From 266d783baaf5f34a5bea3b56489f091451a89767 Mon Sep 17 00:00:00 2001 From: Mika Kahola Date: Fri, 9 Sep 2016 14:10:51 +0300 Subject: [PATCH] drm: Read DP branch device id Read DisplayPort branch device id string. Reviewed-by: Jim Bride Signed-off-by: Mika Kahola Acked-by: Dave Airlie Signed-off-by: Jani Nikula Link: http://patchwork.freedesktop.org/patch/msgid/1473419458-17080-6-git-send-email-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 57c61d126a56..7b3a638725d9 100644 --- a/drivers/gpu/drm/drm_dp_helper.c +++ b/drivers/gpu/drm/drm_dp_helper.c @@ -513,6 +513,18 @@ 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 f3d14240338e..faea76bec514 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); -- 2.20.1