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=-3.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=no 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 5B8F4C433E0 for ; Thu, 11 Jun 2020 11:15:20 +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 2CF022063A for ; Thu, 11 Jun 2020 11:15:20 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="YSi5trCK" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 2CF022063A Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=suse.de 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: MIME-Version:References:In-Reply-To:Date:To:From:Subject:Message-ID: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=JLQZZUna+K8qI2zAQEPdve8cRXLonajYzzHvZXsyqKI=; b=YSi5trCKg7IbY0/ce95c7uZUG IzZKVJ0CapQWiCRgiZwlL3y4HiL/la5Jwnt/Ie8T30NsUQJ1Pbm9ufTxBTPsvoEog6SkLHwmef7yy 1scxuZDr6w9RIS2nGfXECUoY1LnHh/v/F0xABdJNjZbeX2gnR1bJiaU2hbYQOEnFuPYxAST7V3hNz RTB/F1MUnX+jhs9bwli9DXCPnvIbDz56+F517ENZgHLWrh7sKtdKegg09N+EdWaiNe++ETbjO/IOI Iuq62B5PjU+U0L4u2q/0kBDLzyT+MP6PqBX/D7rg9ba65eEdhQXCw2Vu2DritfyAgmbkvA1IV37Dc DM8r3p8oA==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1jjLAs-0002NE-LU; Thu, 11 Jun 2020 11:15:10 +0000 Received: from mx2.suse.de ([195.135.220.15]) by bombadil.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1jjLAp-0002MJ-2v; Thu, 11 Jun 2020 11:15:08 +0000 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx2.suse.de (Postfix) with ESMTP id A4284AAC6; Thu, 11 Jun 2020 11:15:04 +0000 (UTC) Message-ID: <7cf4a213862145abd8e0368b669aab39112ffaeb.camel@suse.de> Subject: Re: [PATCH v4 21/27] clk: bcm: rpi: Discover the firmware clocks From: Nicolas Saenz Julienne To: Maxime Ripard Date: Thu, 11 Jun 2020 13:14:58 +0200 In-Reply-To: <40ab5a9718000636a513d374e7579e2d2b57f961.1591860665.git-series.maxime@cerno.tech> References: <40ab5a9718000636a513d374e7579e2d2b57f961.1591860665.git-series.maxime@cerno.tech> User-Agent: Evolution 3.36.2 MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200611_041507_276573_CC14CED2 X-CRM114-Status: GOOD ( 15.92 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Tim Gover , Dave Stevenson , Stephen Boyd , Mike Turquette , linux-kernel@vger.kernel.org, linux-clk@vger.kernel.org, bcm-kernel-feedback-list@broadcom.com, linux-rpi-kernel@lists.infradead.org, Phil Elwell , linux-arm-kernel@lists.infradead.org Content-Type: multipart/mixed; boundary="===============5823513801403321020==" Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org --===============5823513801403321020== Content-Type: multipart/signed; micalg="pgp-sha256"; protocol="application/pgp-signature"; boundary="=-/HZv/CDJ5nGFBA3EUvfy" --=-/HZv/CDJ5nGFBA3EUvfy Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable On Thu, 2020-06-11 at 09:32 +0200, Maxime Ripard wrote: > The RaspberryPi4 firmware actually exposes more clocks than are currently > handled by the driver and we will need to change some of them directly > based on the pixel rate for the display related clocks, or the load for t= he > GPU. >=20 > Since the firmware implements DVFS, this rate change can have a number of > side-effects, including adjusting the various PLL voltages or the PLL > parents. The firmware also implements thermal throttling, so even some > thermal pressure can change those parameters behind Linux back. >=20 > DVFS is currently implemented on the arm, core, h264, v3d, isp and hevc > clocks, so updating any of them using the MMIO driver (and thus behind th= e > firmware's back) can lead to troubles, the arm clock obviously being the > most problematic. >=20 > In order to make Linux play as nice as possible with those constraints, i= t > makes sense to rely on the firmware clocks as much as possible. However, > the firmware doesn't seem to provide some equivalents to their MMIO > counterparts, so we can't really replace that driver entirely. >=20 > Fortunately, the firmware has an interface to discover the clocks it > exposes. >=20 > Let's use it to discover, register the clocks in the clocks framework and > then expose them through the device tree for consumers to use them. >=20 > Cc: Michael Turquette > Cc: Stephen Boyd > Cc: linux-clk@vger.kernel.org > Reviewed-by: Stephen Boyd > Signed-off-by: Maxime Ripard > --- Acked-by: Nicolas Saenz Julienne Regards, Nicolas --=-/HZv/CDJ5nGFBA3EUvfy Content-Type: application/pgp-signature; name="signature.asc" Content-Description: This is a digitally signed message part Content-Transfer-Encoding: 7bit -----BEGIN PGP SIGNATURE----- iQEzBAABCAAdFiEErOkkGDHCg2EbPcGjlfZmHno8x/4FAl7iEjIACgkQlfZmHno8 x/5O/wgAojiCQn8IWPe5AD2kCeaAi3GY+ivhNVp+ylf43QI1C0rv3ie+dyzYTHFe YBp1ll774sFXWcHYoz2GIfWn1r1xKtsaLmsgQSW6iCOzTr6/jhhmHUZqZSgMcW2Y sozYVnzsEbdAGpbsZ37CFPMbvXdYi91GW9vet+w/lkEvPcP6UOTCW13sFfdsrOVi xUQxHElDMq4cNjMMqBmA57EjCyltxfUYD4eLZ+5dlw93GSH0IsXfFTBRupFApN/Y K4vNFlWJur4B0WzWekZMYGXbePmxV02RTBv+53KLBr1/pDRDTaF/ndPbk9iuq7U+ anDlvK61kOm4M+bXQpdWVlw3dKnKbA== =zn5D -----END PGP SIGNATURE----- --=-/HZv/CDJ5nGFBA3EUvfy-- --===============5823513801403321020== 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 --===============5823513801403321020==--