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1// SPDX-License-Identifier: GPL-2.02/*3 * System Control and Power Interface(SCPI) based hwmon sensor driver4 *5 * Copyright (C) 2015 ARM Ltd.6 * Punit Agrawal <punit.agrawal@arm.com>7 */8 9#include <linux/hwmon.h>10#include <linux/module.h>11#include <linux/of.h>12#include <linux/platform_device.h>13#include <linux/scpi_protocol.h>14#include <linux/slab.h>15#include <linux/sysfs.h>16#include <linux/thermal.h>17 18struct sensor_data {19 unsigned int scale;20 struct scpi_sensor_info info;21 struct device_attribute dev_attr_input;22 struct device_attribute dev_attr_label;23 char input[20];24 char label[20];25};26 27struct scpi_thermal_zone {28 int sensor_id;29 struct scpi_sensors *scpi_sensors;30};31 32struct scpi_sensors {33 struct scpi_ops *scpi_ops;34 struct sensor_data *data;35 struct list_head thermal_zones;36 struct attribute **attrs;37 struct attribute_group group;38 const struct attribute_group *groups[2];39};40 41static const u32 gxbb_scpi_scale[] = {42 [TEMPERATURE] = 1, /* (celsius) */43 [VOLTAGE] = 1000, /* (millivolts) */44 [CURRENT] = 1000, /* (milliamperes) */45 [POWER] = 1000000, /* (microwatts) */46 [ENERGY] = 1000000, /* (microjoules) */47};48 49static const u32 scpi_scale[] = {50 [TEMPERATURE] = 1000, /* (millicelsius) */51 [VOLTAGE] = 1000, /* (millivolts) */52 [CURRENT] = 1000, /* (milliamperes) */53 [POWER] = 1000000, /* (microwatts) */54 [ENERGY] = 1000000, /* (microjoules) */55};56 57static void scpi_scale_reading(u64 *value, struct sensor_data *sensor)58{59 if (scpi_scale[sensor->info.class] != sensor->scale) {60 *value *= scpi_scale[sensor->info.class];61 do_div(*value, sensor->scale);62 }63}64 65static int scpi_read_temp(struct thermal_zone_device *tz, int *temp)66{67 struct scpi_thermal_zone *zone = thermal_zone_device_priv(tz);68 struct scpi_sensors *scpi_sensors = zone->scpi_sensors;69 struct scpi_ops *scpi_ops = scpi_sensors->scpi_ops;70 struct sensor_data *sensor = &scpi_sensors->data[zone->sensor_id];71 u64 value;72 int ret;73 74 ret = scpi_ops->sensor_get_value(sensor->info.sensor_id, &value);75 if (ret)76 return ret;77 78 scpi_scale_reading(&value, sensor);79 80 *temp = value;81 return 0;82}83 84/* hwmon callback functions */85static ssize_t86scpi_show_sensor(struct device *dev, struct device_attribute *attr, char *buf)87{88 struct scpi_sensors *scpi_sensors = dev_get_drvdata(dev);89 struct scpi_ops *scpi_ops = scpi_sensors->scpi_ops;90 struct sensor_data *sensor;91 u64 value;92 int ret;93 94 sensor = container_of(attr, struct sensor_data, dev_attr_input);95 96 ret = scpi_ops->sensor_get_value(sensor->info.sensor_id, &value);97 if (ret)98 return ret;99 100 scpi_scale_reading(&value, sensor);101 102 /*103 * Temperature sensor values are treated as signed values based on104 * observation even though that is not explicitly specified, and105 * because an unsigned u64 temperature does not really make practical106 * sense especially when the temperature is below zero degrees Celsius.107 */108 if (sensor->info.class == TEMPERATURE)109 return sprintf(buf, "%lld\n", (s64)value);110 111 return sprintf(buf, "%llu\n", value);112}113 114static ssize_t115scpi_show_label(struct device *dev, struct device_attribute *attr, char *buf)116{117 struct sensor_data *sensor;118 119 sensor = container_of(attr, struct sensor_data, dev_attr_label);120 121 return sprintf(buf, "%s\n", sensor->info.name);122}123 124static const struct thermal_zone_device_ops scpi_sensor_ops = {125 .get_temp = scpi_read_temp,126};127 128static const struct of_device_id scpi_of_match[] = {129 {.compatible = "arm,scpi-sensors", .data = &scpi_scale},130 {.compatible = "amlogic,meson-gxbb-scpi-sensors", .data = &gxbb_scpi_scale},131 {},132};133MODULE_DEVICE_TABLE(of, scpi_of_match);134 135static int scpi_hwmon_probe(struct platform_device *pdev)136{137 u16 nr_sensors, i;138 const u32 *scale;139 int num_temp = 0, num_volt = 0, num_current = 0, num_power = 0;140 int num_energy = 0;141 