1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Lochnagar hardware monitoring features
4  *
5  * Copyright (c) 2016-2019 Cirrus Logic, Inc. and
6  *                         Cirrus Logic International Semiconductor Ltd.
7  *
8  * Author: Lucas Tanure <tanureal@opensource.cirrus.com>
9  */
10 
11 #include <linux/delay.h>
12 #include <linux/hwmon.h>
13 #include <linux/hwmon-sysfs.h>
14 #include <linux/math64.h>
15 #include <linux/mfd/lochnagar.h>
16 #include <linux/mfd/lochnagar2_regs.h>
17 #include <linux/module.h>
18 #include <linux/of.h>
19 #include <linux/platform_device.h>
20 #include <linux/regmap.h>
21 
22 #define LN2_MAX_NSAMPLE 1023
23 #define LN2_SAMPLE_US   1670
24 
25 #define LN2_CURR_UNITS  1000
26 #define LN2_VOLT_UNITS  1000
27 #define LN2_TEMP_UNITS  1000
28 #define LN2_PWR_UNITS   1000000
29 
30 static const char * const lochnagar_chan_names[] = {
31 	"DBVDD1",
32 	"1V8 DSP",
33 	"1V8 CDC",
34 	"VDDCORE DSP",
35 	"AVDD 1V8",
36 	"SYSVDD",
37 	"VDDCORE CDC",
38 	"MICVDD",
39 };
40 
41 struct lochnagar_hwmon {
42 	struct regmap *regmap;
43 
44 	long power_nsamples[ARRAY_SIZE(lochnagar_chan_names)];
45 
46 	/* Lock to ensure only a single sensor is read at a time */
47 	struct mutex sensor_lock;
48 };
49 
50 enum lochnagar_measure_mode {
51 	LN2_CURR = 0,
52 	LN2_VOLT,
53 	LN2_TEMP,
54 };
55 
56 /**
57  * float_to_long - Convert ieee754 reading from hardware to an integer
58  *
59  * @data: Value read from the hardware
60  * @precision: Units to multiply up to eg. 1000 = milli, 1000000 = micro
61  *
62  * Return: Converted integer reading
63  *
64  * Depending on the measurement type the hardware returns an ieee754
65  * floating point value in either volts, amps or celsius. This function
66  * will convert that into an integer in a smaller unit such as micro-amps
67  * or milli-celsius. The hardware does not return NaN, so consideration of
68  * that is not required.
69  */
70 static long float_to_long(u32 data, u32 precision)
71 {
72 	u64 man = data & 0x007FFFFF;
73 	int exp = ((data & 0x7F800000) >> 23) - 127 - 23;
74 	bool negative = data & 0x80000000;
75 	long result;
76 
77 	man = (man + (1 << 23)) * precision;
78 
79 	if (fls64(man) + exp > (int)sizeof(long) * 8 - 1)
80 		result = LONG_MAX;
81 	else if (exp < 0)
82 		result = (man + (1ull << (-exp - 1))) >> -exp;
83 	else
84 		result = man << exp;
85 
86 	return negative ? -result : result;
87 }
88 
89 static int do_measurement(struct regmap *regmap, int chan,
90 			  enum lochnagar_measure_mode mode, int nsamples)
91 {
92 	unsigned int val;
93 	int ret;
94 
95 	chan = 1 << (chan + LOCHNAGAR2_IMON_MEASURED_CHANNELS_SHIFT);
96 
97 	ret = regmap_write(regmap, LOCHNAGAR2_IMON_CTRL1,
98 			   LOCHNAGAR2_IMON_ENA_MASK | chan | mode);
99 	if (ret < 0)
100 		return ret;
101 
102 	ret = regmap_write(regmap, LOCHNAGAR2_IMON_CTRL2, nsamples);
103 	if (ret < 0)
104 		return ret;
105 
106 	ret = regmap_write(regmap, LOCHNAGAR2_IMON_CTRL3,
107 			   LOCHNAGAR2_IMON_CONFIGURE_MASK);
108 	if (ret < 0)
109 		return ret;
110 
111 	ret =  regmap_read_poll_timeout(regmap, LOCHNAGAR2_IMON_CTRL3, val,
112 					val & LOCHNAGAR2_IMON_DONE_MASK,
113 					1000, 10000);
114 	if (ret < 0)
115 		return ret;
116 
117 	ret = regmap_write(regmap, LOCHNAGAR2_IMON_CTRL3,
118 			   LOCHNAGAR2_IMON_MEASURE_MASK);
119 	if (ret < 0)
120 		return ret;
121 
122 	/*
123 	 * Actual measurement time is ~1.67mS per sample, approximate this
124 	 * with a 1.5mS per sample msleep and then poll for success up to
125 	 * ~0.17mS * 1023 (LN2_MAX_NSAMPLES). Normally for smaller values
126 	 * of nsamples the poll will complete on the first loop due to
127 	 * other latency in the system.
