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 BFDF2C19F21 for ; Thu, 28 Jul 2022 11:46:04 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id DC4BB113364; Thu, 28 Jul 2022 11:45:43 +0000 (UTC) Received: from perceval.ideasonboard.com (perceval.ideasonboard.com [213.167.242.64]) by gabe.freedesktop.org (Postfix) with ESMTPS id 02C428BC70 for ; Thu, 28 Jul 2022 11:45:38 +0000 (UTC) Received: from [192.168.1.111] (91-158-154-79.elisa-laajakaista.fi [91.158.154.79]) by perceval.ideasonboard.com (Postfix) with ESMTPSA id AB30156D; Thu, 28 Jul 2022 13:45:36 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com; s=mail; t=1659008737; bh=3ikDa89hPYF22Nu4Eybw5k3qIbhMbiGDUev623G/ipc=; h=Date:Subject:From:To:Cc:References:In-Reply-To:From; b=efmE0csadS2tbT7C4q6dQr+rNAmoe8cpjcdCIfPwXMd4qS1Hssq/M8zc8MJxcmoty 0o4wzww9oUIU4jNuSQHvj3eMurOAqhsTOqVObvOaHPXs4hulWPgPJwrfq23L3OxPyX brrKEUw92mSMsdwOtUP/YiJZibXzdbP5D7xkeHvU= Message-ID: Date: Thu, 28 Jul 2022 14:45:34 +0300 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.11.0 Subject: Re: [PATCH 4/8] drm/tidss: Add support for Dual Link LVDS Bus Format Content-Language: en-US From: Tomi Valkeinen To: Aradhya Bhatia References: <20220719080845.22122-1-a-bhatia1@ti.com> <20220719080845.22122-5-a-bhatia1@ti.com> In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit 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: , Cc: Nishanth Menon , Devicetree List , Krzysztof Kozlowski , Vignesh Raghavendra , Devarsh Thakkar , David Airlie , Linux Kernel List , DRI Development List , Darren Etheridge , Rob Herring , Jyri Sarha , Rahul T R , Krunal Bhargav Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" On 28/07/2022 14:03, Tomi Valkeinen wrote: > On 19/07/2022 11:08, Aradhya Bhatia wrote: >> The 2 OLDI TXes in the AM625 SoC can be synced together to output a 2K >> resolution video. >> >> Add support in the driver for the discovery of such a dual mode >> connection on the OLDI video port, using the values of "ti,oldi-mode" >> property. >> >> Signed-off-by: Aradhya Bhatia >> --- >>   drivers/gpu/drm/tidss/tidss_dispc.c | 39 +++++++++++++++++++++-------- >>   1 file changed, 28 insertions(+), 11 deletions(-) >> >> diff --git a/drivers/gpu/drm/tidss/tidss_dispc.c >> b/drivers/gpu/drm/tidss/tidss_dispc.c >> index add725fa682b..fb1fdecfc83a 100644 >> --- a/drivers/gpu/drm/tidss/tidss_dispc.c >> +++ b/drivers/gpu/drm/tidss/tidss_dispc.c >> @@ -853,25 +853,36 @@ void dispc_set_irqenable(struct dispc_device >> *dispc, dispc_irq_t mask) >>       } >>   } >> -enum dispc_oldi_mode_reg_val { SPWG_18 = 0, JEIDA_24 = 1, SPWG_24 = 2 }; >> +enum dispc_oldi_mode_reg_val { >> +    SPWG_18        = 0, >> +    JEIDA_24    = 1, >> +    SPWG_24        = 2, >> +    DL_SPWG_18    = 4, >> +    DL_JEIDA_24    = 5, >> +    DL_SPWG_24    = 6, >> +}; >>   struct dispc_bus_format { >>       u32 bus_fmt; >>       u32 data_width; >>       bool is_oldi_fmt; >> +    bool is_dual_link; >>       enum dispc_oldi_mode_reg_val oldi_mode_reg_val; >>   }; >>   static const struct dispc_bus_format dispc_bus_formats[] = { >> -    { MEDIA_BUS_FMT_RGB444_1X12,        12, false, 0 }, >> -    { MEDIA_BUS_FMT_RGB565_1X16,        16, false, 0 }, >> -    { MEDIA_BUS_FMT_RGB666_1X18,        18, false, 0 }, >> -    { MEDIA_BUS_FMT_RGB888_1X24,        24, false, 0 }, >> -    { MEDIA_BUS_FMT_RGB101010_1X30,        30, false, 0 }, >> -    { MEDIA_BUS_FMT_RGB121212_1X36,        36, false, 0 }, >> -    { MEDIA_BUS_FMT_RGB666_1X7X3_SPWG,    18, true, SPWG_18 }, >> -    { MEDIA_BUS_FMT_RGB888_1X7X4_SPWG,    24, true, SPWG_24 }, >> -    { MEDIA_BUS_FMT_RGB888_1X7X4_JEIDA,    24, true, JEIDA_24 }, >> +    { MEDIA_BUS_FMT_RGB444_1X12,        12, false, false, 0 }, >> +    { MEDIA_BUS_FMT_RGB565_1X16,        16, false, false, 0 }, >> +    { MEDIA_BUS_FMT_RGB666_1X18,        18, false, false, 0 }, >> +    { MEDIA_BUS_FMT_RGB888_1X24,        24, false, false, 0 }, >> +    { MEDIA_BUS_FMT_RGB101010_1X30,        30, false, false, 0 }, >> +    { MEDIA_BUS_FMT_RGB121212_1X36,        36, false, false, 0 }, >> +    { MEDIA_BUS_FMT_RGB666_1X7X3_SPWG,    18, true, false, SPWG_18 }, >> +    { MEDIA_BUS_FMT_RGB888_1X7X4_SPWG,    24, true, false, SPWG_24 }, >> +    { MEDIA_BUS_FMT_RGB888_1X7X4_JEIDA,    24, true, false, JEIDA_24 }, >> +    { MEDIA_BUS_FMT_RGB666_1X7X3_SPWG,    18, true, true, DL_SPWG_18 }, >> +    { MEDIA_BUS_FMT_RGB888_1X7X4_SPWG,    24, true, true, DL_SPWG_24 }, >> +    { MEDIA_BUS_FMT_RGB888_1X7X4_JEIDA,    24, true, true, >> DL_JEIDA_24 }, >>   }; > > So the dual link sends two pixels per clock, right? Are there panel or > bridge drivers that support this? My initial thought was that it should > be a new bus format. Looks like we have drm bridges supporting dual link, and they use the "normal" bus format. Did you have a look at them? They require two port nodes for dual link, and use the existence of the second one to decide if dual link is used or not. There are also lvds helpers in drm_of.c. I didn't look closely, but it looked to me that the helpers can tell you if the ports are connected to a dual link bridge. If not, you could fall back to cloning. This way no extra properties are needed. But you will need to add a port node, which I think you need to add anyway for cloning. Tomi