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authorLudovic Desroches <ludovic.desroches@atmel.com>2014-11-14 17:12:54 +0100
committerMark Brown <broonie@kernel.org>2014-11-24 18:57:37 +0000
commit5e9af37e46bceea9f950d2f2ae769f1aa6b6d7a6 (patch)
treeb84f57b2f8d55233718e9be05795e1e61853ac25 /drivers/spi/spi-atmel.c
parent7758e390699fb25bf91642d52734200db38e764b (diff)
spi: atmel: introduce probe deferring
Return probe defer if requesting a dma channel without a dma controller probed. Signed-off-by: Ludovic Desroches <ludovic.desroches@atmel.com> Signed-off-by: Mark Brown <broonie@kernel.org>
Diffstat (limited to 'drivers/spi/spi-atmel.c')
-rw-r--r--drivers/spi/spi-atmel.c20
1 files changed, 16 insertions, 4 deletions
diff --git a/drivers/spi/spi-atmel.c b/drivers/spi/spi-atmel.c
index 3370a3dfd883..e4193ccc4970 100644
--- a/drivers/spi/spi-atmel.c
+++ b/drivers/spi/spi-atmel.c
@@ -427,14 +427,23 @@ static int atmel_spi_configure_dma(struct atmel_spi *as)
dma_cap_zero(mask);
dma_cap_set(DMA_SLAVE, mask);
- as->dma.chan_tx = dma_request_slave_channel(dev, "tx");
- if (!as->dma.chan_tx) {
+ as->dma.chan_tx = dma_request_slave_channel_reason(dev, "tx");
+ if (IS_ERR(as->dma.chan_tx)) {
+ err = PTR_ERR(as->dma.chan_tx);
+ if (err == -EPROBE_DEFER) {
+ dev_warn(dev, "no DMA channel available at the moment\n");
+ return err;
+ }
dev_err(dev,
"DMA TX channel not available, SPI unable to use DMA\n");
err = -EBUSY;
goto error;
}
+ /*
+ * No reason to check EPROBE_DEFER here since we have already requested
+ * tx channel. If it fails here, it's for another reason.
+ */
as->dma.chan_rx = dma_request_slave_channel(dev, "rx");
if (!as->dma.chan_rx) {
@@ -456,7 +465,7 @@ static int atmel_spi_configure_dma(struct atmel_spi *as)
error:
if (as->dma.chan_rx)
dma_release_channel(as->dma.chan_rx);
- if (as->dma.chan_tx)
+ if (!IS_ERR(as->dma.chan_tx))
dma_release_channel(as->dma.chan_tx);
return err;
}
@@ -1328,8 +1337,11 @@ static int atmel_spi_probe(struct platform_device *pdev)
as->use_dma = false;
as->use_pdc = false;
if (as->caps.has_dma_support) {
- if (atmel_spi_configure_dma(as) == 0)
+ ret = atmel_spi_configure_dma(as);
+ if (ret == 0)
as->use_dma = true;
+ else if (ret == -EPROBE_DEFER)
+ return ret;
} else {
as->use_pdc = true;
}