Hello,
I am tasked with writing linux kernel support for the ADT7481 sensor.
This sensor is a dual remote, single local, sensor with an extended
temperature
range capability on the remote sensors.
Most of the register layout of the device is compliant with the LM90
driver but unfortunately the official manufacturer ID and device ID
registers are not in
a LM90 compliant location.
The LM90 driver supports the ADT7481 extended temperature range
registers through it's
ADT7461 support.
The ADT7481 does have register values at 0xfe and 0xff but they are not
documented in
the datasheet.
Here is an i2cdump output:
0 1 2 3 4 5 6 7 8 9 a b c d e f 0123456789abcdef
00: 67 6b 00 24 08 9a 13 a9 13 24 08 9a 13 a9 13 00 gk.$?????$?????.
10: 40 00 00 00 00 00 00 00 00 a4 00 00 00 00 00 00 @........?......
20: 98 05 07 00 00 00 00 00 00 00 00 00 00 00 00 00 ???.............
30: 6d ae 13 c0 00 00 00 00 00 a9 00 00 00 81 41 02 m???.....?...?A?
40: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
50: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
60: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
70: 08 00 00 c0 00 00 00 00 00 00 00 00 00 00 00 00 ?..?............
80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
90: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
a0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
b0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
c0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
d0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
e0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
f0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 41 62 ..............Ab
The official manufacturer ID register is at 0x3e and the official device
ID register is at
0x3d.
My question is whether it would be better to?
1. Modify the lm90 driver, using undocumented registers for detection
and adding second
remote channel support
Or
2. Write a new driver from scratch but borrow code from the existing
LM90 driver
I would like to get this driver included into the kernel.
Thanks for any feedback.
Malcolm Crossley
Malcolm Crossley, Software Engineer,
Embedded Systems, GE Fanuc Intelligent Platforms
GE Fanuc Intelligent Platforms Ltd, registered in England and Wales
(3828642)
at 100 Barbirolli Square, Manchester, M2 3AB, VAT GB 729 849 476