128 	 */
129 	msleep((nsamples * 3) / 2);
130 
131 	ret =  regmap_read_poll_timeout(regmap, LOCHNAGAR2_IMON_CTRL3, val,
132 					val & LOCHNAGAR2_IMON_DONE_MASK,
133 					5000, 200000);
134 	if (ret < 0)
135 		return ret;
136 
137 	return regmap_write(regmap, LOCHNAGAR2_IMON_CTRL3, 0);
138 }
139 
140 static int request_data(struct regmap *regmap, int chan, u32 *data)
141 {
142 	unsigned int val;
143 	int ret;
144 
145 	ret = regmap_write(regmap, LOCHNAGAR2_IMON_CTRL4,
146 			   LOCHNAGAR2_IMON_DATA_REQ_MASK |
147 			   chan << LOCHNAGAR2_IMON_CH_SEL_SHIFT);
148 	if (ret < 0)
149 		return ret;
150 
151 	ret =  regmap_read_poll_timeout(regmap, LOCHNAGAR2_IMON_CTRL4, val,
152 					val & LOCHNAGAR2_IMON_DATA_RDY_MASK,
153 					1000, 10000);
154 	if (ret < 0)
155 		return ret;
156 
157 	ret = regmap_read(regmap, LOCHNAGAR2_IMON_DATA1, &val);
158 	if (ret < 0)
159 		return ret;
160 
161 	*data = val << 16;
162 
163 	ret = regmap_read(regmap, LOCHNAGAR2_IMON_DATA2, &val);
164 	if (ret < 0)
165 		return ret;
166 
167 	*data |= val;
168 
169 	return regmap_write(regmap, LOCHNAGAR2_IMON_CTRL4, 0);
170 }
171 
172 static int read_sensor(struct device *dev, int chan,
173 		       enum lochnagar_measure_mode mode, int nsamples,
174 		       unsigned int precision, long *val)
175 {
176 	struct lochnagar_hwmon *priv = dev_get_drvdata(dev);
177 	struct regmap *regmap = priv->regmap;
178 	u32 data;
179 	int ret;
180 
181 	mutex_lock(&priv->sensor_lock);
182 
183 	ret = do_measurement(regmap, chan, mode, nsamples);
184 	if (ret < 0) {
185 		dev_err(dev, "Failed to perform measurement: %d\n", ret);
186 		goto error;
187 	}
188 
189 	ret = request_data(regmap, chan, &data);
190 	if (ret < 0) {
191 		dev_err(dev, "Failed to read measurement: %d\n", ret);
192 		goto error;
193 	}
194 
195 	*val = float_to_long(data, precision);
196 
197 error:
198 	mutex_unlock(&priv->sensor_lock);
199 
200 	return ret;
201 }
202 
203 static int read_power(struct device *dev, int chan, long *val)
204 {
205 	struct lochnagar_hwmon *priv = dev_get_drvdata(dev);
206 	int nsamples = priv->power_nsamples[chan];
207 	u64 power;
208 	int ret;
209 
210 	if (!strcmp("SYSVDD", lochnagar_chan_names[chan])) {
211 		power = 5 * LN2_PWR_UNITS;
212 	} else {
213 		ret = read_sensor(dev, chan, LN2_VOLT, 1, LN2_PWR_UNITS, val);
214 		if (ret < 0)
215 			return ret;
216 
217 		power = abs(*val);
218 	}
219 
220 	ret = read_sensor(dev, chan, LN2_CURR, nsamples, LN2_PWR_UNITS, val);
221 	if (ret < 0)
222 		return ret;
223 
224 	power *= abs(*val);
225 	power = DIV_ROUND_CLOSEST_ULL(power, LN2_PWR_UNITS);
226 
227 	if (power > LONG_MAX)
228 		*val = LONG_MAX;
229 	else
230 		*val = power;
231 
232 	return 0;
233 }
234 
