_IRUGO;
 190                 sensor->dev_attr_input.show = scpi_show_sensor;
 191                 sensor->dev_attr_input.attr.name = sensor->input;
 192
 193                 sensor->dev_attr_label.attr.mode = S_IRUGO;
 194                 sensor->dev_attr_label.show = scpi_show_label;
 195                 sensor->dev_attr_label.attr.name = sensor->label;
 196
 197                 scpi_sensors->attrs[idx << 1] = &sensor->dev_attr_input.attr;
 198                 scpi_sensors->attrs[(idx << 1) + 1] = &sensor->dev_attr_label.attr;
 199
 200                 sysfs_attr_init(scpi_sensors->attrs[idx << 1]);
 201                 sysfs_attr_init(scpi_sensors->attrs[(idx << 1) + 1]);
 202                 idx++;
 203         }
 204
 205         scpi_sensors->group.attrs = scpi_sensors->attrs;
 206         scpi_sensors->groups[0] = &scpi_sensors->group;
 207
 208         platform_set_drvdata(pdev, scpi_sensors);
 209
 210         hwdev = devm_hwmon_device_register_with_groups(dev,
 211                         "scpi_sensors", scpi_sensors, scpi_sensors->groups);
 212
 213         if (IS_ERR(hwdev))
 214                 return PTR_ERR(hwdev);
 215
 216         /*
 217          * Register the temperature sensors with the thermal framework
 218          * to allow their usage in setting up the thermal zones from
 219          * device tree.
 220          *
 221          * NOTE: Not all temperature sensors maybe used for thermal
 222          * control
 223          */
 224         INIT_LIST_HEAD(&scpi_sensors->thermal_zones);
 225         for (i = 0; i < nr_sensors; i++) {
 226                 struct sensor_data *sensor = &scpi_sensors->data[i];
 227                 struct scpi_thermal_zone *zone;
 228
 229                 if (sensor->info.class != TEMPERATURE)
 230                         continue;
 231
 232                 zone = devm_kzalloc(dev, sizeof(*zone), GFP_KERNEL);
 233                 if (!zone) {
 234                         ret = -ENOMEM;
 235                         goto unregister_tzd;
 236                 }
 237
 238                 zone->sensor_id = i;
 239                 zone->scpi_sensors = scpi_sensors;
 240                 zone->tzd = thermal_zone_of_sensor_register(dev,
 241                                 sensor->info.sensor_id, zone, &scpi_sensor_ops);
 242                 /*
 243                  * The call to thermal_zone_of_sensor_register returns
 244                  * an error for sensors that are not associated with
 245                  * any thermal zones or if the thermal subsystem is
 246                  * not configured.
 247                  */
 248                 if (IS_ERR(zone->tzd)) {
 249                         devm_kfree(dev, zone);
 250                         continue;
 251                 }
 252                 list_add(&zone->list, &scpi_sensors->thermal_zones);
 253         }
 254
 255         return 0;
 256
 257 unregister_tzd:
 258         unregister_thermal_zones(pdev, scpi_sensors);
 259         return ret;
 260 }
 261
 262 static int scpi_hwmon_remove(struct platform_device *pdev)
 263 {
 264         struct scpi_sensors *scpi_sensors = platform_get_drvdata(pdev);
 265
 266         unregister_thermal_zones(pdev, scpi_sensors);
 267
 268         return 0;
 269 }
 270
 271 static const struct of_device_id scpi_of_match[] = {
 272         {.compatible = "arm,scpi-sensors"},
 273         {},
 274 };
 275
 276 static struct platform_driver scpi_hwmon_platdrv = {
 277         .driver = {
 278                 .name   = "scpi-hwmon",
 279                 .owner  = THIS_MODULE,
 280                 .of_match_table = scpi_of_match,
 281         },
 282         .probe          = scpi_hwmon_probe,
 283         .remove         = scpi_hwmon_remove,
 284 };
 285 module_platform_driver(scpi_hwmon_platdrv);
 286
 287 MODULE_AUTHOR("Punit Agrawal <punit.agrawal@arm.com>");
 288 MODULE_DESCRIPTION("ARM SCPI HWMON interface driver");
 289 MODULE_LICENSE("GPL v2");