Commit bafb6863 authored by Chris Morgan's avatar Chris Morgan Committed by Heiko Stuebner
Browse files

drm/bridge: dw-hdmi-qp: Add support for missing HPD 



Add support for the dw-hdmi-qp driver to handle devices with missing
HPD pins.

Since in this situation we are now polling for the EDID data via i2c
change the error message to a rate limited debug message when we are
unable to complete an i2c read, as a disconnected device would
otherwise fill dmesg with i2c read errors.

Reviewed-by: default avatarCristian Ciocaltea <cristian.ciocaltea@collabora.com>
Signed-off-by: default avatarChris Morgan <macromorgan@hotmail.com>
Signed-off-by: default avatarHeiko Stuebner <heiko@sntech.de>
Link: https://patch.msgid.link/20251119225526.70588-3-macroalpha82@gmail.com
parent db04f0d4

drivers/gpu/drm/bridge/synopsys/dw-hdmi-qp.c

+30 −4
Original line number Diff line number Diff line
@@ -165,6 +165,7 @@ struct dw_hdmi_qp { 
	struct regmap *regm;



	unsigned long tmds_char_rate;

	bool no_hpd;

};



static void dw_hdmi_qp_write(struct dw_hdmi_qp *hdmi, unsigned int val,
@@ -555,6 +556,10 @@ static int dw_hdmi_qp_i2c_read(struct dw_hdmi_qp *hdmi, 


		stat = wait_for_completion_timeout(&i2c->cmp, HZ / 10);

		if (!stat) {

			if (hdmi->no_hpd)

				dev_dbg_ratelimited(hdmi->dev,

						    "i2c read timed out\n");

			else

				dev_err(hdmi->dev, "i2c read timed out\n");

			dw_hdmi_qp_write(hdmi, 0x01, I2CM_CONTROL0);

			return -EAGAIN;
@@ -562,6 +567,10 @@ static int dw_hdmi_qp_i2c_read(struct dw_hdmi_qp *hdmi, 


		/* Check for error condition on the bus */

		if (i2c->stat & I2CM_NACK_RCVD_IRQ) {

			if (hdmi->no_hpd)

				dev_dbg_ratelimited(hdmi->dev,

						    "i2c read error\n");

			else

				dev_err(hdmi->dev, "i2c read error\n");

			dw_hdmi_qp_write(hdmi, 0x01, I2CM_CONTROL0);

			return -EIO;
@@ -900,6 +909,15 @@ static enum drm_connector_status 
dw_hdmi_qp_bridge_detect(struct drm_bridge *bridge, struct drm_connector *connector)

{

	struct dw_hdmi_qp *hdmi = bridge->driver_private;

	const struct drm_edid *drm_edid;



	if (hdmi->no_hpd) {

		drm_edid = drm_edid_read_ddc(connector, bridge->ddc);

		if (drm_edid)

			return connector_status_connected;

		else

			return connector_status_disconnected;

	}



	return hdmi->phy.ops->read_hpd(hdmi, hdmi->phy.data);

}
@@ -925,6 +943,11 @@ dw_hdmi_qp_bridge_tmds_char_rate_valid(const struct drm_bridge *bridge, 
{

	struct dw_hdmi_qp *hdmi = bridge->driver_private;



	/*

	 * TODO: when hdmi->no_hpd is 1 we must not support modes that

	 * require scrambling, including every mode with a clock above

	 * HDMI14_MAX_TMDSCLK.

	 */

	if (rate > HDMI14_MAX_TMDSCLK) {

		dev_dbg(hdmi->dev, "Unsupported TMDS char rate: %lld\n", rate);

		return MODE_CLOCK_HIGH;
@@ -1277,12 +1300,15 @@ struct dw_hdmi_qp *dw_hdmi_qp_bind(struct platform_device *pdev, 
	if (ret)

		return ERR_PTR(ret);



	hdmi->no_hpd = device_property_read_bool(dev, "no-hpd");



	hdmi->bridge.driver_private = hdmi;

	hdmi->bridge.ops = DRM_BRIDGE_OP_DETECT |

			   DRM_BRIDGE_OP_EDID |

			   DRM_BRIDGE_OP_HDMI |

			   DRM_BRIDGE_OP_HDMI_AUDIO |

			   DRM_BRIDGE_OP_HPD;

			   DRM_BRIDGE_OP_HDMI_AUDIO;

	if (!hdmi->no_hpd)

		hdmi->bridge.ops |= DRM_BRIDGE_OP_HPD;

	hdmi->bridge.of_node = pdev->dev.of_node;

	hdmi->bridge.type = DRM_MODE_CONNECTOR_HDMIA;

	hdmi->bridge.vendor = "Synopsys";