linux-kernel - Re: [PATCH v4 2/3] drm/bridge: microchip-lvds: switch to use atomic variants

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Message-ID: <20250624-beautiful-goose-of-penetration-c4ffde@houat>
Date: Tue, 24 Jun 2025 13:02:00 +0200
From: Maxime Ripard <mripard@...nel.org>
To: Dharma Balasubiramani <dharma.b@...rochip.com>
Cc: Manikandan Muralidharan <manikandan.m@...rochip.com>, 
	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>, Thomas Zimmermann <tzimmermann@...e.de>, 
	David Airlie <airlied@...il.com>, Simona Vetter <simona@...ll.ch>, dri-devel@...ts.freedesktop.org, 
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH v4 2/3] drm/bridge: microchip-lvds: switch to use atomic
 variants

On Tue, Jun 24, 2025 at 02:54:15PM +0530, Dharma Balasubiramani wrote:
> Modernize the bridge ops to use atomic_enable/disable.
> 
> Signed-off-by: Dharma Balasubiramani <dharma.b@...rochip.com>
> ---
>  drivers/gpu/drm/bridge/microchip-lvds.c | 26 ++++++++++++++++++++++----
>  1 file changed, 22 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/gpu/drm/bridge/microchip-lvds.c b/drivers/gpu/drm/bridge/microchip-lvds.c
> index 42751124b868..e4ff46b03d54 100644
> --- a/drivers/gpu/drm/bridge/microchip-lvds.c
> +++ b/drivers/gpu/drm/bridge/microchip-lvds.c
> @@ -111,7 +111,8 @@ static int mchp_lvds_attach(struct drm_bridge *bridge,
>  				 bridge, flags);
>  }
>  
> -static void mchp_lvds_enable(struct drm_bridge *bridge)
> +static void mchp_lvds_atomic_pre_enable(struct drm_bridge *bridge,
> +					struct drm_atomic_state *state)
>  {
>  	struct mchp_lvds *lvds = bridge_to_lvds(bridge);
>  	int ret;
> @@ -127,11 +128,26 @@ static void mchp_lvds_enable(struct drm_bridge *bridge)
>  		dev_err(lvds->dev, "failed to get pm runtime: %d\n", ret);
>  		return;
>  	}
> +}
>  
> +static void mchp_lvds_atomic_enable(struct drm_bridge *bridge,
> +				    struct drm_atomic_state *state)
> +{
> +	struct mchp_lvds *lvds = bridge_to_lvds(bridge);
>  	lvds_serialiser_on(lvds);
>  }
>
> -static void mchp_lvds_disable(struct drm_bridge *bridge)
> +static void mchp_lvds_atomic_disable(struct drm_bridge *bridge,
> +				     struct drm_atomic_state *state)
> +{
> +	struct mchp_lvds *lvds = bridge_to_lvds(bridge);
> +
> +	/* Turn off the serialiser */
> +	lvds_writel(lvds, LVDSC_CR, 0);
> +}
> +
> +static void mchp_lvds_atomic_post_disable(struct drm_bridge *bridge,
> +					  struct drm_atomic_state *state)
>  {
>  	struct mchp_lvds *lvds = bridge_to_lvds(bridge);
>  
> @@ -141,8 +157,10 @@ static void mchp_lvds_disable(struct drm_bridge *bridge)
>  
>  static const struct drm_bridge_funcs mchp_lvds_bridge_funcs = {
>  	.attach = mchp_lvds_attach,
> -	.enable = mchp_lvds_enable,
> -	.disable = mchp_lvds_disable,
> +	.atomic_pre_enable = mchp_lvds_atomic_pre_enable,
> +	.atomic_enable = mchp_lvds_atomic_enable,
> +	.atomic_disable = mchp_lvds_atomic_disable,
> +	.atomic_post_disable = mchp_lvds_atomic_post_disable,
>  };

Like I said to you earlier today, it's not just what you claim it is.
You're splitting enable into atomic_pre_enable and atomic_enable, and
disable into atomic_disable and atomic_post_disable.

At the *very* least this should be explained in your commit log, and it
would be much better if it was done in another patch.

Maxime

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