drm/amd/display: Replace repeated no-native-i2c checks with force_i2c_over_aux field

[Why]
The compound condition checking dp_connector_no_native_i2c
and no_ddc_pin was duplicated across many files, obscuring
intent at every call site.

[How]
Add bool force_i2c_over_aux to struct dc_link, initialized
once during link creation. Add link_get_ddc_aux_inst()
helper to select the correct aux instance. Wire into
link_service via construct_link_service_ddc(). Replace all
duplicated condition checks and aux instance selection
blocks with the new field and helper. No functional change.

Reviewed-by: Nevenko Stupar <nevenko.stupar@amd.com>
Signed-off-by: Wenjing Liu <wenjing.liu@amd.com>
Signed-off-by: George Zhang <george.zhang@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

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

@@ -1845,6 +1845,10 @@ struct dc_scratch_space {
 	 * of ddc_pin to know which aux instance is associated with link.
 	 */
 	bool no_ddc_pin;
+	/** When set, forces all native I2C communication on this DP connector
+	 *  to use the I2C-over-AUX protocol instead of native I2C signaling.
+	 */
+	bool force_to_use_aux;
 	enum gpio_ddc_line aux_hw_inst;
 
 	enum gpio_ddc_line ddc_hw_inst;

drivers/gpu/drm/amd/display/dc/dce/dce_aux.c

@@ -529,7 +529,7 @@ static uint32_t dce_aux_configure_timeout(struct ddc_service *ddc,
 	uint32_t prev_timeout_val = 0;
 	struct ddc *ddc_pin = ddc->ddc_pin;
 
-	if (ddc->ctx->dc->config.dp_connector_no_native_i2c && ddc->link->no_ddc_pin)
+	if (ddc->link->force_to_use_aux)
 		return dce_aux_configure_timeout_without_ddc_pin(ddc, timeout_in_us);
 
 	struct dce_aux *aux_engine = ddc->ctx->dc->res_pool->engines[ddc_pin->pin_data->en];
@@ -652,7 +652,7 @@ int dce_aux_transfer_raw(struct ddc_service *ddc,
 		struct aux_payload *payload,
 		enum aux_return_code_type *operation_result)
 {
-	if (ddc->ctx->dc->config.dp_connector_no_native_i2c && ddc->link->no_ddc_pin) {
+	if (ddc->link->force_to_use_aux) {
 		/* Check whether aux to be processed via dmub or dcn directly */
 		if (ddc->ctx->dc->debug.enable_dmub_aux_for_legacy_ddc) {
 			return dce_aux_transfer_dmub_raw(ddc, payload, operation_result);
@@ -795,7 +795,7 @@ int dce_aux_transfer_dmub_raw(struct ddc_service *ddc,
 		release_engine(aux_engine);
 	}
 
-	if (ddc->ctx->dc->config.dp_connector_no_native_i2c && ddc->link->no_ddc_pin) {
+	if (ddc->link->force_to_use_aux) {
 		struct dce_aux *aux_engine = ddc->ctx->dc->res_pool->engines[ddc->link->aux_hw_inst];
 
 		if (!acquire_aux_engine_without_ddc_pin(aux_engine, ddc_pin)) {
@@ -893,7 +893,7 @@ bool dce_aux_transfer_with_retries(struct ddc_service *ddc,
 		aux110 = FROM_AUX_ENGINE(aux_engine);
 	}
 
-	if (ddc->ctx->dc->config.dp_connector_no_native_i2c && ddc->link->no_ddc_pin) {
+	if (ddc->link->force_to_use_aux) {
 		aux_engine = ddc->ctx->dc->res_pool->engines[ddc->link->aux_hw_inst];
 		aux110 = FROM_AUX_ENGINE(aux_engine);
 	}

drivers/gpu/drm/amd/display/dc/hwss/dcn401/dcn401_hwseq.c

@@ -321,7 +321,7 @@ void dcn401_init_hw(struct dc *dc)
 			user_level = link->panel_cntl->stored_backlight_registers.USER_LEVEL;
 		}
 
-		if (link->ctx->dc->config.dp_connector_no_native_i2c && link->no_ddc_pin) {
+		if (link->force_to_use_aux) {
 			struct graphics_object_i2c_info i2c_info;
 			struct ddc *ddc_pin;
 			struct gpio_ddc_hw_info hw_info;

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

@@ -193,6 +193,7 @@ struct link_service {
 			struct aux_payload *payload);
 	bool (*is_in_aux_transaction_mode)(struct ddc_service *ddc);
 	uint32_t (*get_aux_defer_delay)(struct ddc_service *ddc);
+	uint8_t (*get_ddc_aux_inst)(const struct dc_link *link);
 
 
 	/*************************** DP Capability ****************************/

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

@@ -143,6 +143,7 @@ static void construct_link_service_ddc(struct link_service *link_srv)
 			link_aux_transfer_with_retries_no_mutex;
 	link_srv->is_in_aux_transaction_mode = link_is_in_aux_transaction_mode;
 	link_srv->get_aux_defer_delay = link_get_aux_defer_delay;
+	link_srv->get_ddc_aux_inst = link_get_ddc_aux_inst;
 }
 
 /* link dp capability implements dp specific link capability retrieval sequence.
@@ -441,7 +442,7 @@ static enum channel_id get_ddc_line(struct dc_link *link)
 
 	channel = CHANNEL_ID_UNKNOWN;
 
-	if (link->ctx->dc->config.dp_connector_no_native_i2c && link->no_ddc_pin) {
+	if (link->force_to_use_aux) {
 		channel = link->aux_hw_inst + 1;
 	} else {
 		ddc = get_ddc_pin(link->ddc);
@@ -576,6 +577,8 @@ static bool construct_phy(struct dc_link *link,
 		link->is_internal_display = (disp_connect_caps_info.INTERNAL_DISPLAY != 0);
 		DC_LOG_DC("BIOS object table - is_internal_display: %d", link->is_internal_display);
 		link->no_ddc_pin = disp_connect_caps_info.NO_DDC_PIN != 0;
+		link->force_to_use_aux = link->dc->config.dp_connector_no_native_i2c
+				&& link->no_ddc_pin;
 	}
 
 	if (link->link_id.type != OBJECT_TYPE_CONNECTOR) {
@@ -598,7 +601,7 @@ static bool construct_phy(struct dc_link *link,
 		goto ddc_create_fail;
 	}
 
-	if (link->ctx->dc->config.dp_connector_no_native_i2c && link->no_ddc_pin) {
+	if (link->force_to_use_aux) {
 		link->ddc_hw_inst = link->aux_hw_inst;
 	} else {
 		/* Embedded display connectors such as LVDS may not have DDC. */

drivers/gpu/drm/amd/display/dc/link/protocols/link_ddc.c

@@ -120,8 +120,7 @@ static void ddc_service_construct(
 	ddc_service->link = init_data->link;
 	ddc_service->ctx = init_data->ctx;
 
-	if (ddc_service->link && ddc_service->ctx->dc->config.dp_connector_no_native_i2c &&
-		ddc_service->link->no_ddc_pin) {
+	if (ddc_service->link && ddc_service->link->force_to_use_aux) {
 		// Obtain aux instance info from i2c_info without GPIO DDC pin info
 		if (dcb->funcs->get_connector_aux_info(dcb, init_data->id, &i2c_info) == BP_RESULT_OK)
 			ddc_service->link->aux_hw_inst = (uint8_t)i2c_info.i2c_line;
@@ -252,6 +251,21 @@ static uint32_t defer_delay_converter_wa(
 
