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>

1 files changed, 22 insertions, 6 deletions

diff --git a/drivers/spi/spi-pl022.c b/drivers/spi/spi-pl022.c
index 94af80676684..5e5fd77e2711 100644
--- 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)