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=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 E315EC10F27 for ; Tue, 10 Mar 2020 09:52:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C35AE24681 for ; Tue, 10 Mar 2020 09:52:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726202AbgCJJwW (ORCPT ); Tue, 10 Mar 2020 05:52:22 -0400 Received: from mail-ot1-f65.google.com ([209.85.210.65]:41577 "EHLO mail-ot1-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726199AbgCJJwW (ORCPT ); Tue, 10 Mar 2020 05:52:22 -0400 Received: by mail-ot1-f65.google.com with SMTP id s15so4292517otq.8; Tue, 10 Mar 2020 02:52:22 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=D2V/UePASyU230tuKRbMCAGcZJI5X8GF+a664jH15CU=; b=Tf/MH0EGmNz33HpbYHLdtiYZEha6NxQEiaSwZg5RvM9GbwAJsKziJBZwV9cOW9HHEI WhQWu05mSDYxVG2RC6jykJKd6wPnL/nlJjQcQj5PlBpIWn/raUBRxozwBBQrirtu8+nB smMa4qde/nxGnnGpDsK3SmHuCXuqHG5+J0ShB9yDg9Sn9aESLmNWHymkqlwor/NyKJuJ nSkl4FU2+Qw2ShPlR1Fra9704UVc/3p/zXZnnwyBeVERj4B8Na6+y46xS3xPekGkTkLD I16EpB9JpGxiIxzHkkQWuJJFlGWjrjqEuX1vZYxHtoJ4BrktqXlQzQq8EDy4odKQt3eu nIPA== X-Gm-Message-State: ANhLgQ0UjllkEEeLuPfV/ETo7QEnQqmYpEK19xJDDW+iQLsmqkHkcb8C W1vB0+5fCrHdLNELy+cO6N5ndLD+VPWh7nSJ6XJYJN8j X-Google-Smtp-Source: ADFU+vsj5UWJdrV7QmKDiwgSvDldXSei2pp+JGaKb/Y7ORMGEFfH2B3XQIlZ+H27C0XBvXY1wG4vDKm2MB7xCJwnqls= X-Received: by 2002:a9d:b89:: with SMTP id 9mr16432511oth.297.1583833941607; Tue, 10 Mar 2020 02:52:21 -0700 (PDT) MIME-Version: 1.0 References: <20200305103228.9686-1-zhang.lyra@gmail.com> In-Reply-To: From: Geert Uytterhoeven Date: Tue, 10 Mar 2020 10:52:10 +0100 Message-ID: Subject: Re: [PATCH 1/2] arm64: change ARCH_SPRD Kconfig to tristate To: Orson Zhai Cc: Chunyan Zhang , Greg Kroah-Hartman , Catalin Marinas , Will Deacon , Jiri Slaby , Linux Kernel Mailing List , Chunyan Zhang , "open list:SERIAL DRIVERS" , Baolin Wang , Linux ARM , Android Kernel Team Content-Type: text/plain; charset="UTF-8" Sender: linux-serial-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-serial@vger.kernel.org Hi Orson, On Tue, Mar 10, 2020 at 10:41 AM Orson Zhai wrote: > On Mon, Mar 9, 2020 at 6:32 PM Geert Uytterhoeven wrote: > > On Mon, Mar 9, 2020 at 9:32 AM Chunyan Zhang wrote: > > > On Mon, 9 Mar 2020 at 16:03, Geert Uytterhoeven wrote: > > > > On Thu, Mar 5, 2020 at 11:33 AM Chunyan Zhang wrote: > > > > > From: Chunyan Zhang > > > > > > > > > > The default value of Kconfig for almost all sprd drivers are the same with > > > > > ARCH_SPRD, making these drivers built as modules as default would be easier > > > > > if we can set ARCH_SPRD as 'm', so this patch change ARCH_SPRD to tristate. > > > > > > > > > > Signed-off-by: Chunyan Zhang > > > > > > > > Can you actually boot a kernel on a Spreadtrum platform when all platform > > > > and driver support is modular? > > > > > > Yes, even if all drivers are modular. > > > > Cool. No hard dependencies on e.g. regulators that are turned off when > > unused? > > > > > But I hope serial can be builtin, then I can have a console to see > > > kernel output before loading modules. > > > > No dependency on the clock driver? > > Oh, I see you have a hack in the serial driver, to assume default > > values when the serial port's parent clock is not found. That may > > limit use of the other serial ports, depending on the actual serial > > hardware. > > There is an function named "sprd_uart_is_console()" in the driver > code. So the hack could be only applied when the > port is identified as console. And other ports might return > PROBE_DEFER until the clock is ready. > > Could it work out of the limitation? Yes, that could work. You also have only a single SPRD_DEFAULT_SOURCE_CLK, which makes it simple to handle. For other SoCs, there may be a variation of possible values, depending on SoC and/or board. Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds