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
 23static inline u64 __pow10(u8 x)
 24{
 25	u64 r = 1;
 26
 27	while (x--)
 28		r *= 10;
 29
 30	return r;
 31}
 32
 33static int scmi_hwmon_scale(const struct scmi_sensor_info *sensor, u64 *value)
 34{
 35	int scale = sensor->scale;
 36	u64 f;
 37
 38	switch (sensor->type) {
 39	case TEMPERATURE_C:
 40	case VOLTAGE:
 41	case CURRENT:
 42		scale += 3;
 43		break;
 44	case POWER:
 45	case ENERGY:
 46		scale += 6;
 47		break;
 48	default:
 49		break;
 50	}
 51
 52	if (scale == 0)
 53		return 0;
 54
 55	if (abs(scale) > 19)
 56		return -E2BIG;
 57
 58	f = __pow10(abs(scale));
 59	if (scale > 0)
 60		*value *= f;
 61	else
 62		*value = div64_u64(*value, f);
 63
 64	return 0;
 65}
 66
 67static int scmi_hwmon_read(struct device *dev, enum hwmon_sensor_types type,
 68			   u32 attr, int channel, long *val)
 69{
 70	int ret;
 71	u64 value;
 72	const struct scmi_sensor_info *sensor;
 73	struct scmi_sensors *scmi_sensors = dev_get_drvdata(dev);
 74
 75	sensor = *(scmi_sensors->info[type] + channel);
 76	ret = sensor_ops->reading_get(scmi_sensors->ph, sensor->id, &value);
 77	if (ret)
 78		return ret;
 79
 80	ret = scmi_hwmon_scale(sensor, &value);
 81	if (!ret)
 82		*val = value;
 83
 84	return ret;
 85}
 86
 87static int
 88scmi_hwmon_read_string(struct device *dev, enum hwmon_sensor_types type,
 89		       u32 attr, int channel, const char **str)
 90{
 91	const struct scmi_sensor_info *sensor;
 92	struct scmi_sensors *scmi_sensors = dev_get_drvdata(dev);
 93
 94	sensor = *(scmi_sensors->info[type] + channel);
 95	*str = sensor->name;
 96
 97	return 0;
 98}
 99
100static umode_t
101scmi_hwmon_is_visible(const void *drvdata, enum hwmon_sensor_types type,
102		      u32 attr, int channel)
103{
104	const struct scmi_sensor_info *sensor;
105	const struct scmi_sensors *scmi_sensors = drvdata;
106
107	sensor = *(scmi_sensors->info[type] + channel);
108	if (sensor)
109		return 0444;
110
111	return 0;
112}
113
114static const struct hwmon_ops scmi_hwmon_ops = {
115	.is_visible = scmi_hwmon_is_visible,
116	.read = scmi_hwmon_read,
117	.read_string = scmi_hwmon_read_string,
118};
119
120static struct hwmon_chip_info scmi_chip_info = {
121	.ops = &scmi_hwmon_ops,
122	.info = NULL,
123};
124
125static int scmi_hwmon_add_chan_info(struct hwmon_channel_info *scmi_hwmon_chan,
126				    struct device *dev, int num,
127				    enum hwmon_sensor_types type, u32 config)
128{
129	int i;
130	u32 *cfg = devm_kcalloc(dev, num + 1, sizeof(*cfg), GFP_KERNEL);
131
132	if (!cfg)
133		return -ENOMEM;
134
135	scmi_hwmon_chan->type = type;
136	scmi_hwmon_chan->config = cfg;
137	for (i = 0; i < num; i++, cfg++)
138		*cfg = config;
139
140	return 0;
141}
142
143static enum hwmon_sensor_types scmi_types[] = {
144	[TEMPERATURE_C] = hwmon_temp,
145	[VOLTAGE] = hwmon_in,
146	[CURRENT] = hwmon_curr,
147	[POWER] = hwmon_power,
148	[ENERGY] = hwmon_energy,
149};
150
151static u32 hwmon_attributes[hwmon_max] = {
152	[hwmon_chip] = HWMON_C_REGISTER_TZ,
153	[hwmon_temp] = HWMON_T_INPUT | HWMON_T_LABEL,
154	[hwmon_in] = HWMON_I_INPUT | HWMON_I_LABEL,
155	[hwmon_curr] = HWMON_C_INPUT | HWMON_C_LABEL,
156	[hwmon_power] = HWMON_P_INPUT | HWMON_P_LABEL,
157	[hwmon_energy] = HWMON_E_INPUT | HWMON_E_LABEL,
158};
159
160static int scmi_hwmon_probe(struct scmi_device *sdev)
