0001 Kernel driver lm90
0002 ==================
0003
0004 Supported chips:
0005
0006 * National Semiconductor LM84
0007
0008 Prefix: 'lm84'
0009
0010 Addresses scanned: I2C 0x18 - 0x1a, 0x29 - 0x2b, 0x4c - 0x4e
0011
0012 Datasheet: Publicly available at the National Semiconductor website
0013
0014 * National Semiconductor LM90
0015
0016 Prefix: 'lm90'
0017
0018 Addresses scanned: I2C 0x4c
0019
0020 Datasheet: Publicly available at the National Semiconductor website
0021
0022 http://www.national.com/pf/LM/LM90.html
0023
0024 * National Semiconductor LM89
0025
0026 Prefix: 'lm89' (no auto-detection)
0027
0028 Addresses scanned: I2C 0x4c and 0x4d
0029
0030 Datasheet: Publicly available at the National Semiconductor website
0031
0032 http://www.national.com/mpf/LM/LM89.html
0033
0034 * National Semiconductor LM99
0035
0036 Prefix: 'lm99'
0037
0038 Addresses scanned: I2C 0x4c and 0x4d
0039
0040 Datasheet: Publicly available at the National Semiconductor website
0041
0042 http://www.national.com/pf/LM/LM99.html
0043
0044 * National Semiconductor LM86
0045
0046 Prefix: 'lm86'
0047
0048 Addresses scanned: I2C 0x4c
0049
0050 Datasheet: Publicly available at the National Semiconductor website
0051
0052 http://www.national.com/mpf/LM/LM86.html
0053
0054 * Analog Devices ADM1020
0055
0056 Prefix: 'adm1020'
0057
0058 Addresses scanned: I2C 0x4c - 0x4e
0059
0060 Datasheet: Publicly available at the Analog Devices website
0061
0062 * Analog Devices ADM1021
0063
0064 Prefix: 'adm1021'
0065
0066 Addresses scanned: I2C 0x18 - 0x1a, 0x29 - 0x2b, 0x4c - 0x4e
0067
0068 Datasheet: Publicly available at the Analog Devices website
0069
0070 * Analog Devices ADM1021A/ADM1023
0071
0072 Prefix: 'adm1023'
0073
0074 Addresses scanned: I2C 0x18 - 0x1a, 0x29 - 0x2b, 0x4c - 0x4e
0075
0076 Datasheet: Publicly available at the Analog Devices website
0077
0078 * Analog Devices ADM1032
0079
0080 Prefix: 'adm1032'
0081
0082 Addresses scanned: I2C 0x4c and 0x4d
0083
0084 Datasheet: Publicly available at the ON Semiconductor website
0085
0086 https://www.onsemi.com/PowerSolutions/product.do?id=ADM1032
0087
0088 * Analog Devices ADT7461
0089
0090 Prefix: 'adt7461'
0091
0092 Addresses scanned: I2C 0x4c and 0x4d
0093
0094 Datasheet: Publicly available at the ON Semiconductor website
0095
0096 https://www.onsemi.com/PowerSolutions/product.do?id=ADT7461
0097
0098 * Analog Devices ADT7461A
0099
0100 Prefix: 'adt7461a'
0101
0102 Addresses scanned: I2C 0x4c and 0x4d
0103
0104 Datasheet: Publicly available at the ON Semiconductor website
0105
0106 https://www.onsemi.com/PowerSolutions/product.do?id=ADT7461A
0107
0108 * Analog Devices ADT7481
0109
0110 Prefix: 'adt7481'
0111
0112 Addresses scanned: I2C 0x4b and 0x4c
0113
0114 Datasheet: Publicly available at the ON Semiconductor website
0115
0116 https://www.onsemi.com/PowerSolutions/product.do?id=ADT7481
0117
0118 * Analog Devices ADT7482
0119
0120 Prefix: 'adt7482'
0121
0122 Addresses scanned: I2C 0x4c
0123
0124 Datasheet: Publicly available at the ON Semiconductor website
0125
0126 https://www.onsemi.com/PowerSolutions/product.do?id=ADT7482
0127
0128 * Analog Devices ADT7483A
0129
0130 Prefix: 'adt7483a'
0131
0132 Addresses scanned: I2C 0x18, 0x19, 0x1a, 0x29, 0x2a, 0x2b, 0x4c, 0x4d, 0x4e
0133
0134 Datasheet: Publicly available at the ON Semiconductor website
0135
0136 https://www.onsemi.com/PowerSolutions/product.do?id=ADT7483A
0137
0138 * ON Semiconductor NCT1008
0139
0140 Prefix: 'nct1008'
0141
0142 Addresses scanned: I2C 0x4c and 0x4d
0143
0144 Datasheet: Publicly available at the ON Semiconductor website
