From: Mario Kicherer <dev@kicherer.org>
To: "han.xu" <han.xu@nxp.com>
Cc: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>,
Rob Herring <robh@kernel.org>,
linux-spi@vger.kernel.org, broonie@kernel.org,
krzysztof.kozlowski+dt@linaro.org, devicetree@vger.kernel.org
Subject: Re: [PATCH 1/2] spi: dt-bindings: spi-fsl-qspi: add optional sampling-delay
Date: Wed, 18 Jan 2023 15:58:48 +0100 [thread overview]
Message-ID: <c11967cae4bebba15c719e6609a7c01c@kicherer.org> (raw)
In-Reply-To: <20230117210500.oimf4yjkkqh3o4hi@umbrella>
Hello Han,
on my SoC (LS1021a), the QSPI clock is derived from the CPU clock
(cluster1)
and neither is controlled by the Linux kernel (afair) but by the RCW (or
U-Boot).
I could create a function to read the corresponding registers but I do
not know
where I should place this function and how I should call this function
in a
portable way in the QSPI module to convert the nanoseconds into delay
cycles.
I thought this would be a small and simple patch but I guess these
changes will
require quite some time with my knowledge level that I do not have right
now.
Thank you all for the review!
Best regards,
Mario
On 2023-01-17 22:05, han.xu wrote:
> On 23/01/17 06:10PM, Krzysztof Kozlowski wrote:
>> On 17/01/2023 17:33, Mario Kicherer wrote:
>> > Hello,
>> >
>> > unfortunately, the rx-sample-delay-ns property does not fit here, as we
>> > can only delay
>> > the sampling point between zero and three "half cycles" (or edges), not
>> > by an arbitrary
>> > number of nanoseconds.
>>
>> Why this is a problem for FSL but not for other platforms having
>> exactly
>> the same constraints/property?
>
> Hi Mario,
>
> Please use the common delay in DT and calculate to half cycle in
> driver, we have
> the similar discussion before for fspi controller delay settings.
>
>>
>> Best regards,
>> Krzysztof
>>
next prev parent reply other threads:[~2023-01-18 15:02 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-01-16 11:50 [PATCH 0/2] spi: spi-fsl-qspi: support setting sampling delay through devicetree Mario Kicherer
2023-01-16 11:50 ` [PATCH 1/2] spi: dt-bindings: spi-fsl-qspi: add optional sampling-delay Mario Kicherer
2023-01-16 16:36 ` Rob Herring
2023-01-17 14:10 ` Rob Herring
2023-01-17 16:33 ` Mario Kicherer
2023-01-17 17:10 ` Krzysztof Kozlowski
2023-01-17 21:05 ` han.xu
2023-01-18 8:01 ` Michael Walle
2023-01-18 8:03 ` Krzysztof Kozlowski
2023-01-18 8:51 ` Michael Walle
2023-01-18 14:58 ` Mario Kicherer [this message]
2023-01-16 11:50 ` [PATCH 2/2] spi: spi-fsl-qspi: support setting sampling delay through devicetree Mario Kicherer
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=c11967cae4bebba15c719e6609a7c01c@kicherer.org \
--to=dev@kicherer.org \
--cc=broonie@kernel.org \
--cc=devicetree@vger.kernel.org \
--cc=han.xu@nxp.com \
--cc=krzysztof.kozlowski+dt@linaro.org \
--cc=krzysztof.kozlowski@linaro.org \
--cc=linux-spi@vger.kernel.org \
--cc=robh@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.