spi: 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@ti.com>
Link: https://lore.kernel.org/r/20191212135550.4634-4-peter.ujfalusi@ti.com
Signed-off-by: Mark Brown <broonie@kernel.org>

diff --git a/drivers/spi/spi-bcm2835.c b/drivers/spi/spi-bcm2835.c
index 662d55e..69df799 100644 (file)
--- a/drivers/spi/spi-bcm2835.c
+++ b/drivers/spi/spi-bcm2835.c
@@ -888,8 +888,8 @@ static void bcm2835_dma_release(struct spi_controller *ctlr,
        }
 }
 
-static void bcm2835_dma_init(struct spi_controller *ctlr, struct device *dev,
-                            struct bcm2835_spi *bs)
+static int bcm2835_dma_init(struct spi_controller *ctlr, struct device *dev,
+                           struct bcm2835_spi *bs)
 {
        struct dma_slave_config slave_config;
        const __be32 *addr;
@@ -900,19 +900,24 @@ static void bcm2835_dma_init(struct spi_controller *ctlr, struct device *dev,
        addr = of_get_address(ctlr->dev.of_node, 0, NULL, NULL);
        if (!addr) {
                dev_err(dev, "could not get DMA-register address - not using dma mode\n");
-               goto err;
+               /* Fall back to interrupt mode */
+               return 0;
        }
        dma_reg_base = be32_to_cpup(addr);
 
        /* get tx/rx dma */
-       ctlr->dma_tx = dma_request_slave_channel(dev, "tx");
-       if (!ctlr->dma_tx) {
+       ctlr->dma_tx = dma_request_chan(dev, "tx");
+       if (IS_ERR(ctlr->dma_tx)) {
                dev_err(dev, "no tx-dma configuration found - not using dma mode\n");
+               ret = PTR_ERR(ctlr->dma_tx);
+               ctlr->dma_tx = NULL;
                goto err;
        }
-       ctlr->dma_rx = dma_request_slave_channel(dev, "rx");
-       if (!ctlr->dma_rx) {
+       ctlr->dma_rx = dma_request_chan(dev, "rx");
+       if (IS_ERR(ctlr->dma_rx)) {
                dev_err(dev, "no rx-dma configuration found - not using dma mode\n");
+               ret = PTR_ERR(ctlr->dma_rx);
+               ctlr->dma_rx = NULL;
                goto err_release;
        }
 
@@ -997,7 +1002,7 @@ static void bcm2835_dma_init(struct spi_controller *ctlr, struct device *dev,
        /* all went well, so set can_dma */
        ctlr->can_dma = bcm2835_spi_can_dma;
 
-       return;
+       return 0;
 
 err_config:
        dev_err(dev, "issue configuring dma: %d - not using DMA mode\n",
@@ -1005,7 +1010,14 @@ err_config:
 err_release:
        bcm2835_dma_release(ctlr, bs);
 err:
-       return;
+       /*
+        * Only report error for deferred probing, otherwise fall back to
+        * interrupt mode
+        */
+       if (ret != -EPROBE_DEFER)
+               ret = 0;
+
+       return ret;
 }
 
 static int bcm2835_spi_transfer_one_poll(struct spi_controller *ctlr,
@@ -1317,7 +1329,9 @@ static int bcm2835_spi_probe(struct platform_device *pdev)
 
        clk_prepare_enable(bs->clk);
 
-       bcm2835_dma_init(ctlr, &pdev->dev, bs);
+       err = bcm2835_dma_init(ctlr, &pdev->dev, bs);
+       if (err)
+               goto out_clk_disable;
 
        /* initialise the hardware with the default polarities */
        bcm2835_wr(bs, BCM2835_SPI_CS,