From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 0595ACD6E4A for ; Thu, 4 Jun 2026 08:53:25 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id C02FD113DB9; Thu, 4 Jun 2026 08:53:22 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=pass (1024-bit key; unprotected) header.d=rock-chips.com header.i=@rock-chips.com header.b="ISOkaqn3"; dkim-atps=neutral Received: from mail-m9326.xmail.ntesmail.com (mail-m9326.xmail.ntesmail.com [103.126.93.26]) by gabe.freedesktop.org (Postfix) with ESMTPS id 6005F113DB9 for ; Thu, 4 Jun 2026 08:53:20 +0000 (UTC) Received: from zyb-HP-ProDesk-680-G2-MT.. (unknown [61.154.14.86]) by smtp.qiye.163.com (Hmail) with ESMTP id 410f6c9da; Thu, 4 Jun 2026 16:53:16 +0800 (GMT+08:00) From: Damon Ding 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 Subject: [PATCH v5 2/4] drm/dp: Add helper to validate DP lane counts Date: Thu, 4 Jun 2026 16:52:18 +0800 Message-Id: <20260604085220.2862986-3-damon.ding@rock-chips.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20260604085220.2862986-1-damon.ding@rock-chips.com> References: <20260604085220.2862986-1-damon.ding@rock-chips.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-HM-Tid: 0a9e91d63bbd03a8kunm52a01cd0409908 X-HM-MType: 1 X-HM-Spam-Status: e1kfGhgUHx5ZQUpXWQgPGg8OCBgUHx5ZQUlOS1dZFg8aDwILHllBWSg2Ly tZV1koWUFITzdXWRgWCB1ZQUpXWS1ZQUlXWQ8JGhUIEh9ZQVlDTktCVhkdGh1DGE4YQkoaTVYVFA kWGhdVEwETFhoSFyQUDg9ZV1kYEgtZQVlNSlVKTk9VSk9VQ01ZV1kWGg8SFR0UWUFZT0tIVUpLSE pKQk1VSktLVUpCWQY+ DKIM-Signature: a=rsa-sha256; b=ISOkaqn33xDGR1+G5j0ZVei2/HBuEVAzaVlXIYZNFH8pjcu3U5DesmPqPNH3xI8kRkuc9lksYWo2zhgHIGxFzozvq2/jyGOz45rHazQTFzXJs0heJ4v4QmH9QEv9GZMb08zLj5fMOMQkzCO4W6QdTmohhmv5cMekmME4J1EyPEI=; c=relaxed/relaxed; s=default; d=rock-chips.com; v=1; bh=9dIv0NNIoT30XW+12t9f4ox/v0SxbNDGY/P6QADqWYk=; h=date:mime-version:subject:message-id:from; X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" 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 Signed-off-by: Damon Ding --- 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