redonkable/alistair23-linux
redonkable/alistair23-linux
1
0
Fork 0
Code Releases Activity

spi: bcm2835: Use dma_request_chan() instead dma_request_slave_channel()

Browse source 
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>
This commit is contained in:
Peter Ujfalusi 2019-12-12 15:55:44 +02:00 committed by Mark Brown
parent 666224b43b
commit 6133fed053
No known key found for this signature in database
GPG key ID: 24D68B725D5487D0
1 changed files with 24 additions and 10 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

34
drivers/spi/spi-bcm2835.c
View file

@ -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,