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

From: Dmitry Baryshkov
Date: Mon Oct 14 2024 - 07:23:40 EST

On Mon, Oct 14, 2024 at 04:28:29PM +0800, Liu Ying wrote:
> On 10/14/2024, Dmitry Baryshkov wrote:
> > 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@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.
> >
> > Then you need a similar function for the sink side. Add it to the
> > drm_of.c
>
> How about getting remote LVDS source ports first and use
> drm_of_lvds_get_dual_link_pixel_order() like the snippet below?
> This way, no need to add a similar function or modify
> drm_of_lvds_get_dual_link_pixel_order() implementation.
>
> If you don't like this, can you please suggest a similar function
> name or maybe an additional parameter(with type and name) for
> drm_of_lvds_get_dual_link_pixel_order()?
>
> ---8<---
> port0_ep = of_graph_get_endpoint_by_regs(dev->of_node, 0, -1);
> if (port0_ep) {
> remote_port0 = of_graph_get_remote_port(port0_ep);
> of_node_put(port0_ep);
> }
> port1_ep = of_graph_get_endpoint_by_regs(dev->of_node, 1, -1);
> if (port1_ep) {
> remote_port1 = of_graph_get_remote_port(port1_ep);
> of_node_put(port1_ep);
> }

I think getting remotes just to get remotes back is a little bit clumsy.
Adding drm_of_lvds_get_dual_link_pixel_order_sink() looks like a claner
solution.

>
> if (remote_port0 && remote_port1) {
> order = drm_of_lvds_get_dual_link_pixel_order(remote_port0,
> remote_port1);
> if (order < 0) {
> dev_err(dev,
> "failed to get dual link pixel order: %d\n",
> order);
> ret = order;
> } else if (order == DRM_LVDS_DUAL_LINK_ODD_EVEN_PIXELS) {
> it->lvds_dual_link = true;
> } else if (order == DRM_LVDS_DUAL_LINK_EVEN_ODD_PIXELS) {
> it->lvds_dual_link = true;
> it->lvds_link12_swap = true;
> }

it->lvds_dual_link = true;
order = drm_of_lvds_get_dual_link_pixel_order_sink(port0_ep,
port1_ep);
if (order < 0) {
dev_err(...);
ret = order;
} else if (order == DRM_LVDS_DUAL_LINK_EVEN_ODD_PIXELS) {
it->lvds_link12_swap = true;
}

> } else if (remote_port1) {
> ret = -EINVAL;
> dev_err(dev, "single input LVDS port1 is not supported\n");
> } else if (!remote_port0) {
> ret = -EINVAL;
> dev_err(dev, "no input LVDS port\n");
> }
>
> of_node_put(remote_port0);
> of_node_put(remote_port1);
> ---8<---
>
> >
> >>
> >> * 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
> >>
> >
>
> --
> Regards,
> Liu Ying
>

--
With best wishes
Dmitry