Re: [PATCH v2 2/2] drm/bridge: add support for lontium lt9211c bridge
From: Marek Vasut
Date: Fri Nov 07 2025 - 10:11:33 EST
On 11/7/25 2:52 PM, Nilesh Laad wrote:
On Fri, Nov 07, 2025 at 02:20:58PM +0100, Marek Vasut wrote:
On 11/7/25 2:02 PM, Nilesh Laad wrote:LT9211 and LT9211C differ completely in register programming sequences.
From: Yi Zhang <zhanyi@xxxxxxxxxxxxxxxx>How does this differ from existing drivers/gpu/drm/bridge/lontium-lt9211.c ?
LT9211c is a Single/Dual-Link DSI/LVDS or Single DPI input to
Single-link/Dual-Link DSI/LVDS or Single DPI output bridge chip.
Add support for DSI to LVDS bridge configuration.
Can existing lt9211 driver be extended instead ? If not, why ? Details
please ...
Even lontium mentioned that register configuration are different for lt9211 and lt9211c.
Lontium seems to often suggest, that users should use their provided register patches without thinking about the content at all.
Do you have access to the register documentation, and can you compare LT9211 and LT9211C register layout? Are they identical or do they differ?
Nearly every function would require duplicated logic with if (chip_type) branching,
as register sequence are completely different.
Having both sequences in single file is not looking good, hence want to merge as separate driver.
Can we somehow use regmap_register_patch() and register patches in driver data to avoid duplication ?
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Best regards,
Marek Vasut