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From: Damon Ding <damon.ding@rock-chips.com>
To: Andrzej Hajda <andrzej.hajda@intel.com>,
	Neil Armstrong <neil.armstrong@linaro.org>,
	Robert Foss <rfoss@kernel.org>,
	Maarten Lankhorst <maarten.lankhorst@linux.intel.com>,
	Maxime Ripard <mripard@kernel.org>,
	Thomas Zimmermann <tzimmermann@suse.de>,
	David Airlie <airlied@gmail.com>, Simona Vetter <simona@ffwll.ch>,
	Rob Herring <robh@kernel.org>,
	Krzysztof Kozlowski <krzk+dt@kernel.org>,
	Conor Dooley <conor+dt@kernel.org>,
	Sandy Huang <hjc@rock-chips.com>,
	Heiko Stuebner <heiko@sntech.de>,
	Andy Yan <andy.yan@rock-chips.com>
Cc: Laurent Pinchart <Laurent.pinchart@ideasonboard.com>,
	Jonas Karlman <jonas@kwiboo.se>,
	Jernej Skrabec <jernej.skrabec@gmail.com>,
	Luca Ceresoli <luca.ceresoli@bootlin.com>,
	Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>,
	Marek Szyprowski <m.szyprowski@samsung.com>,
	Sebastian Reichel <sebastian.reichel@collabora.com>,
	dri-devel@lists.freedesktop.org, devicetree@vger.kernel.org,
	linux-kernel@vger.kernel.org, linux-rockchip@lists.infradead.org,
	linux-arm-kernel@lists.infradead.org,
	Damon Ding <damon.ding@rock-chips.com>
Subject: [PATCH v8 2/5] drm/dp: Add helper to validate DP lane counts
Date: Fri, 28 Aug 2026 14:51:50 +0800	[thread overview]
Message-ID: <20260828065153.590802-3-damon.ding@rock-chips.com> (raw)
In-Reply-To: <20260828065153.590802-1-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>
Reviewed-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
Signed-off-by: Damon Ding <damon.ding@rock-chips.com>

---

Changes in v6:
- Add Reviewed-by tag.
---
 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 ab16c1be3900..5b05a7fbe174 100644
--- a/include/drm/display/drm_dp_helper.h
+++ b/include/drm/display/drm_dp_helper.h
@@ -139,6 +139,12 @@ 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


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WARNING: multiple messages have this Message-ID (diff)
From: Damon Ding <damon.ding@rock-chips.com>
To: Andrzej Hajda <andrzej.hajda@intel.com>,
	Neil Armstrong <neil.armstrong@linaro.org>,
	Robert Foss <rfoss@kernel.org>,
	Maarten Lankhorst <maarten.lankhorst@linux.intel.com>,
	Maxime Ripard <mripard@kernel.org>,
	Thomas Zimmermann <tzimmermann@suse.de>,
	David Airlie <airlied@gmail.com>, Simona Vetter <simona@ffwll.ch>,
	Rob Herring <robh@kernel.org>,
	Krzysztof Kozlowski <krzk+dt@kernel.org>,
	Conor Dooley <conor+dt@kernel.org>,
	Sandy Huang <hjc@rock-chips.com>,
	Heiko Stuebner <heiko@sntech.de>,
	Andy Yan <andy.yan@rock-chips.com>
Cc: Laurent Pinchart <Laurent.pinchart@ideasonboard.com>,
	Jonas Karlman <jonas@kwiboo.se>,
	Jernej Skrabec <jernej.skrabec@gmail.com>,
	Luca Ceresoli <luca.ceresoli@bootlin.com>,
	Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>,
	Marek Szyprowski <m.szyprowski@samsung.com>,
	Sebastian Reichel <sebastian.reichel@collabora.com>,
	dri-devel@lists.freedesktop.org, devicetree@vger.kernel.org,
	linux-kernel@vger.kernel.org, linux-rockchip@lists.infradead.org,
	linux-arm-kernel@lists.infradead.org,
	Damon Ding <damon.ding@rock-chips.com>
Subject: [PATCH v8 2/5] drm/dp: Add helper to validate DP lane counts
Date: Fri, 28 Aug 2026 14:51:50 +0800	[thread overview]
Message-ID: <20260828065153.590802-3-damon.ding@rock-chips.com> (raw)
In-Reply-To: <20260828065153.590802-1-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>
Reviewed-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
Signed-off-by: Damon Ding <damon.ding@rock-chips.com>

---

Changes in v6:
- Add Reviewed-by tag.
---
 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 ab16c1be3900..5b05a7fbe174 100644
--- a/include/drm/display/drm_dp_helper.h
+++ b/include/drm/display/drm_dp_helper.h
@@ -139,6 +139,12 @@ 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



  parent reply	other threads:[~2026-08-28  6:52 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-08-28  6:51 [PATCH v8 0/5] Add eDP lane mapping support Damon Ding
2026-08-28  6:51 ` Damon Ding
2026-08-28  6:51 ` [PATCH v8 1/5] dt-bindings: display: bridge: analogix-dp: Add data-lanes support for endpoint Damon Ding
2026-08-28  6:51   ` Damon Ding
2026-08-28  6:51 ` Damon Ding [this message]
2026-08-28  6:51   ` [PATCH v8 2/5] drm/dp: Add helper to validate DP lane counts Damon Ding
2026-08-28  6:51 ` [PATCH v8 3/5] drm/bridge: analogix_dp: Restore mandatory samsung DP DT properties Damon Ding
2026-08-28  6:51   ` Damon Ding
2026-08-28  6:51 ` [PATCH v8 4/5] drm/bridge: analogix_dp: Add validation for samsung, lane-count property Damon Ding
2026-08-28  6:51   ` [PATCH v8 4/5] drm/bridge: analogix_dp: Add validation for samsung,lane-count property Damon Ding
2026-08-28  6:51   ` Damon Ding
2026-08-28  7:02   ` sashiko-bot
2026-08-28  6:51 ` [PATCH v8 5/5] drm/bridge: analogix_dp: Add support for optional data-lanes mapping Damon Ding
2026-08-28  6:51   ` Damon Ding
2026-08-28  7:02   ` sashiko-bot

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