0145
0146 https://www.onsemi.com/PowerSolutions/product.do?id=NCT1008
0147
0148 * ON Semiconductor NCT210
0149
0150 Prefix: 'adm1021'
0151
0152 Addresses scanned: I2C 0x18 - 0x1a, 0x29 - 0x2b, 0x4c - 0x4e
0153
0154 Datasheet: Publicly available at the ON Semiconductor website
0155
0156 https://www.onsemi.com/PowerSolutions/product.do?id=NCT210
0157
0158 * ON Semiconductor NCT214
0159
0160 Prefix: 'nct214'
0161
0162 Addresses scanned: I2C 0x18 - 0x1a, 0x29 - 0x2b, 0x4c - 0x4e
0163
0164 Datasheet: Publicly available at the ON Semiconductor website
0165
0166 https://www.onsemi.com/PowerSolutions/product.do?id=NCT214
0167
0168 * ON Semiconductor NCT218
0169
0170 Prefix: 'nct218'
0171
0172 Addresses scanned: I2C 0x4c - 0x4d
0173
0174 Datasheet: Publicly available at the ON Semiconductor website
0175
0176 https://www.onsemi.com/PowerSolutions/product.do?id=NCT218
0177
0178 * ON Semiconductor NCT72
0179
0180 Prefix: 'nct72'
0181
0182 Addresses scanned: I2C 0x4c - 0x4d
0183
0184 Datasheet: Publicly available at the ON Semiconductor website
0185
0186 https://www.onsemi.com/PowerSolutions/product.do?id=NCT72
0187
0188 * Maxim MAX1617
0189
0190 Prefix: 'max1617'
0191
0192 Addresses scanned: I2C 0x18 - 0x1a, 0x29 - 0x2b, 0x4c - 0x4e
0193
0194 Datasheet: Publicly available at the Maxim website
0195
0196 * Maxim MAX1617A
0197
0198 Prefix: 'max1617a'
0199
0200 Addresses scanned: I2C 0x18 - 0x1a, 0x29 - 0x2b, 0x4c - 0x4e
0201
0202 Datasheet: Publicly available at the Maxim website
0203
0204 * Maxim MAX6642
0205
0206 Prefix: 'max6642'
0207
0208 Addresses scanned: I2C 0x48-0x4f
0209
0210 Datasheet: Publicly available at the Maxim website
0211
0212 http://datasheets.maxim-ic.com/en/ds/MAX6642.pdf
0213
0214 * Maxim MAX6646
0215
0216 Prefix: 'max6646'
0217
0218 Addresses scanned: I2C 0x4d
0219
0220 Datasheet: Publicly available at the Maxim website
0221
0222 http://www.maxim-ic.com/quick_view2.cfm/qv_pk/3497
0223
0224 * Maxim MAX6647
0225
0226 Prefix: 'max6646'
0227
0228 Addresses scanned: I2C 0x4e
0229
0230 Datasheet: Publicly available at the Maxim website
0231
0232 http://www.maxim-ic.com/quick_view2.cfm/qv_pk/3497
0233
0234 * Maxim MAX6648
0235
0236 Prefix: 'max6648'
0237
0238 Addresses scanned: I2C 0x4c
0239
0240 Datasheet: Publicly available at the Maxim website
0241
0242 http://www.maxim-ic.com/quick_view2.cfm/qv_pk/3500
0243
0244 * Maxim MAX6649
0245
0246 Prefix: 'max6646'
0247
0248 Addresses scanned: I2C 0x4c
0249
0250 Datasheet: Publicly available at the Maxim website
0251
0252 http://www.maxim-ic.com/quick_view2.cfm/qv_pk/3497
0253
0254 * Maxim MAX6654
0255
0256 Prefix: 'max6654'
0257
0258 Addresses scanned: I2C 0x18, 0x19, 0x1a, 0x29, 0x2a, 0x2b,
0259
0260 0x4c, 0x4d and 0x4e
0261
0262 Datasheet: Publicly available at the Maxim website
0263
0264 https://www.maximintegrated.com/en/products/sensors/MAX6654.html
0265
0266 * Maxim MAX6657
0267
0268 Prefix: 'max6657'
0269
0270 Addresses scanned: I2C 0x4c
0271
0272 Datasheet: Publicly available at the Maxim website
0273
0274 http://www.maxim-ic.com/quick_view2.cfm/qv_pk/2578
0275
0276 * Maxim MAX6658
0277
0278 Prefix: 'max6657'
0279
0280 Addresses scanned: I2C 0x4c
0281
0282 Datasheet: Publicly available at the Maxim website
0283
0284 http://www.maxim-ic.com/quick_view2.cfm/qv_pk/2578
0285
0286 * Maxim MAX6659
0287
0288 Prefix: 'max6659'
0289
0290 Addresses scanned: I2C 0x4c, 0x4d, 0x4e
0291
0292 Datasheet: Publicly available at the Maxim website
0293
0294 http://www.maxim-ic.com/quick_view2.cfm/qv_pk/2578
0295
0296 * Maxim MAX6680
0297
0298 Prefix: 'max6680'
0299