struct scpi_ops *scpi_ops;142 struct device *hwdev, *dev = &pdev->dev;143 struct scpi_sensors *scpi_sensors;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 scale = of_device_get_match_data(&pdev->dev);174 if (!scale) {175 dev_err(&pdev->dev, "Unable to initialize scpi-hwmon data\n");176 return -ENODEV;177 }178 179 for (i = 0, idx = 0; i < nr_sensors; i++) {180 struct sensor_data *sensor = &scpi_sensors->data[idx];181 182 ret = scpi_ops->sensor_get_info(i, &sensor->info);183 if (ret)184 return ret;185 186 switch (sensor->info.class) {187 case TEMPERATURE:188 snprintf(sensor->input, sizeof(sensor->input),189 "temp%d_input", num_temp + 1);190 snprintf(sensor->label, sizeof(sensor->input),191 "temp%d_label", num_temp + 1);192 num_temp++;193 break;194 case VOLTAGE:195 snprintf(sensor->input, sizeof(sensor->input),196 "in%d_input", num_volt);197 snprintf(sensor->label, sizeof(sensor->input),198 "in%d_label", num_volt);199 num_volt++;200 break;201 case CURRENT:202 snprintf(sensor->input, sizeof(sensor->input),203 "curr%d_input", num_current + 1);204 snprintf(sensor->label, sizeof(sensor->input),205 "curr%d_label", num_current + 1);206 num_current++;207 break;208 case POWER:209 snprintf(sensor->input, sizeof(sensor->input),210 "power%d_input", num_power + 1);211 snprintf(sensor->label, sizeof(sensor->input),212 "power%d_label", num_power + 1);213 num_power++;214 break;215 case ENERGY:216 snprintf(sensor->input, sizeof(sensor->input),217 "energy%d_input", num_energy + 1);218 snprintf(sensor->label, sizeof(sensor->input),219 "energy%d_label", num_energy + 1);220 num_energy++;221 break;222 default:223 continue;224 }225 226 sensor->scale = scale[sensor->info.class];227 228 sensor->dev_attr_input.attr.mode = 0444;229 sensor->dev_attr_input.show = scpi_show_sensor;230 sensor->dev_attr_input.attr.name = sensor->input;231 232 sensor->dev_attr_label.attr.mode = 0444;233 sensor->dev_attr_label.show = scpi_show_label;234 sensor->dev_attr_label.attr.name = sensor->label;235 236 scpi_sensors->attrs[idx << 1] = &sensor->dev_attr_input.attr;237 scpi_sensors->attrs[(idx << 1) + 1] = &sensor->dev_attr_label.attr;238 239 sysfs_attr_init(scpi_sensors->attrs[idx << 1]);240 sysfs_attr_init(scpi_sensors->attrs[(idx << 1) + 1]);241 idx++;242 }243 244 scpi_sensors->group.attrs = scpi_sensors->attrs;245 scpi_sensors->groups[0] = &scpi_sensors->group;246 247 platform_set_drvdata(pdev, scpi_sensors);248 249 hwdev = devm_hwmon_device_register_with_groups(dev,250 "scpi_sensors", scpi_sensors, scpi_sensors->groups);251 252 if (IS_ERR(hwdev))253 return PTR_ERR(hwdev);254 255 /*256 * Register the temperature sensors with the thermal framework257 * to allow their usage in setting up the thermal zones from258 * device tree.259 *260 * NOTE: Not all temperature sensors maybe used for thermal261 * control262 */263 INIT_LIST_HEAD(&scpi_sensors->thermal_zones);264 for (i = 0; i < nr_sensors; i++) {265 struct sensor_data *sensor = &scpi_sensors->data[i];266 struct thermal_zone_device *z;267 struct scpi_thermal_zone *zone;268 269 if (sensor->info.class != TEMPERATURE)270 continue;271 272 zone = devm_kzalloc(dev, sizeof(*zone), GFP_KERNEL);273 if (!zone)274 return -ENOMEM;275 276 zone->sensor_id = i;277 zone->scpi_sensors = scpi_sensors;278 z = devm_thermal_of_zone_register(dev,279 sensor->info.sensor_id,280 zone,281 &scpi_sensor_ops);282 /*283 * The call to thermal_zone_of_sensor_register returns284 * an error for sensors that are not associated with285 * any thermal zones or if the thermal subsystem is286 * not configured.287 */288 if (IS_ERR(z))289 devm_kfree(dev, zone);290 }291 292 return 0;293}294 295static struct platform_driver scpi_hwmon_platdrv = {296 .driver = {297 .name = "scpi-hwmon",298 .of_match_table = scpi_of_match,299 },300 .probe = scpi_hwmon_probe,301};302module_platform_driver(scpi_hwmon_platdrv);303 304MODULE_AUTHOR("Punit Agrawal <punit.agrawal@arm.com>");305MODULE_DESCRIPTION("ARM SCPI HWMON interface driver");306MODULE_LICENSE("GPL v2");307