 #define DP_TRANSLATOR_DELAY 5
 
+/**
+ * link_get_ddc_aux_inst - Return the AUX/DDC hardware instance for a link.
+ * @link: the link to query
+ *
+ * Return: aux_hw_inst when I2C is forced over AUX, otherwise the DDC pin
+ * channel index.
+ */
+uint8_t link_get_ddc_aux_inst(const struct dc_link *link)
+{
+	if (link->force_to_use_aux)
+		return link->aux_hw_inst;
+	ASSERT(link->ddc->ddc_pin->hw_info.ddc_channel <= 0xFF);
+	return (uint8_t)link->ddc->ddc_pin->hw_info.ddc_channel;
+}
+
 uint32_t link_get_aux_defer_delay(struct ddc_service *ddc)
 {
 	uint32_t defer_delay = 0;
@@ -526,7 +540,7 @@ bool try_to_configure_aux_timeout(struct ddc_service *ddc,
 	if (ddc->link->ep_type != DISPLAY_ENDPOINT_PHY)
 		return true;
 
-	if (ddc->ctx->dc->config.dp_connector_no_native_i2c && ddc->link->no_ddc_pin) {
+	if (ddc->link->force_to_use_aux) {
 		if (ddc->ctx->dc->res_pool->engines[ddc->link->aux_hw_inst]->funcs->configure_timeout) {
 			ddc->ctx->dc->res_pool->engines[ddc->link->aux_hw_inst]->funcs->configure_timeout(ddc, timeout);
 			result = true;

drivers/gpu/drm/amd/display/dc/link/protocols/link_ddc.h

@@ -46,6 +46,8 @@ void set_ddc_transaction_type(
 		struct ddc_service *ddc,
 		enum ddc_transaction_type type);
 
+uint8_t link_get_ddc_aux_inst(const struct dc_link *link);
+
 uint32_t link_get_aux_defer_delay(struct ddc_service *ddc);
 
 bool link_is_in_aux_transaction_mode(struct ddc_service *ddc);

drivers/gpu/drm/amd/display/dc/link/protocols/link_dp_capability.c

@@ -2583,7 +2583,7 @@ bool dp_is_sink_present(struct dc_link *link)
 	/* We can't perform the step below for ASICs with no Native
 	 * I2C signaling support on DP connectors, so skip it.
 	 */
-	if (link->ctx->dc->config.dp_connector_no_native_i2c && link->no_ddc_pin)
+	if (link->force_to_use_aux)
 		return present;
 
 	ddc = get_ddc_pin(link->ddc);

drivers/gpu/drm/amd/display/dc/link/protocols/link_dp_panel_replay.c

@@ -25,6 +25,7 @@
 
 #include "link_dp_panel_replay.h"
 #include "link_edp_panel_control.h"
+#include "link_ddc.h"
 #include "link_dpcd.h"
 #include "dm_helpers.h"
 #include "dc/dc_dmub_srv.h"
@@ -119,11 +120,7 @@ static bool dp_setup_panel_replay(struct dc_link *link, const struct dc_stream_s
 	if (!dp_pr_get_panel_inst(dc, link, &panel_inst))
 		return false;
 
-	if (dc->config.dp_connector_no_native_i2c && link->no_ddc_pin) {
-		replay_context.aux_inst = (enum channel_id) link->aux_hw_inst;
-	} else {
-		replay_context.aux_inst = link->ddc->ddc_pin->hw_info.ddc_channel;
-	}
+	replay_context.aux_inst = (enum channel_id) link_get_ddc_aux_inst(link);
 	replay_context.digbe_inst = link->link_enc->transmitter;
 	replay_context.digfe_inst = link->link_enc->preferred_engine;
 

drivers/gpu/drm/amd/display/dc/link/protocols/link_edp_panel_control.c

@@ -29,6 +29,7 @@
  */
 
 #include "link_edp_panel_control.h"
+#include "link_ddc.h"
 #include "link_dpcd.h"
 #include "link_dp_capability.h"
 #include "dm_helpers.h"
@@ -788,11 +789,7 @@ bool edp_setup_psr(struct dc_link *link,
 		}
 	}
 
