linux-kernel - Re: [PATCH v2 6/9] drm/bridge: Add ITE IT6263 LVDS to HDMI converter

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Message-ID: <kaoqse23we5lyhaawk6xe2ouxwwjtjfpkiqb3j7xe64o2jscny@3yswlkjhuuxw>
Date: Mon, 14 Oct 2024 10:32:02 +0300
From: Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
To: Liu Ying <victor.liu@....com>
Cc: dri-devel@...ts.freedesktop.org, devicetree@...r.kernel.org, 
	linux-kernel@...r.kernel.org, imx@...ts.linux.dev, linux-arm-kernel@...ts.infradead.org, 
	andrzej.hajda@...el.com, neil.armstrong@...aro.org, rfoss@...nel.org, 
	Laurent.pinchart@...asonboard.com, jonas@...boo.se, jernej.skrabec@...il.com, airlied@...il.com, 
	simona@...ll.ch, maarten.lankhorst@...ux.intel.com, mripard@...nel.org, 
	tzimmermann@...e.de, robh@...nel.org, krzk+dt@...nel.org, conor+dt@...nel.org, 
	shawnguo@...nel.org, s.hauer@...gutronix.de, kernel@...gutronix.de, 
	festevam@...il.com, catalin.marinas@....com, will@...nel.org, 
	quic_bjorande@...cinc.com, geert+renesas@...der.be, arnd@...db.de, nfraprado@...labora.com, 
	o.rempel@...gutronix.de, y.moog@...tec.de, marex@...x.de, isaac.scott@...asonboard.com, 
	biju.das.jz@...renesas.com
Subject: Re: [PATCH v2 6/9] drm/bridge: Add ITE IT6263 LVDS to HDMI converter

On Mon, Oct 14, 2024 at 03:18:15PM +0800, Liu Ying wrote:
> On 10/14/2024, Dmitry Baryshkov wrote:
> > On Sat, Oct 12, 2024 at 03:35:40PM +0800, Liu Ying wrote:
> >> Add basic HDMI video output support. Currently, only RGB888 output
> >> pixel format is supported.  At the LVDS input side, the driver
> >> supports single LVDS link and dual LVDS links with "jeida-24" LVDS
> >> mapping.
> >>
> >> Product link:
> >> https://www.ite.com.tw/en/product/cate1/IT6263
> >>
> >> Signed-off-by: Liu Ying <victor.liu@....com>
> >> ---
> >> v2:
> >> * Add AVI inforframe support.  (Maxime)
> >> * Add DRM_MODE_CONNECTOR_HDMIA.  (Biju)
> >> * Rename it6263_reset() to it6263_hw_reset().  (Biju)
> >> * Check number of LVDS link data lanes.  (Biju)
> >>
> >>  drivers/gpu/drm/bridge/Kconfig      |   8 +
> >>  drivers/gpu/drm/bridge/Makefile     |   1 +
> >>  drivers/gpu/drm/bridge/ite-it6263.c | 919 ++++++++++++++++++++++++++++
> >>  3 files changed, 928 insertions(+)
> >>  create mode 100644 drivers/gpu/drm/bridge/ite-it6263.c
> >>
> > 
> > [...]
> > 
> >> +static int it6263_parse_dt(struct it6263 *it)
> >> +{
> >> +	struct device *dev = it->dev;
> >> +	struct device_node *port0, *port1;
> >> +	int ret;
> >> +
> >> +	ret = of_property_read_u8(dev->of_node, "ite,lvds-link-num-data-lanes",
> >> +				  &it->lvds_link_num_dlanes);
> >> +	if (ret) {
> >> +		dev_err(dev, "failed to get LVDS link number of data lanes: %d\n",
> >> +			ret);
> >> +		return ret;
> >> +	}
> >> +
> >> +	it->next_bridge = devm_drm_of_get_bridge(dev, dev->of_node, 2, 0);
> >> +	if (IS_ERR(it->next_bridge))
> >> +		return dev_err_probe(dev, PTR_ERR(it->next_bridge),
> >> +				     "failed to get next bridge\n");
> >> +
> >> +	port0 = of_graph_get_port_by_id(dev->of_node, 0);
> >> +	port1 = of_graph_get_port_by_id(dev->of_node, 1);
> >> +	if (port0 && port1) {
> >> +		if (of_property_read_bool(port0, "dual-lvds-even-pixels") &&
> >> +		    of_property_read_bool(port1, "dual-lvds-odd-pixels")) {
> >> +			it->lvds_dual_link = true;
> >> +			it->lvds_link12_swap = true;
> >> +		} else if (of_property_read_bool(port0, "dual-lvds-odd-pixels") &&
> >> +			   of_property_read_bool(port1, "dual-lvds-even-pixels")) {
> >> +			it->lvds_dual_link = true;
> >> +		}
> >> +
> >> +		if (!it->lvds_dual_link) {
> >> +			dev_err(dev,
> >> +				"failed to get LVDS dual link pixel order\n");
> >> +			ret = -EINVAL;
> >> +		}
> > 
> > Please use drm_of_lvds_get_dual_link_pixel_order(), it validates that
> > the DT definition is sound: one port for odd pixels, one port for even
> > pixels.
> 
> It cannot be used, because it get the pixel order for the LVDS
> source not sink. IT6263 is the LVDS sink.

Then you need a similar function for the sink side. Add it to the
drm_of.c

> 
>  * drm_of_lvds_get_dual_link_pixel_order - Get LVDS dual-link pixel order        
>  * @port1: First DT port node of the Dual-link LVDS source                       
>  * @port2: Second DT port node of the Dual-link LVDS source      
> 
> > 
> >> +	} else if (port1) {
> >> +		ret = -EINVAL;
> >> +		dev_err(dev, "single input LVDS port1 is not supported\n");
> >> +	} else if (!port0) {
> >> +		ret = -EINVAL;
> >> +		dev_err(dev, "no input LVDS port\n");
> >> +	}
> >> +
> >> +	of_node_put(port0);
> >> +	of_node_put(port1);
> >> +
> >> +	return ret;
> >> +}
> >> +
> > 
> 
> -- 
> Regards,
> Liu Ying
> 

-- 
With best wishes
Dmitry