1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * System Control and Power Interface(SCPI) based hwmon sensor driver 4 * 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_device.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 18 struct 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 27 struct scpi_thermal_zone { 28 int sensor_id; 29 struct scpi_sensors *scpi_sensors; 30 }; 31 32 struct 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 41 static 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 49 static 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 57 static 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 65 static int scpi_read_temp(void *dev, int *temp) 66 { 67 struct scpi_thermal_zone *zone = dev; 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 */ 85 static ssize_t 86 scpi_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 on 104 * observation even though that is not explicitly specified, and 105 * because an unsigned u64 temperature does not really make practical 106 * 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 } 113 114 static ssize_t 115 scpi_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 } 123 124 static const struct thermal_zone_of_device_ops scpi_sensor_ops = { 125 .get_temp = scpi_read_temp, 126 }; 127 128 static 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 }; 133 MODULE_DEVICE_TABLE(of, scpi_of_match); 134 135 static 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 const struct of_device_id *of_id; 145 int idx, ret; 146 147 scpi_ops = get_scpi_ops(); 148 if (!scpi_ops) 149 return -EPROBE_DEFER; 150 151 ret = scpi_ops->sensor_get_capability(&nr_sensors); 152 if (ret) 153 return ret; 154 155 if (!nr_sensors) 156 return -ENODEV; 157 158 scpi_sensors = devm_kzalloc(dev, sizeof(*scpi_sensors), GFP_KERNEL); 159 if (!scpi_sensors) 160 return -ENOMEM; 161 162 scpi_sensors->data = devm_kcalloc(dev, nr_sensors, 163 sizeof(*scpi_sensors->data), GFP_KERNEL); 164 if (!scpi_sensors->data) 165 return -ENOMEM; 166 167 scpi_sensors->attrs = devm_kcalloc(dev, (nr_sensors * 2) + 1, 168 sizeof(*scpi_sensors->attrs), GFP_KERNEL); 169 if (!scpi_sensors->attrs) 170 return -ENOMEM; 171 172 scpi_sensors->scpi_ops = scpi_ops; 173 174 of_id = of_match_device(scpi_of_match, &pdev->dev); 175 if (!of_id) { 176 dev_err(&pdev->dev, "Unable to initialize scpi-hwmon data\n"); 177 return -ENODEV; 178 } 179 scale = of_id->data; 180 181 for (i = 0, idx = 0; i < nr_sensors; i++) { 182 struct sensor_data *sensor = &scpi_sensors->data[idx]; 183 184 ret = scpi_ops->sensor_get_info(i, &sensor->info); 185 if (ret) 186 return ret; 187 188 switch (sensor->info.class) { 189 case TEMPERATURE: 190 snprintf(sensor->input, sizeof(sensor->input), 191 "temp%d_input", num_temp + 1); 192 snprintf(sensor->label, sizeof(sensor->input), 193 "temp%d_label", num_temp + 1); 194 num_temp++; 195 break; 196 case VOLTAGE: 197 snprintf(sensor->input, sizeof(sensor->input), 198 "in%d_input", num_volt); 199 snprintf(sensor->label, sizeof(sensor->input), 200 "in%d_label", num_volt); 201 num_volt++; 202 break; 203 case CURRENT: 204 snprintf(sensor->input, sizeof(sensor->input), 205 "curr%d_input", num_current + 1); 206 snprintf(sensor->label, sizeof(sensor->input), 207 "curr%d_label", num_current + 1); 208 num_current++; 209 break; 210 case POWER: 211 snprintf(sensor->input, sizeof(sensor->input), 212 "power%d_input", num_power + 1); 213 snprintf(sensor->label, sizeof(sensor->input), 214 "power%d_label", num_power + 1); 215 num_power++; 216 break; 217 case ENERGY: 218 snprintf(sensor->input, sizeof(sensor->input), 219 "energy%d_input", num_energy + 1); 220 snprintf(sensor->label, sizeof(sensor->input), 221 "energy%d_label", num_energy + 1); 222 num_energy++; 223 break; 224 default: 225 continue; 226 } 227 228 sensor->scale = scale[sensor->info.class]; 229 230 sensor->dev_attr_input.attr.mode = 0444; 231 sensor->dev_attr_input.show = scpi_show_sensor; 232 sensor->dev_attr_input.attr.name = sensor->input; 233 234 sensor->dev_attr_label.attr.mode = 0444; 235 sensor->dev_attr_label.show = scpi_show_label; 236 sensor->dev_attr_label.attr.name = sensor->label; 237 238 scpi_sensors->attrs[idx << 1] = &sensor->dev_attr_input.attr; 239 scpi_sensors->attrs[(idx << 1) + 1] = &sensor->dev_attr_label.attr; 240 241 sysfs_attr_init(scpi_sensors->attrs[idx << 1]); 242 sysfs_attr_init(scpi_sensors->attrs[(idx << 1) + 1]); 243 idx++; 244 } 245 246 scpi_sensors->group.attrs = scpi_sensors->attrs; 247 scpi_sensors->groups[0] = &scpi_sensors->group; 248 249 platform_set_drvdata(pdev, scpi_sensors); 250 251 hwdev = devm_hwmon_device_register_with_groups(dev, 252 "scpi_sensors", scpi_sensors, scpi_sensors->groups); 253 254 if (IS_ERR(hwdev)) 255 return PTR_ERR(hwdev); 256 257 /* 258 * Register the temperature sensors with the thermal framework 259 * to allow their usage in setting up the thermal zones from 260 * device tree. 261 * 262 * NOTE: Not all temperature sensors maybe used for thermal 263 * control 264 */ 265 INIT_LIST_HEAD(&scpi_sensors->thermal_zones); 266 for (i = 0; i < nr_sensors; i++) { 267 struct sensor_data *sensor = &scpi_sensors->data[i]; 268 struct thermal_zone_device *z; 269 struct scpi_thermal_zone *zone; 270 271 if (sensor->info.class != TEMPERATURE) 272 continue; 273 274 zone = devm_kzalloc(dev, sizeof(*zone), GFP_KERNEL); 275 if (!zone) 276 return -ENOMEM; 277 278 zone->sensor_id = i; 279 zone->scpi_sensors = scpi_sensors; 280 z = devm_thermal_zone_of_sensor_register(dev, 281 sensor->info.sensor_id, 282 zone, 283 &scpi_sensor_ops); 284 /* 285 * The call to thermal_zone_of_sensor_register returns 286 * an error for sensors that are not associated with 287 * any thermal zones or if the thermal subsystem is 288 * not configured. 289 */ 290 if (IS_ERR(z)) 291 devm_kfree(dev, zone); 292 } 293 294 return 0; 295 } 296 297 static struct platform_driver scpi_hwmon_platdrv = { 298 .driver = { 299 .name = "scpi-hwmon", 300 .of_match_table = scpi_of_match, 301 }, 302 .probe = scpi_hwmon_probe, 303 }; 304 module_platform_driver(scpi_hwmon_platdrv); 305 306 MODULE_AUTHOR("Punit Agrawal <punit.agrawal@arm.com>"); 307 MODULE_DESCRIPTION("ARM SCPI HWMON interface driver"); 308 MODULE_LICENSE("GPL v2"); 309