-	if (dc->config.dp_connector_no_native_i2c && link->no_ddc_pin) {
-		psr_context->channel = (enum channel_id)link->aux_hw_inst;
-	} else {
-		psr_context->channel = link->ddc->ddc_pin->hw_info.ddc_channel;
-	}
+	psr_context->channel = link_get_ddc_aux_inst(link);
 	psr_context->transmitterId = link->link_enc->transmitter;
 	psr_context->engineId = link->link_enc->preferred_engine;
 
@@ -1025,11 +1022,7 @@ bool edp_setup_freesync_replay(struct dc_link *link, const struct dc_stream_stat
 	if (!dp_pr_get_panel_inst(dc, link, &panel_inst))
 		return false;
 
-	if (dc->config.dp_connector_no_native_i2c && link->no_ddc_pin) {
-		replay_context.aux_inst = (enum channel_id) link->aux_hw_inst;
-	} else {
-		replay_context.aux_inst = link->ddc->ddc_pin->hw_info.ddc_channel;
-	}
+	replay_context.aux_inst = link_get_ddc_aux_inst(link);
 	replay_context.digbe_inst = link->link_enc->transmitter;
 	replay_context.digfe_inst = link->link_enc->preferred_engine;
 

drivers/gpu/drm/amd/display/modules/power/power.c

@@ -483,12 +483,7 @@ bool mod_power_notify_mode_change(struct mod_power *mod_power,
 	link = dc_stream_get_link(stream);
 
 	if (link != NULL && dc_get_edp_link_panel_inst(dc, link, &panel_inst)) {
-		if (link->ctx->dc->config.dp_connector_no_native_i2c && link->no_ddc_pin) {
-			aux_inst = (uint8_t)link->aux_hw_inst;
-		} else {
-			ASSERT(link->ddc->ddc_pin->hw_info.ddc_channel <= 0xFF);
-			aux_inst = (uint8_t)link->ddc->ddc_pin->hw_info.ddc_channel;
-		}
+		aux_inst = link->dc->link_srv->get_ddc_aux_inst(link);
 
 		mod_power_update_backlight_on_mode_change(core_power, link, panel_inst, aux_inst, is_hdr);
 

drivers/gpu/drm/amd/display/modules/power/power_abm.c

@@ -849,12 +849,7 @@ bool mod_power_set_backlight_nits(struct mod_power *mod_power,
 	core_power = MOD_POWER_TO_CORE(mod_power);
 	link = dc_stream_get_link(stream);
 
-	if (link->ctx->dc->config.dp_connector_no_native_i2c && link->no_ddc_pin) {
-		aux_inst = (uint8_t)link->aux_hw_inst;
-	} else {
-		ASSERT(link->ddc->ddc_pin->hw_info.ddc_channel <= 0xFF);
-		aux_inst = (uint8_t)link->ddc->ddc_pin->hw_info.ddc_channel;
-	}
+	aux_inst = link->dc->link_srv->get_ddc_aux_inst(link);
 
 	if (!dc_get_edp_link_panel_inst(core_power->dc, stream->link, &panel_inst))
 		return false;
@@ -941,12 +936,7 @@ bool mod_power_set_backlight_percent(struct mod_power *mod_power,
 
 	core_power = MOD_POWER_TO_CORE(mod_power);
 	link = dc_stream_get_link(stream);
-	if (link->ctx->dc->config.dp_connector_no_native_i2c && link->no_ddc_pin) {
-		aux_inst = (uint8_t)link->aux_hw_inst;
-	} else {
-		ASSERT(link->ddc->ddc_pin->hw_info.ddc_channel <= 0xFF);
-		aux_inst = (uint8_t)link->ddc->ddc_pin->hw_info.ddc_channel;
-	}
+	aux_inst = link->dc->link_srv->get_ddc_aux_inst(link);
 
 	if (!dc_get_edp_link_panel_inst(core_power->dc, stream->link, &panel_inst))
 		return false;