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| author | Jani Nikula <jani.nikula@intel.com> | 2021-09-09 15:51:56 +0300 |
|---|---|---|
| committer | Jani Nikula <jani.nikula@intel.com> | 2021-09-20 18:45:35 +0300 |
| commit | c78b4a85721f3905ba9baeac4e0bb99a36211d9b (patch) | |
| tree | c4a7290e152f7a946362f52307597535a09843e3 | |
| parent | 762520e310258aa69add29261cef106fddf8f915 (diff) | |
| download | lwn-c78b4a85721f3905ba9baeac4e0bb99a36211d9b.tar.gz lwn-c78b4a85721f3905ba9baeac4e0bb99a36211d9b.zip | |
drm/dp: add helper for extracting adjust 128b/132b TX FFE preset
The DP 2.0 128b/132b channel coding uses TX FFE presets instead of
vswing and pre-emphasis.
Cc: dri-devel@lists.freedesktop.org
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Acked-by: Maxime Ripard <mripard@kernel.org>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/4ba129c51aeb01a5f210de7026abe704a554a178.1631191763.git.jani.nikula@intel.com
| -rw-r--r-- | drivers/gpu/drm/drm_dp_helper.c | 14 | ||||
| -rw-r--r-- | include/drm/drm_dp_helper.h | 2 |
2 files changed, 16 insertions, 0 deletions
diff --git a/drivers/gpu/drm/drm_dp_helper.c b/drivers/gpu/drm/drm_dp_helper.c index 2e74b02ed96b..4d0d1e8e51fa 100644 --- a/drivers/gpu/drm/drm_dp_helper.c +++ b/drivers/gpu/drm/drm_dp_helper.c @@ -130,6 +130,20 @@ u8 drm_dp_get_adjust_request_pre_emphasis(const u8 link_status[DP_LINK_STATUS_SI } EXPORT_SYMBOL(drm_dp_get_adjust_request_pre_emphasis); +/* DP 2.0 128b/132b */ +u8 drm_dp_get_adjust_tx_ffe_preset(const u8 link_status[DP_LINK_STATUS_SIZE], + int lane) +{ + int i = DP_ADJUST_REQUEST_LANE0_1 + (lane >> 1); + int s = ((lane & 1) ? + DP_ADJUST_TX_FFE_PRESET_LANE1_SHIFT : + DP_ADJUST_TX_FFE_PRESET_LANE0_SHIFT); + u8 l = dp_link_status(link_status, i); + + return (l >> s) & 0xf; +} +EXPORT_SYMBOL(drm_dp_get_adjust_tx_ffe_preset); + u8 drm_dp_get_adjust_request_post_cursor(const u8 link_status[DP_LINK_STATUS_SIZE], unsigned int lane) { diff --git a/include/drm/drm_dp_helper.h b/include/drm/drm_dp_helper.h index f3a61341011d..3ee0b3ffb8a5 100644 --- a/include/drm/drm_dp_helper.h +++ b/include/drm/drm_dp_helper.h @@ -1494,6 +1494,8 @@ u8 drm_dp_get_adjust_request_voltage(const u8 link_status[DP_LINK_STATUS_SIZE], int lane); u8 drm_dp_get_adjust_request_pre_emphasis(const u8 link_status[DP_LINK_STATUS_SIZE], int lane); +u8 drm_dp_get_adjust_tx_ffe_preset(const u8 link_status[DP_LINK_STATUS_SIZE], + int lane); u8 drm_dp_get_adjust_request_post_cursor(const u8 link_status[DP_LINK_STATUS_SIZE], unsigned int lane); |