From mboxrd@z Thu Jan 1 00:00:00 1970 From: Greg KH Subject: Re: Fwd: [PULL REQUEST] Tweak to support 1Mbaud and similar baudrates that require Mode16 instead of Mode13 Date: Tue, 27 Nov 2012 16:42:04 -0800 Message-ID: <20121128004204.GB3857@kroah.com> References: Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from mail-pb0-f46.google.com ([209.85.160.46]:47381 "EHLO mail-pb0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753625Ab2K1Akr (ORCPT ); Tue, 27 Nov 2012 19:40:47 -0500 Received: by mail-pb0-f46.google.com with SMTP id wy7so9293741pbc.19 for ; Tue, 27 Nov 2012 16:40:47 -0800 (PST) Content-Disposition: inline In-Reply-To: Sender: linux-serial-owner@vger.kernel.org List-Id: linux-serial@vger.kernel.org To: Alexey Pelykh Cc: linux-serial@vger.kernel.org On Tue, Nov 27, 2012 at 11:56:06PM +0200, Alexey Pelykh wrote: > Hello everyone, > > Original table in OMAP TRM named "UART Mode Baud Rates, Divisor > Values, and Error Rates" determines modes not for all common baud > rates. E.g. for 1000000 baud rate mode should be 16x, but according to > that table it's determined as 13x. According to current implementation > of mode > divisor selection, after requesting 1000000 baudrate from driver, > later one will configure chip to use MODE13 divisor. Assuming 48Mhz as > common UART clock speed, MODE13 divisor will effectively give 1230769 > baudrate, what is quite far from desired 1000000 baudrate. While with > MODE16 divisor, chip will produce exact 1000000 baudrate. > > In old driver that served UART devices (8250.c and serial_core.c) this > divisor could have been configured by user-space program, but in > omap_serial.c driver implementation this ability was not implemented > (afaik, by design) thus disallowing proper usage of MODE16-compatible > baudrates. > > Best regards, > Alexey Pelykh > > The following changes since commit 77b67063bb6bce6d475e910d3b886a606d0d91f7: > > Linux 3.7-rc5 (2012-11-11 13:44:33 +0100) > > are available in the git repository at: > > git://github.com/alexey-pelykh/linux.git omap_serial_mode_fix > > for you to fetch changes up to cf827bb4057fdcdaeac20b95b01c29c068109185: > > Tweak to support 1Mbaud and similar baudrates that require Mode16 > instead of Mode13 (2012-11-12 19:29:27 +0200) Sorry, I can't take a git pull request for a single patch, please just send it in an email (the patch that is), with the correct signed-off-by: information, as described in Documentation/SubmittingPatches, and I will be glad to queue it up. thanks, greg k-h