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