From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.4 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 92E73C33CA3 for ; Thu, 9 Jan 2020 10:31:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 69C5120678 for ; Thu, 9 Jan 2020 10:31:46 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=ti.com header.i=@ti.com header.b="kqfAtqYy" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730136AbgAIKbp (ORCPT ); Thu, 9 Jan 2020 05:31:45 -0500 Received: from fllv0016.ext.ti.com ([198.47.19.142]:35114 "EHLO fllv0016.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728614AbgAIKbp (ORCPT ); Thu, 9 Jan 2020 05:31:45 -0500 Received: from fllv0034.itg.ti.com ([10.64.40.246]) by fllv0016.ext.ti.com (8.15.2/8.15.2) with ESMTP id 009AVYNC091024; Thu, 9 Jan 2020 04:31:34 -0600 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ti.com; s=ti-com-17Q1; t=1578565894; bh=vRdA7ZpngQM+5zB53J/t9D79iFD6d3CN4ckUSA2NKZU=; h=Subject:To:CC:References:From:Date:In-Reply-To; b=kqfAtqYyVFSJwV7sAQM96ZsH51Cc8Qfcgjh49mQJZW+5wcv9MqpoyEgdaP2YFpDcb +2PxadaY9hVlfjIC/8oPqSWQkfi/UFY2Ko2xjxTcHFUwar0CUx/N7aNr3jborunuex KcLERc0GHTymkwpkF6fTlikayArqWYj+LJOBXOeg= Received: from DFLE100.ent.ti.com (dfle100.ent.ti.com [10.64.6.21]) by fllv0034.itg.ti.com (8.15.2/8.15.2) with ESMTPS id 009AVYmK079645 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=FAIL); Thu, 9 Jan 2020 04:31:34 -0600 Received: from DFLE105.ent.ti.com (10.64.6.26) by DFLE100.ent.ti.com (10.64.6.21) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.1847.3; Thu, 9 Jan 2020 04:31:32 -0600 Received: from fllv0040.itg.ti.com (10.64.41.20) by DFLE105.ent.ti.com (10.64.6.26) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.1847.3 via Frontend Transport; Thu, 9 Jan 2020 04:31:32 -0600 Received: from [192.168.2.6] (ileax41-snat.itg.ti.com [10.172.224.153]) by fllv0040.itg.ti.com (8.15.2/8.15.2) with ESMTP id 009AVU9e033718; Thu, 9 Jan 2020 04:31:30 -0600 Subject: Re: [PATCH v2] iio: adc: stm32-dfsdm: Use dma_request_chan() instead dma_request_slave_channel() To: Fabrice Gasnier , , , CC: , , , , , Olivier MOYSAN References: <20200107114532.6697-1-peter.ujfalusi@ti.com> From: Peter Ujfalusi Message-ID: <4c0b7e3e-cd98-860a-e931-c216f1bc6e7a@ti.com> Date: Thu, 9 Jan 2020 12:32:02 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.9.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset="utf-8" Content-Language: en-US Content-Transfer-Encoding: 8bit X-EXCLAIMER-MD-CONFIG: e1e8a2fd-e40a-4ac6-ac9b-f7e9cc9ee180 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 09/01/2020 11.13, Fabrice Gasnier wrote: > On 1/7/20 12:45 PM, Peter Ujfalusi wrote: >> dma_request_slave_channel() is a wrapper on top of dma_request_chan() >> eating up the error code. >> >> By using dma_request_chan() directly the driver can support deferred >> probing against DMA. >> >> Signed-off-by: Peter Ujfalusi >> --- >> Hi, >> >> Changes since v1: >> - Fall back to IRQ mode for ADC only in case of ENODEV > > Hi Peter, > > Thanks for the patch, > > Please find a minor comment here after. Apart from that, you can add my: > > Acked-by: Fabrice Gasnier > > >> >> Regards, >> Peter >> >> drivers/iio/adc/stm32-dfsdm-adc.c | 21 +++++++++++++++++---- >> 1 file changed, 17 insertions(+), 4 deletions(-) >> >> diff --git a/drivers/iio/adc/stm32-dfsdm-adc.c b/drivers/iio/adc/stm32-dfsdm-adc.c >> index e493242c266e..74a2211bdff4 100644 >> --- a/drivers/iio/adc/stm32-dfsdm-adc.c >> +++ b/drivers/iio/adc/stm32-dfsdm-adc.c >> @@ -1383,9 +1383,13 @@ static int stm32_dfsdm_dma_request(struct iio_dev *indio_dev) >> { >> struct stm32_dfsdm_adc *adc = iio_priv(indio_dev); >> >> - adc->dma_chan = dma_request_slave_channel(&indio_dev->dev, "rx"); >> - if (!adc->dma_chan) >> - return -EINVAL; >> + adc->dma_chan = dma_request_chan(&indio_dev->dev, "rx"); >> + if (IS_ERR(adc->dma_chan)) { >> + int ret = PTR_ERR(adc->dma_chan); >> + >> + adc->dma_chan = NULL; >> + return ret; > > You may "return PTR_ERR(adc->dma_chan);" directly here. I don't make decision here on behalf of the adc path on to go forward w/ or w/o DMA support and if we go ahead the stm32_dfsdm_dma_release() needs the dma_chan to be NULL in case we don't use DMA. It is much cleaner to set dma_chan to NULL here than doing it in other paths. > > Best Regards, > Fabrice > >> + } >> >> adc->rx_buf = dma_alloc_coherent(adc->dma_chan->device->dev, >> DFSDM_DMA_BUFFER_SIZE, >> @@ -1509,7 +1513,16 @@ static int stm32_dfsdm_adc_init(struct iio_dev *indio_dev) >> init_completion(&adc->completion); >> >> /* Optionally request DMA */ >> - if (stm32_dfsdm_dma_request(indio_dev)) { >> + ret = stm32_dfsdm_dma_request(indio_dev); >> + if (ret) { >> + if (ret != -ENODEV) { >> + if (ret != -EPROBE_DEFER) >> + dev_err(&indio_dev->dev, >> + "DMA channel request failed with %d\n", >> + ret); >> + return ret; >> + } >> + >> dev_dbg(&indio_dev->dev, "No DMA support\n"); >> return 0; >> } >> - Péter Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki. 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