1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  *  power_supply_hwmon.c - power supply hwmon support.
4  */
5 
6 #include <linux/err.h>
7 #include <linux/hwmon.h>
8 #include <linux/power_supply.h>
9 #include <linux/slab.h>
10 
11 struct power_supply_hwmon {
12 	struct power_supply *psy;
13 	unsigned long *props;
14 };
15 
16 static const char *const ps_temp_label[] = {
17 	"temp",
18 	"ambient temp",
19 };
20 
21 static int power_supply_hwmon_in_to_property(u32 attr)
22 {
23 	switch (attr) {
24 	case hwmon_in_average:
25 		return POWER_SUPPLY_PROP_VOLTAGE_AVG;
26 	case hwmon_in_min:
27 		return POWER_SUPPLY_PROP_VOLTAGE_MIN;
28 	case hwmon_in_max:
29 		return POWER_SUPPLY_PROP_VOLTAGE_MAX;
30 	case hwmon_in_input:
31 		return POWER_SUPPLY_PROP_VOLTAGE_NOW;
32 	default:
33 		return -EINVAL;
34 	}
35 }
36 
37 static int power_supply_hwmon_curr_to_property(u32 attr)
38 {
39 	switch (attr) {
40 	case hwmon_curr_average:
41 		return POWER_SUPPLY_PROP_CURRENT_AVG;
42 	case hwmon_curr_max:
43 		return POWER_SUPPLY_PROP_CURRENT_MAX;
44 	case hwmon_curr_input:
45 		return POWER_SUPPLY_PROP_CURRENT_NOW;
46 	default:
47 		return -EINVAL;
48 	}
49 }
50 
51 static int power_supply_hwmon_temp_to_property(u32 attr, int channel)
52 {
53 	if (channel) {
54 		switch (attr) {
55 		case hwmon_temp_input:
56 			return POWER_SUPPLY_PROP_TEMP_AMBIENT;
57 		case hwmon_temp_min_alarm:
58 			return POWER_SUPPLY_PROP_TEMP_AMBIENT_ALERT_MIN;
59 		case hwmon_temp_max_alarm:
60 			return POWER_SUPPLY_PROP_TEMP_AMBIENT_ALERT_MAX;
61 		default:
62 			break;
63 		}
64 	} else {
65 		switch (attr) {
66 		case hwmon_temp_input:
67 			return POWER_SUPPLY_PROP_TEMP;
68 		case hwmon_temp_max:
69 			return POWER_SUPPLY_PROP_TEMP_MAX;
70 		case hwmon_temp_min:
71 			return POWER_SUPPLY_PROP_TEMP_MIN;
72 		case hwmon_temp_min_alarm:
73 			return POWER_SUPPLY_PROP_TEMP_ALERT_MIN;
74 		case hwmon_temp_max_alarm:
75 			return POWER_SUPPLY_PROP_TEMP_ALERT_MAX;
76 		default:
77 			break;
78 		}
79 	}
80 
81 	return -EINVAL;
82 }
83 
84 static int
85 power_supply_hwmon_to_property(enum hwmon_sensor_types type,
86 			       u32 attr, int channel)
87 {
88 	switch (type) {
89 	case hwmon_in:
90 		return power_supply_hwmon_in_to_property(attr);
91 	case hwmon_curr:
92 		return power_supply_hwmon_curr_to_property(attr);
93 	case hwmon_temp:
94 		return power_supply_hwmon_temp_to_property(attr, channel);
95 	default:
96 		return -EINVAL;
97 	}
98 }
99 
100 static bool power_supply_hwmon_is_a_label(enum hwmon_sensor_types type,
101 					   u32 attr)
102 {
103 	return type == hwmon_temp && attr == hwmon_temp_label;
104 }
105 
106 struct hwmon_type_attr_list {
107 	const u32 *attrs;
108 	size_t n_attrs;
109 };
110 
111 static const u32 ps_temp_attrs[] = {
112 	hwmon_temp_input,
113 	hwmon_temp_min, hwmon_temp_max,
114 	hwmon_temp_min_alarm, hwmon_temp_max_alarm,
115 };
116 
117 static const struct hwmon_type_attr_list ps_type_attrs[hwmon_max] = {
118 	[hwmon_temp] = { ps_temp_attrs, ARRAY_SIZE(ps_temp_attrs) },
119 };
120 
121 static bool power_supply_hwmon_has_input(
122 	const struct power_supply_hwmon *psyhw,
123 	enum hwmon_sensor_types type, int channel)
124 {
125 	const struct hwmon_type_attr_list *attr_list = &ps_type_attrs[type];
126 	size_t i;
127 
128 	for (i = 0; i < attr_list->n_attrs; ++i) {
129 		int prop = power_supply_hwmon_to_property(type,
130 			attr_list->attrs[i], channel);
131 
132 		if (prop >= 0 && test_bit(prop, psyhw->props))
133 			return true;
134 	}
135 
136 	return false;
137 }
138 
139 static bool power_supply_hwmon_is_writable(enum hwmon_sensor_types type,
140 					   u32 attr)
141 {
142 	switch (type) {
143 	case hwmon_in:
