diff options
Diffstat (limited to 'drivers/dma/dmaengine.c')
| -rw-r--r-- | drivers/dma/dmaengine.c | 35 |
1 files changed, 31 insertions, 4 deletions
diff --git a/drivers/dma/dmaengine.c b/drivers/dma/dmaengine.c index ef63b9058f3c..92caad629d99 100644 --- a/drivers/dma/dmaengine.c +++ b/drivers/dma/dmaengine.c @@ -540,6 +540,8 @@ EXPORT_SYMBOL_GPL(dma_get_slave_channel); * @mask: capabilities that the channel must satisfy * @fn: optional callback to disposition available channels * @fn_param: opaque parameter to pass to dma_filter_fn + * + * Returns pointer to appropriate DMA channel on success or NULL. */ struct dma_chan *__dma_request_channel(const dma_cap_mask_t *mask, dma_filter_fn fn, void *fn_param) @@ -591,18 +593,43 @@ EXPORT_SYMBOL_GPL(__dma_request_channel); * dma_request_slave_channel - try to allocate an exclusive slave channel * @dev: pointer to client device structure * @name: slave channel name + * + * Returns pointer to appropriate DMA channel on success or an error pointer. */ -struct dma_chan *dma_request_slave_channel(struct device *dev, const char *name) +struct dma_chan *dma_request_slave_channel_reason(struct device *dev, + const char *name) { + struct dma_chan *chan; + /* If device-tree is present get slave info from here */ if (dev->of_node) return of_dma_request_slave_channel(dev->of_node, name); /* If device was enumerated by ACPI get slave info from here */ - if (ACPI_HANDLE(dev)) - return acpi_dma_request_slave_chan_by_name(dev, name); + if (ACPI_HANDLE(dev)) { + chan = acpi_dma_request_slave_chan_by_name(dev, name); + if (chan) + return chan; + } - return NULL; + return ERR_PTR(-ENODEV); +} +EXPORT_SYMBOL_GPL(dma_request_slave_channel_reason); + +/** + * dma_request_slave_channel - try to allocate an exclusive slave channel + * @dev: pointer to client device structure + * @name: slave channel name + * + * Returns pointer to appropriate DMA channel on success or NULL. + */ +struct dma_chan *dma_request_slave_channel(struct device *dev, + const char *name) +{ + struct dma_chan *ch = dma_request_slave_channel_reason(dev, name); + if (IS_ERR(ch)) + return NULL; + return ch; } EXPORT_SYMBOL_GPL(dma_request_slave_channel); |