| David Brazdil | 0f672f6 | 2019-12-10 10:32:29 +0000 | [diff] [blame^] | 1 | Kernel driver lm70 |
| 2 | ================== |
| 3 | |
| 4 | Supported chips: |
| 5 | |
| 6 | * National Semiconductor LM70 |
| 7 | |
| 8 | Datasheet: http://www.national.com/pf/LM/LM70.html |
| 9 | |
| 10 | * Texas Instruments TMP121/TMP123 |
| 11 | |
| 12 | Information: http://focus.ti.com/docs/prod/folders/print/tmp121.html |
| 13 | |
| 14 | * Texas Instruments TMP122/TMP124 |
| 15 | |
| 16 | Information: http://www.ti.com/product/tmp122 |
| 17 | |
| 18 | * National Semiconductor LM71 |
| 19 | |
| 20 | Datasheet: http://www.ti.com/product/LM71 |
| 21 | |
| 22 | * National Semiconductor LM74 |
| 23 | |
| 24 | Datasheet: http://www.ti.com/product/LM74 |
| 25 | |
| 26 | |
| 27 | Author: |
| 28 | Kaiwan N Billimoria <kaiwan@designergraphix.com> |
| 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 | |
| 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 | |
| 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. |
| 55 | |
| 56 | The LM71 is also very similar; main difference is 14-bit temperature |
| 57 | data (0.03125 degrees celsius resolution). |
| 58 | |
| 59 | Thanks to |
| 60 | --------- |
| 61 | Jean Delvare <jdelvare@suse.de> for mentoring the hwmon-side driver |
| 62 | development. |