Crossley, Malcolm (GE EntSol, Intelligent Platforms) wrote: > 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. > I think one would be the best, if the changes are not to invasive (which they probably are not). Regards, Hans
