linux-kernel - Re: [PATCH] drm/bridge: adv7511_audio: Update Audio InfoFrame properly

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Message-ID: <nramdgi4pziet3ypwdi32zolnhdzualv4rpov372s4mfsakdhs@7qjro2oaef7i>
Date: Fri, 15 Nov 2024 10:16:56 +0200
From: Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
To: Stefan Ekenberg <stefan.ekenberg@...s.com>
Cc: 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>, dri-devel@...ts.freedesktop.org, 
	linux-kernel@...r.kernel.org, kernel@...s.com
Subject: Re: [PATCH] drm/bridge: adv7511_audio: Update Audio InfoFrame
 properly

On Wed, Nov 13, 2024 at 08:38:11AM +0100, Stefan Ekenberg wrote:
> AUDIO_UPDATE bit (Bit 5 of MAIN register 0x4A) needs to be set to 1
> while updating Audio InfoFrame information and then set to 0 when done.
> Otherwise partially updated Audio InfoFrames could be sent out. Two
> cases where this rule were not followed are fixed:
>  - In adv7511_hdmi_hw_params() make sure AUDIO_UPDATE bit is updated
>    before/after setting ADV7511_REG_AUDIO_INFOFRAME.
>  - In audio_startup() use the correct register for clearing
>    AUDIO_UPDATE bit.
> 
> The problem with corrupted audio infoframes were discovered by letting
> a HDMI logic analyser check the output of ADV7535.
> 
> Signed-off-by: Stefan Ekenberg <stefan.ekenberg@...s.com>

Missing Fixes tag,

> ---
>  drivers/gpu/drm/bridge/adv7511/adv7511_audio.c | 14 ++++++++++++--
>  1 file changed, 12 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/bridge/adv7511/adv7511_audio.c b/drivers/gpu/drm/bridge/adv7511/adv7511_audio.c
> index 61f4a38e7d2bf6905683cbc9e762b28ecc999d05..8f786592143b6c81e5a434768b51508d5e5f3c73 100644
> --- a/drivers/gpu/drm/bridge/adv7511/adv7511_audio.c
> +++ b/drivers/gpu/drm/bridge/adv7511/adv7511_audio.c
> @@ -153,7 +153,16 @@ static int adv7511_hdmi_hw_params(struct device *dev, void *data,
>  			   ADV7511_AUDIO_CFG3_LEN_MASK, len);
>  	regmap_update_bits(adv7511->regmap, ADV7511_REG_I2C_FREQ_ID_CFG,
>  			   ADV7511_I2C_FREQ_ID_CFG_RATE_MASK, rate << 4);
> -	regmap_write(adv7511->regmap, 0x73, 0x1);
> +
> +	/* send current Audio infoframe values while updating */
> +	regmap_update_bits(adv7511->regmap, ADV7511_REG_INFOFRAME_UPDATE,
> +			   BIT(5), BIT(5));
> +
> +	regmap_write(adv7511->regmap, ADV7511_REG_AUDIO_INFOFRAME(0), 0x1);
> +
> +	/* use Audio infoframe updated info */
> +	regmap_update_bits(adv7511->regmap, ADV7511_REG_INFOFRAME_UPDATE,
> +			   BIT(5), 0);
>  
>  	return 0;
>  }
> @@ -184,8 +193,9 @@ static int audio_startup(struct device *dev, void *data)
>  	regmap_update_bits(adv7511->regmap, ADV7511_REG_GC(0),
>  				BIT(7) | BIT(6), BIT(7));
>  	/* use Audio infoframe updated info */
> -	regmap_update_bits(adv7511->regmap, ADV7511_REG_GC(1),
> +	regmap_update_bits(adv7511->regmap, ADV7511_REG_INFOFRAME_UPDATE,
>  				BIT(5), 0);

Should the REG_GC(1) still be written?

> +
>  	/* enable SPDIF receiver */
>  	if (adv7511->audio_source == ADV7511_AUDIO_SOURCE_SPDIF)
>  		regmap_update_bits(adv7511->regmap, ADV7511_REG_AUDIO_CONFIG,
> 
> ---
> base-commit: 59b723cd2adbac2a34fc8e12c74ae26ae45bf230
> change-id: 20241108-adv7511-audio-info-frame-54614dd4bf57
> 
> Best regards,
> -- 
> Stefan Ekenberg <stefan.ekenberg@...s.com>
> 

-- 
With best wishes
Dmitry