From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751866Ab2LTRDr (ORCPT ); Thu, 20 Dec 2012 12:03:47 -0500 Received: from avon.wwwdotorg.org ([70.85.31.133]:54320 "EHLO avon.wwwdotorg.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751218Ab2LTRDj (ORCPT ); Thu, 20 Dec 2012 12:03:39 -0500 Message-ID: <50D344E9.70305@wwwdotorg.org> Date: Thu, 20 Dec 2012 10:03:37 -0700 From: Stephen Warren User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/17.0 Thunderbird/17.0 MIME-Version: 1.0 To: Laxman Dewangan CC: "linux@arm.linux.org.uk" , "linux-tegra@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" , "linux-kernel@vger.kernel.org" Subject: Re: [PATCH] ARM: tegra: dts: add aliases and DMA requestor for serial controller References: <1355898671-3960-1-git-send-email-ldewangan@nvidia.com> <50D1F2CB.3090206@wwwdotorg.org> <50D2AD02.6060101@nvidia.com> In-Reply-To: <50D2AD02.6060101@nvidia.com> X-Enigmail-Version: 1.4.6 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 12/19/2012 11:15 PM, Laxman Dewangan wrote: > On Wednesday 19 December 2012 10:30 PM, Stephen Warren wrote: >> On 12/18/2012 11:31 PM, Laxman Dewangan wrote: >>> Add APB DMA requestor and serial aliases for serial controller. >>> There will be two serial driver i.e. 8250 based simple serial driver >>> and APB DMA based serial driver for higher baudrate and performace. >>> >>> The simple serial driver get enabled with compatible nvidia,tegra20-uart >>> and APB DMA based driver will get enabled with compatible >>> nvidia,tegra20-hsuart. >> This patch seems to do two things: >> >> 1) Add a comment describing how to select the basic or DMA-based driver. >> I can see why this is useful. >> >> 2) Add aliases for the serial ports. I have no idea why this is useful. > > Serial aliases are added because we want to get the port number like > /dev/ttyTHS0, /d/ttyTHS2 etc. The uarta should be /dev/ttyTHS0 and > uartc should be /dev/ttyTHS2. The port number can be found using aliases > and of_alias_get_id() in driver file: > > port_number = of_alias_get_id(np, "serial"); Oh, I see. I guess the aliases make sense then. But, wouldn't you only add aliases for the specific UARTs that are in use on a particular board (so put them in tegraNN-board.dts) rather than all UARTs on Tegra (i.e. the current patch which puts them into tegraNN.dtsi)?