144 		return attr == hwmon_in_min ||
145 		       attr == hwmon_in_max;
146 	case hwmon_curr:
147 		return attr == hwmon_curr_max;
148 	case hwmon_temp:
149 		return attr == hwmon_temp_max ||
150 		       attr == hwmon_temp_min ||
151 		       attr == hwmon_temp_min_alarm ||
152 		       attr == hwmon_temp_max_alarm;
153 	default:
154 		return false;
155 	}
156 }
157 
158 static umode_t power_supply_hwmon_is_visible(const void *data,
159 					     enum hwmon_sensor_types type,
160 					     u32 attr, int channel)
161 {
162 	const struct power_supply_hwmon *psyhw = data;
163 	int prop;
164 
165 	if (power_supply_hwmon_is_a_label(type, attr)) {
166 		if (power_supply_hwmon_has_input(psyhw, type, channel))
167 			return 0444;
168 		else
169 			return 0;
170 	}
171 
172 	prop = power_supply_hwmon_to_property(type, attr, channel);
173 	if (prop < 0 || !test_bit(prop, psyhw->props))
174 		return 0;
175 
176 	if (power_supply_property_is_writeable(psyhw->psy, prop) > 0 &&
177 	    power_supply_hwmon_is_writable(type, attr))
178 		return 0644;
179 
180 	return 0444;
181 }
182 
183 static int power_supply_hwmon_read_string(struct device *dev,
184 					  enum hwmon_sensor_types type,
185 					  u32 attr, int channel,
186 					  const char **str)
187 {
188 	switch (type) {
189 	case hwmon_temp:
190 		*str = ps_temp_label[channel];
191 		break;
192 	default:
193 		/* unreachable, but see:
194 		 * gcc bug #51513 [1] and clang bug #978 [2]
195 		 *
196 		 * [1] https://gcc.gnu.org/bugzilla/show_bug.cgi?id=51513
197 		 * [2] https://github.com/ClangBuiltLinux/linux/issues/978
198 		 */
199 		break;
200 	}
201 
202 	return 0;
203 }
204 
205 static int
206 power_supply_hwmon_read(struct device *dev, enum hwmon_sensor_types type,
207 			u32 attr, int channel, long *val)
208 {
209 	struct power_supply_hwmon *psyhw = dev_get_drvdata(dev);
210 	struct power_supply *psy = psyhw->psy;
211 	union power_supply_propval pspval;
212 	int ret, prop;
213 
214 	prop = power_supply_hwmon_to_property(type, attr, channel);
215 	if (prop < 0)
216 		return prop;
217 
218 	ret  = power_supply_get_property(psy, prop, &pspval);
219 	if (ret)
220 		return ret;
221 
222 	switch (type) {
223 	/*
224 	 * Both voltage and current is reported in units of
225 	 * microvolts/microamps, so we need to adjust it to
226 	 * milliamps(volts)
227 	 */
228 	case hwmon_curr:
229 	case hwmon_in:
230 		pspval.intval = DIV_ROUND_CLOSEST(pspval.intval, 1000);
231 		break;
232 	/*
233 	 * Temp needs to be converted from 1/10 C to milli-C
234 	 */
235 	case hwmon_temp:
236 		if (check_mul_overflow(pspval.intval, 100,
237 				       &pspval.intval))
238 			return -EOVERFLOW;
239 		break;
240 	default:
241 		return -EINVAL;
242 	}
243 
244 	*val = pspval.intval;
245 
246 	return 0;
247 }
248 
249 static int
250 power_supply_hwmon_write(struct device *dev, enum hwmon_sensor_types type,
251 			 u32 attr, int channel, long val)
252 {
253 	struct power_supply_hwmon *psyhw = dev_get_drvdata(dev);
254 	struct power_supply *psy = psyhw->psy;
255 	union power_supply_propval pspval;
256 	int prop;
257 
258 	prop = power_supply_hwmon_to_property(type, attr, channel);
259 	if (prop < 0)
260 		return prop;
261 
262 	pspval.intval = val;
263 
264 	switch (type) {
265 	/*
266 	 * Both voltage and current is reported in units of
267 	 * microvolts/microamps, so we need to adjust it to
268 	 * milliamps(volts)
269 	 */
270 	case hwmon_curr:
271 	case hwmon_in:
272 		if (check_mul_overflow(pspval.intval, 1000,
273 				       &pspval.intval))
274 			return -EOVERFLOW;
275 		break;
276 	/*
277 	 * Temp needs to be converted from 1/10 C to milli-C
278 	 */
279 	case hwmon_temp:
280 		pspval.intval = DIV_ROUND_CLOSEST(pspval.intval, 100);
