1// SPDX-License-Identifier: GPL-2.0
2/*
3 * System Control and Management Interface(SCMI) based hwmon sensor driver
4 *
5 * Copyright (C) 2018-2021 ARM Ltd.
6 * Sudeep Holla <sudeep.holla@arm.com>
7 */
8
9#include <linux/hwmon.h>
10#include <linux/module.h>
11#include <linux/scmi_protocol.h>
12#include <linux/slab.h>
13#include <linux/sysfs.h>
14#include <linux/thermal.h>
15
16static const struct scmi_sensor_proto_ops *sensor_ops;
17
18struct scmi_sensors {
19 const struct scmi_protocol_handle *ph;
20 const struct scmi_sensor_info **info[hwmon_max];
21};
22
23struct scmi_thermal_sensor {
24 const struct scmi_protocol_handle *ph;
25 const struct scmi_sensor_info *info;
26};
27
28static inline u64 __pow10(u8 x)
29{
30 u64 r = 1;
31
32 while (x--)
33 r *= 10;
34
35 return r;
36}
37
38static int scmi_hwmon_scale(const struct scmi_sensor_info *sensor, u64 *value)
39{
40 int scale = sensor->scale;
41 u64 f;
42
43 switch (sensor->type) {
44 case TEMPERATURE_C:
45 case VOLTAGE:
46 case CURRENT:
47 scale += 3;
48 break;
49 case POWER:
50 case ENERGY:
51 scale += 6;
52 break;
53 default:
54 break;
55 }
56
57 if (scale == 0)
58 return 0;
59
60 if (abs(scale) > 19)
61 return -E2BIG;
62
63 f = __pow10(abs(scale));
64 if (scale > 0)
65 *value *= f;
66 else
67 *value = div64_u64(dividend: *value, divisor: f);
68
69 return 0;
70}
71
72static int scmi_hwmon_read_scaled_value(const struct scmi_protocol_handle *ph,
73 const struct scmi_sensor_info *sensor,
74 long *val)
75{
76 int ret;
77 u64 value;
78
79 ret = sensor_ops->reading_get(ph, sensor->id, &value);
80 if (ret)
81 return ret;
82
83 ret = scmi_hwmon_scale(sensor, value: &value);
84 if (!ret)
85 *val = value;
86
87 return ret;
88}
89
90static int scmi_hwmon_read(struct device *dev, enum hwmon_sensor_types type,
91 u32 attr, int channel, long *val)
92{
93 const struct scmi_sensor_info *sensor;
94 struct scmi_sensors *scmi_sensors = dev_get_drvdata(dev);
95
96 sensor = *(scmi_sensors->info[type] + channel);
97
98 return scmi_hwmon_read_scaled_value(ph: scmi_sensors->ph, sensor, val);
99}
100
101static int
102scmi_hwmon_read_string(struct device *dev, enum hwmon_sensor_types type,
103 u32 attr, int channel, const char **str)
104{
105 const struct scmi_sensor_info *sensor;
106 struct scmi_sensors *scmi_sensors = dev_get_drvdata(dev);
107
108 sensor = *(scmi_sensors->info[type] + channel);
109 *str = sensor->name;
110
111 return 0;
112}
113
114static umode_t
115scmi_hwmon_is_visible(const void *drvdata, enum hwmon_sensor_types type,
116 u32 attr, int channel)
117{
118 const struct scmi_sensor_info *sensor;
119 const struct scmi_sensors *scmi_sensors = drvdata;
120
121 sensor = *(scmi_sensors->info[type] + channel);
122 if (sensor)
123 return 0444;
124
125 return 0;
126}
127
128static const struct hwmon_ops scmi_hwmon_ops = {
129 .is_visible = scmi_hwmon_is_visible,
130 .read = scmi_hwmon_read,
131 .read_string = scmi_hwmon_read_string,
132};
133
134static struct hwmon_chip_info scmi_chip_info = {
135 .ops = &scmi_hwmon_ops,
136 .info = NULL,
137};
138
139static int scmi_hwmon_thermal_get_temp(struct thermal_zone_device *tz,
140 int *temp)
141{
142 int ret;
143 long value;
