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/i2c.h>
15 #include <linux/math64.h>
16 #include <linux/mfd/lochnagar.h>
17 #include <linux/mfd/lochnagar2_regs.h>
18 #include <linux/module.h>
19 #include <linux/of.h>
20 #include <linux/of_device.h>
21 #include <linux/platform_device.h>
22 #include <linux/regmap.h>
23 
24 #define LN2_MAX_NSAMPLE 1023
25 #define LN2_SAMPLE_US   1670
26 
27 #define LN2_CURR_UNITS  1000
28 #define LN2_VOLT_UNITS  1000
29 #define LN2_TEMP_UNITS  1000
30 #define LN2_PWR_UNITS   1000000
31 
32 static const char * const lochnagar_chan_names[] = {
33 	"DBVDD1",
34 	"1V8 DSP",
35 	"1V8 CDC",
36 	"VDDCORE DSP",
37 	"AVDD 1V8",
38 	"SYSVDD",
39 	"VDDCORE CDC",
40 	"MICVDD",
41 };
42 
43 struct lochnagar_hwmon {
44 	struct regmap *regmap;
45 
46 	long power_nsamples[ARRAY_SIZE(lochnagar_chan_names)];
47 
48 	/* Lock to ensure only a single sensor is read at a time */
49 	struct mutex sensor_lock;
50 };
51 
52 enum lochnagar_measure_mode {
53 	LN2_CURR = 0,
54 	LN2_VOLT,
55 	LN2_TEMP,
56 };
57 
58 /**
59  * float_to_long - Convert ieee754 reading from hardware to an integer
60  *
61  * @data: Value read from the hardware
62  * @precision: Units to multiply up to eg. 1000 = milli, 1000000 = micro
63  *
64  * Return: Converted integer reading
65  *
66  * Depending on the measurement type the hardware returns an ieee754
67  * floating point value in either volts, amps or celsius. This function
68  * will convert that into an integer in a smaller unit such as micro-amps
69  * or milli-celsius. The hardware does not return NaN, so consideration of
70  * that is not required.
71  */
float_to_long(u32 data,u32 precision)72 static long float_to_long(u32 data, u32 precision)
73 {
74 	u64 man = data & 0x007FFFFF;
75 	int exp = ((data & 0x7F800000) >> 23) - 127 - 23;
76 	bool negative = data & 0x80000000;
77 	long result;
78 
79 	man = (man + (1 << 23)) * precision;
80 
81 	if (fls64(man) + exp > (int)sizeof(long) * 8 - 1)
82 		result = LONG_MAX;
83 	else if (exp < 0)
84 		result = (man + (1ull << (-exp - 1))) >> -exp;
85 	else
86 		result = man << exp;
87 
88 	return negative ? -result : result;
89 }
90 
do_measurement(struct regmap * regmap,int chan,enum lochnagar_measure_mode mode,int nsamples)91 static int do_measurement(struct regmap *regmap, int chan,
92 			  enum lochnagar_measure_mode mode, int nsamples)
93 {
94 	unsigned int val;
95 	int ret;
96 
97 	chan = 1 << (chan + LOCHNAGAR2_IMON_MEASURED_CHANNELS_SHIFT);
98 
99 	ret = regmap_write(regmap, LOCHNAGAR2_IMON_CTRL1,
100 			   LOCHNAGAR2_IMON_ENA_MASK | chan | mode);
101 	if (ret < 0)
102 		return ret;
103 
104 	ret = regmap_write(regmap, LOCHNAGAR2_IMON_CTRL2, nsamples);
105 	if (ret < 0)
106 		return ret;
107 
108 	ret = regmap_write(regmap, LOCHNAGAR2_IMON_CTRL3,
109 			   LOCHNAGAR2_IMON_CONFIGURE_MASK);
110 	if (ret < 0)
111 		return ret;
112 
113 	ret =  regmap_read_poll_timeout(regmap, LOCHNAGAR2_IMON_CTRL3, val,
114 					val & LOCHNAGAR2_IMON_DONE_MASK,
115 					1000, 10000);
116 	if (ret < 0)
117 		return ret;
118 
119 	ret = regmap_write(regmap, LOCHNAGAR2_IMON_CTRL3,
120 			   LOCHNAGAR2_IMON_MEASURE_MASK);
121 	if (ret < 0)
122 		return ret;
123 
124 	/*
125 	 * Actual measurement time is ~1.67mS per sample, approximate this
126 	 * with a 1.5mS per sample msleep and then poll for success up to
127 	 * ~0.17mS * 1023 (LN2_MAX_NSAMPLES). Normally for smaller values
128 	 * of nsamples the poll will complete on the first loop due to
129 	 * other latency in the system.
