Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S964811AbcKDPqT (ORCPT ); Fri, 4 Nov 2016 11:46:19 -0400 Received: from galahad.ideasonboard.com ([185.26.127.97]:59713 "EHLO galahad.ideasonboard.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934249AbcKDPqR (ORCPT ); Fri, 4 Nov 2016 11:46:17 -0400 From: Laurent Pinchart To: Peter Ujfalusi Cc: mchehab@osg.samsung.com, linux-media@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2] media: omap3isp: Use dma_request_chan_by_mask() to request the DMA channel Date: Fri, 04 Nov 2016 17:46:03 +0200 Message-ID: <4166499.xzsPgrmGQ7@avalon> User-Agent: KMail/4.14.10 (Linux/4.8.6-gentoo; KDE/4.14.24; x86_64; ; ) In-Reply-To: <20161104075802.19063-1-peter.ujfalusi@ti.com> References: <20161104075802.19063-1-peter.ujfalusi@ti.com> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2950 Lines: 98 Hi Peter, Thank you for the patch. On Friday 04 Nov 2016 09:58:02 Peter Ujfalusi wrote: > When requesting the DMA channel it was mandatory that we do not have DMA > resource nor valid DMA channel via DT. In this case the > dma_request_slave_channel_compat() would fall back and request any channel > with SW trigger. > > The same can be achieved with the dma_request_chan_by_mask() without the > misleading use of the DMAengine API - implying that the omap3isp does > need to have DMA resource or valid dma binding in DT. > > Signed-off-by: Peter Ujfalusi > CC: Laurent Pinchart > CC: Mauro Carvalho Chehab Reviewed-by: Laurent Pinchart and added to my tree. > --- > Hi, > > Changes sicne v1: > - use dma_request_chan_by_mask() to request the channel as for the histogram > data reading we do not have hw syncronisation. Add comment about this also > to clarify the reason. > > Regards, > Peter > > drivers/media/platform/omap3isp/isphist.c | 28 +++++++++++++++------------- > 1 file changed, 15 insertions(+), 13 deletions(-) > > diff --git a/drivers/media/platform/omap3isp/isphist.c > b/drivers/media/platform/omap3isp/isphist.c index > 7138b043a4aa..a4ed5d140d48 100644 > --- a/drivers/media/platform/omap3isp/isphist.c > +++ b/drivers/media/platform/omap3isp/isphist.c > @@ -18,7 +18,6 @@ > #include > #include > #include > -#include > #include > #include > > @@ -486,27 +485,30 @@ int omap3isp_hist_init(struct isp_device *isp) > hist->isp = isp; > > if (HIST_CONFIG_DMA) { > - struct platform_device *pdev = to_platform_device(isp->dev); > - struct resource *res; > - unsigned int sig = 0; > dma_cap_mask_t mask; > > + /* > + * We need slave capable channel without DMA request line for > + * reading out the data. > + * For this we can use dma_request_chan_by_mask() as we are > + * happy with any channel as long as it is capable of slave > + * configuration. > + */ > dma_cap_zero(mask); > dma_cap_set(DMA_SLAVE, mask); > + hist->dma_ch = dma_request_chan_by_mask(&mask); > + if (IS_ERR(hist->dma_ch)) { > + ret = PTR_ERR(hist->dma_ch); > + if (ret == -EPROBE_DEFER) > + return ret; > > - res = platform_get_resource_byname(pdev, IORESOURCE_DMA, > - "hist"); > - if (res) > - sig = res->start; > - > - hist->dma_ch = dma_request_slave_channel_compat(mask, > - omap_dma_filter_fn, &sig, isp->dev, "hist"); > - if (!hist->dma_ch) > + hist->dma_ch = NULL; > dev_warn(isp->dev, > "hist: DMA channel request failed, using PIO\n"); > - else > + } else { > dev_dbg(isp->dev, "hist: using DMA channel %s\n", > dma_chan_name(hist->dma_ch)); > + } > } > > hist->ops = &hist_ops; -- Regards, Laurent Pinchart