linux/drivers/hwmon/scpi-hwmon.c
<<
>>
Prefs
   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
  26struct 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
  35struct scpi_thermal_zone {
  36        int sensor_id;
  37        struct scpi_sensors *scpi_sensors;
  38};
  39
  40struct 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
  49static 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
  57static 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
  65static 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
  73static 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 */
  93static ssize_t
  94scpi_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        return sprintf(buf, "%llu\n", value);
 111}
 112
 113static ssize_t
 114scpi_show_label(struct device *dev, struct device_attribute *attr, char *buf)
 115{
 116        struct sensor_data *sensor;
 117
 118        sensor = container_of(attr, struct sensor_data, dev_attr_label);
 119
 120        return sprintf(buf, "%s\n", sensor->info.name);
 121}
 122
 123static const struct thermal_zone_of_device_ops scpi_sensor_ops = {
 124        .get_temp = scpi_read_temp,
 125};
 126
 127static const struct of_device_id scpi_of_match[] = {
 128        {.compatible = "arm,scpi-sensors", .data = &scpi_scale},
 129        {.compatible = "amlogic,meson-gxbb-scpi-sensors", .data = &gxbb_scpi_scale},
 130        {},
 131};
 132MODULE_DEVICE_TABLE(of, scpi_of_match);
 133
 134static int scpi_hwmon_probe(struct platform_device *pdev)
 135{
 136        u16 nr_sensors, i;
 137        const u32 *scale;
 138        int num_temp = 0, num_volt = 0, num_current = 0, num_power = 0;
 139        int num_energy = 0;
 140        struct scpi_ops *scpi_ops;
 141        struct device *hwdev, *dev = &pdev->dev;
 142        struct scpi_sensors *scpi_sensors;
 143        const struct of_device_id *of_id;
 144        int idx, ret;
 145
 146        scpi_ops = get_scpi_ops();
 147        if (!scpi_ops)
 148                return -EPROBE_DEFER;
 149
 150        ret = scpi_ops->sensor_get_capability(&nr_sensors);
 151        if (ret)
 152                return ret;
 153
 154        if (!nr_sensors)
 155                return -ENODEV;
 156
 157        scpi_sensors = devm_kzalloc(dev, sizeof(*scpi_sensors), GFP_KERNEL);
 158        if (!scpi_sensors)
 159                return -ENOMEM;
 160
 161        scpi_sensors->data = devm_kcalloc(dev, nr_sensors,
 162                                   sizeof(*scpi_sensors->data), GFP_KERNEL);
 163        if (!scpi_sensors->data)
 164                return -ENOMEM;
 165
 166        scpi_sensors->attrs = devm_kcalloc(dev, (nr_sensors * 2) + 1,
 167                                   sizeof(*scpi_sensors->attrs), GFP_KERNEL);
 168        if (!scpi_sensors->attrs)
 169                return -ENOMEM;
 170
 171        scpi_sensors->scpi_ops = scpi_ops;
 172
 173        of_id = of_match_device(scpi_of_match, &pdev->dev);
 174        if (!of_id) {
 175                dev_err(&pdev->dev, "Unable to initialize scpi-hwmon data\n");
 176                return -ENODEV;
 177        }
 178        scale = of_id->data;
 179
 180        for (i = 0, idx = 0; i < nr_sensors; i++) {
 181                struct sensor_data *sensor = &scpi_sensors->data[idx];
 182
 183                ret = scpi_ops->sensor_get_info(i, &sensor->info);
 184                if (ret)
 185                        return ret;
 186
 187                switch (sensor->info.class) {
 188                case TEMPERATURE:
 189                        snprintf(sensor->input, sizeof(sensor->input),
 190                                 "temp%d_input", num_temp + 1);
 191                        snprintf(sensor->label, sizeof(sensor->input),
 192                                 "temp%d_label", num_temp + 1);
 193                        num_temp++;
 194                        break;
 195                case VOLTAGE:
 196                        snprintf(sensor->input, sizeof(sensor->input),
 197                                 "in%d_input", num_volt);
 198                        snprintf(sensor->label, sizeof(sensor->input),
 199                                 "in%d_label", num_volt);
 200                        num_volt++;
 201                        break;
 202                case CURRENT:
 203                        snprintf(sensor->input, sizeof(sensor->input),
 204                                 "curr%d_input", num_current + 1);
 205                        snprintf(sensor->label, sizeof(sensor->input),
