From: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
To: Frieder Schrempf <frieder.schrempf@kontron.de>,
Marek Vasut <marex@denx.de>,
Alexander Stein <alexander.stein@ew.tq-group.com>
Cc: Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
Andrzej Hajda <andrzej.hajda@intel.com>,
Neil Armstrong <neil.armstrong@linaro.org>,
Robert Foss <robert.foss@linaro.org>,
Laurent Pinchart <Laurent.pinchart@ideasonboard.com>,
Jonas Karlman <jonas@kwiboo.se>,
Jernej Skrabec <jernej.skrabec@gmail.com>,
David Airlie <airlied@gmail.com>, Daniel Vetter <daniel@ffwll.ch>,
Rob Herring <robh+dt@kernel.org>,
dri-devel@lists.freedesktop.org, devicetree@vger.kernel.org
Subject: Re: [PATCH 1/2] dt-bindings: drm/bridge: ti-sn65dsi83: Add enable delay property
Date: Mon, 12 Dec 2022 10:23:26 +0100 [thread overview]
Message-ID: <5f61cc70-9501-ee4e-010f-5188f87e3ef1@linaro.org> (raw)
In-Reply-To: <9f8b1c17-0bc5-ae99-b7b1-cb2f52f9310d@kontron.de>
On 12/12/2022 10:09, Frieder Schrempf wrote:
>>>> This does seem like a hardware bug right there, can you double-check
>>>> this with the hardware engineer ?
>>>
>>> Yep, checked with hardware engineer. An 470nF is attached, together
>>> with an
>>> open drain output and only the internal pull-up. So yes ~113ms rising
>>> time
>>> until 0.7 x VCC.
>>
>> I don't suppose you can have that capacitor reduced or better yet, some
>> external pull up added, can you ?
>
> Actually our HW engineers have implemented a similar RC circuit to
> provide a hardware delay for the EN signal. I think this is due to a
> design note in the datasheet (see chapter 7.4.1) and therefore it's
> probably widely spread.
If I read section 7.4.1 correctly, it would be enough to just add delay
Ten=1ms instead of the capacitor, right? And that would be
device-specific. But if one chooses the capacitor solution, it becomes
now board specific.
Best regards,
Krzysztof
next prev parent reply other threads:[~2022-12-12 9:24 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-12-09 8:33 [PATCH 0/2] TI SN65DSI83 GPIO enable delay support Alexander Stein
2022-12-09 8:33 ` [PATCH 1/2] dt-bindings: drm/bridge: ti-sn65dsi83: Add enable delay property Alexander Stein
2022-12-09 8:39 ` Krzysztof Kozlowski
2022-12-09 8:54 ` Alexander Stein
2022-12-09 9:07 ` Krzysztof Kozlowski
2022-12-09 9:36 ` Alexander Stein
2022-12-09 9:50 ` Krzysztof Kozlowski
2022-12-09 9:51 ` Krzysztof Kozlowski
2022-12-09 12:02 ` Marek Vasut
2022-12-09 12:10 ` Krzysztof Kozlowski
2022-12-09 12:23 ` Alexander Stein
2022-12-09 12:21 ` Alexander Stein
2022-12-09 12:43 ` Marek Vasut
2022-12-09 13:38 ` Alexander Stein
2022-12-09 14:49 ` Marek Vasut
2022-12-12 9:09 ` Frieder Schrempf
2022-12-12 9:23 ` Krzysztof Kozlowski [this message]
2022-12-12 12:29 ` Frieder Schrempf
2022-12-12 12:50 ` Marek Vasut
2022-12-12 9:32 ` Laurent Pinchart
2022-12-12 11:49 ` Frieder Schrempf
2022-12-12 12:05 ` Laurent Pinchart
2022-12-11 18:50 ` Laurent Pinchart
2022-12-09 8:33 ` [PATCH 2/2] drm: bridge: ti-sn65dsi83: Add enable delay support Alexander Stein
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