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 X-Spam-Level: X-Spam-Status: No, score=-3.0 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS, URIBL_BLOCKED,USER_AGENT_NEOMUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7DD8EC4360F for ; Tue, 2 Apr 2019 14:40:15 +0000 (UTC) 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 mail.kernel.org (Postfix) with ESMTPS id 4E09120882 for ; Tue, 2 Apr 2019 14:40:15 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="mvj1+fuX" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 4E09120882 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=bootlin.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender:Content-Type:Cc: List-Subscribe:List-Help:List-Post:List-Archive:List-Unsubscribe:List-Id: In-Reply-To:MIME-Version:References:Message-ID:Subject:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=NkCbOXJTUslgyhsQLXUMPdOfKDQAoLX7uny52KlBoXc=; b=mvj1+fuXBWdQMv47Y17iSwnZG KTz4c9qHwA5w9bxfMljmsGxbQkdFUeFLuBO89XMlBdQJg8xIqGYupXk7VfcnlU+Ap+XjAHog9sirf m/rVj1A3CxYY/sSmAUputOK8gc+Ey11dSKHAXpAv1DxuflEa7kebQ4uLW21rgkZpj49HiRI7bitfs WzZs/9h/pU95kFGNMWwiX6Z15grz0KY/AvYFfVMC5cLL/srVfNFgzAcxoYdG8eUUtfXaJE/9a1TTs IynTCyzW1dXzxsvpD37ZZE/u/AYLeUmF98ak3PBRnx2ZdyFfAkZCIJbO4emgbdYjAMC/OtWOqtIY/ sS4ybag6w==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1hBKa8-0007Fb-7D; Tue, 02 Apr 2019 14:40:08 +0000 Received: from relay3-d.mail.gandi.net ([217.70.183.195]) by bombadil.infradead.org with esmtps (Exim 4.90_1 #2 (Red Hat Linux)) id 1hBKa3-0006M5-Qm for linux-arm-kernel@lists.infradead.org; Tue, 02 Apr 2019 14:40:06 +0000 X-Originating-IP: 90.88.30.125 Received: from localhost (aaubervilliers-681-1-89-125.w90-88.abo.wanadoo.fr [90.88.30.125]) (Authenticated sender: maxime.ripard@bootlin.com) by relay3-d.mail.gandi.net (Postfix) with ESMTPSA id B431760028; Tue, 2 Apr 2019 14:39:56 +0000 (UTC) Date: Tue, 2 Apr 2019 16:39:56 +0200 From: Maxime Ripard To: Jagan Teki Subject: Re: [PATCH v8 02/15] drm/sun4i: tcon: Compute DCLK dividers based on format, lanes Message-ID: <20190402143956.xu2yuyfditx5pbvw@flea> References: <20190311133637.18334-1-jagan@amarulasolutions.com> <20190311133637.18334-3-jagan@amarulasolutions.com> <20190311153847.oz6ruqmptaq2befn@flea> <20190319105307.omowzyhqu33e3pzy@flea> MIME-Version: 1.0 In-Reply-To: User-Agent: NeoMutt/20180716 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20190402_074004_199621_EECEC9C0 X-CRM114-Status: GOOD ( 24.58 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Mark Rutland , devicetree , David Airlie , Michael Turquette , linux-sunxi , linux-kernel , dri-devel , Chen-Yu Tsai , Rob Herring , Daniel Vetter , Michael Trimarchi , linux-amarula@amarulasolutions.com, linux-clk , linux-arm-kernel Content-Type: multipart/mixed; boundary="===============0562166706840275180==" Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org --===============0562166706840275180== Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="bq55zguk5gxjx22z" Content-Disposition: inline --bq55zguk5gxjx22z Content-Type: text/plain; charset=us-ascii Content-Disposition: inline On Thu, Mar 21, 2019 at 07:40:32PM +0530, Jagan Teki wrote: > On Tue, Mar 19, 2019 at 4:23 PM Maxime Ripard wrote: > > > > On Mon, Mar 11, 2019 at 09:36:27PM +0530, Jagan Teki wrote: > > > On Mon, Mar 11, 2019 at 9:08 PM Maxime Ripard wrote: > > > > > > > > On Mon, Mar 11, 2019 at 07:06:24PM +0530, Jagan Teki wrote: > > > > > pll-video => pll-mipi => tcon0 => tcon0-pixel-clock is the typical > > > > > MIPI clock topology in Allwinner DSI controller. > > > > > > > > > > TCON