From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from ug-out-1314.google.com (ug-out-1314.google.com [66.249.92.171]) by ozlabs.org (Postfix) with ESMTP id 19377DDE3F for ; Tue, 17 Apr 2007 15:34:16 +1000 (EST) Received: by ug-out-1314.google.com with SMTP id k3so63053ugf for ; Mon, 16 Apr 2007 22:34:14 -0700 (PDT) Message-ID: <528646bc0704162234o48efc330w98bf933e3c4a7533@mail.gmail.com> Date: Mon, 16 Apr 2007 23:34:14 -0600 From: "Grant Likely" Sender: glikely@gmail.com To: "Dale Farnsworth" Subject: Re: RFC: MPC52xx serial port configuration from DT blob In-Reply-To: <20070413232422.11827.qmail@farnsworth.org> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed References: <461FF442.8090807@semihalf.com> <20070413232422.11827.qmail@farnsworth.org> Cc: linuxppc-embedded@ozlabs.org List-Id: Linux on Embedded PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On 13 Apr 2007 16:24:22 -0700, Dale Farnsworth wrote: > Bartlomiej wrote: > > We have a MPC5200B-based board running an arch/powerpc kernel and we > > need the ability to configure a non-console serial port for a particular > > baud rate during system start-up. It seems that the UART driver in > > drivers/serial/mpc52xx_uart.c does not support this. It only allows to > > set parameters for a port that is used as a console, and for which those > > parameters are passed in the kernel command line. We would like to > > extend the mpc52xx_uart.c driver to be able to retrieve port options > > from the DT blob and configure a given port accordingly. A new > > port-specific property called "options" would be used for this. It would > > have syntax following its namesake in "console" kernel parameter, as > > described in Documentation/kernel-parameters.txt. > > > > For example, the following settings in the .dts file would make UART5 to > > be configured at 115200 baud, no parity, 8 bits. > > > > serial@2800 { // PSC5 > > device_type = "serial"; > > compatible = "mpc5200b-psc-uart\0mpc5200-psc-uart"; > > port-number = <4>; // Logical port assignment > > options = "115200n8" > > cell-index = <4>; > > reg = <2800 100>; > > interrupts = <2 c 0>; > > interrupt-parent = <500>; > > }; > > > > > > In case a console port has conflicting options given in the kernel > > command line and in the DT blob, the command line values would be used. > > > > Any comments on the above will be appreciated. > > The device tree is intended to be an OS-independent description of the > state of the platform hardware as left by firmware (or bootwrapper). > It is not intended to contain kernel configuration parameters or options, > though there are a few exceptions. > > So, this kind of change is unlikely to be accepted. Isn't the /chosen node intended for this kind of data? Although I must admit that I'm not at all familiar with the conventions used in /chosen. g. -- Grant Likely, B.Sc. P.Eng. Secret Lab Technologies Ltd. grant.likely@secretlab.ca (403) 399-0195