130 	 */
131 	msleep((nsamples * 3) / 2);
132 
133 	ret =  regmap_read_poll_timeout(regmap, LOCHNAGAR2_IMON_CTRL3, val,
134 					val & LOCHNAGAR2_IMON_DONE_MASK,
135 					5000, 200000);
136 	if (ret < 0)
137 		return ret;
138 
139 	return regmap_write(regmap, LOCHNAGAR2_IMON_CTRL3, 0);
140 }
141 
request_data(struct regmap * regmap,int chan,u32 * data)142 static int request_data(struct regmap *regmap, int chan, u32 *data)
143 {
144 	unsigned int val;
145 	int ret;
146 
147 	ret = regmap_write(regmap, LOCHNAGAR2_IMON_CTRL4,
148 			   LOCHNAGAR2_IMON_DATA_REQ_MASK |
149 			   chan << LOCHNAGAR2_IMON_CH_SEL_SHIFT);
150 	if (ret < 0)
151 		return ret;
152 
153 	ret =  regmap_read_poll_timeout(regmap, LOCHNAGAR2_IMON_CTRL4, val,
154 					val & LOCHNAGAR2_IMON_DATA_RDY_MASK,
155 					1000, 10000);
156 	if (ret < 0)
157 		return ret;
158 
159 	ret = regmap_read(regmap, LOCHNAGAR2_IMON_DATA1, &val);
160 	if (ret < 0)
161 		return ret;
162 
163 	*data = val << 16;
164 
165 	ret = regmap_read(regmap, LOCHNAGAR2_IMON_DATA2, &val);
166 	if (ret < 0)
167 		return ret;
168 
169 	*data |= val;
170 
171 	return regmap_write(regmap, LOCHNAGAR2_IMON_CTRL4, 0);
172 }
173 
read_sensor(struct device * dev,int chan,enum lochnagar_measure_mode mode,int nsamples,unsigned int precision,long * val)174 static int read_sensor(struct device *dev, int chan,
175 		       enum lochnagar_measure_mode mode, int nsamples,
176 		       unsigned int precision, long *val)
177 {
178 	struct lochnagar_hwmon *priv = dev_get_drvdata(dev);
179 	struct regmap *regmap = priv->regmap;
180 	u32 data;
181 	int ret;
182 
183 	mutex_lock(&priv->sensor_lock);
184 
185 	ret = do_measurement(regmap, chan, mode, nsamples);
186 	if (ret < 0) {
187 		dev_err(dev, "Failed to perform measurement: %d\n", ret);
188 		goto error;
189 	}
190 
191 	ret = request_data(regmap, chan, &data);
192 	if (ret < 0) {
193 		dev_err(dev, "Failed to read measurement: %d\n", ret);
194 		goto error;
195 	}
196 
197 	*val = float_to_long(data, precision);
198 
199 error:
200 	mutex_unlock(&priv->sensor_lock);
201 
202 	return ret;
203 }
204 
read_power(struct device * dev,int chan,long * val)205 static int read_power(struct device *dev, int chan, long *val)
206 {
207 	struct lochnagar_hwmon *priv = dev_get_drvdata(dev);
208 	int nsamples = priv->power_nsamples[chan];
209 	u64 power;
210 	int ret;
211 
212 	if (!strcmp("SYSVDD", lochnagar_chan_names[chan])) {
213 		power = 5 * LN2_PWR_UNITS;
214 	} else {
215 		ret = read_sensor(dev, chan, LN2_VOLT, 1, LN2_PWR_UNITS, val);
216 		if (ret < 0)
217 			return ret;
218 
219 		power = abs(*val);
220 	}
221 
222 	ret = read_sensor(dev, chan, LN2_CURR, nsamples, LN2_PWR_UNITS, val);
223 	if (ret < 0)
224 		return ret;
225 
226 	power *= abs(*val);
227 	power = DIV_ROUND_CLOSEST_ULL(power, LN2_PWR_UNITS);
228 
229 	if (power > LONG_MAX)
230 		*val = LONG_MAX;
231 	else
232 		*val = power;
233 
234 	return 0;
235 }
236 
lochnagar_is_visible(const void * drvdata,enum hwmon_sensor_types type,u32 attr,int chan)237 static umode_t lochnagar_is_visible(const void *drvdata,
238 				    enum hwmon_sensor_types type,
239 				    u32 attr, int chan)
240 {
241 	switch (type) {
242 	case hwmon_in:
243 		if (!strcmp("SYSVDD", lochnagar_chan_names[chan]))
244 			return 0;
245 		break;
246 	case hwmon_power:
247 		if (attr == hwmon_power_average_interval)
248 			return 0644;
249 		break;
250 	default:
251 		break;
252 	}
253 
254 	return 0444;
255 }
256 
lochnagar_read(struct device * dev,enum hwmon_sensor_types type,u32 attr,int chan,long * val)257 static int lochnagar_read(struct device *dev, enum hwmon_sensor_types type,
258 			  u32 attr, int chan, long *val)
259 {
260 	struct lochnagar_hwmon *priv = dev_get_drvdata(dev);
261 	int interval;
262 
263 	switch (type) {
264 	case hwmon_in:
265 		return read_sensor(dev, chan, LN2_VOLT, 1, LN2_VOLT_UNITS, val);
266 	case hwmon_curr:
267 		return read_sensor(dev, chan, LN2_CURR, 1, LN2_CURR_UNITS, val);