dotclock driver is computing the desired DCLK divider based on > > > > > panel pixel clock along with input DCLK min, max divider values from > > > > > tcon driver and that would eventually set the pll-mipi clock rate. > > > > > > > > > > The current code allows the TCON clock divider to have a default 4 > > > > > for min, max ranges that would fail to compute the desired pll-mipi > > > > > rate while supporting new panels. > > > > > > > > > > So, add the computation logic 'format/lanes' to dclk min and max dividers > > > > > and instead of default 4. This computation logic align with Allwinner A64 > > > > > BSP, hoping that would work even for A33. > > > > > > > > Last time we discussed this, we found out that this wasn't the case, > > > > even in the BSP. > > > > > > This was the case for BSP to compute pll-mipi not for TCON_DSI clock > > > register, SUN4I_TCON0_DCLK_REG, which marked the divider 4 by default. > > > > > > > What compelling evidence have you found that makes you say otherwise? > > > > > > divider 4 isn't worked, this I would mentioned before as well. > > > > Maybe you mentionned it before, but it's nowhere to be found in your > > commit log. > > I have added it in 3rd paragraph in commit message, may be you missed > it or you may look for different text. > > "The current code allows the TCON clock divider to have a default 4 > for min, max ranges that would fail to compute the desired pll-mipi > rate while supporting new panels." And you're still not explaining *why* that is an issue, and what makes you think that your solution is the right one. Seriously, I feel like this discussion is going in circles. I've been asking for that since your very first version. > > > Tested this on 4 different panels, and below are the desired divider values > > > and pll-mipi clock rate with respect to pixel clock frequency. > > > > > > - 55MHz pixel clock with 4-lane panel, and the desired DSI clock divider > > > is 6 with the output parent clock rate of 330MHz. > > > - 30MHz pixel clock with 4-lane panel, and the desired DSI clock divider > > > is 6 with parent clock rate of 180MHz. > > > - 27.5Mhz pixel clock with 2-lane pane, and the desired DSI clock divider > > > is 12 with the output parent clock rate of 330MHz. > > > - 147MHz pixel clock with 4-lane panel, and the desired DSI clock divider > > > is 6 with the output parent clock rate of 882MHz. > > > > > > BSP trying to use this format/lane to compute dsi divider that in-turn > > > using pll-mipi set_rate but TCON0_DCLK_REG keep constant 4. > > > > Feel free to reply to > > http://lists.infradead.org/pipermail/linux-arm-kernel/2019-February/629596.html > > Yes, I have replied at that time itself, please check. > > http://lists.infradead.org/pipermail/linux-arm-kernel/2019-February/629673.html > > Here I have taken the pixel clock to 30Mhz for example in Bananapi > panel, and the above gist the pixel is 148Mhz from another panel. Again, without providing any reference, just making vague statements. Maxime -- Maxime Ripard, Bootlin Embedded Linux and Kernel engineering https://bootlin.com --bq55zguk5gxjx22z Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iHUEABYIAB0WIQRcEzekXsqa64kGDp7j7w1vZxhRxQUCXKN0OwAKCRDj7w1vZxhR xVZbAP96ZzoBDc0Pt7lVSk9TviBgP7GCQGg3+WuSAYt9gqUgzgEAlxzjZ38oRP0f FML4gjhqwD8TrJt2HZ3R2m0zWQrMLAM= =qO40 -----END PGP SIGNATURE----- --bq55zguk5gxjx22z-- --===============0562166706840275180== Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Disposition: inline _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel --===============0562166706840275180==--