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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (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 BBBC5C44529 for ; Tue, 21 Jul 2026 10:01:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Type: Content-Transfer-Encoding:MIME-Version:References:In-Reply-To:Message-ID:Date :Subject:Cc:To:From:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=gvD5V6euci/as5s5zTLUVH7L6MHGtAjyvBUswRosovo=; b=NB3F0g1ZECWdyUEIhnQPsBZY2a r0Pi3CAB8QD2RMtoYWEnN+YZx4wS67BJaTTCjSY/SziMojotU5DV2EQr8PPf0kobNknjWX4b2uoXX tEvPoXuY2ZRP/YtaHqvAbH1Xe/SPIuSY5x5TnTk2iG+N7w2TXgXCFu4HhxeIfe6w/d3wH/in5R084 R9GboQBy1jxUNzsUE246g8+ZrndIEW/9Zl3iXVvSWnrCCroBYE+VSeu5XAvVNF1a53xgUy33A/OKl vJ0BxSZng/q3XJg8xkl75hiOnxFb3M1DzLT01zk0CnwDnLteAkl2/N3aZBKuFSlNzxbD/gi/zns74 erbPL33A==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1wm6OK-00000008uu4-342G; Tue, 21 Jul 2026 09:03:56 +0000 Received: from www537.your-server.de ([188.40.3.216]) by bombadil.infradead.org with esmtps (Exim 4.99.1 #2 (Red Hat Linux)) id 1wm6OI-00000008ut1-2lhA for linux-arm-kernel@lists.infradead.org; Tue, 21 Jul 2026 09:03:56 +0000 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=ew.tq-group.com; s=default2602; h=Content-Type:Content-Transfer-Encoding: MIME-Version:References:In-Reply-To:Message-ID:Date:Subject:Cc:To:From:Sender :Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID; bh=gvD5V6euci/as5s5zTLUVH7L6MHGtAjyvBUswRosovo=; b=nlQug6It0yWWP0ig82UACxhpY5 BPz//xjoUN8R4diTMfMEE90uKWveEm21wF1fq/MaXTyyW0XvpsEw3yBU+OBZfnDreWAzeypeiC/xk nv8esCdDuXYhg+pxr0Z5eYOGL1rsG+vC/5HsIAu5uwlNyCKqqozbYAMlLIHgnKTxKOzL1ZZz3DjM9 lf5bO9Joan0ciIZUhhliKUuIfCGX/fPRcLezrBhb04VTlfFx/Bc5K0SFzGaB0Q1z8EbZgRa7aTlvx 28VzfWLihuqotKAX5NKwUCJqfdKWEgRvEti4jlPu491z4JarfwI1ZtDv+ZqUX6WiooDziq0NWIcWu 4doW2p9A==; Received: from sslproxy01.your-server.de ([78.46.139.224]) by www537.your-server.de with esmtpsa (TLS1.3) tls TLS_AES_256_GCM_SHA384 (Exim 4.96.2) (envelope-from ) id 1wm6OE-000DCG-0S; Tue, 21 Jul 2026 11:03:50 +0200 Received: from localhost ([127.0.0.1]) by sslproxy01.your-server.de with esmtpsa (TLS1.3) tls TLS_AES_256_GCM_SHA384 (Exim 4.96) (envelope-from ) id 1wm6OD-000NUe-1r; Tue, 21 Jul 2026 11:03:49 +0200 From: Alexander Stein To: Marek Vasut , Stefan Agner , David Airlie , Simona Vetter , Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , Rob Herring , Krzysztof Kozlowski , Conor Dooley , Frank Li , Sascha Hauer , Pengutronix Kernel Team , Fabio Estevam , dri-devel@lists.freedesktop.org Cc: Francesco Dolcini , dri-devel@lists.freedesktop.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, imx@lists.linux.dev, linux-arm-kernel@lists.infradead.org, Francesco Dolcini Subject: Re: [PATCH v1 2/4] drm: mxsfb: Allow optional LCDIF interface format override Date: Tue, 21 Jul 2026 11:03:48 +0200 Message-ID: <5121074.31r3eYUQgx@steina-w> Organization: TQ-Systems GmbH In-Reply-To: <20260717121847.488148-3-francesco@dolcini.it> References: <20260717121847.488148-1-francesco@dolcini.it> <20260717121847.488148-3-francesco@dolcini.it> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="iso-8859-1" X-Virus-Scanned: Clear (ClamAV 1.4.3/28067/Tue Jul 21 08:23:56 2026) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260721_020354_808269_5C147E82 X-CRM114-Status: GOOD ( 24.31 ) 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 Hi Francesco, thanks for the patch. Am Freitag, 17. Juli 2026, 14:18:44 CEST schrieb Francesco Dolcini: > From: Francesco Dolcini >=20 > LCDIF programs LCD_DATABUS_WIDTH from the selected media bus format. The > format reported by the downstream panel or bridge describes the display > input, but it does not describe how the LCDIF data pins are physically > wired on the board. >=20 > These can differ. For example, a 16-bit LCDIF bus can be connected to a > 24-bit display by wiring the available color bits to the corresponding > display inputs. In that