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Subject[PATCH 3/9] spi: bcm2835: Use dma_request_chan() instead dma_request_slave_channel()
Date
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>
---
drivers/spi/spi-bcm2835.c | 34 ++++++++++++++++++++++++----------
1 file changed, 24 insertions(+), 10 deletions(-)

diff --git a/drivers/spi/spi-bcm2835.c b/drivers/spi/spi-bcm2835.c
index 662d55e9f21d..69df79914504 100644
--- 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 @@ static void bcm2835_dma_init(struct spi_controller *ctlr, struct device *dev,
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,
--
Peter
Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki.
Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki

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