From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753066AbcDKJZc (ORCPT ); Mon, 11 Apr 2016 05:25:32 -0400 Received: from smtprelay.synopsys.com ([198.182.47.9]:56450 "EHLO smtprelay.synopsys.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750916AbcDKJZb (ORCPT ); Mon, 11 Apr 2016 05:25:31 -0400 Subject: Re: [alsa-devel] [PATCH 5/5 v4] ASoC: dwc: Update DOCUMENTATION for I2S Driver To: Lars-Peter Clausen , Jose Abreu , Mark Brown References: <20160407175326.GX1924@sirena.org.uk> <570782BF.10402@synopsys.com> <5707D3AD.8030308@metafoo.de> <5707D780.4050406@synopsys.com> <570917E9.8020804@metafoo.de> CC: , , , , , , , , From: Jose Abreu Message-ID: <570B6D66.4080309@synopsys.com> Date: Mon, 11 Apr 2016 10:24:54 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.6.0 MIME-Version: 1.0 In-Reply-To: <570917E9.8020804@metafoo.de> Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.107.19.85] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Lars, On 09-04-2016 15:55, Lars-Peter Clausen wrote: > On 04/08/2016 06:08 PM, Jose Abreu wrote: >> Hi Lars, >> >> >> On 08-04-2016 16:52, Lars-Peter Clausen wrote: >>> On 04/08/2016 12:06 PM, Jose Abreu wrote: >>>> Hi Mark, >>>> >>>> >>>> On 07-04-2016 18:53, Mark Brown wrote: >>>>> On Thu, Apr 07, 2016 at 05:53:59PM +0100, Jose Abreu wrote: >>>>> >>>>>> + Optional properties: >>>>>> + - snps,use-dmaengine: If set the driver will use ALSA DMA engine. If set >>>>>> + it is required to use the properties 'dmas' and 'dma-names'. >>>>> This is not a good interface, it's describing Linux internal APIs. If >>>>> the device needs to operate in PIO mode it should just do that. >>>> I added this interface because there is no direct way to check if DMA is >>>> available on the I2S controller so it is not possible to automatically change >>>> between DMA and PIO mode. As the I2S controller can be built with or without DMA >>>> support it is necessary to somehow check if DMA is enabled or not and according >>>> to that use either ALSA DMA engine or the custom platform driver sent in these >>>> patches. I did not want to remove drivers functionality so I added this property >>>> to the DT. This way a user can select between DMA and PIO mode. >>> That's OK, but you need to describe the hardware, not the indented behavior >>> of the software driver. >>> >> Is this okay: "snps,use-dmaengine: Set this boolean paramater if I2S controller >> has DMA support. If set the properties 'dmas' and 'dma-names' must be also set" ? > The description is better. But the name of the property is still imperative > rather then descriptive. It tells the software what should be done rather > then describing what the hardware looks like. > > Since there is already the dmas property which is present if a DMA is > connected and is absent when no DMA is present it should be enough to just > check that property rather than requiring an additional one. Ok, will then use the DMA property to decide which mode to use: PIO or DMA. > > _______________________________________________ > dri-devel mailing list > dri-devel@lists.freedesktop.org > https://lists.freedesktop.org/mailman/listinfo/dri-devel Best regards, Jose Miguel Abreu