drm/vc4: hdmi: Support BCM2711 CEC interrupt setup

The HDMI controller found in the BCM2711 has an external interrupt
controller for the CEC and hotplug interrupt shared between the two
instances.

Let's add a variant flag to register a single interrupt handler and
deals with the interrupt handler setup, or two interrupt handlers
relying on an external irqchip.
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Reviewed-by: Dave Stevenson <dave.stevenson@raspberrypi.com>
Acked-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Tested-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Link: https://patchwork.freedesktop.org/patch/msgid/20210111142309.193441-11-maxime@cerno.tech

drivers/gpu/drm/vc4/vc4_hdmi.c

@@ -1605,8 +1605,10 @@ static int vc4_hdmi_cec_adap_enable(struct cec_adapter *adap, bool enable)
 			   ((3600 / usecs) << VC4_HDMI_CEC_CNT_TO_3600_US_SHIFT) |
 			   ((3500 / usecs) << VC4_HDMI_CEC_CNT_TO_3500_US_SHIFT));
 
+		if (!vc4_hdmi->variant->external_irq_controller)
 			HDMI_WRITE(HDMI_CEC_CPU_MASK_CLEAR, VC4_HDMI_CPU_CEC);
 	} else {
+		if (!vc4_hdmi->variant->external_irq_controller)
 			HDMI_WRITE(HDMI_CEC_CPU_MASK_SET, VC4_HDMI_CPU_CEC);
 		HDMI_WRITE(HDMI_CEC_CNTRL_5, val |
 			   VC4_HDMI_CEC_TX_SW_RESET | VC4_HDMI_CEC_RX_SW_RESET);
@@ -1682,8 +1684,6 @@ static int vc4_hdmi_cec_init(struct vc4_hdmi *vc4_hdmi)
 	cec_fill_conn_info_from_drm(&conn_info, &vc4_hdmi->connector);
 	cec_s_conn_info(vc4_hdmi->cec_adap, &conn_info);
 
-	HDMI_WRITE(HDMI_CEC_CPU_MASK_SET, 0xffffffff);
-
 	value = HDMI_READ(HDMI_CEC_CNTRL_1);
 	/* Set the logical address to Unregistered */
 	value |= VC4_HDMI_CEC_ADDR_MASK;
@@ -1691,12 +1691,32 @@ static int vc4_hdmi_cec_init(struct vc4_hdmi *vc4_hdmi)
 
 	vc4_hdmi_cec_update_clk_div(vc4_hdmi);
 
+	if (vc4_hdmi->variant->external_irq_controller) {
+		ret = devm_request_threaded_irq(&pdev->dev,
+						platform_get_irq_byname(pdev, "cec-rx"),
+						vc4_cec_irq_handler_rx_bare,
+						vc4_cec_irq_handler_rx_thread, 0,
+						"vc4 hdmi cec rx", vc4_hdmi);
+		if (ret)
+			goto err_delete_cec_adap;
+
+		ret = devm_request_threaded_irq(&pdev->dev,
+						platform_get_irq_byname(pdev, "cec-tx"),
+						vc4_cec_irq_handler_tx_bare,
+						vc4_cec_irq_handler_tx_thread, 0,
+						"vc4 hdmi cec tx", vc4_hdmi);
+		if (ret)
+			goto err_delete_cec_adap;
+	} else {
+		HDMI_WRITE(HDMI_CEC_CPU_MASK_SET, 0xffffffff);
+
 		ret = devm_request_threaded_irq(&pdev->dev, platform_get_irq(pdev, 0),
 						vc4_cec_irq_handler,
 						vc4_cec_irq_handler_thread, 0,
 						"vc4 hdmi cec", vc4_hdmi);
 		if (ret)
 			goto err_delete_cec_adap;
+	}
 
 	ret = cec_register_adapter(vc4_hdmi->cec_adap, &pdev->dev);
 	if (ret < 0)
@@ -2095,6 +2115,7 @@ static const struct vc4_hdmi_variant bcm2711_hdmi0_variant = {
 		PHY_LANE_CK,
 	},
 	.unsupported_odd_h_timings	= true,
+	.external_irq_controller	= true,
 
 	.init_resources		= vc5_hdmi_init_resources,
 	.csc_setup		= vc5_hdmi_csc_setup,
@@ -2121,6 +2142,7 @@ static const struct vc4_hdmi_variant bcm2711_hdmi1_variant = {
 		PHY_LANE_2,
 	},
 	.unsupported_odd_h_timings	= true,
+	.external_irq_controller	= true,
 
 	.init_resources		= vc5_hdmi_init_resources,
 	.csc_setup		= vc5_hdmi_csc_setup,

drivers/gpu/drm/vc4/vc4_hdmi.h

@@ -64,6 +64,13 @@ struct vc4_hdmi_variant {
 	/* The BCM2711 cannot deal with odd horizontal pixel timings */
 	bool unsupported_odd_h_timings;
 
+	/*
+	 * The BCM2711 CEC/hotplug IRQ controller is shared between the
+	 * two HDMI controllers, and we have a proper irqchip driver for
+	 * it.
+	 */
+	bool external_irq_controller;
+
 	/* Callback to get the resources (memory region, interrupts,
 	 * clocks, etc) for that variant.
 	 */