Re: [PATCH] drm/bridge: ite-it6263: Support HDMI vendor specific infoframe

[Liu Ying <victor.liu@nxp.com>]

On 09/05/2025, Dmitry Baryshkov wrote:
> On Thu, Sep 04, 2025 at 05:10:02PM +0800, Liu Ying wrote:
>> IT6263 supports HDMI vendor specific infoframe.  The infoframe header
>> and payload are configurable via NULL packet registers.  The infoframe
>> is enabled and disabled via PKT_NULL_CTRL register.  Add the HDMI vendor
>> specific infoframe support.
>>
>> Signed-off-by: Liu Ying <victor.liu@nxp.com>
>> ---
>>  drivers/gpu/drm/bridge/ite-it6263.c | 72 ++++++++++++++++++++++++++-----------
>>  1 file changed, 52 insertions(+), 20 deletions(-)
>>
>> +	case HDMI_INFOFRAME_TYPE_VENDOR:
>> +		const char zero_bulk[HDMI_PKT_HB_PB_CHUNK_SIZE] = { };
>> +
>> +		/* clear NULL packet registers due to undefined default value */
>> +		regmap_bulk_write(regmap, HDMI_REG_PKT_HB(0),
>> +				  zero_bulk, sizeof(zero_bulk));
> 
> What if you move this to the probe function? Then there will be no need
> to write those registers each time the infoframe is being written.

Good idea.  But looking at drm_hdmi_vendor_infoframe_from_display_mode(),
hdmi_vendor_infoframe_length() and hdmi_vendor_infoframe_pack_only(), the
payload length could be changed in runtime according to display mode's VIC
and flags(see DRM_MODE_FLAG_3D_MASK).  And, IT6263 supports HDMI1.4a 3D
formats according to it's product information[1].  So, it makes sense to
clear HDMI_REG_PKT_PB(5) and HDMI_REG_PKT_PB(6) here which map to ptr[8]
and ptr[9] in hdmi_vendor_infoframe_pack_only().  For v2, I'd move the
NULL packet registers bulk write to it6263_hdmi_config()(i.e., it6263_probe())
and write zero to HDMI_REG_PKT_PB(5) and HDMI_REG_PKT_PB(6) here.

What do you think?

[1] www.ite.com.tw/en/product/cate1/IT6263

> 
> LGTM otherwise.
> 
>> +
>> +		/* write header and payload */
>> +		regmap_bulk_write(regmap, HDMI_REG_PKT_HB(0), buffer, len);
>> +
>> +		regmap_write(regmap, HDMI_REG_PKT_NULL_CTRL,
>> +			     ENABLE_PKT | REPEAT_PKT);
>> +		break;
> 

-- 
Regards,
Liu Ying