146ab288bb
Removing the 3wire limitation on LM70 as the component also allows operation on 4wire SPI bus Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr> Signed-off-by: Guenter Roeck <linux@roeck-us.net>
40 lines
1.3 KiB
Text
40 lines
1.3 KiB
Text
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
|
|
|
|
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 TMP121/TMP123 are very similar; main difference is 13-bit temperature
|
|
data (0.0625 degrees celsius resolution).
|
|
|
|
Thanks to
|
|
---------
|
|
Jean Delvare <khali@linux-fr.org> for mentoring the hwmon-side driver
|
|
development.
|