linux-kernel - Re: [PATCH v5 3/9] drm/bridge: fsl-ldb: Add support for i.MX94

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <DDWD5P3SKWMV.1LITMN6MAKGMA@bootlin.com>
Date: Fri, 31 Oct 2025 09:27:29 +0100
From: "Luca Ceresoli" <luca.ceresoli@...tlin.com>
To: "Laurentiu Palcu" <laurentiu.palcu@....nxp.com>, <imx@...ts.linux.dev>,
 "Andrzej Hajda" <andrzej.hajda@...el.com>, "Neil Armstrong"
 <neil.armstrong@...aro.org>, "Robert Foss" <rfoss@...nel.org>, "Laurent
 Pinchart" <Laurent.pinchart@...asonboard.com>, "Jonas Karlman"
 <jonas@...boo.se>, "Jernej Skrabec" <jernej.skrabec@...il.com>, "Maarten
 Lankhorst" <maarten.lankhorst@...ux.intel.com>, "Maxime Ripard"
 <mripard@...nel.org>, "Thomas Zimmermann" <tzimmermann@...e.de>, "David
 Airlie" <airlied@...il.com>, "Simona Vetter" <simona@...ll.ch>
Cc: <dri-devel@...ts.freedesktop.org>, <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v5 3/9] drm/bridge: fsl-ldb: Add support for i.MX94

Hello Laurentiu,

On Thu Sep 11, 2025 at 1:37 PM CEST, Laurentiu Palcu wrote:
> i.MX94 series LDB controller shares the same LDB and LVDS control
> registers as i.MX8MP and i.MX93 but supports a higher maximum clock
> frequency.
>
> Add a 'max_clk_khz' member to the fsl_ldb_devdata structure in order to
> be able to set different max frequencies for other platforms.
>
> Signed-off-by: Laurentiu Palcu <laurentiu.palcu@....nxp.com>
> Reviewed-by: Frank Li <Frank.Li@....com>

[...]

> @@ -270,8 +281,9 @@ fsl_ldb_mode_valid(struct drm_bridge *bridge,
>  		   const struct drm_display_mode *mode)

I'd suggest a couple possible code style improvements here:

>  {
>  	struct fsl_ldb *fsl_ldb = to_fsl_ldb(bridge);
> +	u32 ch_max_clk_khz = fsl_ldb->devdata->max_clk_khz;

You don't need a variable to use it only once.

>
> -	if (mode->clock > (fsl_ldb_is_dual(fsl_ldb) ? 160000 : 80000))
> +	if (mode->clock > (fsl_ldb_is_dual(fsl_ldb) ? 2 * ch_max_clk_khz : ch_max_clk_khz))

And here you can use the ternary operator to compute the multiplier only:

	if (mode->clock > (fsl_ldb_is_dual(fsl_ldb) ? 2 : 1) * fsl_ldb->devdata->max_clk_khz)

Up to you whether you want to take my proposals above. The patch looks good
anyway, so with or without those changes:

Reviewed-by: Luca Ceresoli <luca.ceresoli@...tlin.com>

--
Luca Ceresoli, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com