summaryrefslogtreecommitdiffstats
path: root/drivers/hwmon/pmbus/ltc2978.c
blob: 820fff48910bfbcd14c0370b2587ec51d0b325f8 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
/*
 * Hardware monitoring driver for LTC2978 and LTC3880
 *
 * Copyright (c) 2011 Ericsson AB.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/err.h>
#include <linux/slab.h>
#include <linux/i2c.h>
#include "pmbus.h"

enum chips { ltc2978, ltc3880 };

/* LTC2978 and LTC3880 */
#define LTC2978_MFR_VOUT_PEAK		0xdd
#define LTC2978_MFR_VIN_PEAK		0xde
#define LTC2978_MFR_TEMPERATURE_PEAK	0xdf
#define LTC2978_MFR_SPECIAL_ID		0xe7

/* LTC2978 only */
#define LTC2978_MFR_VOUT_MIN		0xfb
#define LTC2978_MFR_VIN_MIN		0xfc
#define LTC2978_MFR_TEMPERATURE_MIN	0xfd

/* LTC3880 only */
#define LTC3880_MFR_IOUT_PEAK		0xd7
#define LTC3880_MFR_CLEAR_PEAKS		0xe3
#define LTC3880_MFR_TEMPERATURE2_PEAK	0xf4

#define LTC2978_ID_REV1			0x0121
#define LTC2978_ID_REV2			0x0122
#define LTC3880_ID			0x4000
#define LTC3880_ID_MASK			0xff00

/*
 * LTC2978 clears peak data whenever the CLEAR_FAULTS command is executed, which
 * happens pretty much each time chip data is updated. Raw peak data therefore
 * does not provide much value. To be able to provide useful peak data, keep an
 * internal cache of measured peak data, which is only cleared if an explicit
 * "clear peak" command is executed for the sensor in question.
 */
struct ltc2978_data {
	enum chips id;
	int vin_min, vin_max;
	int temp_min, temp_max;
	int vout_min[8], vout_max[8];
	int iout_max[2];
	int temp2_max[2];
	struct pmbus_driver_info info;
};

#define to_ltc2978_data(x)  container_of(x, struct ltc2978_data, info)

static inline int lin11_to_val(int data)
{
	s16 e = ((s16)data) >> 11;
	s32 m = (((s16)(data << 5)) >> 5);

	/*
	 * mantissa is 10 bit + sign, exponent adds up to 15 bit.
	 * Add 6 bit to exponent for maximum accuracy (10 + 15 + 6 = 31).
	 */
	e += 6;
	return (e < 0 ? m >> -e : m << e);
}

static int ltc2978_read_word_data_common(struct i2c_client *client, int page,
					 int reg)
{
	const struct pmbus_driver_info *info = pmbus_get_driver_info(client);
	struct ltc2978_data *data = to_ltc2978_data(info);
	int ret;

	switch (reg) {
	case PMBUS_VIRT_READ_VIN_MAX:
		ret = pmbus_read_word_data(client, page, LTC2978_MFR_VIN_PEAK);
		if (ret >= 0) {
			if (lin11_to_val(ret) > lin11_to_val(data->vin_max))
				data->vin_max = ret;
			ret = data->vin_max;
		}
		break;
	case PMBUS_VIRT_READ_VOUT_MAX:
		ret = pmbus_read_word_data(client, page, LTC2978_MFR_VOUT_PEAK);
		if (ret >= 0) {
			/*
			 * VOUT is 16 bit unsigned with fixed exponent,
			 * so we can compare it directly
			 */
			if (ret > data->vout_max[page])
				data->vout_max[page] = ret;
			ret = data->vout_max[page];
		}
		break;
	case PMBUS_VIRT_READ_TEMP_MAX:
		ret = pmbus_read_word_data(client, page,
					   LTC2978_MFR_TEMPERATURE_PEAK);
		if (ret >= 0) {
			if (lin11_to_val(ret) > lin11_to_val(data->temp_max))
				data->temp_max = ret;
			ret = data->temp_max;
		}
		break;
	case PMBUS_VIRT_RESET_VOUT_HISTORY:
	case PMBUS_VIRT_RESET_VIN_HISTORY:
	case PMBUS_VIRT_RESET_TEMP_HISTORY:
		ret = 0;
		break;
	default:
		ret = -ENODATA;
		break;
	}
	return ret;
}

static int ltc2978_read_word_data(struct i2c_client *client, int page, int reg)
{
	const struct pmbus_driver_info *info = pmbus_get_driver_info(client);
	struct ltc2978_data *data = to_ltc2978_data(info);
	int ret;

	switch (reg) {
	case PMBUS_VIRT_READ_VIN_MIN:
		ret = pmbus_read_word_data(client, page, LTC2978_MFR_VIN_MIN);
		if (ret >= 0) {
			if (lin11_to_val(ret) < lin11_to_val(data->vin_min))
				data->vin_min = ret;
			ret = data->vin_min;
		}
		break;
	case PMBUS_VIRT_READ_VOUT_MIN:
		ret = pmbus_read_word_data(client, page, LTC2978_MFR_VOUT_MIN);
		if (ret >= 0) {
			/*
			 * VOUT_MIN is known to not be supported on some lots
			 * of LTC2978 revision 1, and will return the maximum
			 * possible voltage if read. If VOUT_MAX is valid and
			 * lower than the reading of VOUT_MIN, use it instead.
			 */
			if (data->vout_max[page] && ret > data->vout_max[page])
				ret = data->vout_max[page];
			if (ret < data->vout_min[page])
				data->vout_min[page] = ret;
			ret = data->vout_min[page];
		}
		break;
	case PMBUS_VIRT_READ_TEMP_MIN:
		ret = pmbus_read_word_data(client, page,
					   LTC2978_MFR_TEMPERATURE_MIN);
		if (ret >= 0) {
			if (lin11_to_val(ret)
			    < lin11_to_val(data->temp_min))
				data->temp_min = ret;
			ret = data->temp_min;
		}
		break;
	case PMBUS_VIRT_READ_IOUT_MAX:
	case PMBUS_VIRT_RESET_IOUT_HISTORY:
	case PMBUS_VIRT_READ_TEMP2_MAX:
	case PMBUS_VIRT_RESET_TEMP2_HISTORY:
		ret = -ENXIO;
		break;
	default:
		ret = ltc2978_read_word_data_common(client, page, reg);
		break;
	}
	return ret;
}

static int ltc3880_read_word_data(struct i2c_client *client, int page, int reg)
{
	const struct pmbus_driver_info *info = pmbus_get_driver_info(client);
	struct ltc2978_data *data = to_ltc2978_data(info);
	int ret;

	switch (reg) {
	case PMBUS_VIRT_READ_IOUT_MAX:
		ret = pmbus_read_word_data(client, page, LTC3880_MFR_IOUT_PEAK);
		if (ret >= 0) {
			if (lin11_to_val(ret)
			    > lin11_to_val(data->iout_max[page]))
				data->iout_max[page] = ret;
			ret = data->iout_max[page];
		}
		break;
	case PMBUS_VIRT_READ_TEMP2_MAX:
		ret = pmbus_read_word_data(client, page,
					   LTC3880_MFR_TEMPERATURE2_PEAK);
		if (ret >= 0) {
			if (lin11_to_val(ret)
			    > lin11_to_val(data->temp2_max[page]))
				data->temp2_max[page] = ret;
			ret = data->temp2_max[page];
		}
		break;
	case PMBUS_VIRT_READ_VIN_MIN:
	case PMBUS_VIRT_READ_VOUT_MIN:
	case PMBUS_VIRT_READ_TEMP_MIN:
		ret = -ENXIO;
		break;
	case PMBUS_VIRT_RESET_IOUT_HISTORY:
	case PMBUS_VIRT_RESET_TEMP2_HISTORY:
		ret = 0;
		break;
	default:
		ret = ltc2978_read_word_data_common(client, page, reg);
		break;
	}
	return ret;
}

static int ltc2978_clear_peaks(struct i2c_client *client, int page,
			       enum chips id)
{
	int ret;

	if (id == ltc2978)
		ret = pmbus_write_byte(client, page, PMBUS_CLEAR_FAULTS);
	else
		ret = pmbus_write_byte(client, 0, LTC3880_MFR_CLEAR_PEAKS);

	return ret;
}

static int ltc2978_write_word_data(struct i2c_client *client, int page,
				    int reg, u16 word)
{
	const struct pmbus_driver_info *info = pmbus_get_driver_info(client);
	struct ltc2978_data *data = to_ltc2978_data(info);
	int ret;

	switch (reg) {
	case PMBUS_VIRT_RESET_IOUT_HISTORY:
		data->iout_max[page] = 0x7fff;
		ret = ltc2978_clear_peaks(client, page, data->id);
		break;
	case PMBUS_VIRT_RESET_TEMP2_HISTORY:
		data->temp2_max[page] = 0x7fff;
		ret = ltc2978_clear_peaks(client, page, data->id);
		break;
	case PMBUS_VIRT_RESET_VOUT_HISTORY:
		data->vout_min[page] = 0xffff;
		data->vout_max[page] = 0;
		ret = ltc2978_clear_peaks(client, page, data->id);
		break;
	case PMBUS_VIRT_RESET_VIN_HISTORY:
		data->vin_min = 0x7bff;
		data->vin_max = 0;
		ret = ltc2978_clear_peaks(client, page, data->id);
		break;
	case PMBUS_VIRT_RESET_TEMP_HISTORY:
		data->temp_min = 0x7bff;
		data->temp_max = 0x7fff;
		ret = ltc2978_clear_peaks(client, page, data->id);
		break;
	default:
		ret = -ENODATA;
		break;
	}
	return ret;
}

