[RFC PATCH 10/13] spi: omap2-mcspi: dma_request_slave_channel() support for DT platforms

From: Matt Porter
Date: Thu Sep 20 2012 - 10:42:32 EST


For platforms with DT populated, use dma_request_slave_channel()
to acquire the DMA channel. For !DT platforms, we fall back to
explicitly passing the omap_dma_filter_fn() to dma_request_channel().
Once all platforms boot from DT, the dma_request_channel() path can
be dropped.

Signed-off-by: Matt Porter <mporter@xxxxxx>
---
drivers/spi/spi-omap2-mcspi.c | 68 +++++++++++++++++++++++++++++------------
1 file changed, 48 insertions(+), 20 deletions(-)

diff --git a/drivers/spi/spi-omap2-mcspi.c b/drivers/spi/spi-omap2-mcspi.c
index 9502566..1cf1072 100644
--- a/drivers/spi/spi-omap2-mcspi.c
+++ b/drivers/spi/spi-omap2-mcspi.c
@@ -104,6 +104,9 @@ struct omap2_mcspi_dma {

struct completion dma_tx_completion;
struct completion dma_rx_completion;
+
+ char dma_rx_ch_name[14];
+ char dma_tx_ch_name[14];
};

/* use PIO for small transfers, avoiding DMA setup/teardown overhead and
@@ -798,14 +801,26 @@ static int omap2_mcspi_request_dma(struct spi_device *spi)
dma_cap_zero(mask);
dma_cap_set(DMA_SLAVE, mask);
sig = mcspi_dma->dma_rx_sync_dev;
- mcspi_dma->dma_rx = dma_request_channel(mask, omap_dma_filter_fn, &sig);
+ if (spi->dev.of_node)
+ mcspi_dma->dma_rx =
+ dma_request_slave_channel(&master->dev,
+ mcspi_dma->dma_rx_ch_name);
+ else
+ mcspi_dma->dma_rx =
+ dma_request_channel(mask, omap_dma_filter_fn, &sig);
if (!mcspi_dma->dma_rx) {
dev_err(&spi->dev, "no RX DMA engine channel for McSPI\n");
return -EAGAIN;
}

sig = mcspi_dma->dma_tx_sync_dev;
- mcspi_dma->dma_tx = dma_request_channel(mask, omap_dma_filter_fn, &sig);
+ if (spi->dev.of_node)
+ mcspi_dma->dma_tx =
+ dma_request_slave_channel(&master->dev,
+ mcspi_dma->dma_tx_ch_name);
+ else
+ mcspi_dma->dma_tx =
+ dma_request_channel(mask, omap_dma_filter_fn, &sig);
if (!mcspi_dma->dma_tx) {
dev_err(&spi->dev, "no TX DMA engine channel for McSPI\n");
dma_release_channel(mcspi_dma->dma_rx);
@@ -1194,29 +1209,42 @@ static int __devinit omap2_mcspi_probe(struct platform_device *pdev)
goto free_master;

for (i = 0; i < master->num_chipselect; i++) {
- char dma_ch_name[14];
+ char *dma_rx_ch_name = mcspi->dma_channels[i].dma_rx_ch_name;
+ char *dma_tx_ch_name = mcspi->dma_channels[i].dma_tx_ch_name;
struct resource *dma_res;

- sprintf(dma_ch_name, "rx%d", i);
- dma_res = platform_get_resource_byname(pdev, IORESOURCE_DMA,
- dma_ch_name);
- if (!dma_res) {
- dev_dbg(&pdev->dev, "cannot get DMA RX channel\n");
- status = -ENODEV;
- break;
- }
+ sprintf(dma_rx_ch_name, "rx%d", i);
+ if (!pdev->dev.of_node) {
+ dma_res =
+ platform_get_resource_byname(pdev,
+ IORESOURCE_DMA,
+ dma_rx_ch_name);
+ if (!dma_res) {
+ dev_dbg(&pdev->dev,
+ "cannot get DMA RX channel\n");
+ status = -ENODEV;
+ break;
+ }

- mcspi->dma_channels[i].dma_rx_sync_dev = dma_res->start;
- sprintf(dma_ch_name, "tx%d", i);
- dma_res = platform_get_resource_byname(pdev, IORESOURCE_DMA,
- dma_ch_name);
- if (!dma_res) {
- dev_dbg(&pdev->dev, "cannot get DMA TX channel\n");
- status = -ENODEV;
- break;
+ mcspi->dma_channels[i].dma_rx_sync_dev =
+ dma_res->start;
}
+ sprintf(dma_tx_ch_name, "tx%d", i);
+ if (!pdev->dev.of_node) {
+ dma_res =
+ platform_get_resource_byname(pdev,
+ IORESOURCE_DMA,
+ dma_tx_ch_name);
+ if (!dma_res) {
+ dev_dbg(&pdev->dev,
+ "cannot get DMA TX channel\n");
+ status = -ENODEV;
+ break;
+ }

- mcspi->dma_channels[i].dma_tx_sync_dev = dma_res->start;
+ mcspi->dma_channels[i].dma_tx_sync_dev =
+ dma_res->start;
+ }
}

if (status < 0)
--
1.7.9.5

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