drm/vc4: hdmi: Add CEC support flag

Similarly to the audio support, CEC support is not there yet for the
BCM2711, so let's skip entirely the CEC initialization through a variant
flag.
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Tested-by: Chanwoo Choi <cw00.choi@samsung.com>
Tested-by: Hoegeun Kwon <hoegeun.kwon@samsung.com>
Tested-by: Stefan Wahren <stefan.wahren@i2se.com>
Reviewed-by: Dave Stevenson <dave.stevenson@raspberrypi.com>
Link: https://patchwork.freedesktop.org/patch/msgid/bd0c4afa83b4e121692352cdc2dd1886162c7552.1599120059.git-series.maxime@cerno.tech

drivers/gpu/drm/vc4/vc4_hdmi.c

@@ -1178,6 +1178,9 @@ static int vc4_hdmi_cec_init(struct vc4_hdmi *vc4_hdmi)
 	u32 value;
 	int ret;
 
+	if (!vc4_hdmi->variant->cec_available)
+		return 0;
+
 	vc4_hdmi->cec_adap = cec_allocate_adapter(&vc4_hdmi_cec_adap_ops,
 						  vc4_hdmi, "vc4",
 						  CEC_CAP_DEFAULTS |
@@ -1476,6 +1479,7 @@ static int vc4_hdmi_dev_remove(struct platform_device *pdev)
 static const struct vc4_hdmi_variant bcm2835_variant = {
 	.encoder_type		= VC4_ENCODER_TYPE_HDMI0,
 	.debugfs_name		= "hdmi_regs",
+	.cec_available		= true,
 	.registers		= vc4_hdmi_fields,
 	.num_registers		= ARRAY_SIZE(vc4_hdmi_fields),
 

drivers/gpu/drm/vc4/vc4_hdmi.h

@@ -33,6 +33,9 @@ struct vc4_hdmi_variant {
 	/* Filename to expose the registers in debugfs */
 	const char *debugfs_name;
 
+	/* Set to true when the CEC support is available */
+	bool cec_available;
+
 	/* List of the registers available on that variant */
 	const struct vc4_hdmi_register *registers;