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 170E2C3A59D for ; Sun, 23 Oct 2022 15:16:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230143AbiJWPQT (ORCPT ); Sun, 23 Oct 2022 11:16:19 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54986 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229867AbiJWPQP (ORCPT ); Sun, 23 Oct 2022 11:16:15 -0400 Received: from aposti.net (aposti.net [89.234.176.197]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CF2416556C; Sun, 23 Oct 2022 08:16:11 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=crapouillou.net; s=mail; t=1666538169; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=76gz1YSbuUIA+tLdwL/4i5a5zfRt4Nv9mdTm/uPed3w=; b=UlzyMNfvxSOmsLFTbpmCgLzlm2t9lt6VDAnPrCvAKxKuPoUcNOKhtEwnaboUeHB4d5tTfe C9xIxNS1OEVeLBs8lNjsFdpeW0L+Zd1F04C8HQinUJl2Fl0S/RoInmia/68XJaTXapOIXb tinDxuX0iCncdtoF63UIOpSF9qTqA30= Date: Sun, 23 Oct 2022 16:15:58 +0100 From: Paul Cercueil Subject: Re: [PATCH v3 2/2] serial: 8250/ingenic: Add support for the JZ4750/JZ4755 To: Siarhei Volkau Cc: Greg Kroah-Hartman , Rob Herring , Krzysztof Kozlowski , Jiri Slaby , linux-serial@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mips@vger.kernel.org Message-Id: In-Reply-To: References: <20221022165047.4020785-1-lis8215@gmail.com> <20221022165047.4020785-3-lis8215@gmail.com> <9W76KR.NVDSVG4IWZ3A3@crapouillou.net> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Le dim. 23 oct. 2022 =C3=A0 17:04:49 +0300, Siarhei Volkau=20 a =C3=A9crit : > =D0=B2=D1=81, 23 =D0=BE=D0=BA=D1=82. 2022 =D0=B3. =D0=B2 12:16, Paul Cerc= ueil=20 > : >> Do you have such hardware? >=20 > No >=20 >> Don't add support for cases you can't test. >=20 > It's just a side effect of that approach. >=20 >> For what we know - all JZ475x use a 24 MHz crystal and all JZ4760(B) >> use a 12 MHz crystal, until proven otherwise. >=20 > Ouf course it just confirms the rule but I found one exception:=20 > JZ4750 & 12MHz > Link:=20 > https://github.com/carlos-wong/uboot_jz4755/blob/master/include/configs/l= ib4750.h Then when this board is upstreamed it will declare a 12 MHz oscillator=20 in its DT, and the ingenic init code won't have to enable the /2=20 divider for that particular board. > Regarding your proposal: > In my opinion enabling the divisor unconditionally is a bad practice, > as it's already enabled (or not) by the bootloader, with respect to=20 > the > hardware capabilities.I think it's better to keep the driver as it is=20 > than > adding such things. Well, I disagree. Linux should not depend on whatever the bootloader=20 configures. -Paul