xref: /openbmc/linux/drivers/hwmon/scmi-hwmon.c (revision c4c3c32d) 
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 
16 static const struct scmi_sensor_proto_ops *sensor_ops;
17 
18 struct scmi_sensors {
19 	const struct scmi_protocol_handle *ph;
20 	const struct scmi_sensor_info **info[hwmon_max];
21 };
22 
23 struct scmi_thermal_sensor {
24 	const struct scmi_protocol_handle *ph;
25 	const struct scmi_sensor_info *info;
26 };
27 
28 static inline u64 __pow10(u8 x)
29 {
30 	u64 r = 1;
31 
32 	while (x--)
33 		r *= 10;
34 
35 	return r;
36 }
37 
38 static 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(*value, f);
68 
69 	return 0;
70 }
71 
72 static 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);
84 	if (!ret)
85 		*val = value;
86 
87 	return ret;
88 }
89 
90 static 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(scmi_sensors->ph, sensor, val);
99 }
100 
101 static int
102 scmi_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 
114 static umode_t
115 scmi_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 
128 static 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 
134 static struct hwmon_chip_info scmi_chip_info = {
135 	.ops = &scmi_hwmon_ops,
136 	.info = NULL,
137 };
138 
139 static 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(tz);
145 
146 	ret = scmi_hwmon_read_scaled_value(th_sensor->ph, th_sensor->info,
147 					   &value);
148 	if (!ret)
149 		*temp = value;
150 
151 	return ret;
152 }
153 
154 static const struct thermal_zone_device_ops scmi_hwmon_thermal_ops = {
155 	.get_temp = scmi_hwmon_thermal_get_temp,
156 };
157 
158 static 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, num + 1, 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 
176 static 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 
184 static 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 
192 static 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, 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, th_sensor->info->id, th_sensor,
212 					    &scmi_hwmon_thermal_ops);
213 	if (IS_ERR(tzd)) {
214 		devm_kfree(dev, th_sensor);
215 
216 		if (PTR_ERR(tzd) != -ENODEV)
217 			return PTR_ERR(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 
229 static 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(sensor_ops))
249 		return PTR_ERR(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, 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, nr_types, sizeof(*scmi_hwmon_chan),
284 				       GFP_KERNEL);
285 	if (!scmi_hwmon_chan)
286 		return -ENOMEM;
287 
288 	ptr_scmi_ci = devm_kcalloc(dev, nr_types + 1, 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, nr_count[type],
301 					 type, hwmon_attributes[type]);
302 		*ptr_scmi_ci++ = scmi_hwmon_chan++;
303 
304 		scmi_sensors->info[type] =
305 			devm_kcalloc(dev, nr_count[type],
306 				     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, "scmi_sensors",
330 						     scmi_sensors, chip_info,
331 						     NULL);
332 	if (IS_ERR(hwdev))
333 		return PTR_ERR(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 
359 static const struct scmi_device_id scmi_id_table[] = {
360 	{ SCMI_PROTOCOL_SENSOR, "hwmon" },
361 	{ },
362 };
363 MODULE_DEVICE_TABLE(scmi, scmi_id_table);
364 
365 static struct scmi_driver scmi_hwmon_drv = {
366 	.name		= "scmi-hwmon",
367 	.probe		= scmi_hwmon_probe,
368 	.id_table	= scmi_id_table,
369 };
370 module_scmi_driver(scmi_hwmon_drv);
371 
372 MODULE_AUTHOR("Sudeep Holla <sudeep.holla@arm.com>");
373 MODULE_DESCRIPTION("ARM SCMI HWMON interface driver");
374 MODULE_LICENSE("GPL v2");
375