mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-23 01:10:04 +00:00
cd929672a9
The TMP125 is a 2 degree Celsius accurate Digital Temperature Sensor with a SPI interface. The temperature register is a 16-bit, read-only register. The MSB (Bit 15) is a leading zero and never set. Bits 14 to 5 are the 1+9 temperature data bits in a two's complement format. Bits 4 to 0 are useless copies of Bit 5 value and therefore ignored. This was tested on a Aerohive HiveAP-350. Bonus: lm70 supports TMP122/TMP124 as well. I added them to the Kconfig module description. Signed-off-by: Christian Lamparter <chunkeey@gmail.com> Link: https://lore.kernel.org/r/43b19cbd4e7f51e9509e561b02b5d8d0e7079fac.1645175187.git.chunkeey@gmail.com Signed-off-by: Guenter Roeck <linux@roeck-us.net>
69 lines
2 KiB
ReStructuredText
69 lines
2 KiB
ReStructuredText
Kernel driver lm70
|
|
==================
|
|
|
|
Supported chips:
|
|
|
|
* National Semiconductor LM70
|
|
|
|
Datasheet: http://www.national.com/pf/LM/LM70.html
|
|
|
|
* Texas Instruments TMP121/TMP123
|
|
|
|
Information: http://focus.ti.com/docs/prod/folders/print/tmp121.html
|
|
|
|
* Texas Instruments TMP122/TMP124
|
|
|
|
Information: https://www.ti.com/product/tmp122
|
|
|
|
* Texas Instruments TMP125
|
|
|
|
Information: https://www.ti.com/product/tmp125
|
|
|
|
* National Semiconductor LM71
|
|
|
|
Datasheet: https://www.ti.com/product/LM71
|
|
|
|
* National Semiconductor LM74
|
|
|
|
Datasheet: https://www.ti.com/product/LM74
|
|
|
|
|
|
Author:
|
|
Kaiwan N Billimoria <kaiwan@designergraphix.com>
|
|
|
|
Description
|
|
-----------
|
|
|
|
This driver implements support for the National Semiconductor LM70
|
|
temperature sensor.
|
|
|
|
The LM70 temperature sensor chip supports a single temperature sensor.
|
|
It communicates with a host processor (or microcontroller) via an
|
|
SPI/Microwire Bus interface.
|
|
|
|
Communication with the LM70 is simple: when the temperature is to be sensed,
|
|
the driver accesses the LM70 using SPI communication: 16 SCLK cycles
|
|
comprise the MOSI/MISO loop. At the end of the transfer, the 11-bit 2's
|
|
complement digital temperature (sent via the SIO line), is available in the
|
|
driver for interpretation. This driver makes use of the kernel's in-core
|
|
SPI support.
|
|
|
|
As a real (in-tree) example of this "SPI protocol driver" interfacing
|
|
with a "SPI master controller driver", see drivers/spi/spi_lm70llp.c
|
|
and its associated documentation.
|
|
|
|
The LM74 and TMP121/TMP122/TMP123/TMP124 are very similar; main difference is
|
|
13-bit temperature data (0.0625 degrees celsius resolution).
|
|
|
|
The TMP122/TMP124 also feature configurable temperature thresholds.
|
|
|
|
The TMP125 is less accurate and provides 10-bit temperature data
|
|
with 0.25 degrees Celsius resolution.
|
|
|
|
The LM71 is also very similar; main difference is 14-bit temperature
|
|
data (0.03125 degrees celsius resolution).
|
|
|
|
Thanks to
|
|
---------
|
|
Jean Delvare <jdelvare@suse.de> for mentoring the hwmon-side driver
|
|
development.
|