1// SPDX-License-Identifier: GPL-2.0
  2/*
  3 * System Control and Management Interface(SCMI) based hwmon sensor driver
  4 *
  5 * Copyright (C) 2018 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
 16struct scmi_sensors {
 17	const struct scmi_handle *handle;
 18	const struct scmi_sensor_info **info[hwmon_max];
 19};
 20
 21static inline u64 __pow10(u8 x)
 22{
 23	u64 r = 1;
 24
 25	while (x--)
 26		r *= 10;
 27
 28	return r;
 29}
 30
 31static int scmi_hwmon_scale(const struct scmi_sensor_info *sensor, u64 *value)
 32{
 33	s8 scale = sensor->scale;
 34	u64 f;
 35
 36	switch (sensor->type) {
 37	case TEMPERATURE_C:
 38	case VOLTAGE:
 39	case CURRENT:
 40		scale += 3;
 41		break;
 42	case POWER:
 43	case ENERGY:
 44		scale += 6;
 45		break;
 46	default:
 47		break;
 48	}
 49
 50	if (scale == 0)
 51		return 0;
 52
 53	if (abs(scale) > 19)
 54		return -E2BIG;
 55
 56	f = __pow10(abs(scale));
 57	if (scale > 0)
 58		*value *= f;
 59	else
 60		*value = div64_u64(*value, f);
 61
 62	return 0;
 63}
 64
 65static int scmi_hwmon_read(struct device *dev, enum hwmon_sensor_types type,
 66			   u32 attr, int channel, long *val)
 67{
 68	int ret;
 69	u64 value;
 70	const struct scmi_sensor_info *sensor;
 71	struct scmi_sensors *scmi_sensors = dev_get_drvdata(dev);
 72	const struct scmi_handle *h = scmi_sensors->handle;
 73
 74	sensor = *(scmi_sensors->info[type] + channel);
 75	ret = h->sensor_ops->reading_get(h, sensor->id, &value);
 76	if (ret)
 77		return ret;
 78
 79	ret = scmi_hwmon_scale(sensor, &value);
 80	if (!ret)
 81		*val = value;
 82
 83	return ret;
 84}
 85
 86static int
 87scmi_hwmon_read_string(struct device *dev, enum hwmon_sensor_types type,
 88		       u32 attr, int channel, const char **str)
 89{
 90	const struct scmi_sensor_info *sensor;
 91	struct scmi_sensors *scmi_sensors = dev_get_drvdata(dev);
 92
 93	sensor = *(scmi_sensors->info[type] + channel);
 94	*str = sensor->name;
 95
 96	return 0;
 97}
 98
 99static umode_t
100scmi_hwmon_is_visible(const void *drvdata, enum hwmon_sensor_types type,
101		      u32 attr, int channel)
102{
103	const struct scmi_sensor_info *sensor;
104	const struct scmi_sensors *scmi_sensors = drvdata;
105
106	sensor = *(scmi_sensors->info[type] + channel);
107	if (sensor)
108		return 0444;
109
110	return 0;
111}
112
113static const struct hwmon_ops scmi_hwmon_ops = {
114	.is_visible = scmi_hwmon_is_visible,
115	.read = scmi_hwmon_read,
116	.read_string = scmi_hwmon_read_string,
117};
118
119static struct hwmon_chip_info scmi_chip_info = {
120	.ops = &scmi_hwmon_ops,
121	.info = NULL,
122};
123
124static int scmi_hwmon_add_chan_info(struct hwmon_channel_info *scmi_hwmon_chan,
125				    struct device *dev, int num,
126				    enum hwmon_sensor_types type, u32 config)
127{
128	int i;
129	u32 *cfg = devm_kcalloc(dev, num + 1, sizeof(*cfg), GFP_KERNEL);
130
131	if (!cfg)
132		return -ENOMEM;
133
134	scmi_hwmon_chan->type = type;
135	scmi_hwmon_chan->config = cfg;
136	for (i = 0; i < num; i++, cfg++)
137		*cfg = config;
138
139	return 0;
140}
141
142static enum hwmon_sensor_types scmi_types[] = {
143	[TEMPERATURE_C] = hwmon_temp,
144	[VOLTAGE] = hwmon_in,
145	[CURRENT] = hwmon_curr,
146	[POWER] = hwmon_power,
147	[ENERGY] = hwmon_energy,
148};
149
150static u32 hwmon_attributes[hwmon_max] = {
151	[hwmon_chip] = HWMON_C_REGISTER_TZ,
152	[hwmon_temp] = HWMON_T_INPUT | HWMON_T_LABEL,
