RE: [PATCH v2 2/3] mmc: davinci_mmc: add DT support

[Manjunathappa, Prakash]

Hi Mark,

On Fri, Feb 08, 2013 at 11:55:09, Manjunathappa, Prakash wrote:
> Hi Mark,
> 
> On Thu, Feb 07, 2013 at 16:16:56, Mark Rutland wrote:
> > Hello,
> > 
> > I have a couple of comments on the dt bindings and the way it's parsed.
> > 
> 
> Thanks for your review comments.
> 
> > On Thu, Feb 07, 2013 at 07:57:04AM +0000, Manjunathappa, Prakash wrote:
> > > Adds device tree support for davinci_mmc. Also add binding documentation.
> > > Tested in non-dma PIO mode and without GPIO card_detect/write_protect
> > > option because of dependencies on EDMA and GPIO module DT support.
> > > 
> > > Signed-off-by: Manjunathappa, Prakash <prakash.pm@xxxxxx>
> > > Cc: linux-mmc@xxxxxxxxxxxxxxx
> > > Cc: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx
> > > Cc: linux-kernel@xxxxxxxxxxxxxxx
> > > Cc: davinci-linux-open-source@xxxxxxxxxxxxxxxxxxxx
> > > Cc: devicetree-discuss@xxxxxxxxxxxxxxxx
> > > Cc: cjb@xxxxxxxxxx
> > > Cc: Sekhar Nori <nsekhar@xxxxxx>
> > > Cc: mporter@xxxxxx
> > > ---
> > > Since v1:
> > > Modified DT parse function to take default values and accomodate controller
> > > version in compatible field.
> > > 
> > >  .../devicetree/bindings/mmc/davinci_mmc.txt        |   30 ++++++++
> > >  drivers/mmc/host/davinci_mmc.c                     |   70 +++++++++++++++++++-
> > >  2 files changed, 99 insertions(+), 1 deletions(-)
> > >  create mode 100644 Documentation/devicetree/bindings/mmc/davinci_mmc.txt
> > > 
> > > diff --git a/Documentation/devicetree/bindings/mmc/davinci_mmc.txt b/Documentation/devicetree/bindings/mmc/davinci_mmc.txt
> > > new file mode 100644
> > > index 0000000..6717ab1
> > > --- /dev/null
> > > +++ b/Documentation/devicetree/bindings/mmc/davinci_mmc.txt
> > > @@ -0,0 +1,30 @@
> > > +* TI Highspeed MMC host controller for DaVinci
> > > +
> > > +The Highspeed MMC Host Controller on TI DaVinci family
> > > +provides an interface for MMC, SD and SDIO types of memory cards.
> > > +
> > > +This file documents the properties used by the davinci_mmc driver.
> > > +
> > > +Required properties:
> > > +- compatible:
> > > + Should be "ti,davinci-mmc-da830": for da830, da850, dm365
> > > + Should be "ti,davinci-mmc-dm355": for dm355, dm644x
> > > +
> > > +Optional properties:
> > > +- bus-width: Number of data lines, can be <4>, or <8>, default <1>
> > > +- max-frequency: Maximum operating clock frequency, default 25MHz.
> > > +- mmc-cap-mmc-highspeed: Indicates support for MMC in high speed mode
> > > +- mmc-cap-sd-highspeed: Indicates support for SD in high speed mode
> > 
> > I thought the last two were derivable from max-frequency?
> > 
> 
> Yes, but I see below comment that it doesnot support MMC/SD.
> arch/arm/mach-davinci/devices.c: davinci_setup_mmc
> 	   "
>          * FIXME dm6441 (no MMC/SD), dm357 (one), and dm335 (two) are
>          * not handled right here ...
>          */"
> I was wondering how do we support such platforms, so I thought it is necessary
> to have these. But I see that on da850-evm even on skipping above flags EVM is able
> to detect card, does it mean there is no way to specify "no SD/MMC" capability?
> I will remove these and decide highspeed capability based on max-frequency.
> 

Since this comment also applies for existing non-DT driver, I will plan to take
up activity later. For now I will submit next version of DT support patch
excluding highspeed card capability.

Thanks,
Prakash

[...]

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