From mboxrd@z Thu Jan 1 00:00:00 1970 From: robert.jarzmik@free.fr (Robert Jarzmik) Date: Mon, 15 Feb 2016 19:22:36 +0100 Subject: [PATCH 4/4] dmaengine: pxa_dma: fix the maximum requestor line In-Reply-To: <20160215173300.GN19598@localhost> (Vinod Koul's message of "Mon, 15 Feb 2016 23:03:00 +0530") References: <1455225798-9510-1-git-send-email-robert.jarzmik@free.fr> <1455225798-9510-5-git-send-email-robert.jarzmik@free.fr> <20160215163524.GI19598@localhost> <87fuwt28eu.fsf@belgarion.home> <20160215173300.GN19598@localhost> Message-ID: <87bn7h25qr.fsf@belgarion.home> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Vinod Koul writes: > On Mon, Feb 15, 2016 at 06:24:57PM +0100, Robert Jarzmik wrote: >> Vinod Koul writes: >> >> > On Thu, Feb 11, 2016 at 10:23:18PM +0100, Robert Jarzmik wrote: >> >> @@ -1399,13 +1405,17 @@ static int pxad_probe(struct platform_device *op) >> >> return PTR_ERR(pdev->base); >> >> >> >> of_id = of_match_device(pxad_dt_ids, &op->dev); >> >> - if (of_id) >> >> + if (of_id) { >> >> of_property_read_u32(op->dev.of_node, "#dma-channels", >> >> &dma_channels); >> >> - else if (pdata && pdata->dma_channels) >> >> + of_property_read_u32(op->dev.of_node, "#requestors", >> >> + &nb_requestors); >> > >> > I think we should check the return value here. This might be err in case >> > when we have older DT on platform, but still should work with default in >> > that case >> >> Okay, but how should the code react to the err case, more specifically to >> -EINVAL or -ENODATA ? As this property is optional as per the device-tree >> description, the current code leaves nb_requestors = 0, as is specified in the >> description, and fits the mmp_pdma case. >> >> What do you think should be done ? A warning message ? Something else ? > > Message is fine, but in order for not to regress we should set this to 32 > (IIRC default before this, right) and not zero. Okay, got you. For v2 I'll implement exactly this, ie. a warning message and a default to 32. I'll amend the device-tree description also to match the 32 (and not the 0 I wrote earlier). Cheers. -- Robert