 206                                 "curr%d_label", num_current + 1);
 207                        num_current++;
 208                        break;
 209                case POWER:
 210                        snprintf(sensor->input, sizeof(sensor->input),
 211                                 "power%d_input", num_power + 1);
 212                        snprintf(sensor->label, sizeof(sensor->input),
 213                                 "power%d_label", num_power + 1);
 214                        num_power++;
 215                        break;
 216                case ENERGY:
 217                        snprintf(sensor->input, sizeof(sensor->input),
 218                                 "energy%d_input", num_energy + 1);
 219                        snprintf(sensor->label, sizeof(sensor->input),
 220                                 "energy%d_label", num_energy + 1);
 221                        num_energy++;
 222                        break;
 223                default:
 224                        continue;
 225                }
 226
 227                sensor->scale = scale[sensor->info.class];
 228
 229                sensor->dev_attr_input.attr.mode = S_IRUGO;
 230                sensor->dev_attr_input.show = scpi_show_sensor;
 231                sensor->dev_attr_input.attr.name = sensor->input;
 232
 233                sensor->dev_attr_label.attr.mode = S_IRUGO;
 234                sensor->dev_attr_label.show = scpi_show_label;
 235                sensor->dev_attr_label.attr.name = sensor->label;
 236
 237                scpi_sensors->attrs[idx << 1] = &sensor->dev_attr_input.attr;
 238                scpi_sensors->attrs[(idx << 1) + 1] = &sensor->dev_attr_label.attr;
 239
 240                sysfs_attr_init(scpi_sensors->attrs[idx << 1]);
 241                sysfs_attr_init(scpi_sensors->attrs[(idx << 1) + 1]);
 242                idx++;
 243        }
 244
 245        scpi_sensors->group.attrs = scpi_sensors->attrs;
 246        scpi_sensors->groups[0] = &scpi_sensors->group;
 247
 248        platform_set_drvdata(pdev, scpi_sensors);
 249
 250        hwdev = devm_hwmon_device_register_with_groups(dev,
 251                        "scpi_sensors", scpi_sensors, scpi_sensors->groups);
 252
 253        if (IS_ERR(hwdev))
 254                return PTR_ERR(hwdev);
 255
 256        /*
 257         * Register the temperature sensors with the thermal framework
 258         * to allow their usage in setting up the thermal zones from
 259         * device tree.
 260         *
 261         * NOTE: Not all temperature sensors maybe used for thermal
 262         * control
 263         */
 264        INIT_LIST_HEAD(&scpi_sensors->thermal_zones);
 265        for (i = 0; i < nr_sensors; i++) {
 266                struct sensor_data *sensor = &scpi_sensors->data[i];
 267                struct thermal_zone_device *z;
 268                struct scpi_thermal_zone *zone;
 269
 270                if (sensor->info.class != TEMPERATURE)
 271                        continue;
 272
 273                zone = devm_kzalloc(dev, sizeof(*zone), GFP_KERNEL);
 274                if (!zone)
 275                        return -ENOMEM;
 276
 277                zone->sensor_id = i;
 278                zone->scpi_sensors = scpi_sensors;
 279                z = devm_thermal_zone_of_sensor_register(dev,
 280                                                         sensor->info.sensor_id,
 281                                                         zone,
 282                                                         &scpi_sensor_ops);
 283                /*
 284                 * The call to thermal_zone_of_sensor_register returns
 285                 * an error for sensors that are not associated with
 286                 * any thermal zones or if the thermal subsystem is
 287                 * not configured.
 288                 */
 289                if (IS_ERR(z)) {
 290                        devm_kfree(dev, zone);
 291                        continue;
 292                }
 293        }
 294
 295        return 0;
 296}
 297
 298static struct platform_driver scpi_hwmon_platdrv = {
 299        .driver = {
 300                .name   = "scpi-hwmon",
 301                .of_match_table = scpi_of_match,
 302        },
 303        .probe          = scpi_hwmon_probe,
 304};
 305module_platform_driver(scpi_hwmon_platdrv);
 306
 307MODULE_AUTHOR("Punit Agrawal <punit.agrawal@arm.com>");
 308MODULE_DESCRIPTION("ARM SCPI HWMON interface driver");
 309MODULE_LICENSE("GPL v2");
 310