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
scpi_scale_reading(u64 * value,struct sensor_data * sensor)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
scpi_read_temp(struct thermal_zone_device * tz,int * temp)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
scpi_show_sensor(struct device * dev,struct device_attribute * attr,char * buf)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
scpi_show_label(struct device * dev,struct device_attribute * attr,char * buf)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
scpi_hwmon_probe(struct platform_device * pdev)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