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/of_device.h> 20 #include <linux/platform_device.h> 21 #include <linux/scpi_protocol.h> 22 #include <linux/slab.h> 23 #include <linux/sysfs.h> 24 #include <linux/thermal.h> 25 26 struct sensor_data { 27 unsigned int scale; 28 struct scpi_sensor_info info; 29 struct device_attribute dev_attr_input; 30 struct device_attribute dev_attr_label; 31 char input[20]; 32 char label[20]; 33 }; 34 35 struct scpi_thermal_zone { 36 int sensor_id; 37 struct scpi_sensors *scpi_sensors; 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 const u32 gxbb_scpi_scale[] = { 50 [TEMPERATURE] = 1, /* (celsius) */ 51 [VOLTAGE] = 1000, /* (millivolts) */ 52 [CURRENT] = 1000, /* (milliamperes) */ 53 [POWER] = 1000000, /* (microwatts) */ 54 [ENERGY] = 1000000, /* (microjoules) */ 55 }; 56 57 static const u32 scpi_scale[] = { 58 [TEMPERATURE] = 1000, /* (millicelsius) */ 59 [VOLTAGE] = 1000, /* (millivolts) */ 60 [CURRENT] = 1000, /* (milliamperes) */ 61 [POWER] = 1000000, /* (microwatts) */ 62 [ENERGY] = 1000000, /* (microjoules) */ 63 }; 64 65 static void scpi_scale_reading(u64 *value, struct sensor_data *sensor) 66 { 67 if (scpi_scale[sensor->info.class] != sensor->scale) { 68 *value *= scpi_scale[sensor->info.class]; 69 do_div(*value, sensor->scale); 70 } 71 } 72 73 static int scpi_read_temp(void *dev, int *temp) 74 { 75 struct scpi_thermal_zone *zone = dev; 76 struct scpi_sensors *scpi_sensors = zone->scpi_sensors; 77 struct scpi_ops *scpi_ops = scpi_sensors->scpi_ops; 78 struct sensor_data *sensor = &scpi_sensors->data[zone->sensor_id]; 79 u64 value; 80 int ret; 81 82 ret = scpi_ops->sensor_get_value(sensor->info.sensor_id, &value); 83 if (ret) 84 return ret; 85 86 scpi_scale_reading(&value, sensor); 87 88 *temp = value; 89 return 0; 90 } 91 92 /* hwmon callback functions */ 93 static ssize_t 94 scpi_show_sensor(struct device *dev, struct device_attribute *attr, char *buf) 95 { 96 struct scpi_sensors *scpi_sensors = dev_get_drvdata(dev); 97 struct scpi_ops *scpi_ops = scpi_sensors->scpi_ops; 98 struct sensor_data *sensor; 99 u64 value; 100 int ret; 101 102 sensor = container_of(attr, struct sensor_data, dev_attr_input); 103 104 ret = scpi_ops->sensor_get_value(sensor->info.sensor_id, &value); 105 if (ret) 106 return ret; 107 108 scpi_scale_reading(&value, sensor); 109 110 return sprintf(buf, "%llu\n", value); 111 } 112 113 static ssize_t 114 scpi_show_label(struct device *dev, struct device_attribute *attr, char *buf) 115 { 116 struct sensor_data *sensor; 117 118 sensor = container_of(attr, struct sensor_data, dev_attr_label); 119 120 return sprintf(buf, "%s\n", sensor->info.name); 121 } 122 123 static const struct thermal_zone_of_device_ops scpi_sensor_ops = { 124 .get_temp = scpi_read_temp, 125 }; 126 127 static const struct of_device_id scpi_of_match[] = { 128 {.compatible = "arm,scpi-sensors", .data = &scpi_scale}, 129 {.compatible = "amlogic,meson-gxbb-scpi-sensors", .data = &gxbb_scpi_scale}, 130 {}, 131 }; 132 MODULE_DEVICE_TABLE(of, scpi_of_match); 133 134 static int scpi_hwmon_probe(struct platform_device *pdev) 135 { 136 u16 nr_sensors, i; 137 const u32 *scale; 138 int num_temp = 0, num_volt = 0, num_current = 0, num_power = 0; 139 int num_energy = 0; 140 struct scpi_ops *scpi_ops; 141 struct device *hwdev, *dev = &pdev->dev; 142 struct scpi_sensors *scpi_sensors; 143 const struct of_device_id *of_id; 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 of_id = of_match_device(scpi_of_match, &pdev->dev); 174 if (!of_id) { 175 dev_err(&pdev->dev, "Unable to initialize scpi-hwmon data\n"); 176 return -ENODEV; 177 } 178 scale = of_id->data; 179 180 for (i = 0, idx = 0; i < nr_sensors; i++) { 181 struct sensor_data *sensor = &scpi_sensors->data[idx]; 182 183 ret = scpi_ops->sensor_get_info(i, &sensor->info); 184 if (ret) 185 return ret; 186 187 switch (sensor->info.class) { 188 case TEMPERATURE: 189 snprintf(sensor->input, sizeof(sensor->input), 190 "temp%d_input", num_temp + 1); 191 snprintf(sensor->label, sizeof(sensor->input), 192 "temp%d_label", num_temp + 1); 193 num_temp++; 194 break; 195 case VOLTAGE: 196 snprintf(sensor->input, sizeof(sensor->input), 197 "in%d_input", num_volt); 198 snprintf(sensor->label, sizeof(sensor->input), 199 "in%d_label", num_volt); 200 num_volt++; 201 break; 202 case CURRENT: 203 snprintf(sensor->input, sizeof(sensor->input), 204 "curr%d_input", num_current + 1); 205 snprintf(sensor->label, sizeof(sensor->input), 206 "curr%d_label", num_current + 1); 207 num_current++; 208 break; 209 case POWER: 210 snprintf(sensor->input, sizeof(sensor->input), 211 "power%d_input", num_power + 1); 212 snprintf(sensor->label, sizeof(sensor->input), 213 "power%d_label", num_power + 1); 214 num_power++; 215 break; 216 case ENERGY: 217 snprintf(sensor->input, sizeof(sensor->input), 218 "energy%d_input", num_energy + 1); 219 snprintf(sensor->label, sizeof(sensor->input), 220 "energy%d_label", num_energy + 1); 221 num_energy++; 222 break; 223 default: 224 continue; 225 } 226 227 sensor->scale = scale[sensor->info.class]; 228 229 sensor->dev_attr_input.attr.mode = S_IRUGO; 230 sensor->dev_attr_input.show = scpi_show_sensor; 231 sensor->dev_attr_input.attr.name = sensor->input; 232 233 sensor->dev_attr_label.attr.mode = S_IRUGO; 234 sensor->dev_attr_label.show = scpi_show_label; 235 sensor->dev_attr_label.attr.name = sensor->label; 236 237 scpi_sensors->attrs[idx << 1] = &sensor->dev_attr_input.attr; 238 scpi_sensors->attrs[(idx << 1) + 1] = &sensor->dev_attr_label.attr; 239 240 sysfs_attr_init(scpi_sensors->attrs[idx << 1]); 241 sysfs_attr_init(scpi_sensors->attrs[(idx << 1) + 1]); 242 idx++; 243 } 244 245 scpi_sensors->group.attrs = scpi_sensors->attrs; 246 scpi_sensors->groups[0] = &scpi_sensors->group; 247 248 platform_set_drvdata(pdev, scpi_sensors); 249 250 hwdev = devm_hwmon_device_register_with_groups(dev, 251 "scpi_sensors", scpi_sensors, scpi_sensors->groups); 252 253 if (IS_ERR(hwdev)) 254 return PTR_ERR(hwdev); 255 256 /* 257 * Register the temperature sensors with the thermal framework 258 * to allow their usage in setting up the thermal zones from 259 * device tree. 260 * 261 * NOTE: Not all temperature sensors maybe used for thermal 262 * control 263 */ 264 INIT_LIST_HEAD(&scpi_sensors->thermal_zones); 265 for (i = 0; i < nr_sensors; i++) { 266 struct sensor_data *sensor = &scpi_sensors->data[i]; 267 struct thermal_zone_device *z; 268 struct scpi_thermal_zone *zone; 269 270 if (sensor->info.class != TEMPERATURE) 271 continue; 272 273 zone = devm_kzalloc(dev, sizeof(*zone), GFP_KERNEL); 274 if (!zone) 275 return -ENOMEM; 276 277 zone->sensor_id = i; 278 zone->scpi_sensors = scpi_sensors; 279 z = devm_thermal_zone_of_sensor_register(dev, 280 sensor->info.sensor_id, 281 zone, 282 &scpi_sensor_ops); 283 /* 284 * The call to thermal_zone_of_sensor_register returns 285 * an error for sensors that are not associated with 286 * any thermal zones or if the thermal subsystem is 287 * not configured. 288 */ 289 if (IS_ERR(z)) 290 devm_kfree(dev, zone); 291 } 292 293 return 0; 294 } 295 296 static struct platform_driver scpi_hwmon_platdrv = { 297 .driver = { 298 .name = "scpi-hwmon", 299 .of_match_table = scpi_of_match, 300 }, 301 .probe = scpi_hwmon_probe, 302 }; 303 module_platform_driver(scpi_hwmon_platdrv); 304 305 MODULE_AUTHOR("Punit Agrawal <punit.agrawal@arm.com>"); 306 MODULE_DESCRIPTION("ARM SCPI HWMON interface driver"); 307 MODULE_LICENSE("GPL v2"); 308