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

[Liu Ying]

On 10/14/2024, Biju Das wrote:
> Hi Liu Ying,

Hi Biju,

> 
>> -----Original Message-----
>> From: Liu Ying <victor.liu@xxxxxxx>
>> Sent: Monday, October 14, 2024 8:18 AM
>> Subject: Re: [PATCH v2 6/9] drm/bridge: Add ITE IT6263 LVDS to HDMI converter
>>
>> 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@xxxxxxx>
>>>> ---
>>>> 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.
>>
>>  * 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
> 
> 
> Can't you use drm_of_lvds_get_dual_link_pixel_order() from host for the same use case. See [1]?

Yes, just need to get the remote LVDS source ports first.
I just proposed a snippet in a separate reply to use this function.
Let's see if Dmitry likes it or not.

> 
> [1]
> https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/tree/drivers/gpu/drm/renesas/rcar-du/rcar_lvds.c?h=next-20241011
> 
> lvds_bridge0: lvds-to-hdmi-bridge@4c {
> 		compatible = "ite,it6263";
> 		reg = <0x4c>;
> 		ports {
> 			#address-cells = <1>;
> 			#size-cells = <0>;
> 
> 			port@0 {
> 				reg = <0>;
> 				dual-lvds-odd-pixels;
> 				lvds0_in0: endpoint@0 {
> 					remote-endpoint = <&lvds0_out>;
> 				};
> 			};
> 
> 			port@1 {
> 				reg = <1>;
> 				dual-lvds-even-pixels;
> 				lvds0_in1: endpoint@1 {
> 					remote-endpoint = <&lvds1_out>;
> 				};
> 			};
> 
> 			port@2 {
> 				reg = <2>;
> 				it6263_out: endpoint@2 {
> 					remote-endpoint = <&lvds_to_hdmi_con_out>;
> 				};
> 			};
> 		};
> 	};
> };
> 
> Cheers,
> Biju
> 
> 
>>
>>>
>>>> +	} 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
> 

-- 
Regards,
Liu Ying