drm/amd/display/dc: add a new helper to fetch the OEM ddc_service

This is the i2c bus used by OEMs for board specific i2c features
like RGB.

Reviewed-by: Harry Wentland <harry.wentland@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

Author: alexdeucher

drivers/gpu/drm/amd/display/dc/core/dc_link_exports.c

@@ -150,6 +150,12 @@ bool dc_link_update_dsc_config(struct pipe_ctx *pipe_ctx)
 	return link->dc->link_srv->update_dsc_config(pipe_ctx);
 }
 
+struct ddc_service *
+dc_get_oem_i2c_device(struct dc *dc)
+{
+	return dc->res_pool->oem_device;
+}
+
 bool dc_is_oem_i2c_device_present(
 	struct dc *dc,
 	size_t slave_address)

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

@@ -1947,6 +1947,9 @@ int dc_link_aux_transfer_raw(struct ddc_service *ddc,
 		struct aux_payload *payload,
 		enum aux_return_code_type *operation_result);
 
+struct ddc_service *
+dc_get_oem_i2c_device(struct dc *dc);
+
 bool dc_is_oem_i2c_device_present(
 	struct dc *dc,
 	size_t slave_address