Re: [PATCH v2] mmc: bcm2835: Use dma_request_chan() instead dma_request_slave_channel()

From: Nicolas Saenz Julienne
Date: Tue Dec 17 2019 - 07:34:58 EST


On Tue, 2019-12-17 at 14:22 +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 <peter.ujfalusi@xxxxxx>
> ---

Reviewed-by: Nicolas Saenz Julienne <nsaenzjulienne@xxxxxxx>

> Hi,
>
> Changes since v1:
> - instead of returning jump to err: to free up resources
>
> Regards,
> Peter
>
> drivers/mmc/host/bcm2835.c | 12 +++++++++++-
> 1 file changed, 11 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/mmc/host/bcm2835.c b/drivers/mmc/host/bcm2835.c
> index 99f61fd2a658..c3d949847cbd 100644
> --- a/drivers/mmc/host/bcm2835.c
> +++ b/drivers/mmc/host/bcm2835.c
> @@ -1393,7 +1393,17 @@ static int bcm2835_probe(struct platform_device *pdev)
> host->dma_chan = NULL;
> host->dma_desc = NULL;
>
> - host->dma_chan_rxtx = dma_request_slave_channel(dev, "rx-tx");
> + host->dma_chan_rxtx = dma_request_chan(dev, "rx-tx");
> + if (IS_ERR(host->dma_chan_rxtx)) {
> + ret = PTR_ERR(host->dma_chan_rxtx);
> + host->dma_chan_rxtx = NULL;
> +
> + if (ret == -EPROBE_DEFER)
> + goto err;
> +
> + /* Ignore errors to fall back to PIO mode */
> + }
> +
>
> clk = devm_clk_get(dev, NULL);
> if (IS_ERR(clk)) {

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