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; 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; i < nr_sensors; i++) { 150 struct sensor_data *sensor = &scpi_sensors->data[i]; 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 break; 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[i << 1] = &sensor->dev_attr_input.attr; 198 scpi_sensors->attrs[(i << 1) + 1] = &sensor->dev_attr_label.attr; 199 200 sysfs_attr_init(scpi_sensors->attrs[i << 1]); 201 sysfs_attr_init(scpi_sensors->attrs[(i << 1) + 1]); 202 } 203 204 scpi_sensors->group.attrs = scpi_sensors->attrs; 205 scpi_sensors->groups[0] = &scpi_sensors->group; 206 207 platform_set_drvdata(pdev, scpi_sensors); 208 209 hwdev = devm_hwmon_device_register_with_groups(dev, 210 "scpi_sensors", scpi_sensors, scpi_sensors->groups); 211 212 if (IS_ERR(hwdev)) 213 return PTR_ERR(hwdev); 214 215 /* 216 * Register the temperature sensors with the thermal framework 217 * to allow their usage in setting up the thermal zones from 218 * device tree. 219 * 220 * NOTE: Not all temperature sensors maybe used for thermal 221 * control 222 */ 223 INIT_LIST_HEAD(&scpi_sensors->thermal_zones); 224 for (i = 0; i < nr_sensors; i++) { 225 struct sensor_data *sensor = &scpi_sensors->data[i]; 226 struct scpi_thermal_zone *zone; 227 228 if (sensor->info.class != TEMPERATURE) 229 continue; 230 231 zone = devm_kzalloc(dev, sizeof(*zone), GFP_KERNEL); 232 if (!zone) { 233 ret = -ENOMEM; 234 goto unregister_tzd; 235 } 236 237 zone->sensor_id = i; 238 zone->scpi_sensors = scpi_sensors; 239 zone->tzd = thermal_zone_of_sensor_register(dev, i, zone, 240 &scpi_sensor_ops); 241 /* 242 * The call to thermal_zone_of_sensor_register returns 243 * an error for sensors that are not associated with 244 * any thermal zones or if the thermal subsystem is 245 * not configured. 246 */ 247 if (IS_ERR(zone->tzd)) { 248 devm_kfree(dev, zone); 249 continue; 250 } 251 list_add(&zone->list, &scpi_sensors->thermal_zones); 252 } 253 254 return 0; 255 256 unregister_tzd: 257 unregister_thermal_zones(pdev, scpi_sensors); 258 return ret; 259 } 260 261 static int scpi_hwmon_remove(struct platform_device *pdev) 262 { 263 struct scpi_sensors *scpi_sensors = platform_get_drvdata(pdev); 264 265 unregister_thermal_zones(pdev, scpi_sensors); 266 267 return 0; 268 } 269 270 static const struct of_device_id scpi_of_match[] = { 271 {.compatible = "arm,scpi-sensors"}, 272 {}, 273 }; 274 275 static struct platform_driver scpi_hwmon_platdrv = { 276 .driver = { 277 .name = "scpi-hwmon", 278 .owner = THIS_MODULE, 279 .of_match_table = scpi_of_match, 280 }, 281 .probe = scpi_hwmon_probe, 282 .remove = scpi_hwmon_remove, 283 }; 284 module_platform_driver(scpi_hwmon_platdrv); 285 286 MODULE_AUTHOR("Punit Agrawal <punit.agrawal@arm.com>"); 287 MODULE_DESCRIPTION("ARM SCPI HWMON interface driver"); 288 MODULE_LICENSE("GPL v2"); 289