From: Wolfgang Grandegger <wg@grandegger•com>
To: Grant Likely <grant.likely@secretlab•ca>
Cc: florian.belser@freenet•de, linuxppc-dev@ozlabs•org
Subject: Re: mpc5200b configure nand driver via dts
Date: Mon, 12 Jan 2009 16:59:21 +0100 [thread overview]
Message-ID: <496B68D9.1040401@grandegger.com> (raw)
In-Reply-To: <fa686aa40901120648x3c224999sd0da6e80e4fd43be@mail.gmail.com>
Grant Likely wrote:
> On Mon, Jan 12, 2009 at 2:07 AM, <florian.belser@freenet•de> wrote:
>> hello,
>>
>> I have some problems with an mpc5200b based board. It's nearly compatible to
>> the lite5200b board.
>> I connected an samsung k9k8g08u0a nand flash via the lpb bus. This works
>> fine with an self written nand driver.
>> Now I try to use the standard nand driver from linux and configure it via
>> the dts file. But this doesn't work and I get
>> the following output:
>>
>> nand@1,0 { //cs1
>> compatible = "samsung, k9k8g08u08", "cfi-flash";
> ^^^^^^^^^
>
> NAND Flash is not a CFI flash device. The cfi-flash driver won't work with it.
>
>> Now my questions are:
>> Is there any error in the dts configuration?
>> Is it principle posible to configure a nand flash via the dts file (in
>> combination with mpc5200b)?
>
> It is possible to *describe* the NAND flash via the dts file. The dts
> file doesn't configure anything. It just describes the hardware
> layout so that you can write or bind the appropriate driver to the
> device. I don't know if a device tree binding has been defined for
> NAND flash yet.
I find 3 MTD NAND drivers with OF bindings in linux-2.6/drivers/mtd/nand
$ grep -l of_device *.c
fsl_elbc_nand.c
fsl_upm.c
pasemi_nand.c
The bindings for the FSL UPM are described in
http://lxr.linux.no/linux+v2.6.28/Documentation/powerpc/dts-bindings/fsl/upm-nand.txt.
Something similar is needed for his board (NAND connected to lpb) as well.
>> I read in some forums that the nand flash must be activated in the u-boot
>> before it can be configured via dts.
>
> You definitely need to set up the CS line for the NAND before using it
> in Linux. Typically this is done in U-Boot, but in a pinch it can be
> done in the platform support code (arch/powerpc/platforms/52xx/*)
Yep, and also the R/B pin should be handled somehow, preferably using
the OF GPIO interface.
Wolfgang.
next prev parent reply other threads:[~2009-01-12 16:08 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-01-12 9:07 mpc5200b configure nand driver via dts florian.belser
2009-01-12 14:48 ` Grant Likely
2009-01-12 15:59 ` Wolfgang Grandegger [this message]
-- strict thread matches above, loose matches on Subject: below --
2009-01-14 7:42 florian.belser
2009-01-14 9:05 ` Wolfgang Grandegger
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