2 * Hardware monitoring driver for LTC2978 and LTC3880
4 * Copyright (c) 2011 Ericsson AB.
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; either version 2 of the License, or
9 * (at your option) any later version.
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
16 * You should have received a copy of the GNU General Public License
17 * along with this program; if not, write to the Free Software
18 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
21 #include <linux/kernel.h>
22 #include <linux/module.h>
23 #include <linux/init.h>
24 #include <linux/err.h>
25 #include <linux/slab.h>
26 #include <linux/i2c.h>
29 enum chips { ltc2978, ltc3880 };
31 /* LTC2978 and LTC3880 */
32 #define LTC2978_MFR_VOUT_PEAK 0xdd
33 #define LTC2978_MFR_VIN_PEAK 0xde
34 #define LTC2978_MFR_TEMPERATURE_PEAK 0xdf
35 #define LTC2978_MFR_SPECIAL_ID 0xe7
38 #define LTC2978_MFR_VOUT_MIN 0xfb
39 #define LTC2978_MFR_VIN_MIN 0xfc
40 #define LTC2978_MFR_TEMPERATURE_MIN 0xfd
43 #define LTC3880_MFR_IOUT_PEAK 0xd7
44 #define LTC3880_MFR_CLEAR_PEAKS 0xe3
45 #define LTC3880_MFR_TEMPERATURE2_PEAK 0xf4
47 #define LTC2978_ID_REV1 0x0121
48 #define LTC2978_ID_REV2 0x0122
49 #define LTC3880_ID 0x4000
50 #define LTC3880_ID_MASK 0xff00
53 * LTC2978 clears peak data whenever the CLEAR_FAULTS command is executed, which
54 * happens pretty much each time chip data is updated. Raw peak data therefore
55 * does not provide much value. To be able to provide useful peak data, keep an
56 * internal cache of measured peak data, which is only cleared if an explicit
57 * "clear peak" command is executed for the sensor in question.
62 int temp_min, temp_max[2];
63 int vout_min[8], vout_max[8];
66 struct pmbus_driver_info info;
69 #define to_ltc2978_data(x) container_of(x, struct ltc2978_data, info)
71 static inline int lin11_to_val(int data)
73 s16 e = ((s16)data) >> 11;
74 s32 m = (((s16)(data << 5)) >> 5);
77 * mantissa is 10 bit + sign, exponent adds up to 15 bit.
78 * Add 6 bit to exponent for maximum accuracy (10 + 15 + 6 = 31).
81 return (e < 0 ? m >> -e : m << e);
84 static int ltc2978_read_word_data_common(struct i2c_client *client, int page,
87 const struct pmbus_driver_info *info = pmbus_get_driver_info(client);
88 struct ltc2978_data *data = to_ltc2978_data(info);
92 case PMBUS_VIRT_READ_VIN_MAX:
93 ret = pmbus_read_word_data(client, page, LTC2978_MFR_VIN_PEAK);
95 if (lin11_to_val(ret) > lin11_to_val(data->vin_max))
100 case PMBUS_VIRT_READ_VOUT_MAX:
101 ret = pmbus_read_word_data(client, page, LTC2978_MFR_VOUT_PEAK);
104 * VOUT is 16 bit unsigned with fixed exponent,
105 * so we can compare it directly
107 if (ret > data->vout_max[page])
108 data->vout_max[page] = ret;
109 ret = data->vout_max[page];
112 case PMBUS_VIRT_READ_TEMP_MAX:
113 ret = pmbus_read_word_data(client, page,
114 LTC2978_MFR_TEMPERATURE_PEAK);
116 if (lin11_to_val(ret)
117 > lin11_to_val(data->temp_max[page]))
118 data->temp_max[page] = ret;
119 ret = data->temp_max[page];
122 case PMBUS_VIRT_RESET_VOUT_HISTORY:
123 case PMBUS_VIRT_RESET_VIN_HISTORY:
124 case PMBUS_VIRT_RESET_TEMP_HISTORY:
134 static int ltc2978_read_word_data(struct i2c_client *client, int page, int reg)
136 const struct pmbus_driver_info *info = pmbus_get_driver_info(client);
137 struct ltc2978_data *data = to_ltc2978_data(info);
141 case PMBUS_VIRT_READ_VIN_MIN:
142 ret = pmbus_read_word_data(client, page, LTC2978_MFR_VIN_MIN);
144 if (lin11_to_val(ret) < lin11_to_val(data->vin_min))
149 case PMBUS_VIRT_READ_VOUT_MIN:
150 ret = pmbus_read_word_data(client, page, LTC2978_MFR_VOUT_MIN);
153 * VOUT_MIN is known to not be supported on some lots
154 * of LTC2978 revision 1, and will return the maximum
155 * possible voltage if read. If VOUT_MAX is valid and
156 * lower than the reading of VOUT_MIN, use it instead.
