drm/amd/display: interface to check if timing can be seamless

[Why]
Need to figure out whether a timing we want to commit matches
something that GOP already programmed, in which case
we can decide to some optimizations

[How]
1. Add way to check for DIG FE
2. Add way to check for matching OTG timing
3. Add way to check for matching pixel clock (if possible)
    - Currently only support DP for pixel clock, since it is easy to calc

Signed-off-by: Anthony Koo <Anthony.Koo@amd.com>
Reviewed-by: Aric Cyr <Aric.Cyr@amd.com>
Acked-by: Bhawanpreet Lakha <Bhawanpreet.Lakha@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

1 files changed, 10 insertions, 0 deletions

diff --git a/drivers/gpu/drm/amd/display/dc/dcn10/dcn10_link_encoder.c b/drivers/gpu/drm/amd/display/dc/dcn10/dcn10_link_encoder.c
index 771449f8984f..a9db372688ff 100644
--- a/drivers/gpu/drm/amd/display/dc/dcn10/dcn10_link_encoder.c
+++ b/drivers/gpu/drm/amd/display/dc/dcn10/dcn10_link_encoder.c
@@ -85,6 +85,7 @@ static const struct link_encoder_funcs dcn10_lnk_enc_funcs = {
 	.enable_hpd = dcn10_link_encoder_enable_hpd,
 	.disable_hpd = dcn10_link_encoder_disable_hpd,
 	.is_dig_enabled = dcn10_is_dig_enabled,
+	.get_dig_frontend = dcn10_get_dig_frontend,
 	.destroy = dcn10_link_encoder_destroy
 };
 
@@ -495,6 +496,15 @@ bool dcn10_is_dig_enabled(struct link_encoder *enc)
 	return value;
 }
 
+unsigned int dcn10_get_dig_frontend(struct link_encoder *enc)
+{
+	struct dcn10_link_encoder *enc10 = TO_DCN10_LINK_ENC(enc);
+	uint32_t value;
+
+	REG_GET(DIG_BE_CNTL, DIG_FE_SOURCE_SELECT, &value);
+	return value;
+}
+
 static void link_encoder_disable(struct dcn10_link_encoder *enc10)
 {
 	/* reset training pattern */