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1 | Kernel driver lm70 |
2 | ================== | |
3 | ||
c8ac32e4 | 4 | Supported chips: |
b04f2f7d | 5 | |
e1a8e913 | 6 | * National Semiconductor LM70 |
b04f2f7d | 7 | |
e1a8e913 | 8 | Datasheet: http://www.national.com/pf/LM/LM70.html |
b04f2f7d | 9 | |
c8ac32e4 | 10 | * Texas Instruments TMP121/TMP123 |
b04f2f7d | 11 | |
c8ac32e4 | 12 | Information: http://focus.ti.com/docs/prod/folders/print/tmp121.html |
b04f2f7d | 13 | |
68f0c8c9 | 14 | * Texas Instruments TMP122/TMP124 |
b04f2f7d | 15 | |
ad736c1a | 16 | Information: https://www.ti.com/product/tmp122 |
b04f2f7d | 17 | |
a86e94dc | 18 | * National Semiconductor LM71 |
b04f2f7d | 19 | |
ad736c1a | 20 | Datasheet: https://www.ti.com/product/LM71 |
b04f2f7d | 21 | |
a86e94dc | 22 | * National Semiconductor LM74 |
b04f2f7d | 23 | |
ad736c1a | 24 | Datasheet: https://www.ti.com/product/LM74 |
e1a8e913 | 25 | |
b04f2f7d | 26 | |
e1a8e913 | 27 | Author: |
b04f2f7d | 28 | Kaiwan N Billimoria <kaiwan@designergraphix.com> |
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29 | |
30 | Description | |
31 | ----------- | |
32 | ||
33 | This driver implements support for the National Semiconductor LM70 | |
34 | temperature sensor. | |
35 | ||
36 | The LM70 temperature sensor chip supports a single temperature sensor. | |
37 | It communicates with a host processor (or microcontroller) via an | |
38 | SPI/Microwire Bus interface. | |
39 | ||
40 | Communication with the LM70 is simple: when the temperature is to be sensed, | |
41 | the driver accesses the LM70 using SPI communication: 16 SCLK cycles | |
42 | comprise the MOSI/MISO loop. At the end of the transfer, the 11-bit 2's | |
43 | complement digital temperature (sent via the SIO line), is available in the | |
44 | driver for interpretation. This driver makes use of the kernel's in-core | |
45 | SPI support. | |
46 | ||
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47 | As a real (in-tree) example of this "SPI protocol driver" interfacing |
48 | with a "SPI master controller driver", see drivers/spi/spi_lm70llp.c | |
49 | and its associated documentation. | |
50 | ||
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51 | The LM74 and TMP121/TMP122/TMP123/TMP124 are very similar; main difference is |
52 | 13-bit temperature data (0.0625 degrees celsius resolution). | |
53 | ||
54 | The TMP122/TMP124 also feature configurable temperature thresholds. | |
a86e94dc CL |
55 | |
56 | The LM71 is also very similar; main difference is 14-bit temperature | |
57 | data (0.03125 degrees celsius resolution). | |
c8ac32e4 | 58 | |
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59 | Thanks to |
60 | --------- | |
7c81c60f | 61 | Jean Delvare <jdelvare@suse.de> for mentoring the hwmon-side driver |
e1a8e913 | 62 | development. |