0300 Addresses scanned: I2C 0x18, 0x19, 0x1a, 0x29, 0x2a, 0x2b,
0301
0302 0x4c, 0x4d and 0x4e
0303
0304 Datasheet: Publicly available at the Maxim website
0305
0306 http://www.maxim-ic.com/quick_view2.cfm/qv_pk/3370
0307
0308 * Maxim MAX6681
0309
0310 Prefix: 'max6680'
0311
0312 Addresses scanned: I2C 0x18, 0x19, 0x1a, 0x29, 0x2a, 0x2b,
0313
0314 0x4c, 0x4d and 0x4e
0315
0316 Datasheet: Publicly available at the Maxim website
0317
0318 http://www.maxim-ic.com/quick_view2.cfm/qv_pk/3370
0319
0320 * Maxim MAX6692
0321
0322 Prefix: 'max6648'
0323
0324 Addresses scanned: I2C 0x4c
0325
0326 Datasheet: Publicly available at the Maxim website
0327
0328 http://www.maxim-ic.com/quick_view2.cfm/qv_pk/3500
0329
0330 * Maxim MAX6695
0331
0332 Prefix: 'max6695'
0333
0334 Addresses scanned: I2C 0x18
0335
0336 Datasheet: Publicly available at the Maxim website
0337
0338 http://www.maxim-ic.com/datasheet/index.mvp/id/4199
0339
0340 * Maxim MAX6696
0341
0342 Prefix: 'max6695'
0343
0344 Addresses scanned: I2C 0x18, 0x19, 0x1a, 0x29, 0x2a, 0x2b,
0345
0346 0x4c, 0x4d and 0x4e
0347
0348 Datasheet: Publicly available at the Maxim website
0349
0350 http://www.maxim-ic.com/datasheet/index.mvp/id/4199
0351
0352 * Winbond/Nuvoton W83L771W/G
0353
0354 Prefix: 'w83l771'
0355
0356 Addresses scanned: I2C 0x4c
0357
0358 Datasheet: No longer available
0359
0360 * Winbond/Nuvoton W83L771AWG/ASG
0361
0362 Prefix: 'w83l771'
0363
0364 Addresses scanned: I2C 0x4c
0365
0366 Datasheet: Not publicly available, can be requested from Nuvoton
0367
0368 * Philips/NXP SA56004X
0369
0370 Prefix: 'sa56004'
0371
0372 Addresses scanned: I2C 0x48 through 0x4F
0373
0374 Datasheet: Publicly available at NXP website
0375
0376 http://ics.nxp.com/products/interface/datasheet/sa56004x.pdf
0377
0378 * GMT G781
0379
0380 Prefix: 'g781'
0381
0382 Addresses scanned: I2C 0x4c, 0x4d
0383
0384 Datasheet: Not publicly available from GMT
0385
0386 * Texas Instruments TMP451
0387
0388 Prefix: 'tmp451'
0389
0390 Addresses scanned: I2C 0x4c
0391
0392 Datasheet: Publicly available at TI website
0393
0394 https://www.ti.com/litv/pdf/sbos686
0395
0396 * Texas Instruments TMP461
0397
0398 Prefix: 'tmp461'
0399
0400 Addresses scanned: I2C 0x48 through 0x4F
0401
0402 Datasheet: Publicly available at TI website
0403
0404 https://www.ti.com/lit/gpn/tmp461
0405
0406 * Philips NE1617, NE1617A
0407
0408 Prefix: 'max1617' (probably detected as a max1617)
0409
0410 Addresses scanned: I2C 0x18 - 0x1a, 0x29 - 0x2b, 0x4c - 0x4e
0411
0412 Datasheets: Publicly available at the Philips website
0413
0414 * Philips NE1618
0415
0416 Prefix: 'ne1618'
0417
0418 Addresses scanned: I2C 0x18 - 0x1a, 0x29 - 0x2b, 0x4c - 0x4e
0419
0420 Datasheets: Publicly available at the Philips website
0421
0422 * Genesys Logic GL523SM
0423
0424 Prefix: 'gl523sm'
0425
0426 Addresses scanned: I2C 0x18 - 0x1a, 0x29 - 0x2b, 0x4c - 0x4e
0427
0428 Datasheet:
0429
0430 * TI THMC10
0431
0432 Prefix: 'thmc10'
0433
0434 Addresses scanned: I2C 0x18 - 0x1a, 0x29 - 0x2b, 0x4c - 0x4e
0435
0436 Datasheet: Publicly available at the TI website
0437
0438 * Onsemi MC1066
0439
0440 Prefix: 'mc1066'
0441
0442 Addresses scanned: I2C 0x18 - 0x1a, 0x29 - 0x2b, 0x4c - 0x4e
0443
0444 Datasheet: Publicly available at the Onsemi website
0445
0446 Author: Jean Delvare <jdelvare@suse.de>
0447
0448
0449 Description
0450 -----------
0451
0452 The LM90 is a digital temperature sensor. It senses its own temperature as
0453 well as the temperature of up to one external diode. It is compatible
0454 with many other devices, many of which are supported by this driver.
