[PATCH] mmc: mxcmmc: Use dma_request_chan() instead dma_request_slave_channel()

From: Peter Ujfalusi
Date: Tue Dec 17 2019 - 06:27:57 EST


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>
---
drivers/mmc/host/mxcmmc.c | 11 ++++++++++-
1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/drivers/mmc/host/mxcmmc.c b/drivers/mmc/host/mxcmmc.c
index 011b59a3602e..b3d654c688e5 100644
--- a/drivers/mmc/host/mxcmmc.c
+++ b/drivers/mmc/host/mxcmmc.c
@@ -1121,7 +1121,16 @@ static int mxcmci_probe(struct platform_device *pdev)
mxcmci_writel(host, host->default_irq_mask, MMC_REG_INT_CNTR);

if (!host->pdata) {
- host->dma = dma_request_slave_channel(&pdev->dev, "rx-tx");
+ host->dma = dma_request_chan(&pdev->dev, "rx-tx");
+ if (IS_ERR(host->dma)) {
+ if (PTR_ERR(host->dma) == -EPROBE_DEFER) {
+ ret = -EPROBE_DEFER;
+ goto out_clk_put;
+ }
+
+ /* Ignore errors to fall back to PIO mode */
+ host->dma = NULL;
+ }
} else {
res = platform_get_resource(pdev, IORESOURCE_DMA, 0);
if (res) {
--
Peter

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