Re: [MeeGo-Dev][PATCH] Topcliff: Update PCH_SPI driver to 2.6.35

[Masayuki Ohtake]

----- Original Message ----- 
> From: "Grant Likely" <grant.likely@xxxxxxxxxxxx>
> To: "Masayuki Ohtake" <masa-korg@xxxxxxxxxxxxxxx>
> Cc: "Thomas Gleixner" <tglx@xxxxxxxxxxxxx>; <meego-dev@xxxxxxxxx>; "LKML" <linux-kernel@xxxxxxxxxxxxxxx>; "David
Brownell" <dbrownell@xxxxxxxxxxxxxxxxxxxxx>; <qi.wang@xxxxxxxxx>; <yong.y.wang@xxxxxxxxx>;
<andrew.chih.howe.khor@xxxxxxxxx>; <arjan@xxxxxxxxxxxxxxx>; <gregkh@xxxxxxx>; "Tomoya MORINAGA"
<morinaga526@xxxxxxxxxxxxxxx>; "David Woodhouse" <dwmw2@xxxxxxxxxxxxx>; "Alan Cox" <alan@xxxxxxxxxxxxxxxxxxx>
> Sent: Tuesday, August 31, 2010 3:23 AM
> Subject: Re: [MeeGo-Dev][PATCH] Topcliff: Update PCH_SPI driver to 2.6.35
>
>
> On Mon, Aug 30, 2010 at 1:28 AM, Masayuki Ohtake
> <masa-korg@xxxxxxxxxxxxxxx> wrote:
> > ----- Original Message -----
> > From: "Grant Likely" <grant.likely@xxxxxxxxxxxx>
> > To: "Thomas Gleixner" <tglx@xxxxxxxxxxxxx>
> > Cc: "Masayuki Ohtak" <masa-korg@xxxxxxxxxxxxxxx>; <meego-dev@xxxxxxxxx>; "LKML" <linux-kernel@xxxxxxxxxxxxxxx>;
"David
> > Brownell" <dbrownell@xxxxxxxxxxxxxxxxxxxxx>; <qi.wang@xxxxxxxxx>; <yong.y.wang@xxxxxxxxx>;
> > <andrew.chih.howe.khor@xxxxxxxxx>; <arjan@xxxxxxxxxxxxxxx>; <gregkh@xxxxxxx>; "Tomoya MORINAGA"
> > <morinaga526@xxxxxxxxxxxxxxx>; "David Woodhouse" <dwmw2@xxxxxxxxxxxxx>; "Alan Cox" <alan@xxxxxxxxxxxxxxxxxxx>
> > Sent: Saturday, August 28, 2010 4:20 AM
> > Subject: Re: [MeeGo-Dev][PATCH] Topcliff: Update PCH_SPI driver to 2.6.35
> >
> >
> >> On Fri, Aug 27, 2010 at 12:53 PM, Thomas Gleixner <tglx@xxxxxxxxxxxxx> wrote:
> >> > B1;2401;0cOn Fri, 27 Aug 2010, Grant Likely wrote:
> >> >> [cc'ing Thomas Gleixner and David Woodhouse since this driver needs to
> >> >> get some data about the platform (to know what spi_devices are
> >> >> present) and I don't know how that is handled for x86 SoCs.]
> >> >
> >> > The best way to do all this platform specific configuration is to use
> >> > device tree. I really don't want to have x86/mach-xyz/board[A-Z]
> >> > horror, which is unavoidable when we don't get a sensible way to
> >> > configure the boards.
> >>
> >> I knew you were going to say that! :-)
> >>
> >> Ohtak-san, for this patch I'd like you to drop the separate driver
> >> that only registers the spi_devices and just submit the core driver.
> >
> > Sorry, I can't follow your discussion by lack of SPI knowledge.
> > Which the above mean that "spi_register_board_info" moves to our spi_pch or
> > delete for our driver ?
>
> I mean remove drivers/spi/spi_pch_device.c and the related Kconfig
> bits from this patch.
> The spi_device registration is a separate task
> which should be submitted in a separate patch, and would be better
> handled in either platform support code or with a device tree.

How should we register spi_device information ?
Could you show reference driver ?

>
> >> (You can of course keep the spi_device registration in your own tree
> >> for debug purposes). I'll expect that the device will get
> >> instantiated using a device tree to determine which spi_devices are
> >> present. The parsing of spi device tree data will be moving into the
> >> core spi subsystem code in the next merge window most likely, so it
> >> can all be handled transparently.
> >>
> >> > SFI was meant to provide a lightweight ACPI, but
> >> > now that device tree is generic and more platforms are using it, I
> >> > really want to standartize on that and forget SFI.
> >> >
> >> > That makes even more sense, as all these AMBA peripherals which are
> >> > duct-taped to a x86 core can be found in other SoCs with different
> >> > cores as well.
> >>
> >> Indeed. BTW, Ohtak-san, is this spi bus device something brand new,
> >> or is it derived from an existing spi device?
> >
> > Yes, Intel Topcliff is new concept device.
>
> As Thomas already commented, what I'm really interested in is whether
> or not this spi controller is based on an older SPI controller.  If it
> is, then it may be possible to add support for this chip to an
> existing driver instead of writing a whole new one.
>



Thanks, Ohtake(OKISemi)



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