235 static umode_t lochnagar_is_visible(const void *drvdata,
236 				    enum hwmon_sensor_types type,
237 				    u32 attr, int chan)
238 {
239 	switch (type) {
240 	case hwmon_in:
241 		if (!strcmp("SYSVDD", lochnagar_chan_names[chan]))
242 			return 0;
243 		break;
244 	case hwmon_power:
245 		if (attr == hwmon_power_average_interval)
246 			return 0644;
247 		break;
248 	default:
249 		break;
250 	}
251 
252 	return 0444;
253 }
254 
255 static int lochnagar_read(struct device *dev, enum hwmon_sensor_types type,
256 			  u32 attr, int chan, long *val)
257 {
258 	struct lochnagar_hwmon *priv = dev_get_drvdata(dev);
259 	int interval;
260 
261 	switch (type) {
262 	case hwmon_in:
263 		return read_sensor(dev, chan, LN2_VOLT, 1, LN2_VOLT_UNITS, val);
264 	case hwmon_curr:
265 		return read_sensor(dev, chan, LN2_CURR, 1, LN2_CURR_UNITS, val);
266 	case hwmon_temp:
267 		return read_sensor(dev, chan, LN2_TEMP, 1, LN2_TEMP_UNITS, val);
268 	case hwmon_power:
269 		switch (attr) {
270 		case hwmon_power_average:
271 			return read_power(dev, chan, val);
272 		case hwmon_power_average_interval:
273 			interval = priv->power_nsamples[chan] * LN2_SAMPLE_US;
274 			*val = DIV_ROUND_CLOSEST(interval, 1000);
275 			return 0;
276 		default:
277 			return -EOPNOTSUPP;
278 		}
279 	default:
280 		return -EOPNOTSUPP;
281 	}
282 }
283 
284 static int lochnagar_read_string(struct device *dev,
285 				 enum hwmon_sensor_types type, u32 attr,
286 				 int chan, const char **str)
287 {
288 	switch (type) {
289 	case hwmon_in:
290 	case hwmon_curr:
291 	case hwmon_power:
292 		*str = lochnagar_chan_names[chan];
293 		return 0;
294 	default:
295 		return -EOPNOTSUPP;
296 	}
297 }
298 
299 static int lochnagar_write(struct device *dev, enum hwmon_sensor_types type,
300 			   u32 attr, int chan, long val)
301 {
302 	struct lochnagar_hwmon *priv = dev_get_drvdata(dev);
303 
304 	if (type != hwmon_power || attr != hwmon_power_average_interval)
305 		return -EOPNOTSUPP;
306 
307 	val = clamp_t(long, val, 1, (LN2_MAX_NSAMPLE * LN2_SAMPLE_US) / 1000);
308 	val = DIV_ROUND_CLOSEST(val * 1000, LN2_SAMPLE_US);
309 
310 	priv->power_nsamples[chan] = val;
311 
312 	return 0;
313 }
314 
315 static const struct hwmon_ops lochnagar_ops = {
316 	.is_visible = lochnagar_is_visible,
317 	.read = lochnagar_read,
318 	.read_string = lochnagar_read_string,
319 	.write = lochnagar_write,
320 };
321 
322 static const struct hwmon_channel_info * const lochnagar_info[] = {
323 	HWMON_CHANNEL_INFO(temp,  HWMON_T_INPUT),
324 	HWMON_CHANNEL_INFO(in,    HWMON_I_INPUT | HWMON_I_LABEL,
325 				  HWMON_I_INPUT | HWMON_I_LABEL,
326 				  HWMON_I_INPUT | HWMON_I_LABEL,
327 				  HWMON_I_INPUT | HWMON_I_LABEL,
