Messages in this thread | | | From | "Masayuki Ohtake" <> | Subject | Re: [MeeGo-Dev][PATCH] Topcliff: Update PCH_SPI driver to 2.6.35 | Date | Tue, 31 Aug 2010 15:47:38 +0900 |
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----- Original Message ----- From: "Grant Likely" <grant.likely@secretlab.ca> To: "Masayuki Ohtake" <masa-korg@dsn.okisemi.com> Cc: "Thomas Gleixner" <tglx@linutronix.de>; <meego-dev@meego.com>; "LKML" <linux-kernel@vger.kernel.org>; "David Brownell" <dbrownell@users.sourceforge.net>; <qi.wang@intel.com>; <yong.y.wang@intel.com>; <andrew.chih.howe.khor@intel.com>; <arjan@linux.intel.com>; <gregkh@suse.de>; "Tomoya MORINAGA" <morinaga526@dsn.okisemi.com>; "David Woodhouse" <dwmw2@infradead.org>; "Alan Cox" <alan@lxorguk.ukuu.org.uk> Sent: Tuesday, August 31, 2010 3:03 PM Subject: Re: [MeeGo-Dev][PATCH] Topcliff: Update PCH_SPI driver to 2.6.35
> On Mon, Aug 30, 2010 at 7:45 PM, Masayuki Ohtake > <masa-korg@dsn.okisemi.com> wrote: > > ----- Original Message ----- > >> From: "Grant Likely" <grant.likely@secretlab.ca> > >> To: "Masayuki Ohtake" <masa-korg@dsn.okisemi.com> > >> Cc: "Thomas Gleixner" <tglx@linutronix.de>; <meego-dev@meego.com>; "LKML" <linux-kernel@vger.kernel.org>; "David > > Brownell" <dbrownell@users.sourceforge.net>; <qi.wang@intel.com>; <yong.y.wang@intel.com>; > > <andrew.chih.howe.khor@intel.com>; <arjan@linux.intel.com>; <gregkh@suse.de>; "Tomoya MORINAGA" > > <morinaga526@dsn.okisemi.com>; "David Woodhouse" <dwmw2@infradead.org>; "Alan Cox" <alan@lxorguk.ukuu.org.uk> > >> 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@dsn.okisemi.com> wrote: > >> > ----- Original Message ----- > >> > From: "Grant Likely" <grant.likely@secretlab.ca> > >> > To: "Thomas Gleixner" <tglx@linutronix.de> > >> > Cc: "Masayuki Ohtak" <masa-korg@dsn.okisemi.com>; <meego-dev@meego.com>; "LKML" <linux-kernel@vger.kernel.org>; > > "David > >> > Brownell" <dbrownell@users.sourceforge.net>; <qi.wang@intel.com>; <yong.y.wang@intel.com>; > >> > <andrew.chih.howe.khor@intel.com>; <arjan@linux.intel.com>; <gregkh@suse.de>; "Tomoya MORINAGA" > >> > <morinaga526@dsn.okisemi.com>; "David Woodhouse" <dwmw2@infradead.org>; "Alan Cox" <alan@lxorguk.ukuu.org.uk> > >> > 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@linutronix.de> 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 ? > > Well, to start with, the registration code currently in > spi_pch_device.c is probably pretty much unusable for any platform > other than the development board that you're working on. Every > machine using the topcliff chip will have a different set of spi > devices attached to the bus. So, you'll need a method for having a > different set of registrations depending on the machine. > > Traditionally with ARM systems, there is a separate .c file for each > machine (see arch/arm/mach-*/*.c) which registers the expected > devices. In PowerPC the spi devices are described in a device tree > file (arch/powerpc/boot/dts/*) which the kernel will parse and > register the devices it finds. x86 doesn't support either approach > because traditionally the kernel is either able to detect the > hardware, or it can get information from the BIOS (which doesn't work > for embedded x86). > > The x86 maintainers want to adopt the device tree approach for > describing devices. Using device tree data in an spi bus driver is > easy. All that is required is to supply the of_node pointer to the > spi bus before registering it. Search for 'of_node' in > drivers/spi/mpc52xx_spi.c for an example. However, device tree > support is not yet available for x86, so there is still some > development that needs to be done. > > Regardless, the topcliff spi driver can still be merged into mainline > without the spi_device registration code, and you can keep your > personal copy of spi_pch_device.c for testing while the details about > device tree support for x86 get worked out. > > g. > Hi Grant,
Thank you very much. I could understand well.
Can I post our SPI patch for Topcliff without 'of_node' code and spi_device registration code?
Thanks, Ohtake(OKISemi)
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