Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754200Ab2EYK03 (ORCPT ); Fri, 25 May 2012 06:26:29 -0400 Received: from mga14.intel.com ([143.182.124.37]:59902 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751868Ab2EYK02 (ORCPT ); Fri, 25 May 2012 06:26:28 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.71,315,1320652800"; d="scan'208";a="147725671" Subject: Re: [alsa-devel] [PATCH v5] sound/soc/lapis: add platform driver for ML7213 From: Vinod Koul To: Tomoya MORINAGA Cc: Mark Brown , alsa-devel@alsa-project.org, lars@metafoo.de, Takashi Iwai , linux-kernel@vger.kernel.org, Liam Girdwood In-Reply-To: References: <1331275160-31757-1-git-send-email-tomoya.rohm@gmail.com> <1332158459-14880-1-git-send-email-tomoya.rohm@gmail.com> <20120321160913.GF3226@opensource.wolfsonmicro.com> <20120326154009.GA17506@sirena.org.uk> <20120523093857.GC4085@opensource.wolfsonmicro.com> <20120524100742.GH5361@opensource.wolfsonmicro.com> Content-Type: text/plain; charset="UTF-8" Date: Fri, 25 May 2012 15:50:31 +0530 Message-ID: <1337941231.1580.19.camel@vkoul-udesk3> Mime-Version: 1.0 X-Mailer: Evolution 2.28.3 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2474 Lines: 55 On Fri, 2012-05-25 at 18:30 +0900, Tomoya MORINAGA wrote: > On Thu, May 24, 2012 at 7:07 PM, Mark Brown > wrote: > >> > Nobody seems to be working on it as far as I can tell, I've certainly > >> > not seen any patches. > > > >> If so, could you accept current platform/machine driver ? > > > > Ideally what would be happening here is that you or other people who > > have such systems would be working to add the required support to the > > core code, there's clearly a need for common code here as there are a > > number of different systems that don't have cyclic DMA and it wouldn't > > be great to end up with duplicated code. > > > > Is there some great difficulty in factoring out the support for > > non-cyclic audio DMA on dmaengine - it seems like if there is we must > > have a serious problem in dmaengine which we should fix? If there is a > > substantial difficulty then that's different but it doesn't feel like > > we've tried doing common code yet, if there's problems doing that I'd > > like to understand what they are before we jump ahead of ourselves. > > I'm not so familiar with Linux's DMA idea. > So we don't know whether non-cyclic dmaengine has problem or not. First you should not be writing your own dma driver, it *needs* to use dmaenegine. We already have bunch of driver supported, so there may be a case that existing driver works straight or with little modifications. Using your own dma driver is a dead road, so sooner you move over better it is. One you move then it would be easy for you to use soc-dmaengine. If your driver doesn't support cyclic; nothing stops from you emulating that in S/W. And given that you have already contributed to dmaengine subsystem, it should be easy for you :) > > Until now, we've developed device drivers use DMA driver like UART, SPI. > These drivers are implemented using the same way, you called > "non-cyclic", and already applied. > > As you said, common code for DMA code can be best solution. > However, currently, the code is nothing. > So, I want you to accept our driver as first step. > Because I think supporting new device is more important for linux than > dmaengine common. > > thanks -- ~Vinod -- 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/