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         int sensor_id;
  35         struct scpi_sensors *scpi_sensors;
  36 };
  37
  38 struct scpi_sensors {
  39         struct scpi_ops *scpi_ops;
  40         struct sensor_data *data;
  41         struct list_head thermal_zones;
  42         struct attribute **attrs;
  43         struct attribute_group group;
  44         const struct attribute_group *groups[2];
  45 };
  46
  47 static int scpi_read_temp(void *dev, int *temp)
  48 {
  49         struct scpi_thermal_zone *zone = dev;
  50         struct scpi_sensors *scpi_sensors = zone->scpi_sensors;
  51         struct scpi_ops *scpi_ops = scpi_sensors->scpi_ops;
  52         struct sensor_data *sensor = &scpi_sensors->data[zone->sensor_id];
  53         u64 value;
  54         int ret;
  55
  56         ret = scpi_ops->sensor_get_value(sensor->info.sensor_id, &value);
  57         if (ret)
  58                 return ret;
  59
  60         *temp = value;
  61         return 0;
  62 }
  63
  64 /* hwmon callback functions */
  65 static ssize_t
  66 scpi_show_sensor(struct device *dev, struct device_attribute *attr, char *buf)
  67 {
  68         struct scpi_sensors *scpi_sensors = dev_get_drvdata(dev);
  69         struct scpi_ops *scpi_ops = scpi_sensors->scpi_ops;
  70         struct sensor_data *sensor;
  71         u64 value;
  72         int ret;
  73
  74         sensor = container_of(attr, struct sensor_data, dev_attr_input);
  75
  76         ret = scpi_ops->sensor_get_value(sensor->info.sensor_id, &value);
  77         if (ret)
  78                 return ret;
  79
  80         return sprintf(buf, "%llu\n", value);
  81 }
  82
  83 static ssize_t
  84 scpi_show_label(struct device *dev, struct device_attribute *attr, char *buf)
  85 {
  86         struct sensor_data *sensor;
  87
  88         sensor = container_of(attr, struct sensor_data, dev_attr_label);
  89
  90         return sprintf(buf, "%s\n", sensor->info.name);
  91 }
  92
  93 static struct thermal_zone_of_device_ops scpi_sensor_ops = {
  94         .get_temp = scpi_read_temp,
  95 };
  96
  97 static int scpi_hwmon_probe(struct platform_device *pdev)
  98 {
  99         u16 nr_sensors, i;
 100         int num_temp = 0, num_volt = 0, num_current = 0, num_power = 0;
 101         int num_energy = 0;
 102         struct scpi_ops *scpi_ops;
 103         struct device *hwdev, *dev = &pdev->dev;
 104         struct scpi_sensors *scpi_sensors;
 105         int idx, ret;
 106
 107         scpi_ops = get_scpi_ops();
 108         if (!scpi_ops)
 109                 return -EPROBE_DEFER;
 110
 111         ret = scpi_ops->sensor_get_capability(&nr_sensors);
 112         if (ret)
 113                 return ret;
 114
 115         if (!nr_sensors)
 116                 return -ENODEV;
 117
 118         scpi_sensors = devm_kzalloc(dev, sizeof(*scpi_sensors), GFP_KERNEL);
 119         if (!scpi_sensors)
 120                 return -ENOMEM;
 121
 122         scpi_sensors->data = devm_kcalloc(dev, nr_sensors,
 123                                    sizeof(*scpi_sensors->data), GFP_KERNEL);
 124         if (!scpi_sensors->data)
 125                 return -ENOMEM;
 126
 127         scpi_sensors->attrs = devm_kcalloc(dev, (nr_sensors * 2) + 1,
 128                                    sizeof(*scpi_sensors->attrs), GFP_KERNEL);
 129         if (!scpi_sensors->attrs)
 130                 return -ENOMEM;
 131
 132         scpi_sensors->scpi_ops = scpi_ops;
 133
 134         for (i = 0, idx = 0; i < nr_sensors; i++) {
 135                 struct sensor_data *sensor = &scpi_sensors->data[idx];
 136
 137                 ret = scpi_ops->sensor_get_info(i, &sensor->info);
 138                 if (ret)
 139                         return ret;
 140
 141                 switch (sensor->info.class) {
 142                 case TEMPERATURE:
 143                         snprintf(sensor->input, sizeof(sensor->input),
 144                                  "temp%d_input", num_temp + 1);
 145                         snprintf(sensor->label, sizeof(sensor->input),
 146                                  "temp%d_label", num_temp + 1);
 147                         num_temp++;
 148                         break;
 149                 case VOLTAGE:
 150                         snprintf(sensor->input, sizeof(sensor->input),
 151                                  "in%d_input", num_volt);
 152                         snprintf(sensor->label, sizeof(sensor->input),
 153                                  "in%d_label", num_volt);
 154                         num_volt++;
 155                         break;
 156                 case CURRENT:
 157                         snprintf(sensor->input, sizeof(sensor->input),
 158                                  "curr%d_input", num_current + 1);
