Read DisplayPort branch device id string.
Reviewed-by: Jim Bride jim.bride@linux.intel.com Signed-off-by: Mika Kahola mika.kahola@intel.com --- drivers/gpu/drm/drm_dp_helper.c | 12 ++++++++++++ include/drm/drm_dp_helper.h | 2 ++ 2 files changed, 14 insertions(+)
diff --git a/drivers/gpu/drm/drm_dp_helper.c b/drivers/gpu/drm/drm_dp_helper.c index 14e8ea0..01ee7af 100644 --- a/drivers/gpu/drm/drm_dp_helper.c +++ b/drivers/gpu/drm/drm_dp_helper.c @@ -514,6 +514,18 @@ int drm_dp_downstream_max_bpc(const u8 dpcd[DP_RECEIVER_CAP_SIZE], } EXPORT_SYMBOL(drm_dp_downstream_max_bpc);
+/** + * drm_dp_downstream_id() - identify branch device + * @aux: DisplayPort AUX channel + * + * Returns branch device id on success or NULL on failure + */ +int drm_dp_downstream_id(struct drm_dp_aux *aux, char id[6]) +{ + return drm_dp_dpcd_read(aux, DP_BRANCH_ID, id, 6); +} +EXPORT_SYMBOL(drm_dp_downstream_id); + /* * I2C-over-AUX implementation */ diff --git a/include/drm/drm_dp_helper.h b/include/drm/drm_dp_helper.h index f3d1424..faea76b 100644 --- a/include/drm/drm_dp_helper.h +++ b/include/drm/drm_dp_helper.h @@ -445,6 +445,7 @@ #define DP_SOURCE_OUI 0x300 #define DP_SINK_OUI 0x400 #define DP_BRANCH_OUI 0x500 +#define DP_BRANCH_ID 0x503
#define DP_SET_POWER 0x600 # define DP_SET_POWER_D0 0x1 @@ -819,6 +820,7 @@ int drm_dp_downstream_max_clock(const u8 dpcd[DP_RECEIVER_CAP_SIZE], const u8 port_cap[4]); int drm_dp_downstream_max_bpc(const u8 dpcd[DP_RECEIVER_CAP_SIZE], const u8 port_cap[4]); +int drm_dp_downstream_id(struct drm_dp_aux *aux, char id[6]);
void drm_dp_aux_init(struct drm_dp_aux *aux); int drm_dp_aux_register(struct drm_dp_aux *aux);