[lm-sensors] [PATCH 1/3] lm78: No longer use i2c-isa

Jean Delvare khali at linux-fr.org
Mon Mar 19 20:02:40 CET 2007

On Mon, 19 Mar 2007 15:20:46 +0100, Hans de Goede wrote:
> Jean Delvare wrote:
> > Contrary to the LM78 / W83781D, which were dedicated hardware
> > monitoring chips, the PC8374L is a Super-I/O, so it is very unlikely to
> > be ever found on a daughter board (while for example the W83781D was
> > used on graphics adapters). So it is rather unlikely that the ISA
> > (actually LPC) access will not be available. If I were you, I'd write
> > an ISA/LPC-only driver to start with, and only think of adding I2C
> > support later if really needed.
> Well unfortunately the person who brought PC8374L support up on the list and
> who is willing todo the testing for me has an intel motherboard and intel loves
> smbus, iow the hwmon logical device is disabled through the superio config
> registers, this doesn't actually disable the device, but does disable isa
> access, so I need to go i2c there, now I could force the logical device to on
> (assuming the config isn't locked by the bios) but that might interfere with
> any ACPI / other bios code accessing it (which doesn't seem to be the case but
> could be) and would require assigning ioports to it. To make things even more
> interesting the chip can be configured for memorymapped access too, now mmap
> access would be ideal, but as said I don't like the idea of changing the
> superio config. Thus the plan is to write a driver with supports all 3, and
> decides which one to use based on the superio config. This is actually easier
> then it sounds, because the only code that needs to take this into account is
> the probe code and the writebyte / readbyte functions.
> I'm also thinking about adding a force ioport / mmap io options, so that those
> modes can be actually tested.
> Any input/advice on this is much appreciated.

Your plan sounds good.

Jean Delvare

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