153	[hwmon_in] = HWMON_I_INPUT | HWMON_I_LABEL,
154	[hwmon_curr] = HWMON_C_INPUT | HWMON_C_LABEL,
155	[hwmon_power] = HWMON_P_INPUT | HWMON_P_LABEL,
156	[hwmon_energy] = HWMON_E_INPUT | HWMON_E_LABEL,
157};
158
159static int scmi_hwmon_probe(struct scmi_device *sdev)
160{
161	int i, idx;
162	u16 nr_sensors;
163	enum hwmon_sensor_types type;
164	struct scmi_sensors *scmi_sensors;
165	const struct scmi_sensor_info *sensor;
166	int nr_count[hwmon_max] = {0}, nr_types = 0;
167	const struct hwmon_chip_info *chip_info;
168	struct device *hwdev, *dev = &sdev->dev;
169	struct hwmon_channel_info *scmi_hwmon_chan;
170	const struct hwmon_channel_info **ptr_scmi_ci;
171	const struct scmi_handle *handle = sdev->handle;
172
173	if (!handle || !handle->sensor_ops)
174		return -ENODEV;
175
176	nr_sensors = handle->sensor_ops->count_get(handle);
177	if (!nr_sensors)
178		return -EIO;
179
180	scmi_sensors = devm_kzalloc(dev, sizeof(*scmi_sensors), GFP_KERNEL);
181	if (!scmi_sensors)
182		return -ENOMEM;
183
184	scmi_sensors->handle = handle;
185
186	for (i = 0; i < nr_sensors; i++) {
187		sensor = handle->sensor_ops->info_get(handle, i);
188		if (!sensor)
189			return -EINVAL;
190
191		switch (sensor->type) {
192		case TEMPERATURE_C:
193		case VOLTAGE:
194		case CURRENT:
195		case POWER:
196		case ENERGY:
197			type = scmi_types[sensor->type];
198			if (!nr_count[type])
199				nr_types++;
200			nr_count[type]++;
201			break;
202		}
203	}
204
205	if (nr_count[hwmon_temp])
206		nr_count[hwmon_chip]++, nr_types++;
207
208	scmi_hwmon_chan = devm_kcalloc(dev, nr_types, sizeof(*scmi_hwmon_chan),
209				       GFP_KERNEL);
210	if (!scmi_hwmon_chan)
211		return -ENOMEM;
212
213	ptr_scmi_ci = devm_kcalloc(dev, nr_types + 1, sizeof(*ptr_scmi_ci),
214				   GFP_KERNEL);
215	if (!ptr_scmi_ci)
216		return -ENOMEM;
217
218	scmi_chip_info.info = ptr_scmi_ci;
219	chip_info = &scmi_chip_info;
220
221	for (type = 0; type < hwmon_max; type++) {
222		if (!nr_count[type])
223			continue;
224
225		scmi_hwmon_add_chan_info(scmi_hwmon_chan, dev, nr_count[type],
226					 type, hwmon_attributes[type]);
227		*ptr_scmi_ci++ = scmi_hwmon_chan++;
228
229		scmi_sensors->info[type] =
230			devm_kcalloc(dev, nr_count[type],
231				     sizeof(*scmi_sensors->info), GFP_KERNEL);
232		if (!scmi_sensors->info[type])
233			return -ENOMEM;
234	}
235
236	for (i = nr_sensors - 1; i >= 0 ; i--) {
237		sensor = handle->sensor_ops->info_get(handle, i);
238		if (!sensor)
239			continue;
240
241		switch (sensor->type) {
242		case TEMPERATURE_C:
243		case VOLTAGE:
244		case CURRENT:
245		case POWER:
246		case ENERGY:
247			type = scmi_types[sensor->type];
248			idx = --nr_count[type];
249			*(scmi_sensors->info[type] + idx) = sensor;
250			break;
251		}
252	}
253
254	hwdev = devm_hwmon_device_register_with_info(dev, "scmi_sensors",
255						     scmi_sensors, chip_info,
256						     NULL);
257
258	return PTR_ERR_OR_ZERO(hwdev);
259}
260
261static const struct scmi_device_id scmi_id_table[] = {
262	{ SCMI_PROTOCOL_SENSOR, "hwmon" },
263	{ },
264};
265MODULE_DEVICE_TABLE(scmi, scmi_id_table);
266
267static struct scmi_driver scmi_hwmon_drv = {
268	.name		= "scmi-hwmon",
269	.probe		= scmi_hwmon_probe,
270	.id_table	= scmi_id_table,
271};
272module_scmi_driver(scmi_hwmon_drv);
273
274MODULE_AUTHOR("Sudeep Holla <sudeep.holla@arm.com>");
275MODULE_DESCRIPTION("ARM SCMI HWMON interface driver");
276MODULE_LICENSE("GPL v2");