On Tue, Aug 27, 2013 at 6:31 PM, Tomasz Figa <[email protected]> wrote:
> Hi Yuvaraj,
>
> On Tuesday 27 of August 2013 17:32:52 Yuvaraj Kumar wrote:
>> On Tue, Aug 27, 2013 at 4:31 PM, Mark Rutland <[email protected]>
> wrote:
>> > On Tue, Aug 27, 2013 at 10:22:31AM +0100, Yuvaraj Kumar C D wrote:
>> >> This patch adds the device tree node entries for exynos5420 SOC.
>> >> Exynos5420 has a different version of DWMMC controller,so a new
>> >> compatible string is used to distinguish it from the prior SOC's.
>> >>
>> >> This patch depends on
>> >>
>> >> mmc: dw_mmc: exynos: Add a new compatible string for exynos5420
>> >>
>> >> changes since V3:
>> >> 1.change fifo-depth size from 0x80 to 0x40
>> >> 2.Move the below properties
>> >>
>> >> a.card-detect-delay
>> >> b.samsung,dw-mshc-ciu-div
>> >> c.samsung,dw-mshc-sdr-timing
>> >> d.samsung,dw-mshc-ddr-timing
>> >>
>> >> from SOC dts to board dts file as suggested by Doug Anderson
>> >>
>> >> changes since V2:
>> >> 1.dropped num-slots property from node as its not required
>> >>
>> >> if number of card slots available is 1.
>> >>
>> >> 2.Move the below properties
>> >>
>> >> a.fifo-depth
>> >> b.card-detect-delay
>> >> c.samsung,dw-mshc-ciu-div
>> >> d.samsung,dw-mshc-sdr-timing
>> >> e.samsung,dw-mshc-ddr-timing
>> >>
>> >> from board dts to SOC dts,as these are not board specific
>> >> properties.
>> >>
>> >> 3.Updated the binding document exynos-dw-mshc.txt.
>> >>
>> >> changes since V1:
>> >> 1.disable node by status = disabled in SOC file
>> >> 2.enable node by status = okay in board specific file
>> >>
>> >> Signed-off-by: Yuvaraj Kumar C D <[email protected]>
>> >> ---
>> >>
>> >> .../devicetree/bindings/mmc/exynos-dw-mshc.txt | 4 ++
>> >> arch/arm/boot/dts/exynos5420-smdk5420.dts | 34
>> >> +++++++++++++++++ arch/arm/boot/dts/exynos5420.dtsi
>> >> | 39 ++++++++++++++++++++ 3 files changed, 77 insertions(+)
>> >>
>> >> diff --git a/Documentation/devicetree/bindings/mmc/exynos-dw-mshc.txt
>> >> b/Documentation/devicetree/bindings/mmc/exynos-dw-mshc.txt index
>> >> 6d1c098..25368e8 100644
>> >> --- a/Documentation/devicetree/bindings/mmc/exynos-dw-mshc.txt
>> >> +++ b/Documentation/devicetree/bindings/mmc/exynos-dw-mshc.txt
>> >>
>> >> @@ -16,6 +16,8 @@ Required Properties:
>> >> specific extensions.
>> >>
>> >> - "samsung,exynos5250-dw-mshc": for controllers with Samsung
>> >> Exynos5250
>> >>
>> >> specific extensions.
>> >>
>> >> + - "samsung,exynos5420-dw-mshc": for controllers with Samsung
>> >> Exynos5420 + specific extensions.
>> >>
>> >> * samsung,dw-mshc-ciu-div: Specifies the divider value for the card
>> >> interface>>
>> >> unit (ciu) clock. This property is applicable only for Exynos5
>> >> SoC's and
>> >>
>> >> @@ -31,6 +33,8 @@ Required Properties:
>> >> data rate mode operation. Refer notes below for the order of the
>> >> cells and the valid values.
>> >>
>> >> +* bypass-smu: Bypass Security Management Unit of eMMC channel 0 and
>> >> channel 1. +
>> >
>> > Could you elaborate on why this is needed?
>>
>> Exynos5420 Mobile Storage Host controller has a Security Management
>> Unit (SMU) for
>> channel 0 and channel 1 (mainly for eMMC). This binding property
>> requires to add a quirk
>> to bypass SMU as it is not being used yet.
>
> This looks like a configuration property, not hardware description to me
> then. If presence of SMU depends on particular channel, then either the
> property should be "snps,has-smu" or something like this, to indicate that
> particular channel supports it and it's up to the driver how to handle this
> feature.
>
>> > Is the SMU broken or not present in some hardware revisions?
>>
>> SMU is only present in channel 0 and channel 1,but not in channel 2.So
>> to distinguish this,
>> bypass-smu property has been added as quirks in the channel.
>
> Also a good question is what you mean with "channel". Is it the whole mshc
> entity having compatible property or its subnodes aka slots?
Its with the whole MSHC entity.
>
> If it's the former and channel 2 does not have SMU, making it compatible
> with "samsung,exynos5250-dw-mshc", then it should be marked as such. In
> this case the ideal solution would be to determine the SMU quirk only by
> compatible value.
Good one.I tried this,works perfect.Will repost the patch soon.
>
> Best regards,
> Tomasz
>
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