drm/amd/display: Implement HDMI Read Request

[Why]
Read Request provides alterative method to polling to
the HDMI sinks that support it.

[How]
Implement Read Request where interrupt can be generated
by the sink.

Reviewed-by: Joshua Aberback <[e-mail]>
Signed-off-by: Chris Park <[e-mail]>
Signed-off-by: Zaeem Mohamed <[e-mail]>
Tested-by: Mark Broadworth <[e-mail]>
Signed-off-by: Alex Deucher <[e-mail]>

drivers/gpu/drm/amd/display/dc/dc.h

···
 	enum signal_type connector_signal;
 	enum dc_irq_source irq_source_hpd;
 	enum dc_irq_source irq_source_hpd_rx;/* aka DP Short Pulse  */
+	enum dc_irq_source irq_source_read_request;/* Read Request */
 
 	bool is_hpd_filter_disabled;
 	bool dp_ss_off;

drivers/gpu/drm/amd/display/dc/dc_types.h

···
 
 	bool edid_hdmi;
 	bool hdr_supported;
+	bool rr_capable;
 
 	struct dc_panel_patch panel_patch;
 };

drivers/gpu/drm/amd/display/dc/gpio/gpio_service.c

···
 	}
 }
 
+enum dc_irq_source dal_irq_get_read_request(
+	const struct gpio *irq)
+{
+	enum gpio_id id = dal_gpio_get_id(irq);
+
+	switch (id) {
+	case GPIO_ID_HPD:
+		return (enum dc_irq_source)(DC_IRQ_SOURCE_DCI2C_RR_DDC1 +
+			dal_gpio_get_enum(irq));
+	default:
+		return DC_IRQ_SOURCE_INVALID;
+	}
+}
+
 enum gpio_result dal_irq_setup_hpd_filter(
 	struct gpio *irq,
 	struct gpio_hpd_config *config)

drivers/gpu/drm/amd/display/dc/irq_types.h

···
 	DC_IRQ_SOURCE_DC5_VLINE2,
 	DC_IRQ_SOURCE_DC6_VLINE2,
 
+	DC_IRQ_SOURCE_DCI2C_RR_DDC1,
+	DC_IRQ_SOURCE_DCI2C_RR_DDC2,
+	DC_IRQ_SOURCE_DCI2C_RR_DDC3,
+	DC_IRQ_SOURCE_DCI2C_RR_DDC4,
+	DC_IRQ_SOURCE_DCI2C_RR_DDC5,
+	DC_IRQ_SOURCE_DCI2C_RR_DDC6,
+
 	DAL_IRQ_SOURCES_NUMBER
 };
 

drivers/gpu/drm/amd/display/dc/link/link_factory.c

···
 
 	link->irq_source_hpd = DC_IRQ_SOURCE_INVALID;
 	link->irq_source_hpd_rx = DC_IRQ_SOURCE_INVALID;
+	link->irq_source_read_request = DC_IRQ_SOURCE_INVALID;
 	link->link_status.dpcd_caps = &link->dpcd_caps;
 
 	link->dc = init_params->dc;
···
 	case CONNECTOR_ID_HDMI_TYPE_A:
 		link->connector_signal = SIGNAL_TYPE_HDMI_TYPE_A;
 
+		if (link->hpd_gpio)
+			link->irq_source_read_request =
+					dal_irq_get_read_request(link->hpd_gpio);
 		break;
 	case CONNECTOR_ID_SINGLE_LINK_DVID:
 	case CONNECTOR_ID_SINGLE_LINK_DVII:

drivers/gpu/drm/amd/display/include/gpio_service_interface.h

···
 enum dc_irq_source dal_irq_get_rx_source(
 	const struct gpio *irq);
 
+enum dc_irq_source dal_irq_get_read_request(
+	const struct gpio *irq);
+
 enum gpio_result dal_irq_setup_hpd_filter(
 	struct gpio *irq,
 	struct gpio_hpd_config *config);