diff options
| author | Mika Kahola <mika.kahola@intel.com> | 2016-09-09 14:10:50 +0300 |
|---|---|---|
| committer | Jani Nikula <jani.nikula@intel.com> | 2016-09-15 14:50:01 +0300 |
| commit | 7529d6af1cd16b0ecd286a1bf6ceee5328ab9809 (patch) | |
| tree | d20ab3af9417ae038fec481715d2e96f7c635157 /drivers/gpu/drm/drm_dp_helper.c | |
| parent | 1c29bd3d6011bed4cbae215571f6f4c25ab10012 (diff) | |
drm: Helper to read max bits per component
Helper routine to read out maximum supported bits per
component for DisplayPort legay converters.
v2: Return early if detailed port cap info is not available.
Replace if-else ladder with switch-case (Ville)
Reviewed-by: Jim Bride <jim.bride@linux.intel.com>
Signed-off-by: Mika Kahola <mika.kahola@intel.com>
Acked-by: Dave Airlie <airlied@gmail.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1473419458-17080-5-git-send-email-mika.kahola@intel.com
Diffstat (limited to 'drivers/gpu/drm/drm_dp_helper.c')
| -rw-r--r-- | drivers/gpu/drm/drm_dp_helper.c | 42 |
1 files changed, 42 insertions, 0 deletions
diff --git a/drivers/gpu/drm/drm_dp_helper.c b/drivers/gpu/drm/drm_dp_helper.c index f171fbf8b1b9..57c61d126a56 100644 --- a/drivers/gpu/drm/drm_dp_helper.c +++ b/drivers/gpu/drm/drm_dp_helper.c @@ -471,6 +471,48 @@ int drm_dp_downstream_max_clock(const u8 dpcd[DP_RECEIVER_CAP_SIZE], } EXPORT_SYMBOL(drm_dp_downstream_max_clock); +/** + * drm_dp_downstream_max_bpc() - extract branch device max + * bits per component + * @dpcd: DisplayPort configuration data + * @port_cap: port capabilities + * + * Returns max bpc on success or 0 if max bpc not defined + */ +int drm_dp_downstream_max_bpc(const u8 dpcd[DP_RECEIVER_CAP_SIZE], + const u8 port_cap[4]) +{ + int type = port_cap[0] & DP_DS_PORT_TYPE_MASK; + bool detailed_cap_info = dpcd[DP_DOWNSTREAMPORT_PRESENT] & + DP_DETAILED_CAP_INFO_AVAILABLE; + int bpc; + + if (!detailed_cap_info) + return 0; + + switch (type) { + case DP_DS_PORT_TYPE_VGA: + case DP_DS_PORT_TYPE_DVI: + case DP_DS_PORT_TYPE_HDMI: + case DP_DS_PORT_TYPE_DP_DUALMODE: + bpc = port_cap[2] & DP_DS_MAX_BPC_MASK; + + switch (bpc) { + case DP_DS_8BPC: + return 8; + case DP_DS_10BPC: + return 10; + case DP_DS_12BPC: + return 12; + case DP_DS_16BPC: + return 16; + } + default: + return 0; + } +} +EXPORT_SYMBOL(drm_dp_downstream_max_bpc); + /* * I2C-over-AUX implementation */ |