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
__pow10(u8 x)23 static inline u64 __pow10(u8 x)
24 {
25 u64 r = 1;
26
27 while (x--)
28 r *= 10;
29
30 return r;
31 }
32
scmi_hwmon_scale(const struct scmi_sensor_info * sensor,u64 * value)33 static 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
scmi_hwmon_read(struct device * dev,enum hwmon_sensor_types type,u32 attr,int channel,long * val)67 static 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
87 static int
scmi_hwmon_read_string(struct device * dev,enum hwmon_sensor_types type,u32 attr,int channel,const char ** str)88 scmi_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
100 static umode_t
scmi_hwmon_is_visible(const void * drvdata,enum hwmon_sensor_types type,u32 attr,int channel)101 scmi_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
114 static 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
120 static struct hwmon_chip_info scmi_chip_info = {
121 .ops = &scmi_hwmon_ops,
122 .info = NULL,
123 };
124
scmi_hwmon_add_chan_info(struct hwmon_channel_info * scmi_hwmon_chan,struct device * dev,int num,enum hwmon_sensor_types type,u32 config)125 static 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
143 static 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
151 static 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
scmi_hwmon_probe(struct scmi_device * sdev)160 static 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
269 static const struct scmi_device_id scmi_id_table[] = {
270 { SCMI_PROTOCOL_SENSOR, "hwmon" },
271 { },
272 };
273 MODULE_DEVICE_TABLE(scmi, scmi_id_table);
274
275 static struct scmi_driver scmi_hwmon_drv = {
276 .name = "scmi-hwmon",
277 .probe = scmi_hwmon_probe,
278 .id_table = scmi_id_table,
279 };
280 module_scmi_driver(scmi_hwmon_drv);
281
282 MODULE_AUTHOR("Sudeep Holla <sudeep.holla@arm.com>");
283 MODULE_DESCRIPTION("ARM SCMI HWMON interface driver");
284 MODULE_LICENSE("GPL v2");
285