scmi-hwmon.c

  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(*value, 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);
 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(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(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
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, 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
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, 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
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	u32 sensor_config = FIELD_PREP(SCMI_SENS_CFG_SENSOR_ENABLED_MASK,
244				       SCMI_SENS_CFG_SENSOR_ENABLE);
245
246	if (!handle)
247		return -ENODEV;
248
249	sensor_ops = handle->devm_protocol_get(sdev, SCMI_PROTOCOL_SENSOR, &ph);
250	if (IS_ERR(sensor_ops))
251		return PTR_ERR(sensor_ops);
252
253	nr_sensors = sensor_ops->count_get(ph);
254	if (!nr_sensors)
255		return -EIO;
256
257	scmi_sensors = devm_kzalloc(dev, sizeof(*scmi_sensors), GFP_KERNEL);
258	if (!scmi_sensors)
259		return -ENOMEM;
260
261	scmi_sensors->ph = ph;
262
263	for (i = 0; i < nr_sensors; i++) {
264		sensor = sensor_ops->info_get(ph, i);
265		if (!sensor)
266			return -EINVAL;
267
268		switch (sensor->type) {
269		case TEMPERATURE_C:
270		case VOLTAGE:
271		case CURRENT:
272		case POWER:
273		case ENERGY:
274			type = scmi_types[sensor->type];
275			if (!nr_count[type])
276				nr_types++;
277			nr_count[type]++;
278			break;
279		}
280	}
281
282	if (nr_count[hwmon_temp])
283		nr_count_temp = nr_count[hwmon_temp];
284
285	scmi_hwmon_chan = devm_kcalloc(dev, nr_types, sizeof(*scmi_hwmon_chan),
286				       GFP_KERNEL);
287	if (!scmi_hwmon_chan)
288		return -ENOMEM;
289
290	ptr_scmi_ci = devm_kcalloc(dev, nr_types + 1, sizeof(*ptr_scmi_ci),
291				   GFP_KERNEL);
292	if (!ptr_scmi_ci)
293		return -ENOMEM;
294
295	scmi_chip_info.info = ptr_scmi_ci;
296	chip_info = &scmi_chip_info;
297
298	for (type = 0; type < hwmon_max; type++) {
299		if (!nr_count[type])
300			continue;
301
302		scmi_hwmon_add_chan_info(scmi_hwmon_chan, dev, nr_count[type],
303					 type, hwmon_attributes[type]);
304		*ptr_scmi_ci++ = scmi_hwmon_chan++;
305
306		scmi_sensors->info[type] =
307			devm_kcalloc(dev, nr_count[type],
308				     sizeof(*scmi_sensors->info), GFP_KERNEL);
309		if (!scmi_sensors->info[type])
310			return -ENOMEM;
311	}
312
313	for (i = nr_sensors - 1; i >= 0 ; i--) {
314		sensor = sensor_ops->info_get(ph, i);
315		if (!sensor)
316			continue;
317
318		switch (sensor->type) {
319		case TEMPERATURE_C:
320		case VOLTAGE:
321		case CURRENT:
322		case POWER:
323		case ENERGY:
324			type = scmi_types[sensor->type];
325			idx = --nr_count[type];
326			*(scmi_sensors->info[type] + idx) = sensor;
327			break;
328		}
329	}
330
331	hwdev = devm_hwmon_device_register_with_info(dev, "scmi_sensors",
332						     scmi_sensors, chip_info,
333						     NULL);
334	if (IS_ERR(hwdev))
335		return PTR_ERR(hwdev);
336
337	for (i = 0; i < nr_count_temp; i++) {
338		int ret;
339
340		sensor = *(scmi_sensors->info[hwmon_temp] + i);
341		if (!sensor)
342			continue;
343
344		ret = sensor_ops->config_set(ph, i, sensor_config);
345		if (ret) {
346			dev_err(dev, "Error enabling sensor %s. err=%d\n",
347				sensor->name, ret);
348			continue;
349		}
350
351		/*
352		 * Warn on any misconfiguration related to thermal zones but
353		 * bail out of probing only on memory errors.
354		 */
355		ret = scmi_thermal_sensor_register(dev, ph, sensor);
356		if (ret) {
357			if (ret == -ENOMEM)
358				return ret;
359			dev_warn(dev,
360				 "Thermal zone misconfigured for %s. err=%d\n",
361				 sensor->name, ret);
362		}
363	}
364
365	return 0;
366}
367
368static const struct scmi_device_id scmi_id_table[] = {
369	{ SCMI_PROTOCOL_SENSOR, "hwmon" },
370	{ },
371};
372MODULE_DEVICE_TABLE(scmi, scmi_id_table);
373
374static struct scmi_driver scmi_hwmon_drv = {
375	.name		= "scmi-hwmon",
376	.probe		= scmi_hwmon_probe,
377	.id_table	= scmi_id_table,
378};
379module_scmi_driver(scmi_hwmon_drv);
380
381MODULE_AUTHOR("Sudeep Holla <sudeep.holla@arm.com>");
382MODULE_DESCRIPTION("ARM SCMI HWMON interface driver");
383MODULE_LICENSE("GPL v2");