case, using the display's 24-bit format to > configure LCDIF selects the wrong data-bus mode and changes the assignment > of color bits on the LCD_DATA pins. >=20 > Read the optional interface-pix-fmt property from the LCDIF node and use > it to select the media bus format used to configure LCDIF. This allows > the LCDIF bus mode to describe the physical interface independently of > the downstream display format. >=20 > When the optional property is absent, continue using the format reported > by the downstream display device, preserving the existing behavior. >=20 > This follows the same approach already implemented in > drivers/gpu/drm/imx/ipuv3/parallel-display.c. >=20 > Signed-off-by: Francesco Dolcini Nice, this work on my imx6ul based hardware where a 18-bit display is attached as a 24-bit one. Using interface-pix-fmt =3D "rgb24" this works as expected. Tested-by: Alexander Stein > --- > drivers/gpu/drm/mxsfb/mxsfb_drv.c | 16 ++++++++++++++++ > drivers/gpu/drm/mxsfb/mxsfb_drv.h | 2 ++ > drivers/gpu/drm/mxsfb/mxsfb_kms.c | 8 ++++++++ > 3 files changed, 26 insertions(+) >=20 > diff --git a/drivers/gpu/drm/mxsfb/mxsfb_drv.c b/drivers/gpu/drm/mxsfb/mx= sfb_drv.c > index 9b8fbda85d28..edf347968fd2 100644 > --- a/drivers/gpu/drm/mxsfb/mxsfb_drv.c > +++ b/drivers/gpu/drm/mxsfb/mxsfb_drv.c > @@ -12,7 +12,9 @@ > #include > #include > #include > +#include > #include > +#include > #include > #include > #include > @@ -209,7 +211,10 @@ static int mxsfb_load(struct drm_device *drm, > const struct mxsfb_devdata *devdata) > { > struct platform_device *pdev =3D to_platform_device(drm->dev); > + struct device_node *np =3D pdev->dev.of_node; > struct mxsfb_drm_private *mxsfb; > + u32 bus_format =3D 0; > + const char *fmt; > int ret; > =20 > mxsfb =3D devm_kzalloc(&pdev->dev, sizeof(*mxsfb), GFP_KERNEL); > @@ -236,6 +241,17 @@ static int mxsfb_load(struct drm_device *drm, > if (IS_ERR(mxsfb->clk_disp_axi)) > mxsfb->clk_disp_axi =3D NULL; > =20 > + ret =3D of_property_read_string(np, "interface-pix-fmt", &fmt); > + if (!ret) { > + if (!strcmp(fmt, "rgb24")) > + bus_format =3D MEDIA_BUS_FMT_RGB888_1X24; > + else if (!strcmp(fmt, "rgb565")) > + bus_format =3D MEDIA_BUS_FMT_RGB565_1X16; > + else if (!strcmp(fmt, "rgb666")) > + bus_format =3D MEDIA_BUS_FMT_RGB666_1X18; > + } > + mxsfb->bus_format =3D bus_format; > + > ret =3D dma_set_mask_and_coherent(drm->dev, DMA_BIT_MASK(32)); > if (ret) > return ret; > diff --git a/drivers/gpu/drm/mxsfb/mxsfb_drv.h b/drivers/gpu/drm/mxsfb/mx= sfb_drv.h > index d160d921b25f..f64800f06a69 100644 > --- a/drivers/gpu/drm/mxsfb/mxsfb_drv.h > +++ b/drivers/gpu/drm/mxsfb/mxsfb_drv.h > @@ -46,6 +46,8 @@ struct mxsfb_drm_private { > struct drm_connector *connector; > struct drm_bridge *bridge; > =20 > + u32 bus_format; Indent broken. > + > bool crc_active; > }; > =20 > diff --git a/drivers/gpu/drm/mxsfb/mxsfb_kms.c b/drivers/gpu/drm/mxsfb/mx= sfb_kms.c > index d8ebebc5314b..8b482727aed5 100644 > --- a/drivers/gpu/drm/mxsfb/mxsfb_kms.c > +++ b/drivers/gpu/drm/mxsfb/mxsfb_kms.c > @@ -386,6 +386,14 @@ static void mxsfb_crtc_atomic_enable(struct drm_crtc= *crtc, > if (!bus_format) > bus_format =3D MEDIA_BUS_FMT_RGB888_1X24; > =20 > + /* > + * Prefer bus format set via optional "interface-pix-fmt" DT property, > + * over panel or next bridge bus format. This is necessary to support > + * 24bit DPI panels connected to a 18bit interface, for example. Maybe rephrase and state "mismatching interface" as it goes both ways. Best regards, Alexander > + */ > + if (mxsfb->bus_format) > + bus_format =3D mxsfb->bus_format; > + > mxsfb_crtc_mode_set_nofb(mxsfb, bridge_state, bus_format); > =20 > /* Write cur_buf as well to avoid an initial corrupt frame */ >=20 =2D-=20 TQ-Systems GmbH | M=FChlstra=DFe 2, Gut Delling | 82229 Seefeld, Germany Amtsgericht M=FCnchen, HRB 105018 Gesch=E4ftsf=FChrer: Detlef Schneider, R=FCdiger Stahl, Stefan Schneider http://www.tq-group.com/