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=-8.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_2 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 2D271C2D0D0 for ; Mon, 23 Dec 2019 15:45:45 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id EB7A220715 for ; Mon, 23 Dec 2019 15:45:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1577115945; bh=dMvuhm75mr3sKsjJ7Ywmef0XPGuVcGPnp7cfWIxsSCQ=; h=Date:From:To:Cc:Subject:In-Reply-To:References:List-ID:From; b=Md5H1PeD2KKtC826BGQ/k07zp2mEiMU/yFw9Lq/6fg/WRAskTXR4VrZFgK7wd7wms jgsrci0GPRerFs5o5gO2Hq/4j84WzV2+fsvP/Ara696PJNezILJg/MuobJj9UW2/uc EPBcgge+0+rJEOiT5IVyQCbZT1gsHb0z24GCyqso= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726871AbfLWPpn (ORCPT ); Mon, 23 Dec 2019 10:45:43 -0500 Received: from mail.kernel.org ([198.145.29.99]:44238 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725912AbfLWPpn (ORCPT ); Mon, 23 Dec 2019 10:45:43 -0500 Received: from archlinux (cpc149474-cmbg20-2-0-cust94.5-4.cable.virginm.net [82.4.196.95]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 2E788205C9; Mon, 23 Dec 2019 15:45:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1577115942; bh=dMvuhm75mr3sKsjJ7Ywmef0XPGuVcGPnp7cfWIxsSCQ=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=DaHSqFaCNmeahbQvTb1DfZhJNooZK+BVo6taxtGIlc5mPJD4W3/FyBXlDK2WofP/V 9EFQtQCR7tggAtHZKUrGnV/EsHhMKe2KKfkzC9cP1pre4W3q2jMtYbPkpIgyG5bGxX /kVcHXicrY2042NtyLlZClV0KvhGolQp//VCTKB0= Date: Mon, 23 Dec 2019 15:45:38 +0000 From: Jonathan Cameron To: Peter Ujfalusi Cc: , , , , , , Subject: Re: [PATCH] iio: adc: stm32-dfsdm: Use dma_request_chan() instead dma_request_slave_channel() Message-ID: <20191223154538.74a76f94@archlinux> In-Reply-To: <20191217075221.23895-1-peter.ujfalusi@ti.com> References: <20191217075221.23895-1-peter.ujfalusi@ti.com> X-Mailer: Claws Mail 3.17.4 (GTK+ 2.24.32; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 17 Dec 2019 09:52:21 +0200 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 I don't think this one goes far enough. One of the paths does: /* Optionally request DMA */ if (stm32_dfsdm_dma_request(indio_dev)) { dev_dbg(&indio_dev->dev, "No DMA support\n"); return 0; } That needs specific handling for deferred probing. > --- > drivers/iio/adc/stm32-dfsdm-adc.c | 6 +++--- > 1 file changed, 3 insertions(+), 3 deletions(-) > > diff --git a/drivers/iio/adc/stm32-dfsdm-adc.c b/drivers/iio/adc/stm32-dfsdm-adc.c > index e493242c266e..3aac1a21f9d0 100644 > --- a/drivers/iio/adc/stm32-dfsdm-adc.c > +++ b/drivers/iio/adc/stm32-dfsdm-adc.c > @@ -1383,9 +1383,9 @@ 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)) > + return PTR_ERR(adc->dma_chan); > > adc->rx_buf = dma_alloc_coherent(adc->dma_chan->device->dev, > DFSDM_DMA_BUFFER_SIZE,