Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754288Ab2BVI4q (ORCPT ); Wed, 22 Feb 2012 03:56:46 -0500 Received: from lxorguk.ukuu.org.uk ([81.2.110.251]:45367 "EHLO lxorguk.ukuu.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751280Ab2BVI4p convert rfc822-to-8bit (ORCPT ); Wed, 22 Feb 2012 03:56:45 -0500 Date: Wed, 22 Feb 2012 08:58:30 +0000 From: Alan Cox To: Tomoya MORINAGA Cc: Darren Hart , Linux Kernel Mailing List , Feng Tang , Greg Kroah-Hartman , Alan Cox , linux-serial@vger.kernel.org Subject: Re: [PATCH 0/4] pch_uart: Cleanups, board quirks, and user uartclk parameter Message-ID: <20120222085830.1ed8c25e@pyramind.ukuu.org.uk> In-Reply-To: References: X-Mailer: Claws Mail 3.8.0 (GTK+ 2.24.8; x86_64-redhat-linux-gnu) Face: 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 Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 964 Lines: 23 > > assume a 192 MHz clock on all boards. The problem with this approach is > > that the CLKCFG register may have been set to something other than the > > 192MHz configuration by the firmware. So you can use the early PCI hooks or even bash the register directly in your early bootup code. You won't be the only early boot console that does this sort of thing. There are even people bitbanging PCI I?C interfaces at boot time for such purpose. > So, I think default uart_clock 192MHz setting is better than Darren's opinion. It's certainly easier to maintain, but it would be good to know if the setting can be written or retrieved directly in the early console setup using the early PCI ops or similar. Alan Alan -- 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/