From: Kevin Hilman <khilman@baylibre.com>
To: Roger Quadros <rogerq@kernel.org>,
Geert Uytterhoeven <geert+renesas@glider.be>,
Tony Lindgren <tony@atomide.com>,
Robert Nelson <robertcnelson@gmail.com>,
Colin Foster <colin.foster@in-advantage.com>
Cc: linux-omap@vger.kernel.org, linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH] ARM: dts: am335x-bone-common: Increase MDIO reset deassert delay to 50ms
Date: Fri, 01 Nov 2024 07:35:01 -0700 [thread overview]
Message-ID: <7h34kbowdm.fsf@baylibre.com> (raw)
In-Reply-To: <c3c60bcb-186e-462d-aedb-ab90d52a58bd@kernel.org>
Roger Quadros <rogerq@kernel.org> writes:
> On 31/10/2024 11:29, Geert Uytterhoeven wrote:
>> Commit b9bf5612610aa7e3 ("ARM: dts: am335x-bone-common: Increase MDIO
>> reset deassert time") already increased the MDIO reset deassert delay
>> from 6.5 to 13 ms, but this may still cause Ethernet PHY probe failures:
>>
>> SMSC LAN8710/LAN8720 4a101000.mdio:00: probe with driver SMSC LAN8710/LAN8720 failed with error -5
>>
>> On BeagleBone Black Rev. C3, ETH_RESETn is controlled by an open-drain
>> AND gate. It is pulled high by a 10K resistor, and has a 4.7µF
>> capacitor to ground, giving an RC time constant of 47ms. As it takes
>> 0.7RC to charge the capacitor above the threshold voltage of a CMOS
>> input (VDD/2), the delay should be at least 33ms. Considering the
>> typical tolerance of 20% on capacitors, 40ms would be safer. Add an
>> additional safety margin and settle for 50ms.
>>
>> Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
>
> Reviewed-by: Roger Quadros <rogerq@kernel.org>
Reviewed-by: Kevin Hilman <khilman@baylibre.com>
Tested-by: Kevin Hilman <khilman@baylibre.com>
next prev parent reply other threads:[~2024-11-01 14:51 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-10-31 9:29 [PATCH] ARM: dts: am335x-bone-common: Increase MDIO reset deassert delay to 50ms Geert Uytterhoeven
2024-10-31 10:44 ` Roger Quadros
2024-11-01 14:35 ` Kevin Hilman [this message]
2024-11-01 14:36 ` Kevin Hilman
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=7h34kbowdm.fsf@baylibre.com \
--to=khilman@baylibre.com \
--cc=colin.foster@in-advantage.com \
--cc=geert+renesas@glider.be \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-omap@vger.kernel.org \
--cc=robertcnelson@gmail.com \
--cc=rogerq@kernel.org \
--cc=tony@atomide.com \
/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.