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 25struct 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 33struct 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 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 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 */ 67static ssize_t 68scpi_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 85static ssize_t 86scpi_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 95static void 96unregister_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 109static struct thermal_zone_of_device_ops scpi_sensor_ops = { 110 .get_temp = scpi_read_temp, 111}; 112 113static 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 257unregister_tzd: 258 unregister_thermal_zones(pdev, scpi_sensors); 259 return ret; 260} 261 262static 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 271static const struct of_device_id scpi_of_match[] = { 272 {.compatible = "arm,scpi-sensors"}, 273 {}, 274}; 275 276static 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}; 285module_platform_driver(scpi_hwmon_platdrv); 286 287MODULE_AUTHOR("Punit Agrawal <punit.agrawal@arm.com>"); 288MODULE_DESCRIPTION("ARM SCPI HWMON interface driver"); 289MODULE_LICENSE("GPL v2"); 290