158 if (data->vout_max[page] && ret > data->vout_max[page])
159 ret = data->vout_max[page];
160 if (ret < data->vout_min[page])
161 data->vout_min[page] = ret;
162 ret = data->vout_min[page];
165 case PMBUS_VIRT_READ_TEMP_MIN:
166 ret = pmbus_read_word_data(client, page,
167 LTC2978_MFR_TEMPERATURE_MIN);
169 if (lin11_to_val(ret)
170 < lin11_to_val(data->temp_min))
171 data->temp_min = ret;
172 ret = data->temp_min;
175 case PMBUS_VIRT_READ_IOUT_MAX:
176 case PMBUS_VIRT_RESET_IOUT_HISTORY:
177 case PMBUS_VIRT_READ_TEMP2_MAX:
178 case PMBUS_VIRT_RESET_TEMP2_HISTORY:
182 ret = ltc2978_read_word_data_common(client, page, reg);
188 static int ltc3880_read_word_data(struct i2c_client *client, int page, int reg)
190 const struct pmbus_driver_info *info = pmbus_get_driver_info(client);
191 struct ltc2978_data *data = to_ltc2978_data(info);
195 case PMBUS_VIRT_READ_IOUT_MAX:
196 ret = pmbus_read_word_data(client, page, LTC3880_MFR_IOUT_PEAK);
198 if (lin11_to_val(ret)
199 > lin11_to_val(data->iout_max[page]))
200 data->iout_max[page] = ret;
201 ret = data->iout_max[page];
204 case PMBUS_VIRT_READ_TEMP2_MAX:
205 ret = pmbus_read_word_data(client, page,
206 LTC3880_MFR_TEMPERATURE2_PEAK);
208 if (lin11_to_val(ret) > lin11_to_val(data->temp2_max))
209 data->temp2_max = ret;
210 ret = data->temp2_max;
213 case PMBUS_VIRT_READ_VIN_MIN:
214 case PMBUS_VIRT_READ_VOUT_MIN:
215 case PMBUS_VIRT_READ_TEMP_MIN:
218 case PMBUS_VIRT_RESET_IOUT_HISTORY:
219 case PMBUS_VIRT_RESET_TEMP2_HISTORY:
223 ret = ltc2978_read_word_data_common(client, page, reg);
229 static int ltc2978_clear_peaks(struct i2c_client *client, int page,
235 ret = pmbus_write_byte(client, page, PMBUS_CLEAR_FAULTS);
237 ret = pmbus_write_byte(client, 0, LTC3880_MFR_CLEAR_PEAKS);
242 static int ltc2978_write_word_data(struct i2c_client *client, int page,
245 const struct pmbus_driver_info *info = pmbus_get_driver_info(client);
246 struct ltc2978_data *data = to_ltc2978_data(info);
250 case PMBUS_VIRT_RESET_IOUT_HISTORY:
251 data->iout_max[page] = 0x7c00;
252 ret = ltc2978_clear_peaks(client, page, data->id);
254 case PMBUS_VIRT_RESET_TEMP2_HISTORY:
255 data->temp2_max = 0x7c00;
256 ret = ltc2978_clear_peaks(client, page, data->id);
258 case PMBUS_VIRT_RESET_VOUT_HISTORY:
259 data->vout_min[page] = 0xffff;
260 data->vout_max[page] = 0;
261 ret = ltc2978_clear_peaks(client, page, data->id);
263 case PMBUS_VIRT_RESET_VIN_HISTORY:
264 data->vin_min = 0x7bff;
265 data->vin_max = 0x7c00;
266 ret = ltc2978_clear_peaks(client, page, data->id);
268 case PMBUS_VIRT_RESET_TEMP_HISTORY:
