2 * System Control and Power Interface(SCPI) based hwmon sensor driver
4 * Copyright (C) 2015 ARM Ltd.
5 * Punit Agrawal <punit.agrawal@arm.com>
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.
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.
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>
28 struct scpi_sensor_info info;
29 struct device_attribute dev_attr_input;
30 struct device_attribute dev_attr_label;
35 struct scpi_thermal_zone {
37 struct scpi_sensors *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];
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) */
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) */
65 static void scpi_scale_reading(u64 *value, struct sensor_data *sensor)
67 if (scpi_scale[sensor->info.class] != sensor->scale) {
68 *value *= scpi_scale[sensor->info.class];
69 do_div(*value, sensor->scale);
73 static int scpi_read_temp(void *dev, int *temp)
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];
82 ret = scpi_ops->sensor_get_value(sensor->info.sensor_id, &value);
86 scpi_scale_reading(&value, sensor);
92 /* hwmon callback functions */
94 scpi_show_sensor(struct device *dev, struct device_attribute *attr, char *buf)
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;
102 sensor = container_of(attr, struct sensor_data, dev_attr_input);
104 ret = scpi_ops->sensor_get_value(sensor->info.sensor_id, &value);
108 scpi_scale_reading(&value, sensor);
111 * Temperature sensor values are treated as signed values based on
112 * observation even though that is not explicitly specified, and
113 * because an unsigned u64 temperature does not really make practical
114 * sense especially when the temperature is below zero degrees Celsius.
116 if (sensor->info.class == TEMPERATURE)
117 return sprintf(buf, "%lld\n", (s64)value);
119 return sprintf(buf, "%llu\n", value);
123 scpi_show_label(struct device *dev, struct device_attribute *attr, char *buf)
125 struct sensor_data *sensor;
127 sensor = container_of(attr, struct sensor_data, dev_attr_label);
129 return sprintf(buf, "%s\n", sensor->info.name);
132 static const struct thermal_zone_of_device_ops scpi_sensor_ops = {
133 .get_temp = scpi_read_temp,
136 static const struct of_device_id scpi_of_match[] = {
137 {.compatible = "arm,scpi-sensors", .data = &scpi_scale},
138 {.compatible = "amlogic,meson-gxbb-scpi-sensors", .data = &gxbb_scpi_scale},
141 MODULE_DEVICE_TABLE(of, scpi_of_match);
143 static int scpi_hwmon_probe(struct platform_device *pdev)
147 int num_temp = 0, num_volt = 0, num_current = 0, num_power = 0;
149 struct scpi_ops *scpi_ops;
150 struct device *hwdev, *dev = &pdev->dev;
151 struct scpi_sensors *scpi_sensors;
152 const struct of_device_id *of_id;
155 scpi_ops = get_scpi_ops();
157 return -EPROBE_DEFER;
159 ret = scpi_ops->sensor_get_capability(&nr_sensors);
166 scpi_sensors = devm_kzalloc(dev, sizeof(*scpi_sensors), GFP_KERNEL);
170 scpi_sensors->data = devm_kcalloc(dev, nr_sensors,
171 sizeof(*scpi_sensors->data), GFP_KERNEL);
172 if (!scpi_sensors->data)
175 scpi_sensors->attrs = devm_kcalloc(dev, (nr_sensors * 2) + 1,
176 sizeof(*scpi_sensors->attrs), GFP_KERNEL);
177 if (!scpi_sensors->attrs)
180 scpi_sensors->scpi_ops = scpi_ops;
182 of_id = of_match_device(scpi_of_match, &pdev->dev);
184 dev_err(&pdev->dev, "Unable to initialize scpi-hwmon data\n");
189 for (i = 0, idx = 0; i < nr_sensors; i++) {
190 struct sensor_data *sensor = &scpi_sensors->data[idx];
192 ret = scpi_ops->sensor_get_info(i, &sensor->info);
196 switch (sensor->info.class) {
198 snprintf(sensor->input, sizeof(sensor->input),
199 "temp%d_input", num_temp + 1);
200 snprintf(sensor->label, sizeof(sensor->input),
201 "temp%d_label", num_temp + 1);
205 snprintf(sensor->input, sizeof(sensor->input),
206 "in%d_input", num_volt);
207 snprintf(sensor->label, sizeof(sensor->input),
208 "in%d_label", num_volt);
212 snprintf(sensor->input, sizeof(sensor->input),
213 "curr%d_input", num_current + 1);
214 snprintf(sensor->label, sizeof(sensor->input),
215 "curr%d_label", num_current + 1);
219 snprintf(sensor->input, sizeof(sensor->input),
220 "power%d_input", num_power + 1);
221 snprintf(sensor->label, sizeof(sensor->input),
222 "power%d_label", num_power + 1);
226 snprintf(sensor->input, sizeof(sensor->input),
227 "energy%d_input", num_energy + 1);
228 snprintf(sensor->label, sizeof(sensor->input),
229 "energy%d_label", num_energy + 1);
236 sensor->scale = scale[sensor->info.class];
238 sensor->dev_attr_input.attr.mode = S_IRUGO;
239 sensor->dev_attr_input.show = scpi_show_sensor;
240 sensor->dev_attr_input.attr.name = sensor->input;
242 sensor->dev_attr_label.attr.mode = S_IRUGO;
243 sensor->dev_attr_label.show = scpi_show_label;
244 sensor->dev_attr_label.attr.name = sensor->label;
246 scpi_sensors->attrs[idx << 1] = &sensor->dev_attr_input.attr;
247 scpi_sensors->attrs[(idx << 1) + 1] = &sensor->dev_attr_label.attr;
249 sysfs_attr_init(scpi_sensors->attrs[idx << 1]);
250 sysfs_attr_init(scpi_sensors->attrs[(idx << 1) + 1]);
254 scpi_sensors->group.attrs = scpi_sensors->attrs;
255 scpi_sensors->groups[0] = &scpi_sensors->group;
257 platform_set_drvdata(pdev, scpi_sensors);
259 hwdev = devm_hwmon_device_register_with_groups(dev,
260 "scpi_sensors", scpi_sensors, scpi_sensors->groups);
263 return PTR_ERR(hwdev);
266 * Register the temperature sensors with the thermal framework
267 * to allow their usage in setting up the thermal zones from
270 * NOTE: Not all temperature sensors maybe used for thermal
273 INIT_LIST_HEAD(&scpi_sensors->thermal_zones);
274 for (i = 0; i < nr_sensors; i++) {
275 struct sensor_data *sensor = &scpi_sensors->data[i];
276 struct thermal_zone_device *z;
277 struct scpi_thermal_zone *zone;
279 if (sensor->info.class != TEMPERATURE)
282 zone = devm_kzalloc(dev, sizeof(*zone), GFP_KERNEL);
287 zone->scpi_sensors = scpi_sensors;
288 z = devm_thermal_zone_of_sensor_register(dev,
289 sensor->info.sensor_id,
293 * The call to thermal_zone_of_sensor_register returns
294 * an error for sensors that are not associated with
295 * any thermal zones or if the thermal subsystem is
299 devm_kfree(dev, zone);
307 static struct platform_driver scpi_hwmon_platdrv = {
309 .name = "scpi-hwmon",
310 .of_match_table = scpi_of_match,
312 .probe = scpi_hwmon_probe,
314 module_platform_driver(scpi_hwmon_platdrv);
316 MODULE_AUTHOR("Punit Agrawal <punit.agrawal@arm.com>");
317 MODULE_DESCRIPTION("ARM SCPI HWMON interface driver");
318 MODULE_LICENSE("GPL v2");