From mboxrd@z Thu Jan 1 00:00:00 1970 From: Roger Quadros Subject: Re: [PATCH 1/5] mtd: nand: omap2: Support parsing dma channel information from DT Date: Wed, 14 Oct 2015 17:11:43 +0300 Message-ID: <561E629F.5070202@ti.com> References: <1444700338-27582-1-git-send-email-fcooper@ti.com> <1444700338-27582-2-git-send-email-fcooper@ti.com> <561E3E4F.9020302@ti.com> <561E41EB.3050005@ti.com> <561E5803.5090609@ti.com> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <561E5803.5090609@ti.com> Sender: linux-kernel-owner@vger.kernel.org To: "Franklin S Cooper Jr." Cc: linux-kernel@vger.kernel.org, devicetree@vger.kernel.org, linux-omap@vger.kernel.org, linux-mtd@lists.infradead.org, nsekhar@ti.com, computersforpeace@gmail.com, dwmw2@infradead.org, tony@atomide.com List-Id: devicetree@vger.kernel.org On 14/10/15 16:26, Franklin S Cooper Jr. wrote: > > > On 10/14/2015 06:52 AM, Roger Quadros wrote: >> Franklin, >> >> On 14/10/15 14:36, Roger Quadros wrote: >>> On 13/10/15 04:38, Franklin S Cooper Jr wrote: >>>> Switch from dma_request_channel to allow passing dma channel >>>> information from DT rather than hardcoding a value. >>>> >>>> Signed-off-by: Franklin S Cooper Jr >>> Acked-by: Roger Quadros >>> >>>> --- >>>> drivers/mtd/nand/omap2.c | 4 +++- >>>> 1 file changed, 3 insertions(+), 1 deletion(-) >>>> >>>> diff --git a/drivers/mtd/nand/omap2.c b/drivers/mtd/nand/omap2.c >>>> index d0f2620..957c32f 100644 >>>> --- a/drivers/mtd/nand/omap2.c >>>> +++ b/drivers/mtd/nand/omap2.c >>>> @@ -1866,7 +1866,9 @@ static int omap_nand_probe(struct platform_device *pdev) >>>> dma_cap_zero(mask); >>>> dma_cap_set(DMA_SLAVE, mask); >>>> sig = OMAP24XX_DMA_GPMC; >>>> - info->dma = dma_request_channel(mask, omap_dma_filter_fn, &sig); >>>> + info->dma = dma_request_slave_channel_compat(mask, >>>> + omap_dma_filter_fn, &sig, pdev->dev.parent, "rxtx"); >>>> + >> Just discovered that you are using the parent device node. >> >> How about moving the dma bindings to the nand node instead and using >> pdev->dev here? > Roger, > > From what I can tell the interrupt number and the dma channel will always be > the same no matter what. Doesn't matter if you have multiple nands or a > combination of nands and nors. Since that is the case I think it just makes > sense to leave it in the gpmc parent node and define it once. Is prefetch/writepost dma used for NOR or any other GPMC peripheral or only for NAND? Let's also get Tony's inputs on this. >>>> if (!info->dma) { >>>> dev_err(&pdev->dev, "DMA engine request failed\n"); >>>> err = -ENXIO; >>>> -- cheers, -roger