328 				  HWMON_I_INPUT | HWMON_I_LABEL,
329 				  HWMON_I_INPUT | HWMON_I_LABEL,
330 				  HWMON_I_INPUT | HWMON_I_LABEL,
331 				  HWMON_I_INPUT | HWMON_I_LABEL),
332 	HWMON_CHANNEL_INFO(curr,  HWMON_C_INPUT | HWMON_C_LABEL,
333 				  HWMON_C_INPUT | HWMON_C_LABEL,
334 				  HWMON_C_INPUT | HWMON_C_LABEL,
335 				  HWMON_C_INPUT | HWMON_C_LABEL,
336 				  HWMON_C_INPUT | HWMON_C_LABEL,
337 				  HWMON_C_INPUT | HWMON_C_LABEL,
338 				  HWMON_C_INPUT | HWMON_C_LABEL,
339 				  HWMON_C_INPUT | HWMON_C_LABEL),
340 	HWMON_CHANNEL_INFO(power, HWMON_P_AVERAGE | HWMON_P_AVERAGE_INTERVAL |
341 				  HWMON_P_LABEL,
342 				  HWMON_P_AVERAGE | HWMON_P_AVERAGE_INTERVAL |
343 				  HWMON_P_LABEL,
344 				  HWMON_P_AVERAGE | HWMON_P_AVERAGE_INTERVAL |
345 				  HWMON_P_LABEL,
346 				  HWMON_P_AVERAGE | HWMON_P_AVERAGE_INTERVAL |
347 				  HWMON_P_LABEL,
348 				  HWMON_P_AVERAGE | HWMON_P_AVERAGE_INTERVAL |
349 				  HWMON_P_LABEL,
350 				  HWMON_P_AVERAGE | HWMON_P_AVERAGE_INTERVAL |
351 				  HWMON_P_LABEL,
352 				  HWMON_P_AVERAGE | HWMON_P_AVERAGE_INTERVAL |
353 				  HWMON_P_LABEL,
354 				  HWMON_P_AVERAGE | HWMON_P_AVERAGE_INTERVAL |
355 				  HWMON_P_LABEL),
356 	NULL
357 };
358 
359 static const struct hwmon_chip_info lochnagar_chip_info = {
360 	.ops = &lochnagar_ops,
361 	.info = lochnagar_info,
362 };
363 
364 static const struct of_device_id lochnagar_of_match[] = {
365 	{ .compatible = "cirrus,lochnagar2-hwmon" },
366 	{}
367 };
368 MODULE_DEVICE_TABLE(of, lochnagar_of_match);
369 
370 static int lochnagar_hwmon_probe(struct platform_device *pdev)
371 {
372 	struct device *dev = &pdev->dev;
373 	struct device *hwmon_dev;
374 	struct lochnagar_hwmon *priv;
375 	int i;
376 
377 	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
378 	if (!priv)
379 		return -ENOMEM;
380 
381 	mutex_init(&priv->sensor_lock);
382 
383 	priv->regmap = dev_get_regmap(dev->parent, NULL);
384 	if (!priv->regmap) {
385 		dev_err(dev, "No register map found\n");
386 		return -EINVAL;
387 	}
388 
389 	for (i = 0; i < ARRAY_SIZE(priv->power_nsamples); i++)
390 		priv->power_nsamples[i] = 96;
391 
392 	hwmon_dev = devm_hwmon_device_register_with_info(dev, "Lochnagar", priv,
393 							 &lochnagar_chip_info,
394 							 NULL);
395 
396 	return PTR_ERR_OR_ZERO(hwmon_dev);
397 }
398 
399 static struct platform_driver lochnagar_hwmon_driver = {
400 	.driver = {
401 		.name = "lochnagar-hwmon",
402 		.of_match_table = lochnagar_of_match,
403 	},
404 	.probe = lochnagar_hwmon_probe,
405 };
406 module_platform_driver(lochnagar_hwmon_driver);
407 
408 MODULE_AUTHOR("Lucas Tanure <tanureal@opensource.cirrus.com>");
409 MODULE_DESCRIPTION("Lochnagar hardware monitoring features");
410 MODULE_LICENSE("GPL");
411