0455
0456 The family of chips supported by this driver is derived from MAX1617.
0457 This chip as well as various compatible chips support a local and a remote
0458 temperature sensor with 8 bit accuracy. Later chips provide improved accuracy
0459 and other additional features such as hysteresis and temperature offset
0460 registers.
0461
0462 Note that there is no easy way to differentiate between the MAX6657,
0463 MAX6658 and MAX6659 variants. The extra features of the MAX6659 are only
0464 supported by this driver if the chip is located at address 0x4d or 0x4e,
0465 or if the chip type is explicitly selected as max6659.
0466 The MAX6680 and MAX6681 only differ in their pinout, therefore they obviously
0467 can't (and don't need to) be distinguished.
0468
0469 The different chipsets of the family are not strictly identical, although
0470 very similar. For reference, here comes a non-exhaustive list of specific
0471 features:
0472
0473 LM84:
0474 * 8 bit sensor resolution
0475
0476 ADM1020, ADM1021, GL523SM, MAX1617, NE1617, NE1617A, THMC10:
0477 * 8 bit sensor resolution
0478 * Low temperature limits
0479
0480 NCT210, NE1618:
0481 * 11 bit sensor resolution for remote temperature sensor
0482 * Low temperature limits
0483
0484 ADM1021A, ADM1023:
0485 * Temperature offset register for remote temperature sensor
0486 * 11 bit resolution for remote temperature sensor
0487 * Low temperature limits
0488
0489 LM90:
0490 * 11 bit resolution for remote temperature sensor
0491 * Temperature offset register for remote temperature sensor
0492 * Low and critical temperature limits
0493 * Configurable conversion rate
0494 * Filter and alert configuration register at 0xBF.
0495 * ALERT is triggered by temperatures over critical limits.
0496
0497 LM86 and LM89:
0498 * Same as LM90
0499 * Better external channel accuracy
0500
0501 LM99:
0502 * Same as LM89
0503 * External temperature shifted by 16 degrees down
0504
0505 ADM1032:
0506 * Consecutive alert register at 0x22.
0507 * Conversion averaging.
0508 * Up to 64 conversions/s.
0509 * ALERT is triggered by open remote sensor.
0510 * SMBus PEC support for Write Byte and Receive Byte transactions.
0511
0512 ADT7461, ADT7461A, NCT1008:
0513 * Extended temperature range (breaks compatibility)
0514 * Lower resolution for remote temperature
0515 * SMBus PEC support for Write Byte and Receive Byte transactions.
