linux-kernel - Re: [PATCH v4 1/3] drm/tidss: oldi: Add property to identify OLDI supported VP

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Message-ID: <94f54b9b-174c-44b7-861e-a90e9c6a0bb5@ideasonboard.com>
Date: Thu, 17 Jul 2025 19:10:23 +0300
From: Tomi Valkeinen <tomi.valkeinen@...asonboard.com>
To: Jayesh Choudhary <j-choudhary@...com>
Cc: airlied@...il.com, simona@...ll.ch, linux-kernel@...r.kernel.org,
 jyri.sarha@....fi, maarten.lankhorst@...ux.intel.com, mripard@...nel.org,
 tzimmermann@...e.de, dri-devel@...ts.freedesktop.org, devarsht@...com,
 mwalle@...nel.org
Subject: Re: [PATCH v4 1/3] drm/tidss: oldi: Add property to identify OLDI
 supported VP

Hi,

On 04/07/2025 12:48, Jayesh Choudhary wrote:
> TIDSS should know which VP has OLDI output to avoid calling clock
> functions for that VP as those are controlled by oldi driver. Add a

"OLDI"

> property "is_oldi_vp" to "tidss_device" structure for that. Mark it
> 'true' in tidss_oldi_init() and 'false' in tidss_oldi_deinit().

The above is not wrong, but I think it would be nicer to be more
specific what's this about: it's not really about OLDI, but whether
tidss crtc/dispc controls the clock. I would name the field
"is_ext_vp_clk" or something similar.

 Tomi

> Fixes: 7246e0929945 ("drm/tidss: Add OLDI bridge support")
> Reviewed-by: Devarsh Thakkar <devarsht@...com>
> Signed-off-by: Jayesh Choudhary <j-choudhary@...com>
> ---
>  drivers/gpu/drm/tidss/tidss_drv.h  | 2 ++
>  drivers/gpu/drm/tidss/tidss_oldi.c | 2 ++
>  2 files changed, 4 insertions(+)
> 
> diff --git a/drivers/gpu/drm/tidss/tidss_drv.h b/drivers/gpu/drm/tidss/tidss_drv.h
> index 0ae24f645582..82beaaceadb3 100644
> --- a/drivers/gpu/drm/tidss/tidss_drv.h
> +++ b/drivers/gpu/drm/tidss/tidss_drv.h
> @@ -24,6 +24,8 @@ struct tidss_device {
>  
>  	const struct dispc_features *feat;
>  	struct dispc_device *dispc;
> +	bool is_oldi_vp[TIDSS_MAX_PORTS];
> +
>  
>  	unsigned int num_crtcs;
>  	struct drm_crtc *crtcs[TIDSS_MAX_PORTS];
> diff --git a/drivers/gpu/drm/tidss/tidss_oldi.c b/drivers/gpu/drm/tidss/tidss_oldi.c
> index b0f99656e87e..63e07c8edeaa 100644
> --- a/drivers/gpu/drm/tidss/tidss_oldi.c
> +++ b/drivers/gpu/drm/tidss/tidss_oldi.c
> @@ -430,6 +430,7 @@ void tidss_oldi_deinit(struct tidss_device *tidss)
>  	for (int i = 0; i < tidss->num_oldis; i++) {
>  		if (tidss->oldis[i]) {
>  			drm_bridge_remove(&tidss->oldis[i]->bridge);
> +			tidss->is_oldi_vp[tidss->oldis[i]->parent_vp] = false;
>  			tidss->oldis[i] = NULL;
>  		}
>  	}
> @@ -579,6 +580,7 @@ int tidss_oldi_init(struct tidss_device *tidss)
>  		oldi->bridge.timings = &default_tidss_oldi_timings;
>  
>  		tidss->oldis[tidss->num_oldis++] = oldi;
> +		tidss->is_oldi_vp[oldi->parent_vp] = true;
>  		oldi->tidss = tidss;
>  
>  		drm_bridge_add(&oldi->bridge);