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
16 struct scmi_sensors {
17 const struct scmi_handle *handle;
18 const struct scmi_sensor_info **info[hwmon_max];
19 };
20
__pow10(u8 x)21 static inline u64 __pow10(u8 x)
22 {
23 u64 r = 1;
24
25 while (x--)
26 r *= 10;
27
28 return r;
29 }
30
scmi_hwmon_scale(const struct scmi_sensor_info * sensor,u64 * value)31 static 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
scmi_hwmon_read(struct device * dev,enum hwmon_sensor_types type,u32 attr,int channel,long * val)65 static 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
86 static int
scmi_hwmon_read_string(struct device * dev,enum hwmon_sensor_types type,u32 attr,int channel,const char ** str)87 scmi_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
99 static umode_t
scmi_hwmon_is_visible(const void * drvdata,enum hwmon_sensor_types type,u32 attr,int channel)100 scmi_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
113 static 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
119 static struct hwmon_chip_info scmi_chip_info = {
120 .ops = &scmi_hwmon_ops,
121 .info = NULL,
122 };
123
scmi_hwmon_add_chan_info(struct hwmon_channel_info * scmi_hwmon_chan,struct device * dev,int num,enum hwmon_sensor_types type,u32 config)124 static 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
142 static 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
150 static u32 hwmon_attributes[] = {
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
scmi_hwmon_probe(struct scmi_device * sdev)159 static 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
261 static const struct scmi_device_id scmi_id_table[] = {
262 { SCMI_PROTOCOL_SENSOR },
263 { },
264 };
265 MODULE_DEVICE_TABLE(scmi, scmi_id_table);
266
267 static struct scmi_driver scmi_hwmon_drv = {
268 .name = "scmi-hwmon",
269 .probe = scmi_hwmon_probe,
270 .id_table = scmi_id_table,
271 };
272 module_scmi_driver(scmi_hwmon_drv);
273
274 MODULE_AUTHOR("Sudeep Holla <sudeep.holla@arm.com>");
275 MODULE_DESCRIPTION("ARM SCMI HWMON interface driver");
276 MODULE_LICENSE("GPL v2");
277
