[Linaro-mm-sig] Re: [PATCH v2 6/6] drm/vs: Add hdmi driver

On Thu, Oct 26, 2023 at 01:23:53AM +0300, Dmitry Baryshkov wrote:

...

+static int starfive_hdmi_register(struct drm_device *drm, struct starfive_hdmi *hdmi) +{

• struct drm_encoder *encoder = &hdmi->encoder;
• struct device *dev = hdmi->dev;
• encoder->possible_crtcs = drm_of_find_possible_crtcs(drm, dev->of_node);
• /*

• * If we failed to find the CRTC(s) which this encoder is
  

• * supposed to be connected to, it's because the CRTC has
  

• * not been registered yet.  Defer probing, and hope that
  

• * the required CRTC is added later.
  

• */
  

• if (encoder->possible_crtcs == 0)

• return -EPROBE_DEFER;
  

• drm_encoder_helper_add(encoder, &starfive_hdmi_encoder_helper_funcs);
• hdmi->connector.polled = DRM_CONNECTOR_POLL_HPD;
• drm_connector_helper_add(&hdmi->connector,

• 		 &starfive_hdmi_connector_helper_funcs);
  

• drmm_connector_init(drm, &hdmi->connector,

• 	    &starfive_hdmi_connector_funcs,
  

• 	    DRM_MODE_CONNECTOR_HDMIA,
  

On an embedded device one can not be so sure. There can be MHL or HDMI Alternative Mode. Usually we use drm_bridge here and drm_bridge_connector.

On an HDMI driver, it's far from being a requirement, especially given the limitations bridges have.

Maxime