lkml.org 
[lkml]   [2019]   [May]   [8]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [PATCH v7 07/13] dt-bindings: memory-controllers: add Exynos5422 DMC device description
From
Date

On 5/8/19 9:19 AM, Krzysztof Kozlowski wrote:
> On Tue, 7 May 2019 at 19:04, Rob Herring <robh@kernel.org> wrote:
>>> +- devfreq-events : phandles of the PPMU events used by the controller.
>>> +- samsung,syscon-chipid : phandle of the ChipID used by the controller.
>>> +- samsung,syscon-clk : phandle of the clock register set used by the controller.
>>
>> Looks like a hack. Can't you get this from the clocks property? What is
>> this for?
>
> Hi Rob,
>
> Lukasz uses these two syscon regmaps to read certain registers. For
> chipid he reads it to check the size of attached memory (only 2 GB
> version is supported). This indeed looks like a hack. However the
> second regmap (clk) is needed to get the timing data from registers
> from DMC clock driver address space. These are registers with memory
> timing so their data is not exposed anyway in common clk framework.
>
> Best regards,
> Krzysztof

Thank you Krzysztof for a fast response. I have also responded to Rob.
I wouldn't call accessing chipid registers as a hack, though. The DMC
registers do not contain information about the memory chip since it is
in phase of production the board not the chip. Thus, chipid regs (which
loads from e-fuses) are best place to put information about memory
type/size.

Regards,
Lukasz

\
 
 \ /
  Last update: 2019-05-08 11:46    [W:0.131 / U:0.244 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site