Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753825AbaJTLPV (ORCPT ); Mon, 20 Oct 2014 07:15:21 -0400 Received: from mail-wg0-f44.google.com ([74.125.82.44]:51663 "EHLO mail-wg0-f44.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753371AbaJTLPR (ORCPT ); Mon, 20 Oct 2014 07:15:17 -0400 MIME-Version: 1.0 In-Reply-To: <20141020103213.GA26235@leverpostej> References: <1413539665-11484-1-git-send-email-chunyan.zhang@spreadtrum.com> <1413539665-11484-6-git-send-email-chunyan.zhang@spreadtrum.com> <20141017130354.GC5587@leverpostej> <20141020103213.GA26235@leverpostej> Date: Mon, 20 Oct 2014 19:15:15 +0800 Message-ID: Subject: Re: [PATCH v2 5/5] tty/serial: Add earlycon support for Spreadtrum serial driver From: Lyra Zhang To: Mark Rutland Cc: Chunyan Zhang , Catalin Marinas , "gregkh@linuxfoundation.org" , "ijc+devicetree@hellion.org.uk" , "jslaby@suse.cz" , "galak@codeaurora.org" , "broonie@linaro.org" , "m-karicheri2@ti.com" , Pawel Moll , "artagnon@gmail.com" , "rrichter@cavium.com" , "robh+dt@kernel.org" , Will Deacon , "orsonzhai@gmail.com" , "geng.ren@spreadtrum.com" , "zhizhou.zhang@spreadtrum.com" , "devicetree@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" , "linux-kernel@vger.kernel.org" , "sprdlinux@freelists.org" Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 2014-10-20 18:32 GMT+08:00 Mark Rutland : > On Mon, Oct 20, 2014 at 08:27:24AM +0100, Lyra Zhang wrote: >> 2014-10-17 21:03 GMT+08:00 Mark Rutland : >> > On Fri, Oct 17, 2014 at 10:54:25AM +0100, Chunyan Zhang wrote: >> >> Add serial driver for spreadtrum sharkl platform with earlycon >> >> support at first. >> >> >> >> Signed-off-by: Chunyan Zhang >> >> --- >> >> drivers/tty/serial/Kconfig | 24 ++++++++++++++ >> >> drivers/tty/serial/Makefile | 1 + >> >> drivers/tty/serial/sprd-serial.c | 64 ++++++++++++++++++++++++++++++++++++++ >> >> 3 files changed, 89 insertions(+) >> >> create mode 100644 drivers/tty/serial/sprd-serial.c >> >> >> >> diff --git a/drivers/tty/serial/Kconfig b/drivers/tty/serial/Kconfig >> >> index 26cec64..33b8f90 100644 >> >> --- a/drivers/tty/serial/Kconfig >> >> +++ b/drivers/tty/serial/Kconfig >> >> @@ -113,6 +113,30 @@ config SERIAL_SB1250_DUART_CONSOLE >> >> >> >> If unsure, say Y. >> >> >> >> +config SERIAL_SPRD >> >> + tristate "Support for SPRD serial" >> >> + depends on ARM || ARM64 >> >> + select SERIAL_CORE >> >> + help >> >> + This enables the driver for the Spreadtrum's serial. >> >> + >> >> +config SERIAL_SPRD_NR >> >> + int "Maximum number of sprd serial ports" >> >> + depends on SERIAL_SPRD >> >> + default "4" >> > >> > This is not used below. >> > >> Ok, I'll remove it in v3. >> >> >> + >> >> +config SERIAL_SPRD_CONSOLE >> >> + bool "SPRD UART console support" >> >> + depends on SERIAL_SPRD=y >> >> + select SERIAL_CORE_CONSOLE >> >> + select SERIAL_EARLYCON >> >> + help >> >> + Support for early debug console using Spreadtrum's serial. This enables >> >> + the console before standard serial driver is probed. This is enabled >> >> + with "earlycon=serial_sprd" on the kernel command line. The console is >> >> + enabled when early_param is processed. >> > >> > There only appears to be an earlycon driver, and not "standard serial >> > driver". >> > >> > What happens after earlycon? >> > >> > Surely there should be a real driver to take ownership of the UART? >> > >> > As far as I can see it won't be possible to boot your platform to a >> > prompt, because earlycon will have gone before that. >> > >> > Thanks, >> > Mark. >> > >> >> We are planed to add standard serial driver after this patch-set is approved. >> In the first patch we contribute to the upstream, I'd like to add >> architecture related code of >> Spreadtrum's Sharkl, and then we will add more functions about Sharkl3 >> SoC step by step. > > The series is simple enough that the only issues I've noticed are minor. > I'm happy with that. > > However, the absence of a real UART driver means that this series alone > is not sufficient to boot your platform to a usable state. Given that > the rest of the series is simply plumbing, I think it would make sense > for that to accompany a full UART driver (or perhaps some other I/O like > ethernet) such that it's possible to interact with the platform. > Ok, I see. I'll add a full UART driver in v3. Thanks for your suggestion. Best regards, Chunyan -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/