From: Arnd Bergmann <arnd@arndb.de>
To: Sylwester Nawrocki <s.nawrocki@samsung.com>
Cc: ulf.hansson@linaro.org, linux-samsung-soc@vger.kernel.org,
sam.van.den.berge@telenet.be, linux-mmc@vger.kernel.org
Subject: Re: [PATCH] mmc: s3cmci: Use DMA slave map rather than exported DMA filter
Date: Wed, 26 Oct 2016 15:31:08 +0200 [thread overview]
Message-ID: <5765449.Er1VJf0Pit@wuerfel> (raw)
In-Reply-To: <11c41f92-5591-dd45-816f-6740da76b91f@samsung.com>
On Wednesday, October 26, 2016 2:49:44 PM CEST Sylwester Nawrocki wrote:
> On 10/26/2016 11:21 AM, Arnd Bergmann wrote:
> > On Wednesday, October 26, 2016 11:08:27 AM CEST Sylwester Nawrocki wrote:
> >> > @@ -1685,13 +1684,7 @@ static int s3cmci_probe(struct platform_device *pdev)
> >> > /* depending on the dma state, get a dma channel to use. */
> >> >
> >> > if (s3cmci_host_usedma(host)) {
> >> > - dma_cap_mask_t mask;
> >> > -
> >> > - dma_cap_zero(mask);
> >> > - dma_cap_set(DMA_SLAVE, mask);
> >> > -
> >> > - host->dma = dma_request_slave_channel_compat(mask,
> >> > - s3c24xx_dma_filter, (void *)DMACH_SDI, &pdev->dev, "rx-tx");
> >> > + host->dma = dma_request_slave_channel(&pdev->dev, "rx-tx");
> >> > if (!host->dma) {
> >> > dev_err(&pdev->dev, "cannot get DMA channel.\n");
> >> > ret = -EBUSY;
> >
> > Can you convert it to use dma_request_chan()+PTR_ERR_OR_ZERO() instead?
>
> Thanks for your review. dma_request_chan() seems to be returning
> either valid pointer or ERR_PTR(), so it would be sufficient
> to use just PTR_ERR(host->dma) on error path?
Correct. You can use either
if (IS_ERR(host->dma) {
ret = PTR_ERR(host->dma);
goto probe_free_gpio_wp;
}
or
ret = PTR_ERR_OR_ZERO(host->dma);
if (ret)
goto probe_free_gpio_wp;
The two do exactly the same, I just find the second one slightly more
intuitive, and I've seen a couple of spurious warnings caused by
the first (that won't happen here).
Arnd
prev parent reply other threads:[~2016-10-26 13:31 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-10-26 9:08 [PATCH] mmc: s3cmci: Use DMA slave map rather than exported DMA filter Sylwester Nawrocki
2016-10-26 9:21 ` Arnd Bergmann
2016-10-26 12:49 ` Sylwester Nawrocki
2016-10-26 13:31 ` Arnd Bergmann [this message]
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