268 	case hwmon_temp:
269 		return read_sensor(dev, chan, LN2_TEMP, 1, LN2_TEMP_UNITS, val);
270 	case hwmon_power:
271 		switch (attr) {
272 		case hwmon_power_average:
273 			return read_power(dev, chan, val);
274 		case hwmon_power_average_interval:
275 			interval = priv->power_nsamples[chan] * LN2_SAMPLE_US;
276 			*val = DIV_ROUND_CLOSEST(interval, 1000);
277 			return 0;
278 		default:
279 			return -EOPNOTSUPP;
280 		}
281 	default:
282 		return -EOPNOTSUPP;
283 	}
284 }
285 
lochnagar_read_string(struct device * dev,enum hwmon_sensor_types type,u32 attr,int chan,const char ** str)286 static int lochnagar_read_string(struct device *dev,
287 				 enum hwmon_sensor_types type, u32 attr,
288 				 int chan, const char **str)
289 {
290 	switch (type) {
291 	case hwmon_in:
292 	case hwmon_curr:
293 	case hwmon_power:
294 		*str = lochnagar_chan_names[chan];
295 		return 0;
296 	default:
297 		return -EOPNOTSUPP;
298 	}
299 }
300 
lochnagar_write(struct device * dev,enum hwmon_sensor_types type,u32 attr,int chan,long val)301 static int lochnagar_write(struct device *dev, enum hwmon_sensor_types type,
302 			   u32 attr, int chan, long val)
303 {
304 	struct lochnagar_hwmon *priv = dev_get_drvdata(dev);
305 
306 	if (type != hwmon_power || attr != hwmon_power_average_interval)
307 		return -EOPNOTSUPP;
308 
309 	val = clamp_t(long, val, 1, (LN2_MAX_NSAMPLE * LN2_SAMPLE_US) / 1000);
310 	val = DIV_ROUND_CLOSEST(val * 1000, LN2_SAMPLE_US);
311 
312 	priv->power_nsamples[chan] = val;
313 
314 	return 0;
315 }
316 
317 static const struct hwmon_ops lochnagar_ops = {
318 	.is_visible = lochnagar_is_visible,
319 	.read = lochnagar_read,
320 	.read_string = lochnagar_read_string,
321 	.write = lochnagar_write,
322 };
323 
324 static const struct hwmon_channel_info *lochnagar_info[] = {
325 	HWMON_CHANNEL_INFO(temp,  HWMON_T_INPUT),
326 	HWMON_CHANNEL_INFO(in,    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_I_INPUT | HWMON_I_LABEL,
333 				  HWMON_I_INPUT | HWMON_I_LABEL),
334 	HWMON_CHANNEL_INFO(curr,  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_C_INPUT | HWMON_C_LABEL,
341 				  HWMON_C_INPUT | HWMON_C_LABEL),
342 	HWMON_CHANNEL_INFO(power, 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 				  HWMON_P_AVERAGE | HWMON_P_AVERAGE_INTERVAL |
357 				  HWMON_P_LABEL),
358 	NULL
359 };
360 
361 static const struct hwmon_chip_info lochnagar_chip_info = {
362 	.ops = &lochnagar_ops,
363 	.info = lochnagar_info,
364 };
365 
366 static const struct of_device_id lochnagar_of_match[] = {
367 	{ .compatible = "cirrus,lochnagar2-hwmon" },
368 	{}
369 };
370 MODULE_DEVICE_TABLE(of, lochnagar_of_match);
371 
lochnagar_hwmon_probe(struct platform_device * pdev)372 static int lochnagar_hwmon_probe(struct platform_device *pdev)
373 {
374 	struct device *dev = &pdev->dev;
375 	struct device *hwmon_dev;
376 	struct lochnagar_hwmon *priv;
377 	int i;
378 
379 	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
380 	if (!priv)
381 		return -ENOMEM;
382 
383 	mutex_init(&priv->sensor_lock);
384 
385 	priv->regmap = dev_get_regmap(dev->parent, NULL);
386 	if (!priv->regmap) {
387 		dev_err(dev, "No register map found\n");
388 		return -EINVAL;
389 	}
390 
391 	for (i = 0; i < ARRAY_SIZE(priv->power_nsamples); i++)
392 		priv->power_nsamples[i] = 96;
393 
394 	hwmon_dev = devm_hwmon_device_register_with_info(dev, "Lochnagar", priv,
395 							 &lochnagar_chip_info,
396 							 NULL);
397 
398 	return PTR_ERR_OR_ZERO(hwmon_dev);
399 }
400 
401 static struct platform_driver lochnagar_hwmon_driver = {
402 	.driver = {
403 		.name = "lochnagar-hwmon",
404 		.of_match_table = lochnagar_of_match,
405 	},
406 	.probe = lochnagar_hwmon_probe,
407 };
408 module_platform_driver(lochnagar_hwmon_driver);
409 
410 MODULE_AUTHOR("Lucas Tanure <tanureal@opensource.cirrus.com>");
411 MODULE_DESCRIPTION("Lochnagar hardware monitoring features");
412 MODULE_LICENSE("GPL");
413