[RFC v02 11/15] spi: davinci: Use dma_request_chan() to requesting DMA channel

Peter Ujfalusi
2015-11-30T13:45:41Z

With the new dma_request_chan() the clinet driver does not need to look for
the DMA resource and it does not need to pass filter_fn anymore.
By switching to the new API the davinci_mmc driver can now support deferred
probing against DMA.

Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
---
drivers/spi/spi-davinci.c | 76 +++++++++++++++--------------------------------
1 file changed, 24 insertions(+), 52 deletions(-)

diff --git a/drivers/spi/spi-davinci.c b/drivers/spi/spi-davinci.c
index 7d3af3eacf57..540fc8754085 100644
--- a/drivers/spi/spi-davinci.c
+++ b/drivers/spi/spi-davinci.c
@@ -23,7 +23,6 @@
#include <linux/clk.h>
#include <linux/dmaengine.h>
#include <linux/dma-mapping.h>
-#include <linux/edma.h>
#include <linux/of.h>
#include <linux/of_device.h>
#include <linux/of_gpio.h>
@@ -33,8 +32,6 @@

#include <linux/platform_data/spi-davinci.h>

-#define SPI_NO_RESOURCE ((resource_size_t)-1)
-
#define CS_DEFAULT 0xFF

#define SPIFMT_PHASE_MASK BIT(16)
@@ -130,8 +127,6 @@ struct davinci_spi {

struct dma_chan *dma_rx;
struct dma_chan *dma_tx;
- int dma_rx_chnum;
- int dma_tx_chnum;

struct davinci_spi_platform_data pdata;

@@ -796,35 +791,19 @@ static irqreturn_t davinci_spi_irq(s32 irq, void *data)

static int davinci_spi_request_dma(struct davinci_spi *dspi)
{
- dma_cap_mask_t mask;
struct device *sdev = dspi->bitbang.master->dev.parent;
- int r;
-
- dma_cap_zero(mask);
- dma_cap_set(DMA_SLAVE, mask);

- dspi->dma_rx = dma_request_channel(mask, edma_filter_fn,
- &dspi->dma_rx_chnum);
- if (!dspi->dma_rx) {
- dev_err(sdev, "request RX DMA channel failed\n");
- r = -ENODEV;
- goto rx_dma_failed;
- }
+ dspi->dma_rx = dma_request_chan(sdev, "rx");
+ if (IS_ERR(dspi->dma_rx))
+ return PTR_ERR(dspi->dma_rx);

- dspi->dma_tx = dma_request_channel(mask, edma_filter_fn,
- &dspi->dma_tx_chnum);
- if (!dspi->dma_tx) {
- dev_err(sdev, "request TX DMA channel failed\n");
- r = -ENODEV;
- goto tx_dma_failed;
+ dspi->dma_tx = dma_request_chan(sdev, "tx");
+ if (IS_ERR(dspi->dma_tx)) {
+ dma_release_channel(dspi->dma_rx);
+ return PTR_ERR(dspi->dma_tx);
}

return 0;
-
-tx_dma_failed:
- dma_release_channel(dspi->dma_rx);
-rx_dma_failed:
- return r;
}

#if defined(CONFIG_OF)
@@ -935,8 +914,6 @@ static int davinci_spi_probe(struct platform_device *pdev)
struct davinci_spi *dspi;
struct davinci_spi_platform_data *pdata;
struct resource *r;
- resource_size_t dma_rx_chan = SPI_NO_RESOURCE;
- resource_size_t dma_tx_chan = SPI_NO_RESOURCE;
int ret = 0;
u32 spipc0;

@@ -1043,27 +1020,15 @@ static int davinci_spi_probe(struct platform_device *pdev)
}
}

- r = platform_get_resource(pdev, IORESOURCE_DMA, 0);
- if (r)
- dma_rx_chan = r->start;
- r = platform_get_resource(pdev, IORESOURCE_DMA, 1);
- if (r)
- dma_tx_chan = r->start;
-
dspi->bitbang.txrx_bufs = davinci_spi_bufs;
- if (dma_rx_chan != SPI_NO_RESOURCE &&
- dma_tx_chan != SPI_NO_RESOURCE) {
- dspi->dma_rx_chnum = dma_rx_chan;
- dspi->dma_tx_chnum = dma_tx_chan;
-
- ret = davinci_spi_request_dma(dspi);
- if (ret)
- goto free_clk;
-
- dev_info(&pdev->dev, "DMA: supported\n");
- dev_info(&pdev->dev, "DMA: RX channel: %pa, TX channel: %pa, event queue: %d\n",
- &dma_rx_chan, &dma_tx_chan,
- pdata->dma_event_q);
+
+ ret = davinci_spi_request_dma(dspi);
+ if (ret == -EPROBE_DEFER) {
+ goto free_clk;
+ } else if (ret) {
+ dev_info(&pdev->dev, "DMA is not supported (%d)\n", ret);
+ dspi->dma_rx = NULL;
+ dspi->dma_tx = NULL;
}

dspi->get_rx = davinci_spi_rx_buf_u8;
@@ -1101,8 +1066,10 @@ static int davinci_spi_probe(struct platform_device *pdev)
return ret;

free_dma:
- dma_release_channel(dspi->dma_rx);
- dma_release_channel(dspi->dma_tx);
+ if (dspi->dma_rx) {
+ dma_release_channel(dspi->dma_rx);
+ dma_release_channel(dspi->dma_tx);
+ }
free_clk:
clk_disable_unprepare(dspi->clk);
free_master:
@@ -1133,6 +1100,11 @@ static int davinci_spi_remove(struct platform_device *pdev)
clk_disable_unprepare(dspi->clk);
spi_master_put(master);

+ if (dspi->dma_rx) {
+ dma_release_channel(dspi->dma_rx);
+ dma_release_channel(dspi->dma_tx);
+ }
+
return 0;
}

--
2.6.3