linux-kernel - [PATCH v2] mmc: bcm2835: Use dma_request_chan() instead dma_request_slave

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Date:   Tue, 17 Dec 2019 14:22:54 +0200
From:   Peter Ujfalusi <peter.ujfalusi@...com>
To:     <ulf.hansson@...aro.org>, <f.fainelli@...il.com>,
        <rjui@...adcom.com>, <sbranden@...adcom.com>,
        <nsaenzjulienne@...e.de>
CC:     <vkoul@...nel.org>, <linux-mmc@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>,
        <bcm-kernel-feedback-list@...adcom.com>,
        <linux-rpi-kernel@...ts.infradead.org>,
        <linux-arm-kernel@...ts.infradead.org>
Subject: [PATCH v2] mmc: bcm2835: Use dma_request_chan() instead dma_request_slave_channel()

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@...com>
---
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)) {
-- 
Peter

Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki.
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