281 		break;
282 	default:
283 		return -EINVAL;
284 	}
285 
286 	return power_supply_set_property(psy, prop, &pspval);
287 }
288 
289 static const struct hwmon_ops power_supply_hwmon_ops = {
290 	.is_visible	= power_supply_hwmon_is_visible,
291 	.read		= power_supply_hwmon_read,
292 	.write		= power_supply_hwmon_write,
293 	.read_string	= power_supply_hwmon_read_string,
294 };
295 
296 static const struct hwmon_channel_info * const power_supply_hwmon_info[] = {
297 	HWMON_CHANNEL_INFO(temp,
298 			   HWMON_T_LABEL     |
299 			   HWMON_T_INPUT     |
300 			   HWMON_T_MAX       |
301 			   HWMON_T_MIN       |
302 			   HWMON_T_MIN_ALARM |
303 			   HWMON_T_MAX_ALARM,
304 
305 			   HWMON_T_LABEL     |
306 			   HWMON_T_INPUT     |
307 			   HWMON_T_MIN_ALARM |
308 			   HWMON_T_MAX_ALARM),
309 
310 	HWMON_CHANNEL_INFO(curr,
311 			   HWMON_C_AVERAGE |
312 			   HWMON_C_MAX     |
313 			   HWMON_C_INPUT),
314 
315 	HWMON_CHANNEL_INFO(in,
316 			   HWMON_I_AVERAGE |
317 			   HWMON_I_MIN     |
318 			   HWMON_I_MAX     |
319 			   HWMON_I_INPUT),
320 	NULL
321 };
322 
323 static const struct hwmon_chip_info power_supply_hwmon_chip_info = {
324 	.ops = &power_supply_hwmon_ops,
325 	.info = power_supply_hwmon_info,
326 };
327 
328 int power_supply_add_hwmon_sysfs(struct power_supply *psy)
329 {
330 	const struct power_supply_desc *desc = psy->desc;
331 	struct power_supply_hwmon *psyhw;
332 	struct device *dev = &psy->dev;
333 	struct device *hwmon;
334 	int ret, i;
335 	const char *name;
336 
337 	if (!devres_open_group(dev, power_supply_add_hwmon_sysfs,
338 			       GFP_KERNEL))
339 		return -ENOMEM;
340 
341 	psyhw = devm_kzalloc(dev, sizeof(*psyhw), GFP_KERNEL);
342 	if (!psyhw) {
343 		ret = -ENOMEM;
344 		goto error;
345 	}
346 
347 	psyhw->psy = psy;
348 	psyhw->props = devm_bitmap_zalloc(dev,
349 					  POWER_SUPPLY_PROP_TIME_TO_FULL_AVG + 1,
350 					  GFP_KERNEL);
351 	if (!psyhw->props) {
352 		ret = -ENOMEM;
353 		goto error;
354 	}
355 
356 	for (i = 0; i < desc->num_properties; i++) {
357 		const enum power_supply_property prop = desc->properties[i];
358 
359 		switch (prop) {
360 		case POWER_SUPPLY_PROP_CURRENT_AVG:
361 		case POWER_SUPPLY_PROP_CURRENT_MAX:
362 		case POWER_SUPPLY_PROP_CURRENT_NOW:
363 		case POWER_SUPPLY_PROP_TEMP:
364 		case POWER_SUPPLY_PROP_TEMP_MAX:
365 		case POWER_SUPPLY_PROP_TEMP_MIN:
366 		case POWER_SUPPLY_PROP_TEMP_ALERT_MIN:
367 		case POWER_SUPPLY_PROP_TEMP_ALERT_MAX:
368 		case POWER_SUPPLY_PROP_TEMP_AMBIENT:
369 		case POWER_SUPPLY_PROP_TEMP_AMBIENT_ALERT_MIN:
370 		case POWER_SUPPLY_PROP_TEMP_AMBIENT_ALERT_MAX:
371 		case POWER_SUPPLY_PROP_VOLTAGE_AVG:
372 		case POWER_SUPPLY_PROP_VOLTAGE_MIN:
373 		case POWER_SUPPLY_PROP_VOLTAGE_MAX:
374 		case POWER_SUPPLY_PROP_VOLTAGE_NOW:
375 			set_bit(prop, psyhw->props);
376 			break;
377 		default:
378 			break;
379 		}
380 	}
381 
382 	name = psy->desc->name;
383 	if (strchr(name, '-')) {
384 		char *new_name;
385 
386 		new_name = devm_kstrdup(dev, name, GFP_KERNEL);
387 		if (!new_name) {
388 			ret = -ENOMEM;
389 			goto error;
390 		}
391 		strreplace(new_name, '-', '_');
392 		name = new_name;
393 	}
394 	hwmon = devm_hwmon_device_register_with_info(dev, name,
395 						psyhw,
396 						&power_supply_hwmon_chip_info,
397 						NULL);
398 	ret = PTR_ERR_OR_ZERO(hwmon);
399 	if (ret)
400 		goto error;
401 
402 	devres_close_group(dev, power_supply_add_hwmon_sysfs);
403 	return 0;
404 error:
405 	devres_release_group(dev, NULL);
406 	return ret;
407 }
408 
409 void power_supply_remove_hwmon_sysfs(struct power_supply *psy)
410 {
411 	devres_release_group(&psy->dev, power_supply_add_hwmon_sysfs);
412 }
413