From: Marek Vasut <marex@nabladev.com>
To: "Börge Strümpfel" <bstruempfel@data-modul.com>
Cc: Andrzej Hajda <andrzej.hajda@intel.com>,
Neil Armstrong <neil.armstrong@linaro.org>,
Robert Foss <rfoss@kernel.org>,
Laurent Pinchart <Laurent.pinchart@ideasonboard.com>,
Jonas Karlman <jonas@kwiboo.se>,
Jernej Skrabec <jernej.skrabec@gmail.com>,
Maarten Lankhorst <maarten.lankhorst@linux.intel.com>,
Maxime Ripard <mripard@kernel.org>,
Thomas Zimmermann <tzimmermann@suse.de>,
David Airlie <airlied@gmail.com>, Simona Vetter <simona@ffwll.ch>,
Rob Herring <robh@kernel.org>,
Krzysztof Kozlowski <krzk+dt@kernel.org>,
Conor Dooley <conor+dt@kernel.org>,
dri-devel@lists.freedesktop.org, devicetree@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2/2] drm/bridge: lt9211: Add drive-strength-microamp DT property
Date: Wed, 13 May 2026 13:33:01 +0200 [thread overview]
Message-ID: <eb0b8aa2-a728-4e66-80b1-4c7ef37d24dc@nabladev.com> (raw)
In-Reply-To: <agQ4pVGFEMGaMqgc@DATAMODULBOERGELINUX>
On 5/13/26 11:02 AM, Börge Strümpfel wrote:
[...]
>>> + ctx->lvds_hsdrv_isel = 8; /* default: 25 uA */
>>> + ret = of_property_read_u32(dev->of_node, "drive-strength-microamp",
>>> + µamp);
>>
>> if ret != 0 , then what happens here ?
>>
>
> if ret != 0, we will keep the default value of 8 (corresponding to 25 uA
> as written above), which is the behavior that the driver had previously.
>
> According to the documentation, of_property_read_u32() will return 0 on
> success, -EINVAL if the property does not exist, -ENODATA if property
> does not have a value, and -EOVERFLOW if the property data isn't large
> enough. I think we only would need to give a warning or similar if the
> -ENODATA or -EOVERFLOW cases. However, I personally do not think that is
> necessary, as the usage is specified unambiguously in the devicetree
> bindings.
Users can pass in malformed DT, so a warning is a good idea. Thanks.
prev parent reply other threads:[~2026-05-13 11:33 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-05-12 16:46 [PATCH 0/2] drm/bridge: lt9211: Add drive-strength-microamp DT property Boerge Struempfel
2026-05-12 16:46 ` [PATCH 1/2] dt-bindings: display/bridge: lt9211: Add drive-strength-microamp property Boerge Struempfel
2026-05-12 17:05 ` Conor Dooley
2026-05-12 16:46 ` [PATCH 2/2] drm/bridge: lt9211: Add drive-strength-microamp DT property Boerge Struempfel
2026-05-12 18:29 ` Marek Vasut
2026-05-13 9:02 ` Börge Strümpfel
2026-05-13 11:33 ` Marek Vasut [this message]
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