 159                         snprintf(sensor->label, sizeof(sensor->input),
 160                                  "curr%d_label", num_current + 1);
 161                         num_current++;
 162                         break;
 163                 case POWER:
 164                         snprintf(sensor->input, sizeof(sensor->input),
 165                                  "power%d_input", num_power + 1);
 166                         snprintf(sensor->label, sizeof(sensor->input),
 167                                  "power%d_label", num_power + 1);
 168                         num_power++;
 169                         break;
 170                 case ENERGY:
 171                         snprintf(sensor->input, sizeof(sensor->input),
 172                                  "energy%d_input", num_energy + 1);
 173                         snprintf(sensor->label, sizeof(sensor->input),
 174                                  "energy%d_label", num_energy + 1);
 175                         num_energy++;
 176                         break;
 177                 default:
 178                         continue;
 179                 }
 180
 181                 sensor->dev_attr_input.attr.mode = S_IRUGO;
 182                 sensor->dev_attr_input.show = scpi_show_sensor;
 183                 sensor->dev_attr_input.attr.name = sensor->input;
 184
 185                 sensor->dev_attr_label.attr.mode = S_IRUGO;
 186                 sensor->dev_attr_label.show = scpi_show_label;
 187                 sensor->dev_attr_label.attr.name = sensor->label;
 188
 189                 scpi_sensors->attrs[idx << 1] = &sensor->dev_attr_input.attr;
 190                 scpi_sensors->attrs[(idx << 1) + 1] = &sensor->dev_attr_label.attr;
 191
 192                 sysfs_attr_init(scpi_sensors->attrs[idx << 1]);
 193                 sysfs_attr_init(scpi_sensors->attrs[(idx << 1) + 1]);
 194                 idx++;
 195         }
 196
 197         scpi_sensors->group.attrs = scpi_sensors->attrs;
 198         scpi_sensors->groups[0] = &scpi_sensors->group;
 199
 200         platform_set_drvdata(pdev, scpi_sensors);
 201
 202         hwdev = devm_hwmon_device_register_with_groups(dev,
 203                         "scpi_sensors", scpi_sensors, scpi_sensors->groups);
 204
 205         if (IS_ERR(hwdev))
 206                 return PTR_ERR(hwdev);
 207
 208         /*
 209          * Register the temperature sensors with the thermal framework
 210          * to allow their usage in setting up the thermal zones from
 211          * device tree.
 212          *
 213          * NOTE: Not all temperature sensors maybe used for thermal
 214          * control
 215          */
 216         INIT_LIST_HEAD(&scpi_sensors->thermal_zones);
 217         for (i = 0; i < nr_sensors; i++) {
 218                 struct sensor_data *sensor = &scpi_sensors->data[i];
 219                 struct thermal_zone_device *z;
 220                 struct scpi_thermal_zone *zone;
 221
 222                 if (sensor->info.class != TEMPERATURE)
 223                         continue;
 224
 225                 zone = devm_kzalloc(dev, sizeof(*zone), GFP_KERNEL);
 226                 if (!zone)
 227                         return -ENOMEM;
 228
 229                 zone->sensor_id = i;
 230                 zone->scpi_sensors = scpi_sensors;
 231                 z = devm_thermal_zone_of_sensor_register(dev,
 232                                                          sensor->info.sensor_id,
 233                                                          zone,
 234                                                          &scpi_sensor_ops);
 235                 /*
 236                  * The call to thermal_zone_of_sensor_register returns
 237                  * an error for sensors that are not associated with
 238                  * any thermal zones or if the thermal subsystem is
 239                  * not configured.
 240                  */
 241                 if (IS_ERR(z)) {
 242                         devm_kfree(dev, zone);
 243                         continue;
 244                 }
 245         }
 246
 247         return 0;
 248 }
 249
 250 static const struct of_device_id scpi_of_match[] = {
 251         {.compatible = "arm,scpi-sensors"},
 252         {},
 253 };
 254
 255 static struct platform_driver scpi_hwmon_platdrv = {
 256         .driver = {
 257                 .name   = "scpi-hwmon",
 258                 .of_match_table = scpi_of_match,
 259         },
 260         .probe          = scpi_hwmon_probe,
 261 };
 262 module_platform_driver(scpi_hwmon_platdrv);
 263
 264 MODULE_AUTHOR("Punit Agrawal <punit.agrawal@arm.com>");
 265 MODULE_DESCRIPTION("ARM SCPI HWMON interface driver");
 266 MODULE_LICENSE("GPL v2");