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(unknown [61.154.14.86]) by smtp.qiye.163.com (Hmail) with ESMTP id 452ef5832; Tue, 7 Jul 2026 12:07:19 +0800 (GMT+08:00) From: Damon Ding To: Andrzej Hajda , Neil Armstrong , Robert Foss , Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , David Airlie , Simona Vetter , Rob Herring , Krzysztof Kozlowski , Conor Dooley , Sandy Huang , =?UTF-8?q?Heiko=20St=C3=BCbner?= , Andy Yan Cc: Laurent Pinchart , Jonas Karlman , Jernej Skrabec , Luca Ceresoli , Dmitry Baryshkov , Marek Szyprowski , Sebastian Reichel , 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 Subject: [PATCH v6 2/5] drm/dp: Add helper to validate DP lane counts Date: Tue, 7 Jul 2026 12:06:10 +0800 Message-Id: <20260707040613.1992841-3-damon.ding@rock-chips.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20260707040613.1992841-1-damon.ding@rock-chips.com> References: <20260707040613.1992841-1-damon.ding@rock-chips.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-HM-Tid: 0a9f3ac2496a03a8kunme8126cdf5bc75 X-HM-MType: 1 X-HM-Spam-Status: e1kfGhgUHx5ZQUpXWQgPGg8OCBgUHx5ZQUlOS1dZFg8aDwILHllBWSg2Ly tZV1koWUFITzdXWRgWCB1ZQUpXWS1ZQUlXWQ8JGhUIEh9ZQVkZSx5IVkpLShhJTx8aSUlLQ1YVFA kWGhdVEwETFhoSFyQUDg9ZV1kYEgtZQVlNSlVKTk9VSk9VQ01ZV1kWGg8SFR0UWUFZT0tIVUpLSU 9PT0hVSktLVUpCS0tZBg++ DKIM-Signature: a=rsa-sha256; b=koHL70Yy2rbsbm3CZpRjj1j7EvlqXB+rZQYjLgINLySwtAydfj4S9JTkFzxf/5EJlc+Swz77+y9xAcP5ImC6cAShrhGRV7xfwA2AvixN3v8RmxyYLNbwyDOTkY7X2bAH97IVc0fLNb7RX8bLHRqmQE7TWqPkujYnCmTvL9sGewU=; c=relaxed/relaxed; s=default; d=rock-chips.com; v=1; bh=lWH0Sk73+0p13PY6uyYH4gl84FiS6O5rP+nrrrsCjNY=; h=date:mime-version:subject:message-id:from; X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260706_210723_347736_C8A4D722 X-CRM114-Status: UNSURE ( 6.60 ) X-CRM114-Notice: Please train this message. X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org 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 Reviewed-by: Luca Ceresoli Signed-off-by: Damon Ding --- 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 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