Re: [PATCH RESEND v2 3/7] mfd: cros_ec: Add cros_ec_lpc driver for x86 devices

From: Lee Jones
Date: Thu Jan 22 2015 - 05:56:22 EST


On Thu, 22 Jan 2015, Javier Martinez Canillas wrote:
> On 01/22/2015 10:46 AM, Lee Jones wrote:
> >>
> >> But there doesn't seem to be a LPC subsystem in the kernel so we don't have a
> >> nice abstraction layer in this case.
> >
> > This is the crux of the problem. However, I feel bad for MFD, as it
> > is, once more, being used as an "well it doesn't fit anywhere else, so
> > let's shoehorn it in there" type of dumping ground.
> >
> Yes, I completely understand your point, is that I didn't think that a ~300
> lines driver was that bad specially since the communication bits that reads
> and writes the register is not a complex logic IMHO.

This has nothing to do with LoC, it's the principle of the matter.

> >> > Are there any other Low Pin Count drivers in the kernel?
> >> >
> >>
> >> I don't know tbh, I didn't even know what LPC was before I picked this patch
> >> to push it upstream. I searched in the Linux codebase for other LPC drivers
> >> but I didn't find anything, that doesn't mean that it doesn't exist though.
> >
> > I agree. Perhaps a suitable driver should live in drivers/misc until
> > there are enough of them to warrant its own subsystem.
> >
>
> Yes, I can move the driver to drivers/misc if you think that is more suitable
> to be there.
>
> I've taken another look and AFAICT there are two other mfd drivers that use an
> LPC bus, these are drivers/mfd/lpc_{i,s}ch.c for Intel's I/O Controller HUB and
> System Controller Hub respectively.

These looked like PCI aggregates when I looked at them last?

--
Lee Jones
Linaro STMicroelectronics Landing Team Lead
Linaro.org â Open source software for ARM SoCs
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