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.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(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 */ 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_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 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 framework 257 * to allow their usage in setting up the thermal zones from 258 * device tree. 259 * 260 * NOTE: Not all temperature sensors maybe used for thermal 261 * control 262 */ 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 returns 284 * an error for sensors that are not associated with 285 * any thermal zones or if the thermal subsystem is 286 * not configured. 287 */ 288 if (IS_ERR(z)) 289 devm_kfree(dev, zone); 290 } 291 292 return 0; 293 } 294 295 static 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 }; 302 module_platform_driver(scpi_hwmon_platdrv); 303 304 MODULE_AUTHOR("Punit Agrawal <punit.agrawal@arm.com>"); 305 MODULE_DESCRIPTION("ARM SCPI HWMON interface driver"); 306 MODULE_LICENSE("GPL v2"); 307