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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id AE511C433F5 for ; Fri, 15 Oct 2021 04:12:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8DA79611C5 for ; Fri, 15 Oct 2021 04:12:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233273AbhJOEPB (ORCPT ); Fri, 15 Oct 2021 00:15:01 -0400 Received: from mail.kernel.org ([198.145.29.99]:35454 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233083AbhJOEPA (ORCPT ); Fri, 15 Oct 2021 00:15:00 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 8F9AA61168; Fri, 15 Oct 2021 04:12:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1634271174; bh=ep/IXH3UxYH/vOBTWCg7qNPyVSjQ3xGnQubpgz0v/V4=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=n6LAhMRKZOIopPXdzW0rHn0TXO9aq6GW48M95bssT/Qu4/N/zKrqxhEC+tdhU4LXx 37HChB1W3b8uppBWdpYXJa+B5jEuFb3dLe8w0Xl9YWTxb/IT8jI5bBVPAfVabk5SNI 0BFoipCGiQ/R8iG4KucsrtUfqilWjEVxSWMNV7bF8Tissco4BmKrQCfmMpx3E5cSFv F7osaIOhPrLvwyaurfG7ggqIZaClT76RNMrpOCmHyqijwhjBNTsy9UoXbmD0heoCZG zVtz8ENURA5dAofGoZ433BOAdlSWnQivCpQ+63WCi1ude9iKDYKjQyDfcHcNVlJ0lP 322unydic2xsQ== Date: Fri, 15 Oct 2021 12:12:40 +0800 From: Shawn Guo To: Frieder Schrempf Cc: Frieder Schrempf , devicetree@vger.kernel.org, Krzysztof Kozlowski , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Rob Herring , Sascha Hauer , stable@vger.kernel.org, Fabio Estevam , NXP Linux Team , Pengutronix Kernel Team Subject: Re: [PATCH 5/8] arm64: dts: imx8mm-kontron: Fix CAN SPI clock frequency Message-ID: <20211015041239.GH22881@dragon> References: <20210930155633.2745201-1-frieder@fris.de> <20210930155633.2745201-6-frieder@fris.de> <20211005071230.GC20743@dragon> <37c1845d-9323-3187-ed0b-b9795758649d@kontron.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <37c1845d-9323-3187-ed0b-b9795758649d@kontron.de> User-Agent: Mutt/1.9.4 (2018-02-28) Precedence: bulk List-ID: X-Mailing-List: devicetree@vger.kernel.org On Tue, Oct 05, 2021 at 07:17:13PM +0200, Frieder Schrempf wrote: > On 05.10.21 09:12, Shawn Guo wrote: > > On Thu, Sep 30, 2021 at 05:56:28PM +0200, Frieder Schrempf wrote: > >> From: Frieder Schrempf > >> > >> The MCP2515 can be used with an SPI clock of up to 10 MHz. Set the > >> limit accordingly to prevent any performance issues caused by the > >> really low clock speed of 100 kHz. > > > > Could you share some testing result of this change? > > Without this change, receiving CAN messages on the board beyond a > certain bitrate will cause overrun errors (see 'ip -det -stat link show > can0'). > > With this fix, receiving messages on the bus works without any overrun > errors for bitrates up to 1 MBit. > > > > > >> > >> Fixes: 21c4f45b335f ("arm64: dts: Add the Kontron i.MX8M Mini SoMs and baseboards") > > > > It's really an optimization rather than fix, isn't it? > > It removes the arbitrarily low limit on the SPI frequency, that was > caused by a typo in the original dts. As the usage of the CAN bus is > seriously affected by this I would consider it a fix. But if you think > otherwise, feel free to remove the Fixes tag. Put all these good information into commit log, and I will be happy to take it as a fix. Shawn > >> Cc: stable@vger.kernel.org > >> Signed-off-by: Frieder Schrempf > >> --- > >> arch/arm64/boot/dts/freescale/imx8mm-kontron-n801x-s.dts | 2 +- > >> 1 file changed, 1 insertion(+), 1 deletion(-) > >> > >> diff --git a/arch/arm64/boot/dts/freescale/imx8mm-kontron-n801x-s.dts b/arch/arm64/boot/dts/freescale/imx8mm-kontron-n801x-s.dts > >> index f2c8ccefd1bf..dbf11e03ecce 100644 > >> --- a/arch/arm64/boot/dts/freescale/imx8mm-kontron-n801x-s.dts > >> +++ b/arch/arm64/boot/dts/freescale/imx8mm-kontron-n801x-s.dts > >> @@ -98,7 +98,7 @@ can0: can@0 { > >> clocks = <&osc_can>; > >> interrupt-parent = <&gpio4>; > >> interrupts = <28 IRQ_TYPE_EDGE_FALLING>; > >> - spi-max-frequency = <100000>; > >> + spi-max-frequency = <10000000>; > >> vdd-supply = <®_vdd_3v3>; > >> xceiver-supply = <®_vdd_5v>; > >> }; > >> -- > >> 2.33.0 > >>