[PATCH 15/37] staging: comedi: ni_labpc_isadma: tidy up labpc_init_dma_chan()

[H Hartley Sweeten]

DMA support is optional for the labpc driver. The return value from
labpc_init_dma_chan() is not even checked by the caller.

Change the return type to void and tidy up the function a bit.

Signed-off-by: H Hartley Sweeten <hswee...@visionengravers.com>
Cc: Ian Abbott <abbo...@mev.co.uk>
Cc: Greg Kroah-Hartman <gre...@linuxfoundation.org>
---
 drivers/staging/comedi/drivers/ni_labpc_isadma.c | 22 ++++++++--------------
 drivers/staging/comedi/drivers/ni_labpc_isadma.h |  7 +++----
 2 files changed, 11 insertions(+), 18 deletions(-)

diff --git a/drivers/staging/comedi/drivers/ni_labpc_isadma.c 
b/drivers/staging/comedi/drivers/ni_labpc_isadma.c
index b7217a7..829c4e4 100644
--- a/drivers/staging/comedi/drivers/ni_labpc_isadma.c
+++ b/drivers/staging/comedi/drivers/ni_labpc_isadma.c
@@ -163,28 +163,24 @@ void labpc_handle_dma_status(struct comedi_device *dev)
 }
 EXPORT_SYMBOL_GPL(labpc_handle_dma_status);
 
-int labpc_init_dma_chan(struct comedi_device *dev, unsigned int dma_chan)
+void labpc_init_dma_chan(struct comedi_device *dev, unsigned int dma_chan)
 {
        struct labpc_private *devpriv = dev->private;
        struct labpc_dma_desc *dma = &devpriv->dma_desc;
-       void *dma_buffer;
        unsigned long dma_flags;
-       int ret;
 
        if (dma_chan != 1 && dma_chan != 3)
-               return -EINVAL;
+               return;
 
-       dma_buffer = kmalloc(dma_buffer_size, GFP_KERNEL | GFP_DMA);
-       if (!dma_buffer)
-               return -ENOMEM;
+       if (request_dma(dma_chan, dev->board_name))
+               return;
 
-       ret = request_dma(dma_chan, dev->board_name);
-       if (ret) {
-               kfree(dma_buffer);
-               return ret;
+       dma->virt_addr = kmalloc(dma_buffer_size, GFP_KERNEL | GFP_DMA);
+       if (!dma->virt_addr) {
+               free_dma(dma_chan);
+               return;
        }
 
-       dma->virt_addr = dma_buffer;
        dma->chan = dma_chan;
        dma->hw_addr = virt_to_bus(dma->virt_addr);
 
@@ -192,8 +188,6 @@ int labpc_init_dma_chan(struct comedi_device *dev, unsigned 
int dma_chan)
        disable_dma(dma->chan);
        set_dma_mode(dma->chan, DMA_MODE_READ);
        release_dma_lock(dma_flags);
-
-       return 0;
 }
 EXPORT_SYMBOL_GPL(labpc_init_dma_chan);
 
diff --git a/drivers/staging/comedi/drivers/ni_labpc_isadma.h 
b/drivers/staging/comedi/drivers/ni_labpc_isadma.h
index 2582f22..8f062f7 100644
--- a/drivers/staging/comedi/drivers/ni_labpc_isadma.h
+++ b/drivers/staging/comedi/drivers/ni_labpc_isadma.h
@@ -16,7 +16,7 @@ static inline bool labpc_have_dma_chan(struct comedi_device 
*dev)
        return (bool)devpriv->dma_desc.chan;
 }
 
-int labpc_init_dma_chan(struct comedi_device *dev, unsigned int dma_chan);
+void labpc_init_dma_chan(struct comedi_device *dev, unsigned int dma_chan);
 void labpc_free_dma_chan(struct comedi_device *dev);
 void labpc_setup_dma(struct comedi_device *dev, struct comedi_subdevice *s);
 void labpc_drain_dma(struct comedi_device *dev);
@@ -29,10 +29,9 @@ static inline bool labpc_have_dma_chan(struct comedi_device 
*dev)
        return false;
 }
 
-static inline int labpc_init_dma_chan(struct comedi_device *dev,
-                                     unsigned int dma_chan)
+static inline void labpc_init_dma_chan(struct comedi_device *dev,
+                                      unsigned int dma_chan)
 {
-       return -ENOTSUPP;
 }
 
 static inline void labpc_free_dma_chan(struct comedi_device *dev)
-- 
2.0.3

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