161{
162	int i, idx;
163	u16 nr_sensors;
164	enum hwmon_sensor_types type;
165	struct scmi_sensors *scmi_sensors;
166	const struct scmi_sensor_info *sensor;
167	int nr_count[hwmon_max] = {0}, nr_types = 0;
168	const struct hwmon_chip_info *chip_info;
169	struct device *hwdev, *dev = &sdev->dev;
170	struct hwmon_channel_info *scmi_hwmon_chan;
171	const struct hwmon_channel_info **ptr_scmi_ci;
172	const struct scmi_handle *handle = sdev->handle;
173	struct scmi_protocol_handle *ph;
174
175	if (!handle)
176		return -ENODEV;
177
178	sensor_ops = handle->devm_protocol_get(sdev, SCMI_PROTOCOL_SENSOR, &ph);
179	if (IS_ERR(sensor_ops))
180		return PTR_ERR(sensor_ops);
181
182	nr_sensors = sensor_ops->count_get(ph);
183	if (!nr_sensors)
184		return -EIO;
185
186	scmi_sensors = devm_kzalloc(dev, sizeof(*scmi_sensors), GFP_KERNEL);
187	if (!scmi_sensors)
188		return -ENOMEM;
189
190	scmi_sensors->ph = ph;
191
192	for (i = 0; i < nr_sensors; i++) {
193		sensor = sensor_ops->info_get(ph, i);
194		if (!sensor)
195			return -EINVAL;
196
197		switch (sensor->type) {
198		case TEMPERATURE_C:
199		case VOLTAGE:
200		case CURRENT:
201		case POWER:
202		case ENERGY:
203			type = scmi_types[sensor->type];
204			if (!nr_count[type])
205				nr_types++;
206			nr_count[type]++;
207			break;
208		}
209	}
210
211	if (nr_count[hwmon_temp]) {
212		nr_count[hwmon_chip]++;
213		nr_types++;
214	}
215
216	scmi_hwmon_chan = devm_kcalloc(dev, nr_types, sizeof(*scmi_hwmon_chan),
217				       GFP_KERNEL);
218	if (!scmi_hwmon_chan)
219		return -ENOMEM;
220
221	ptr_scmi_ci = devm_kcalloc(dev, nr_types + 1, sizeof(*ptr_scmi_ci),
222				   GFP_KERNEL);
223	if (!ptr_scmi_ci)
224		return -ENOMEM;
225
226	scmi_chip_info.info = ptr_scmi_ci;
227	chip_info = &scmi_chip_info;
228
229	for (type = 0; type < hwmon_max; type++) {
230		if (!nr_count[type])
231			continue;
232
233		scmi_hwmon_add_chan_info(scmi_hwmon_chan, dev, nr_count[type],
234					 type, hwmon_attributes[type]);
235		*ptr_scmi_ci++ = scmi_hwmon_chan++;
236
237		scmi_sensors->info[type] =
238			devm_kcalloc(dev, nr_count[type],
239				     sizeof(*scmi_sensors->info), GFP_KERNEL);
240		if (!scmi_sensors->info[type])
241			return -ENOMEM;
242	}
243
244	for (i = nr_sensors - 1; i >= 0 ; i--) {
245		sensor = sensor_ops->info_get(ph, i);
246		if (!sensor)
247			continue;
248
249		switch (sensor->type) {
250		case TEMPERATURE_C:
251		case VOLTAGE:
252		case CURRENT:
253		case POWER:
254		case ENERGY:
255			type = scmi_types[sensor->type];
256			idx = --nr_count[type];
257			*(scmi_sensors->info[type] + idx) = sensor;
258			break;
259		}
260	}
261
262	hwdev = devm_hwmon_device_register_with_info(dev, "scmi_sensors",
263						     scmi_sensors, chip_info,
264						     NULL);
265
266	return PTR_ERR_OR_ZERO(hwdev);
267}
268
269static const struct scmi_device_id scmi_id_table[] = {
270	{ SCMI_PROTOCOL_SENSOR, "hwmon" },
271	{ },
272};
273MODULE_DEVICE_TABLE(scmi, scmi_id_table);
274
275static struct scmi_driver scmi_hwmon_drv = {
276	.name		= "scmi-hwmon",
277	.probe		= scmi_hwmon_probe,
278	.id_table	= scmi_id_table,
279};
280module_scmi_driver(scmi_hwmon_drv);
281
282MODULE_AUTHOR("Sudeep Holla <sudeep.holla@arm.com>");
283MODULE_DESCRIPTION("ARM SCMI HWMON interface driver");
284MODULE_LICENSE("GPL v2");