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(tzd: 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: &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: &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, fmt: "%lld\n" , (s64)value); |
110 | |
111 | return sprintf(buf, fmt: "%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, fmt: "%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, size: sizeof(*scpi_sensors), GFP_KERNEL); |
158 | if (!scpi_sensors) |
159 | return -ENOMEM; |
160 | |
161 | scpi_sensors->data = devm_kcalloc(dev, n: nr_sensors, |
162 | size: sizeof(*scpi_sensors->data), GFP_KERNEL); |
163 | if (!scpi_sensors->data) |
164 | return -ENOMEM; |
165 | |
166 | scpi_sensors->attrs = devm_kcalloc(dev, n: (nr_sensors * 2) + 1, |
167 | size: 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(dev: &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(buf: sensor->input, size: sizeof(sensor->input), |
189 | fmt: "temp%d_input" , num_temp + 1); |
190 | snprintf(buf: sensor->label, size: sizeof(sensor->input), |
191 | fmt: "temp%d_label" , num_temp + 1); |
192 | num_temp++; |
193 | break; |
194 | case VOLTAGE: |
195 | snprintf(buf: sensor->input, size: sizeof(sensor->input), |
196 | fmt: "in%d_input" , num_volt); |
197 | snprintf(buf: sensor->label, size: sizeof(sensor->input), |
198 | fmt: "in%d_label" , num_volt); |
199 | num_volt++; |
200 | break; |
201 | case CURRENT: |
202 | snprintf(buf: sensor->input, size: sizeof(sensor->input), |
203 | fmt: "curr%d_input" , num_current + 1); |
204 | snprintf(buf: sensor->label, size: sizeof(sensor->input), |
205 | fmt: "curr%d_label" , num_current + 1); |
206 | num_current++; |
207 | break; |
208 | case POWER: |
209 | snprintf(buf: sensor->input, size: sizeof(sensor->input), |
210 | fmt: "power%d_input" , num_power + 1); |
211 | snprintf(buf: sensor->label, size: sizeof(sensor->input), |
212 | fmt: "power%d_label" , num_power + 1); |
213 | num_power++; |
214 | break; |
215 | case ENERGY: |
216 | snprintf(buf: sensor->input, size: sizeof(sensor->input), |
217 | fmt: "energy%d_input" , num_energy + 1); |
218 | snprintf(buf: sensor->label, size: sizeof(sensor->input), |
219 | fmt: "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, data: scpi_sensors); |
248 | |
249 | hwdev = devm_hwmon_device_register_with_groups(dev, |
250 | name: "scpi_sensors" , drvdata: scpi_sensors, groups: scpi_sensors->groups); |
251 | |
252 | if (IS_ERR(ptr: hwdev)) |
253 | return PTR_ERR(ptr: 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(list: &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, size: 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 | id: sensor->info.sensor_id, |
280 | data: zone, |
281 | ops: &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(ptr: z)) |
289 | devm_kfree(dev, p: 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 | |