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Date: Tue, 14 Oct 2025 16:03:37 +0200
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Subject: Re: [PATCH 05/39] drm/imx: dc: Rework dc_subdev_get_id() to drop
 ARRAY_SIZE() use
To: Frank Li <Frank.li@nxp.com>
Cc: dri-devel@lists.freedesktop.org, Abel Vesa <abelvesa@kernel.org>,
 Conor Dooley <conor+dt@kernel.org>, Fabio Estevam <festevam@gmail.com>,
 Krzysztof Kozlowski <krzk+dt@kernel.org>,
 Laurent Pinchart <Laurent.pinchart@ideasonboard.com>,
 Liu Ying <victor.liu@nxp.com>, Lucas Stach <l.stach@pengutronix.de>,
 Peng Fan <peng.fan@nxp.com>, Pengutronix Kernel Team
 <kernel@pengutronix.de>, Rob Herring <robh@kernel.org>,
 Shawn Guo <shawnguo@kernel.org>, Thomas Zimmermann <tzimmermann@suse.de>,
 devicetree@vger.kernel.org, imx@lists.linux.dev,
 linux-arm-kernel@lists.infradead.org, linux-clk@vger.kernel.org
References: <20251011170213.128907-1-marek.vasut@mailbox.org>
 <20251011170213.128907-6-marek.vasut@mailbox.org>
 <aO0vLbkpXejre2Ta@lizhi-Precision-Tower-5810>
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From: Marek Vasut <marek.vasut@mailbox.org>
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On 10/13/25 6:56 PM, Frank Li wrote:
> On Sat, Oct 11, 2025 at 06:51:20PM +0200, Marek Vasut wrote:
>> Rework dc_subdev_get_id() to drop ARRAY_SIZE() use and use empty trailing
>> entry in each ID look up array instead. This allows passing of those arrays
>> around as OF match data, which will be useful when using this pipeline on
>> i.MX95, which has different address-to-ID mapping.
>>
>> Signed-off-by: Marek Vasut <marek.vasut@mailbox.org>
> 
> This change is okay. but my questions is why need map register to id.

This seems to be a recurring pattern in the driver, where some 
components need to find other components to link with them. The mapping 
is fixed, and since the DT does not encode link IDs, the resolution of 
the mapping has to happen by mapping the component base addresses to the 
IDs first.