0516 * 10 bit temperature resolution
0517
0518 ADT7481, ADT7482, ADT7483:
0519 * Temperature offset register
0520 * SMBus PEC support
0521 * 10 bit temperature resolution for external sensors
0522 * Two remote sensors
0523 * Selectable address (ADT7483)
0524
0525 MAX6642:
0526 * No critical limit register
0527 * Conversion rate not configurable
0528 * Better local resolution (10 bit)
0529 * 10 bit external sensor resolution
0530
0531 MAX6646, MAX6647, MAX6649:
0532 * Better local resolution
0533 * Extended range unsigned external temperature
0534
0535 MAX6648, MAX6692:
0536 * Better local resolution
0537 * Unsigned temperature
0538
0539 MAX6654, MAX6690:
0540 * Better local resolution
0541 * Selectable address
0542 * Remote sensor type selection
0543 * Extended temperature range
0544 * Extended resolution only available when conversion rate <= 1 Hz
0545
0546 MAX6657 and MAX6658:
0547 * Better local resolution
0548 * Remote sensor type selection
0549
0550 MAX6659:
0551 * Better local resolution
0552 * Selectable address
0553 * Second critical temperature limit
0554 * Remote sensor type selection
0555
0556 MAX6680 and MAX6681:
0557 * Selectable address
0558 * Remote sensor type selection
0559
0560 MAX6695 and MAX6696:
0561 * Better local resolution
0562 * Selectable address (max6696)
0563 * Second critical temperature limit
0564 * Two remote sensors
0565
0566 W83L771W/G
0567 * The G variant is lead-free, otherwise similar to the W.
0568 * Filter and alert configuration register at 0xBF
0569 * Moving average (depending on conversion rate)
0570
0571 W83L771AWG/ASG
0572 * Successor of the W83L771W/G, same features.
0573 * The AWG and ASG variants only differ in package format.
0574 * Diode ideality factor configuration (remote sensor) at 0xE3
0575
0576 SA56004X:
0577 * Better local resolution
0578
0579 All temperature values are given in degrees Celsius. Resolution
0580 is 1.0 degree for the local temperature, 0.125 degree for the remote
0581 temperature, except for the MAX6654, MAX6657, MAX6658 and MAX6659 which have
0582 a resolution of 0.125 degree for both temperatures.
0583
0584 Each sensor has its own high and low limits, plus a critical limit.
0585 Additionally, there is a relative hysteresis value common to both critical
0586 values. To make life easier to user-space applications, two absolute values
0587 are exported, one for each channel, but these values are of course linked.
0588 Only the local hysteresis can be set from user-space, and the same delta
0589 applies to the remote hysteresis.
0590
0591 The lm90 driver will not update its values more frequently than configured with
0592 the update_interval attribute; reading them more often will do no harm, but will
0593 return 'old' values.
0594
0595 SMBus Alert Support
0596 -------------------
0597
0598 This driver has basic support for SMBus alert. When an alert is received,
0599 the status register is read and the faulty temperature channel is logged.
0600
0601 The Analog Devices chips (ADM1032, ADT7461 and ADT7461A) and ON
0602 Semiconductor chips (NCT1008) do not implement the SMBus alert protocol
0603 properly so additional care is needed: the ALERT output is disabled when
0604 an alert is received, and is re-enabled only when the alarm is gone.
0605 Otherwise the chip would block alerts from other chips in the bus as long
0606 as the alarm is active.
0607
0608 PEC Support
0609 -----------
0610
0611 The ADM1032 is the only chip of the family which supports PEC. It does
0612 not support PEC on all transactions though, so some care must be taken.
0613
0614 When reading a register value, the PEC byte is computed and sent by the
0615 ADM1032 chip. However, in the case of a combined transaction (SMBus Read
0616 Byte), the ADM1032 computes the CRC value over only the second half of
0617 the message rather than its entirety, because it thinks the first half
0618 of the message belongs to a different transaction. As a result, the CRC
0619 value differs from what the SMBus master expects, and all reads fail.
0620
0621 For this reason, the lm90 driver will enable PEC for the ADM1032 only if
0622 the bus supports the SMBus Send Byte and Receive Byte transaction types.
0623 These transactions will be used to read register values, instead of
0624 SMBus Read Byte, and PEC will work properly.
0625
0626 Additionally, the ADM1032 doesn't support SMBus Send Byte with PEC.
0627 Instead, it will try to write the PEC value to the register (because the
0628 SMBus Send Byte transaction with PEC is similar to a Write Byte transaction
0629 without PEC), which is not what we want. Thus, PEC is explicitly disabled
0630 on SMBus Send Byte transactions in the lm90 driver.
0631
0632 PEC on byte data transactions represents a significant increase in bandwidth
0633 usage (+33% for writes, +25% for reads) in normal conditions. With the need
0634 to use two SMBus transaction for reads, this overhead jumps to +50%. Worse,
0635 two transactions will typically mean twice as much delay waiting for
0636 transaction completion, effectively doubling the register cache refresh time.
0637 I guess reliability comes at a price, but it's quite expensive this time.
0638
0639 So, as not everyone might enjoy the slowdown, PEC is disabled by default and
0640 can be enabled through sysfs. Just write 1 to the "pec" file and PEC will be
0641 enabled. Write 0 to that file to disable PEC again.