269 data->temp_min = 0x7bff;
270 data->temp_max[page] = 0x7c00;
271 ret = ltc2978_clear_peaks(client, page, data->id);
280 static const struct i2c_device_id ltc2978_id[] = {
281 {"ltc2978", ltc2978},
282 {"ltc3880", ltc3880},
285 MODULE_DEVICE_TABLE(i2c, ltc2978_id);
287 static int ltc2978_probe(struct i2c_client *client,
288 const struct i2c_device_id *id)
291 struct ltc2978_data *data;
292 struct pmbus_driver_info *info;
294 if (!i2c_check_functionality(client->adapter,
295 I2C_FUNC_SMBUS_READ_WORD_DATA))
298 data = devm_kzalloc(&client->dev, sizeof(struct ltc2978_data),
303 chip_id = i2c_smbus_read_word_data(client, LTC2978_MFR_SPECIAL_ID);
307 if (chip_id == LTC2978_ID_REV1 || chip_id == LTC2978_ID_REV2) {
309 } else if ((chip_id & LTC3880_ID_MASK) == LTC3880_ID) {
312 dev_err(&client->dev, "Unsupported chip ID 0x%x\n", chip_id);
315 if (data->id != id->driver_data)
316 dev_warn(&client->dev,
317 "Device mismatch: Configured %s, detected %s\n",
319 ltc2978_id[data->id].name);
322 info->write_word_data = ltc2978_write_word_data;
324 data->vin_min = 0x7bff;
325 data->vin_max = 0x7c00;
326 data->temp_min = 0x7bff;
327 for (i = 0; i < ARRAY_SIZE(data->temp_max); i++)
328 data->temp_max[i] = 0x7c00;
329 data->temp2_max = 0x7c00;
333 info->read_word_data = ltc2978_read_word_data;
335 info->func[0] = PMBUS_HAVE_VIN | PMBUS_HAVE_STATUS_INPUT
336 | PMBUS_HAVE_VOUT | PMBUS_HAVE_STATUS_VOUT
337 | PMBUS_HAVE_TEMP | PMBUS_HAVE_STATUS_TEMP;
338 for (i = 1; i < 8; i++) {
339 info->func[i] = PMBUS_HAVE_VOUT
340 | PMBUS_HAVE_STATUS_VOUT;
344 info->read_word_data = ltc3880_read_word_data;
346 info->func[0] = PMBUS_HAVE_VIN | PMBUS_HAVE_IIN
347 | PMBUS_HAVE_STATUS_INPUT
348 | PMBUS_HAVE_VOUT | PMBUS_HAVE_STATUS_VOUT
349 | PMBUS_HAVE_IOUT | PMBUS_HAVE_STATUS_IOUT
350 | PMBUS_HAVE_POUT | PMBUS_HAVE_TEMP
351 | PMBUS_HAVE_TEMP2 | PMBUS_HAVE_STATUS_TEMP;
352 info->func[1] = PMBUS_HAVE_VOUT | PMBUS_HAVE_STATUS_VOUT
353 | PMBUS_HAVE_IOUT | PMBUS_HAVE_STATUS_IOUT
355 | PMBUS_HAVE_TEMP | PMBUS_HAVE_STATUS_TEMP;
356 data->iout_max[0] = 0x7c00;
357 data->iout_max[1] = 0x7c00;
362 for (i = 0; i < info->pages; i++)
363 data->vout_min[i] = 0xffff;
365 return pmbus_do_probe(client, id, info);
368 /* This is the driver that will be inserted */
369 static struct i2c_driver ltc2978_driver = {
373 .probe = ltc2978_probe,
374 .remove = pmbus_do_remove,
375 .id_table = ltc2978_id,
378 module_i2c_driver(ltc2978_driver);
380 MODULE_AUTHOR("Guenter Roeck");
381 MODULE_DESCRIPTION("PMBus driver for LTC2978 and LTC3880");
382 MODULE_LICENSE("GPL");