[lm-sensors] [PATCH] Support for DS75 thermal sensor

Wolfgang Grandegger wg at grandegger.com
Fri Jul 11 14:40:58 CEST 2008


Jean Delvare wrote:
> On Tue, 08 Jul 2008 15:09:32 +0200, Wolfgang Grandegger wrote:
>> Jean Delvare wrote:
>>> On Tue, 08 Jul 2008 11:22:36 +0200, Wolfgang Grandegger wrote:
>>>> The existing driver for the LM75 is unable to identify a compatible DS75 
>>>> device properly. This patch from
>>>>
>>>> http://lists.lm-sensors.org/pipermail/lm-sensors/2007-February/018838.html 
>>>>
>>>> does fix the problem and I wonder why it did not make it into the kernel yet.
>>> Because meanwhile the lm75 driver was converted to a new-style
>>> i2c driver, with support for the DS75:
>>>
>>> http://lm-sensors.org/kernel?p=kernel/mhoffman/hwmon-2.6.git;a=commit;h=ea6db11742de63324f29d1383122657cabe90940
>>>
>>> This will presumably go in kernel 2.6.27-rc1.
>> Ah, thanks for the info. Unfortunately, this new driver does not work 
>> with the DS75 on our custom board. THe identification fails, because 
>> it's as in the old lm75.c driver (and not like Alan suggested).
> 
> There's no "detection" involved for the new-style i2c devices.
> Presumably you are still using the old binding model, not taking
> benefit of the patch at all. Use i2c_register_board_info() to
> instantiate your "ds75" i2c device from you board's platform code, and
> it should work.

I have some general question on I2C device probing. Our board does have 
two I2C buses. On the first on, there is an RTC at addr 0x32 and a DS75 
at 0x4c. Both are defined in the Flattened Device Tree and therefore 
i2c_register_board_info() will be called for them. On the second bus, 
there are other I2C devices. Nevertheless, probing for RTC and DS75 at 
addr 0x32 and 0x4c will be performed also on that bus. Is this the 
normal/intended behavior? Can such probing be suppressed?

Thanks.

Wolfgang.






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