static const struct i2c_device_id ltc2978_id[] = {
	{"ltc2978", ltc2978},
	{"ltc3880", ltc3880},
	{}
};
MODULE_DEVICE_TABLE(i2c, ltc2978_id);

static int ltc2978_probe(struct i2c_client *client,
			 const struct i2c_device_id *id)
{
	int chip_id, ret, i;
	struct ltc2978_data *data;
	struct pmbus_driver_info *info;

	if (!i2c_check_functionality(client->adapter,
				     I2C_FUNC_SMBUS_READ_WORD_DATA))
		return -ENODEV;

	data = kzalloc(sizeof(struct ltc2978_data), GFP_KERNEL);
	if (!data)
		return -ENOMEM;

	chip_id = i2c_smbus_read_word_data(client, LTC2978_MFR_SPECIAL_ID);
	if (chip_id < 0) {
		ret = chip_id;
		goto err_mem;
	}

	if (chip_id == LTC2978_ID_REV1 || chip_id == LTC2978_ID_REV2) {
		data->id = ltc2978;
	} else if ((chip_id & LTC3880_ID_MASK) == LTC3880_ID) {
		data->id = ltc3880;
	} else {
		dev_err(&client->dev, "Unsupported chip ID 0x%x\n", chip_id);
		ret = -ENODEV;
		goto err_mem;
	}
	if (data->id != id->driver_data)
		dev_warn(&client->dev,
			 "Device mismatch: Configured %s, detected %s\n",
			 id->name,
			 ltc2978_id[data->id].name);

	info = &data->info;
	info->write_word_data = ltc2978_write_word_data;

	data->vout_min[0] = 0xffff;
	data->vin_min = 0x7bff;
	data->temp_min = 0x7bff;
	data->temp_max = 0x7fff;

	switch (id->driver_data) {
	case ltc2978:
		info->read_word_data = ltc2978_read_word_data;
		info->pages = 8;
		info->func[0] = PMBUS_HAVE_VIN | PMBUS_HAVE_STATUS_INPUT
		  | PMBUS_HAVE_VOUT | PMBUS_HAVE_STATUS_VOUT
		  | PMBUS_HAVE_TEMP | PMBUS_HAVE_STATUS_TEMP;
		for (i = 1; i < 8; i++) {
			info->func[i] = PMBUS_HAVE_VOUT
			  | PMBUS_HAVE_STATUS_VOUT;
			data->vout_min[i] = 0xffff;
		}
		break;
	case ltc3880:
		info->read_word_data = ltc3880_read_word_data;
		info->pages = 2;
		info->func[0] = PMBUS_HAVE_VIN | PMBUS_HAVE_IIN
		  | PMBUS_HAVE_STATUS_INPUT
		  | PMBUS_HAVE_VOUT | PMBUS_HAVE_STATUS_VOUT
		  | PMBUS_HAVE_IOUT | PMBUS_HAVE_STATUS_IOUT
		  | PMBUS_HAVE_POUT | PMBUS_HAVE_TEMP
		  | PMBUS_HAVE_TEMP2 | PMBUS_HAVE_STATUS_TEMP;
		info->func[1] = PMBUS_HAVE_VOUT | PMBUS_HAVE_STATUS_VOUT
		  | PMBUS_HAVE_IOUT | PMBUS_HAVE_STATUS_IOUT
		  | PMBUS_HAVE_POUT
		  | PMBUS_HAVE_TEMP | PMBUS_HAVE_STATUS_TEMP;
		data->vout_min[1] = 0xffff;
		break;
	default:
		ret = -ENODEV;
		goto err_mem;
	}

	ret = pmbus_do_probe(client, id, info);
	if (ret)
		goto err_mem;
	return 0;

err_mem:
	kfree(data);
	return ret;
}

static int ltc2978_remove(struct i2c_client *client)
{
	const struct pmbus_driver_info *info = pmbus_get_driver_info(client);
	const struct ltc2978_data *data = to_ltc2978_data(info);

	pmbus_do_remove(client);
	kfree(data);
	return 0;
}

/* This is the driver that will be inserted */
static struct i2c_driver ltc2978_driver = {
	.driver = {
		   .name = "ltc2978",
		   },
	.probe = ltc2978_probe,
	.remove = ltc2978_remove,
	.id_table = ltc2978_id,
};

static int __init ltc2978_init(void)
{
	return i2c_add_driver(&ltc2978_driver);
}

static void __exit ltc2978_exit(void)
{
	i2c_del_driver(&ltc2978_driver);
}

MODULE_AUTHOR("Guenter Roeck");
MODULE_DESCRIPTION("PMBus driver for LTC2978 and LTC3880");
MODULE_LICENSE("GPL");
module_init(ltc2978_init);
module_exit(ltc2978_exit);