144 struct scmi_thermal_sensor *th_sensor = thermal_zone_device_priv(tzd: tz);
145
146 ret = scmi_hwmon_read_scaled_value(ph: th_sensor->ph, sensor: th_sensor->info,
147 val: &value);
148 if (!ret)
149 *temp = value;
150
151 return ret;
152}
153
154static const struct thermal_zone_device_ops scmi_hwmon_thermal_ops = {
155 .get_temp = scmi_hwmon_thermal_get_temp,
156};
157
158static int scmi_hwmon_add_chan_info(struct hwmon_channel_info *scmi_hwmon_chan,
159 struct device *dev, int num,
160 enum hwmon_sensor_types type, u32 config)
161{
162 int i;
163 u32 *cfg = devm_kcalloc(dev, n: num + 1, size: sizeof(*cfg), GFP_KERNEL);
164
165 if (!cfg)
166 return -ENOMEM;
167
168 scmi_hwmon_chan->type = type;
169 scmi_hwmon_chan->config = cfg;
170 for (i = 0; i < num; i++, cfg++)
171 *cfg = config;
172
173 return 0;
174}
175
176static enum hwmon_sensor_types scmi_types[] = {
177 [TEMPERATURE_C] = hwmon_temp,
178 [VOLTAGE] = hwmon_in,
179 [CURRENT] = hwmon_curr,
180 [POWER] = hwmon_power,
181 [ENERGY] = hwmon_energy,
182};
183
184static u32 hwmon_attributes[hwmon_max] = {
185 [hwmon_temp] = HWMON_T_INPUT | HWMON_T_LABEL,
186 [hwmon_in] = HWMON_I_INPUT | HWMON_I_LABEL,
187 [hwmon_curr] = HWMON_C_INPUT | HWMON_C_LABEL,
188 [hwmon_power] = HWMON_P_INPUT | HWMON_P_LABEL,
189 [hwmon_energy] = HWMON_E_INPUT | HWMON_E_LABEL,
190};
191
192static int scmi_thermal_sensor_register(struct device *dev,
193 const struct scmi_protocol_handle *ph,
194 const struct scmi_sensor_info *sensor)
195{
196 struct scmi_thermal_sensor *th_sensor;
197 struct thermal_zone_device *tzd;
198
199 th_sensor = devm_kzalloc(dev, size: sizeof(*th_sensor), GFP_KERNEL);
200 if (!th_sensor)
201 return -ENOMEM;
202
203 th_sensor->ph = ph;
204 th_sensor->info = sensor;
205
206 /*
207 * Try to register a temperature sensor with the Thermal Framework:
208 * skip sensors not defined as part of any thermal zone (-ENODEV) but
209 * report any other errors related to misconfigured zones/sensors.
210 */
211 tzd = devm_thermal_of_zone_register(dev, id: th_sensor->info->id, data: th_sensor,
212 ops: &scmi_hwmon_thermal_ops);
213 if (IS_ERR(ptr: tzd)) {
214 devm_kfree(dev, p: th_sensor);
215
216 if (PTR_ERR(ptr: tzd) != -ENODEV)
217 return PTR_ERR(ptr: tzd);
218
219 dev_dbg(dev, "Sensor '%s' not attached to any thermal zone.\n",
220 sensor->name);
221 } else {
222 dev_dbg(dev, "Sensor '%s' attached to thermal zone ID:%d\n",
223 sensor->name, thermal_zone_device_id(tzd));
224 }
225
226 return 0;
227}
228
229static int scmi_hwmon_probe(struct scmi_device *sdev)
230{
231 int i, idx;
232 u16 nr_sensors;
233 enum hwmon_sensor_types type;
234 struct scmi_sensors *scmi_sensors;
235 const struct scmi_sensor_info *sensor;
236 int nr_count[hwmon_max] = {0}, nr_types = 0, nr_count_temp = 0;
237 const struct hwmon_chip_info *chip_info;
238 struct device *hwdev, *dev = &sdev->dev;
239 struct hwmon_channel_info *scmi_hwmon_chan;
240 const struct hwmon_channel_info **ptr_scmi_ci;
241 const struct scmi_handle *handle = sdev->handle;
242 struct scmi_protocol_handle *ph;
243
244 if (!handle)
245 return -ENODEV;
246
247 sensor_ops = handle->devm_protocol_get(sdev, SCMI_PROTOCOL_SENSOR, &ph);
248 if (IS_ERR(ptr: sensor_ops))
