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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5A644C00144 for ; Mon, 1 Aug 2022 12:13:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234121AbiHAMNU (ORCPT ); Mon, 1 Aug 2022 08:13:20 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57016 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234193AbiHAMKw (ORCPT ); Mon, 1 Aug 2022 08:10:52 -0400 Received: from sin.source.kernel.org (sin.source.kernel.org [145.40.73.55]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CE99D6AA1B; Mon, 1 Aug 2022 04:56:44 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by sin.source.kernel.org (Postfix) with ESMTPS id 2A5F5CE13B9; Mon, 1 Aug 2022 11:56:42 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1C3C3C433D6; Mon, 1 Aug 2022 11:56:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1659355000; bh=oONK/2x2HZCKsDsB+GoDk34waBGsK8OQ/Klc1ODe+zU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=wCpaoGXEBw3pl+pA5nqe1F/phWDjBSf/taSsKZj+A0I9FzcrHuOj8f3/omTy5+6NF 4NLo6JiOyxRU7TAS3w/cFZvzT1yrl5jJb0ldqswteB7yUU9E+NvozwtK8m+JJP04tH R3bmKSYKwat1+2Rv4HedXwILDD8EKBaVgE3OlQUg= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Michael Walle , Kavyasree Kotagiri , Claudiu Beznea Subject: [PATCH 5.18 03/88] ARM: dts: lan966x: fix sys_clk frequency Date: Mon, 1 Aug 2022 13:46:17 +0200 Message-Id: <20220801114138.189784913@linuxfoundation.org> X-Mailer: git-send-email 2.37.1 In-Reply-To: <20220801114138.041018499@linuxfoundation.org> References: <20220801114138.041018499@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Michael Walle commit ef0324b6415db6742bd632dc0dfbb8fbc111473b upstream. The sys_clk frequency is 165.625MHz. The register reference of the Generic Clock controller lists the CPU clock as 600MHz, the DDR clock as 300MHz and the SYS clock as 162.5MHz. This is wrong. It was first noticed during the fan driver development and it was measured and verified via the CLK_MON output of the SoC which can be configured to output sys_clk/64. The core PLL settings (which drives the SYS clock) seems to be as follows: DIVF = 52 DIVQ = 3 DIVR = 1 With a refernce clock of 25MHz, this means we have a post divider clock Fpfd = Fref / (DIVR + 1) = 25MHz / (1 + 1) = 12.5MHz The resulting VCO frequency is then Fvco = Fpfd * (DIVF + 1) * 2 = 12.5MHz * (52 + 1) * 2 = 1325MHz And the output frequency is Fout = Fvco / 2^DIVQ = 1325MHz / 2^3 = 165.625Mhz This all adds up to the constrains of the PLL: 10MHz <= Fpfd <= 200MHz 20MHz <= Fout <= 1000MHz 1000MHz <= Fvco <= 2000MHz Fixes: 290deaa10c50 ("ARM: dts: add DT for lan966 SoC and 2-port board pcb8291") Signed-off-by: Michael Walle Reviewed-by: Kavyasree Kotagiri Signed-off-by: Claudiu Beznea Link: https://lore.kernel.org/r/20220326194028.2945985-1-michael@walle.cc Signed-off-by: Greg Kroah-Hartman --- arch/arm/boot/dts/lan966x.dtsi | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/arm/boot/dts/lan966x.dtsi b/arch/arm/boot/dts/lan966x.dtsi index 3cb02fffe716..38e90a31d2dd 100644 --- a/arch/arm/boot/dts/lan966x.dtsi +++ b/arch/arm/boot/dts/lan966x.dtsi @@ -38,7 +38,7 @@ clocks { sys_clk: sys_clk { compatible = "fixed-clock"; #clock-cells = <0>; - clock-frequency = <162500000>; + clock-frequency = <165625000>; }; cpu_clk: cpu_clk { -- 2.37.1