linux-kernel - Re: [PATCH v6 03/10] drm/bridge: it6505: add AUX operation for HDCP KSV list read

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Message-ID: <ojy6n4hphcohozcqnkbmmiwtyjspbklu5ozmnkkgawzyaz66zk@pozfn4kn3rcs>
Date: Sun, 20 Oct 2024 16:53:04 +0300
From: Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
To: Hermes.wu@....com.tw
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>, 
	AngeloGioacchino Del Regno <angelogioacchino.delregno@...labora.com>, Pin-yen Lin <treapking@...omium.org>, 
	dri-devel@...ts.freedesktop.org, linux-kernel@...r.kernel.org, 
	Kenneth Hung <Kenneth.hung@....com.tw>, Pet Weng <Pet.Weng@....com.tw>
Subject: Re: [PATCH v6 03/10] drm/bridge: it6505: add AUX operation for HDCP
 KSV list read

On Wed, Oct 16, 2024 at 03:54:15PM +0800, Hermes Wu via B4 Relay wrote:
> From: Hermes Wu <Hermes.wu@....com.tw>
> 
> HDCP KSV list readback can choose to use AUX FIFO or
> general data register.
> For some DisplayPort devices, the KSV list must be read
> in 5 byte boundaries.
> The original AUX read command does not support these devices.
> 
> The AUX command operation control register "REG_AUX_CMD_REQ" uses b[3:0]
> as AUX operacion control, and b[7:4] are status bits and read only.
> To change KSV read operation uses "CMD_AUX_NATIVE_READ" from using
> the data registers to using AUX FIFO.
> The extended command "CMD_AUX_GET_KSV_LIST" is added as
> "CMD_AUX_NATIVE_READ" with the 0x10 flag which selects AUX FIFO mode.
> 
> Signed-off-by: Hermes Wu <Hermes.wu@....com.tw>
> ---
>  drivers/gpu/drm/bridge/ite-it6505.c | 16 +++++++++++-----
>  1 file changed, 11 insertions(+), 5 deletions(-)
> 

> @@ -996,7 +1001,7 @@ static ssize_t it6505_aux_operation(struct it6505 *it6505,
>  				  size);
>  
>  	/* Aux Fire */
> -	it6505_write(it6505, REG_AUX_CMD_REQ, cmd);
> +	it6505_write(it6505, REG_AUX_CMD_REQ, FIELD_GET(M_AUX_REQ_CMD, cmd));

This needs #include <linux/bitfield.h>

Other than that

Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@...aro.org>


>  
>  	ret = it6505_aux_wait(it6505);
>  	if (ret < 0)

-- 
With best wishes
Dmitry