spi: rockchip: check requesting dma channel with EPROBE_DEFER

Let's defer probing the driver if the return value of
dma_request_slave_channel is ERR_PTR(-EPROBE_DEFER) instead
of disabling dma capability directly.

Signed-off-by: Shawn Lin <shawn.lin@rock-chips.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

1 files changed, 7 insertions, 1 deletions

diff --git a/drivers/spi/spi-rockchip.c b/drivers/spi/spi-rockchip.c
index b6b8a0bb5b2f..795fd191faa7 100644
--- a/drivers/spi/spi-rockchip.c
+++ b/drivers/spi/spi-rockchip.c
@@ -730,8 +730,14 @@ static int rockchip_spi_probe(struct platform_device *pdev)
         master->handle_err = rockchip_spi_handle_err;
 
         rs->dma_tx.ch = dma_request_slave_channel(rs->dev, "tx");
-        if (!rs->dma_tx.ch)
+        if (IS_ERR_OR_NULL(rs->dma_tx.ch)) {
+                /* Check tx to see if we need defer probing driver */
+                if (PTR_ERR(rs->dma_tx.ch) == -EPROBE_DEFER) {
+                        ret = -EPROBE_DEFER;
+                        goto err_get_fifo_len;
+                }
                 dev_warn(rs->dev, "Failed to request TX DMA channel\n");
+        }
 
         rs->dma_rx.ch = dma_request_slave_channel(rs->dev, "rx");
         if (!rs->dma_rx.ch) {