From: Damon Ding <damon.ding@rock-chips•com>
To: hjc@rock-chips•com, heiko@sntech•de, andy.yan@rock-chips•com,
maarten.lankhorst@linux•intel.com, mripard@kernel•org,
tzimmermann@suse•de, airlied@gmail•com, simona@ffwll•ch,
robh@kernel•org, krzk+dt@kernel•org, conor+dt@kernel•org,
andrzej.hajda@intel•com, neil.armstrong@linaro•org,
rfoss@kernel•org
Cc: Laurent.pinchart@ideasonboard•com, jonas@kwiboo•se,
jernej.skrabec@gmail•com, nicolas.frattaroli@collabora•com,
cristian.ciocaltea@collabora•com,
sebastian.reichel@collabora•com,
dmitry.baryshkov@oss•qualcomm.com, luca.ceresoli@bootlin•com,
dianders@chromium•org, m.szyprowski@samsung•com,
dri-devel@lists•freedesktop.org, devicetree@vger•kernel.org,
linux-arm-kernel@lists•infradead.org,
linux-rockchip@lists•infradead.org, linux-kernel@vger•kernel.org,
Damon Ding <damon.ding@rock-chips•com>
Subject: [PATCH v5 2/4] drm/dp: Add helper to validate DP lane counts
Date: Thu, 4 Jun 2026 16:52:18 +0800 [thread overview]
Message-ID: <20260604085220.2862986-3-damon.ding@rock-chips.com> (raw)
In-Reply-To: <20260604085220.2862986-1-damon.ding@rock-chips.com>
Add a generic helper function drm_dp_lane_count_is_valid() to check
if a DisplayPort lane count is valid. According to the DP specification,
only 1, 2, or 4 lanes are supported.
This helper avoids duplicating DP lane count validation logic across
individual DisplayPort drivers.
Suggested-by: Luca Ceresoli <luca.ceresoli@bootlin•com>
Signed-off-by: Damon Ding <damon.ding@rock-chips•com>
---
include/drm/display/drm_dp_helper.h | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/include/drm/display/drm_dp_helper.h b/include/drm/display/drm_dp_helper.h
index 8c2d77a032f0..c904cb480d84 100644
--- a/include/drm/display/drm_dp_helper.h
+++ b/include/drm/display/drm_dp_helper.h
@@ -138,6 +138,12 @@ bool drm_dp_as_sdp_supported(struct drm_dp_aux *aux, const u8 dpcd[DP_RECEIVER_C
int drm_dp_psr_setup_time(const u8 psr_cap[EDP_PSR_RECEIVER_CAP_SIZE]);
+static inline bool
+drm_dp_lane_count_is_valid(int lane_count)
+{
+ return lane_count == 1 || lane_count == 2 || lane_count == 4;
+}
+
static inline int
drm_dp_max_link_rate(const u8 dpcd[DP_RECEIVER_CAP_SIZE])
{
--
2.34.1
next prev parent reply other threads:[~2026-06-04 8:53 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-06-04 8:52 [PATCH v5 0/4] Add eDP lane mapping support Damon Ding
2026-06-04 8:52 ` [PATCH v5 1/4] dt-bindings: display: bridge: analogix-dp: Add data-lanes support for endpoint Damon Ding
2026-06-04 8:52 ` Damon Ding [this message]
2026-06-04 8:52 ` [PATCH v5 3/4] drm/bridge: analogix_dp: Add validation for samsung,lane-count property Damon Ding
2026-06-04 8:52 ` [PATCH v5 4/4] drm/bridge: analogix_dp: Add support for optional data-lanes mapping Damon Ding
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