spi: pl022: handle EPROBE_DEFER for dma

Handle EPROBE_DEFER explicitly so that we ensure that we get the DMA
channel specified in the device tree, instead of depending on the DMA
controller getting probed before us.

Signed-off-by: Rabin Vincent <rabin.vincent@axis.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

diff --git a/drivers/spi/spi-pl022.c b/drivers/spi/spi-pl022.c
index 94af80676684e4708d373e1551b8a6c46ea118fa..5e5fd77e27119d6ceb8d64f657884ab4ef9f3759 100644 (file)
--- a/drivers/spi/spi-pl022.c
+++ b/drivers/spi/spi-pl022.c
@@ -1171,19 +1171,31 @@ err_no_rxchan:
 static int pl022_dma_autoprobe(struct pl022 *pl022)
 {
        struct device *dev = &pl022->adev->dev;
+       struct dma_chan *chan;
+       int err;
 
        /* automatically configure DMA channels from platform, normally using DT */
-       pl022->dma_rx_channel = dma_request_slave_channel(dev, "rx");
-       if (!pl022->dma_rx_channel)
+       chan = dma_request_slave_channel_reason(dev, "rx");
+       if (IS_ERR(chan)) {
+               err = PTR_ERR(chan);
                goto err_no_rxchan;
+       }
+
+       pl022->dma_rx_channel = chan;
 
-       pl022->dma_tx_channel = dma_request_slave_channel(dev, "tx");
-       if (!pl022->dma_tx_channel)
+       chan = dma_request_slave_channel_reason(dev, "tx");
+       if (IS_ERR(chan)) {
+               err = PTR_ERR(chan);
                goto err_no_txchan;
+       }
+
+       pl022->dma_tx_channel = chan;
 
        pl022->dummypage = kmalloc(PAGE_SIZE, GFP_KERNEL);
-       if (!pl022->dummypage)
+       if (!pl022->dummypage) {
+               err = -ENOMEM;
                goto err_no_dummypage;
+       }
 
        return 0;
 
@@ -1194,7 +1206,7 @@ err_no_txchan:
        dma_release_channel(pl022->dma_rx_channel);
        pl022->dma_rx_channel = NULL;
 err_no_rxchan:
-       return -ENODEV;
+       return err;
 }
                
 static void terminate_dma(struct pl022 *pl022)
@@ -2236,6 +2248,10 @@ static int pl022_probe(struct amba_device *adev, const struct amba_id *id)
 
        /* Get DMA channels, try autoconfiguration first */
        status = pl022_dma_autoprobe(pl022);
+       if (status == -EPROBE_DEFER) {
+               dev_dbg(dev, "deferring probe to get DMA channel\n");
+               goto err_no_irq;
+       }
 
        /* If that failed, use channels from platform_info */
        if (status == 0)