From: Chris Packham <Chris.Packham@alliedtelesis.co.nz>
To: Andrew Lunn <andrew@lunn.ch>
Cc: "robh+dt@kernel.org" <robh+dt@kernel.org>,
"krzysztof.kozlowski+dt@linaro.org"
<krzysztof.kozlowski+dt@linaro.org>,
"catalin.marinas@arm.com" <catalin.marinas@arm.com>,
"will@kernel.org" <will@kernel.org>,
"gregory.clement@bootlin.com" <gregory.clement@bootlin.com>,
"sebastian.hesselbarth@gmail.com"
<sebastian.hesselbarth@gmail.com>,
"kostap@marvell.com" <kostap@marvell.com>,
"robert.marko@sartura.hr" <robert.marko@sartura.hr>,
"devicetree@vger.kernel.org" <devicetree@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>
Subject: Re: [PATCH v6 1/3] dt-bindings: marvell: Document the AC5/AC5X compatibles
Date: Thu, 12 May 2022 00:54:52 +0000 [thread overview]
Message-ID: <429ac287-04bd-af78-2deb-06426af53ea4@alliedtelesis.co.nz> (raw)
In-Reply-To: <YnxYtE9dGn6BwF/8@lunn.ch>
On 12/05/22 12:45, Andrew Lunn wrote:
>> Yes there are registers that you can read to identify the specific chip.
>>
>> It still might be useful to have a expected vs actual check as those ID
>> values are determined by pin strapping resistors.
> That i don't get? Can i turn a
>
> * 98DX2538: 24x1G + 2x10G + 2x10G Stack
>
> into a
>
> * 98DX2535: 24x1G + 4x1G Stack
>
> by strapping its pin differently?
I'm not sure it'd actually work properly but yes there are external
PU/PD resistors that if you fitted differently would at least make the
ID say that a 98DX2538 is a 98DX2535. The HW docs have these as
"reserved" pins that must be pulled up/down depending on the specific part.
In reality I suspect that the different serdes arrangements are based on
what level of screening the silicon passed (similar to how some SoC
speed grades are distinguished). So you might be able to go down (i.e.
2538 -> 2535) but probably not up (i.e 2535 -> 2538).
>
>> It could also be used
>> to validate the dts (e.g. port 20 would be invalid on a 98DX3501). But
>> those are considerations for further down the track.
> Yes, that would be up to the switchdev driver to validate the DT based
> on the ID register.
>
> Andrew
next prev parent reply other threads:[~2022-05-12 0:55 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-05-10 23:09 [PATCH v6 0/3] arm64: mvebu: Support for Marvell 98DX2530 (and variants) Chris Packham
2022-05-10 23:10 ` [PATCH v6 1/3] dt-bindings: marvell: Document the AC5/AC5X compatibles Chris Packham
2022-05-11 16:34 ` Krzysztof Kozlowski
2022-05-12 1:20 ` Chris Packham
2022-05-12 1:51 ` Chris Packham
2022-05-12 14:45 ` Krzysztof Kozlowski
2022-05-12 10:10 ` Krzysztof Kozlowski
2022-05-11 17:02 ` Andrew Lunn
2022-05-11 23:14 ` Chris Packham
2022-05-12 0:27 ` Andrew Lunn
2022-05-12 0:38 ` Chris Packham
2022-05-12 0:45 ` Andrew Lunn
2022-05-12 0:54 ` Chris Packham [this message]
2022-05-10 23:10 ` [PATCH v6 2/3] arm64: dts: marvell: Add Armada 98DX2530 SoC and RD-AC5X board Chris Packham
2022-05-11 16:38 ` Krzysztof Kozlowski
2022-05-11 23:49 ` Chris Packham
2022-05-12 14:45 ` Krzysztof Kozlowski
2022-05-10 23:10 ` [PATCH v6 3/3] arm64: marvell: enable the 98DX2530 pinctrl driver Chris Packham
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=429ac287-04bd-af78-2deb-06426af53ea4@alliedtelesis.co.nz \
--to=chris.packham@alliedtelesis.co.nz \
--cc=andrew@lunn.ch \
--cc=catalin.marinas@arm.com \
--cc=devicetree@vger.kernel.org \
--cc=gregory.clement@bootlin.com \
--cc=kostap@marvell.com \
--cc=krzysztof.kozlowski+dt@linaro.org \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-kernel@vger.kernel.org \
--cc=robert.marko@sartura.hr \
--cc=robh+dt@kernel.org \
--cc=sebastian.hesselbarth@gmail.com \
--cc=will@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 a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).