249 return PTR_ERR(ptr: sensor_ops);
250
251 nr_sensors = sensor_ops->count_get(ph);
252 if (!nr_sensors)
253 return -EIO;
254
255 scmi_sensors = devm_kzalloc(dev, size: sizeof(*scmi_sensors), GFP_KERNEL);
256 if (!scmi_sensors)
257 return -ENOMEM;
258
259 scmi_sensors->ph = ph;
260
261 for (i = 0; i < nr_sensors; i++) {
262 sensor = sensor_ops->info_get(ph, i);
263 if (!sensor)
264 return -EINVAL;
265
266 switch (sensor->type) {
267 case TEMPERATURE_C:
268 case VOLTAGE:
269 case CURRENT:
270 case POWER:
271 case ENERGY:
272 type = scmi_types[sensor->type];
273 if (!nr_count[type])
274 nr_types++;
275 nr_count[type]++;
276 break;
277 }
278 }
279
280 if (nr_count[hwmon_temp])
281 nr_count_temp = nr_count[hwmon_temp];
282
283 scmi_hwmon_chan = devm_kcalloc(dev, n: nr_types, size: sizeof(*scmi_hwmon_chan),
284 GFP_KERNEL);
285 if (!scmi_hwmon_chan)
286 return -ENOMEM;
287
288 ptr_scmi_ci = devm_kcalloc(dev, n: nr_types + 1, size: sizeof(*ptr_scmi_ci),
289 GFP_KERNEL);
290 if (!ptr_scmi_ci)
291 return -ENOMEM;
292
293 scmi_chip_info.info = ptr_scmi_ci;
294 chip_info = &scmi_chip_info;
295
296 for (type = 0; type < hwmon_max; type++) {
297 if (!nr_count[type])
298 continue;
299
300 scmi_hwmon_add_chan_info(scmi_hwmon_chan, dev, num: nr_count[type],
301 type, config: hwmon_attributes[type]);
302 *ptr_scmi_ci++ = scmi_hwmon_chan++;
303
304 scmi_sensors->info[type] =
305 devm_kcalloc(dev, n: nr_count[type],
306 size: sizeof(*scmi_sensors->info), GFP_KERNEL);
307 if (!scmi_sensors->info[type])
308 return -ENOMEM;
309 }
310
311 for (i = nr_sensors - 1; i >= 0 ; i--) {
312 sensor = sensor_ops->info_get(ph, i);
313 if (!sensor)
314 continue;
315
316 switch (sensor->type) {
317 case TEMPERATURE_C:
318 case VOLTAGE:
319 case CURRENT:
320 case POWER:
321 case ENERGY:
322 type = scmi_types[sensor->type];
323 idx = --nr_count[type];
324 *(scmi_sensors->info[type] + idx) = sensor;
325 break;
326 }
327 }
328
329 hwdev = devm_hwmon_device_register_with_info(dev, name: "scmi_sensors",
330 drvdata: scmi_sensors, info: chip_info,
331 NULL);
332 if (IS_ERR(ptr: hwdev))
333 return PTR_ERR(ptr: hwdev);
334
335 for (i = 0; i < nr_count_temp; i++) {
336 int ret;
337
338 sensor = *(scmi_sensors->info[hwmon_temp] + i);
339 if (!sensor)
340 continue;
341
342 /*
343 * Warn on any misconfiguration related to thermal zones but
344 * bail out of probing only on memory errors.
345 */
346 ret = scmi_thermal_sensor_register(dev, ph, sensor);
347 if (ret) {
348 if (ret == -ENOMEM)
349 return ret;
350 dev_warn(dev,
351 "Thermal zone misconfigured for %s. err=%d\n",
352 sensor->name, ret);
353 }
354 }
355
356 return 0;
357}
358
359static const struct scmi_device_id scmi_id_table[] = {
360 { SCMI_PROTOCOL_SENSOR, "hwmon" },
361 { },
362};
363MODULE_DEVICE_TABLE(scmi, scmi_id_table);
364
365static struct scmi_driver scmi_hwmon_drv = {
366 .name = "scmi-hwmon",
367 .probe = scmi_hwmon_probe,
368 .id_table = scmi_id_table,
369};
370module_scmi_driver(scmi_hwmon_drv);
371
372MODULE_AUTHOR("Sudeep Holla <sudeep.holla@arm.com>");
373MODULE_DESCRIPTION("ARM SCMI HWMON interface driver");
374MODULE_LICENSE("GPL v2");
375

source code of linux/drivers/hwmon/scmi-hwmon.c