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From: Thierry Reding <thierry.reding@gmail.com>
To: dri-devel@lists.freedesktop.org
Subject: [PATCH v2 15/21] drm/dp: Add helper to get post-cursor adjustments
Date: Mon,  2 Sep 2019 13:31:15 +0200	[thread overview]
Message-ID: <20190902113121.31323-16-thierry.reding@gmail.com> (raw)
In-Reply-To: <20190902113121.31323-1-thierry.reding@gmail.com>

From: Thierry Reding <treding@nvidia.com>

If the transmitter supports pre-emphasis post cursor2 the sink will
request adjustments in a similar way to how it requests adjustments to
the voltage swing and pre-emphasis settings.

Add a helper to extract these adjustments on a per-lane basis from the
DPCD link status.

Reviewed-by: Philipp Zabel <p.zabel@pengutronix.de>
Signed-off-by: Thierry Reding <treding@nvidia.com>
---
 drivers/gpu/drm/drm_dp_helper.c | 10 ++++++++++
 include/drm/drm_dp_helper.h     | 10 ++++++++++
 2 files changed, 20 insertions(+)

diff --git a/drivers/gpu/drm/drm_dp_helper.c b/drivers/gpu/drm/drm_dp_helper.c
index 1fb3c27cd012..f1f3705fade9 100644
--- a/drivers/gpu/drm/drm_dp_helper.c
+++ b/drivers/gpu/drm/drm_dp_helper.c
@@ -120,6 +120,16 @@ 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);
 
+u8 drm_dp_get_adjust_request_post_cursor(const u8 link_status[DP_LINK_STATUS_SIZE],
+					 unsigned int lane)
+{
+	unsigned int offset = DP_ADJUST_REQUEST_POST_CURSOR2;
+	u8 value = dp_link_status(link_status, offset);
+
+	return (value >> (lane << 1)) & 0x3;
+}
+EXPORT_SYMBOL(drm_dp_get_adjust_request_post_cursor);
+
 void drm_dp_link_train_clock_recovery_delay(const u8 dpcd[DP_RECEIVER_CAP_SIZE])
 {
 	unsigned int rd_interval = drm_dp_aux_rd_interval(dpcd);
diff --git a/include/drm/drm_dp_helper.h b/include/drm/drm_dp_helper.h
index e28b0941a8be..5d262a453878 100644
--- a/include/drm/drm_dp_helper.h
+++ b/include/drm/drm_dp_helper.h
@@ -566,6 +566,14 @@
 # define DP_ADJUST_PRE_EMPHASIS_LANE1_SHIFT  6
 
 #define DP_ADJUST_REQUEST_POST_CURSOR2      0x20c
+# define DP_ADJUST_POST_CURSOR2_LANE0_MASK  0x03
+# define DP_ADJUST_POST_CURSOR2_LANE0_SHIFT 0
+# define DP_ADJUST_POST_CURSOR2_LANE1_MASK  0x0c
+# define DP_ADJUST_POST_CURSOR2_LANE1_SHIFT 2
+# define DP_ADJUST_POST_CURSOR2_LANE2_MASK  0x30
+# define DP_ADJUST_POST_CURSOR2_LANE2_SHIFT 4
+# define DP_ADJUST_POST_CURSOR2_LANE3_MASK  0xc0
+# define DP_ADJUST_POST_CURSOR2_LANE3_SHIFT 6
 
 #define DP_TEST_REQUEST			    0x218
 # define DP_TEST_LINK_TRAINING		    (1 << 0)
@@ -1053,6 +1061,8 @@ 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_request_post_cursor(const u8 link_status[DP_LINK_STATUS_SIZE],
+					 unsigned int lane);
 
 #define DP_BRANCH_OUI_HEADER_SIZE	0xc
 #define DP_RECEIVER_CAP_SIZE		0xf
-- 
2.22.0

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  parent reply	other threads:[~2019-09-02 11:31 UTC|newest]

Thread overview: 28+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-09-02 11:31 [PATCH v2 00/21] drm/dp: Various helper improvements and cleanups Thierry Reding
2019-09-02 11:31 ` [PATCH v2 01/21] drm/dp: Sort includes alphabetically Thierry Reding
2019-09-02 11:31 ` [PATCH v2 02/21] drm/dp: Add missing kerneldoc for struct drm_dp_link Thierry Reding
2019-09-02 11:31 ` [PATCH v2 03/21] drm/dp: Add drm_dp_link_reset() implementation Thierry Reding
2019-09-02 11:31 ` [PATCH v2 04/21] drm/dp: Track link capabilities alongside settings Thierry Reding
2019-09-02 11:31 ` [PATCH v2 05/21] drm/dp: Turn link capabilities into booleans Thierry Reding
2019-09-02 11:31 ` [PATCH v2 06/21] drm/dp: Probe link using existing parsing helpers Thierry Reding
2019-09-02 11:31 ` [PATCH v2 07/21] drm/dp: Read fast training capability from link Thierry Reding
2019-09-02 11:31 ` [PATCH v2 08/21] drm/dp: Read TPS3 capability from sink Thierry Reding
2019-09-02 11:31 ` [PATCH v2 09/21] drm/dp: Read channel coding " Thierry Reding
2019-09-02 11:31 ` [PATCH v2 10/21] drm/dp: Read alternate scrambler reset " Thierry Reding
2019-09-02 11:31 ` [PATCH v2 11/21] drm/dp: Read eDP version from DPCD Thierry Reding
2019-09-02 11:31 ` [PATCH v2 12/21] drm/dp: Read AUX read interval " Thierry Reding
2019-09-02 11:31 ` [PATCH v2 13/21] drm/dp: Do not busy-loop during link training Thierry Reding
2019-09-02 11:31 ` [PATCH v2 14/21] drm/dp: Use drm_dp_aux_rd_interval() Thierry Reding
2019-09-02 11:31 ` Thierry Reding [this message]
2019-09-02 11:31 ` [PATCH v2 16/21] drm/dp: Set channel coding on link configuration Thierry Reding
2019-09-02 11:31 ` [PATCH v2 17/21] drm/dp: Enable alternate scrambler reset when supported Thierry Reding
2019-09-02 11:31 ` [PATCH v2 18/21] drm/dp: Add drm_dp_link_choose() helper Thierry Reding
2019-09-02 11:31 ` [PATCH v2 19/21] drm/dp: Add support for eDP link rates Thierry Reding
2019-09-02 11:31 ` [PATCH v2 20/21] drm/dp: Remove a gratuituous blank line Thierry Reding
2019-09-02 11:31 ` [PATCH v2 21/21] drm/bridge: tc358767: Use DP nomenclature Thierry Reding
2019-09-20 16:00 ` [PATCH v2 00/21] drm/dp: Various helper improvements and cleanups Thierry Reding
2019-09-23 13:52   ` Jani Nikula
2019-09-23 14:52     ` Thierry Reding
2019-10-02 16:14       ` Thierry Reding
2019-10-08  9:42         ` Daniel Vetter
2019-10-08 23:05   ` Lyude Paul

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