staging: comedi: ni_mio_common: add "no_channel" versions of some functions

ni_release_ai_mite_channel(), ni_release_ao_mite_channel(),
ni_release_gpct_mite_channel() and ni_release_cdo_mite_channel()
call functions which interpret -1 as a special value meaning "no channel".
This patch adds explicit "no_channel" versions instead.

On the other hand, after "no_channel" versions are used,
ni_set_ai_dma_channel(), ni_set_ao_dma_channel(),
ni_set_gpct_dma_channel(), ni_set_cdo_dma_channel() are called with actual
"channel" parameter being always unsigned, so their signatures are changed
accordingly.

A side benefit of the changes is suppressesing 4 sparse warnings:
"warning: shift too big (4294967295) for type int".

Signed-off-by: Andrzej Pietrasiewicz <andrzejtp2010@gmail.com>
Reviewed-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/staging/comedi/drivers/ni_mio_common.c b/drivers/staging/comedi/drivers/ni_mio_common.c
index cbb44fc..5e8130a 100644 (file)
--- a/drivers/staging/comedi/drivers/ni_mio_common.c
+++ b/drivers/staging/comedi/drivers/ni_mio_common.c
@@ -579,48 +579,54 @@ static inline unsigned ni_stc_dma_channel_select_bitfield(unsigned channel)
        return 0;
 }
 
-/* negative channel means no channel */
-static inline void ni_set_ai_dma_channel(struct comedi_device *dev, int channel)
+static inline void ni_set_ai_dma_channel(struct comedi_device *dev,
+                                        unsigned channel)
 {
-       unsigned bits = 0;
-
-       if (channel >= 0)
-               bits = ni_stc_dma_channel_select_bitfield(channel);
+       unsigned bits = ni_stc_dma_channel_select_bitfield(channel);
 
        ni_set_bitfield(dev, NI_E_DMA_AI_AO_SEL_REG,
                        NI_E_DMA_AI_SEL_MASK, NI_E_DMA_AI_SEL(bits));
 }
 
-/* negative channel means no channel */
-static inline void ni_set_ao_dma_channel(struct comedi_device *dev, int channel)
+static inline void ni_set_ai_dma_no_channel(struct comedi_device *dev)
 {
-       unsigned bits = 0;
+       ni_set_bitfield(dev, NI_E_DMA_AI_AO_SEL_REG, NI_E_DMA_AI_SEL_MASK, 0);
+}
 
-       if (channel >= 0)
-               bits = ni_stc_dma_channel_select_bitfield(channel);
+static inline void ni_set_ao_dma_channel(struct comedi_device *dev,
+                                        unsigned channel)
+{
+       unsigned bits = ni_stc_dma_channel_select_bitfield(channel);
 
        ni_set_bitfield(dev, NI_E_DMA_AI_AO_SEL_REG,
                        NI_E_DMA_AO_SEL_MASK, NI_E_DMA_AO_SEL(bits));
 }
 
-/* negative channel means no channel */
+static inline void ni_set_ao_dma_no_channel(struct comedi_device *dev)
+{
+       ni_set_bitfield(dev, NI_E_DMA_AI_AO_SEL_REG, NI_E_DMA_AO_SEL_MASK, 0);
+}
+
 static inline void ni_set_gpct_dma_channel(struct comedi_device *dev,
                                           unsigned gpct_index,
-                                          int channel)
+                                          unsigned channel)
 {
-       unsigned bits = 0;
-
-       if (channel >= 0)
-               bits = ni_stc_dma_channel_select_bitfield(channel);
+       unsigned bits = ni_stc_dma_channel_select_bitfield(channel);
 
        ni_set_bitfield(dev, NI_E_DMA_G0_G1_SEL_REG,
                        NI_E_DMA_G0_G1_SEL_MASK(gpct_index),
                        NI_E_DMA_G0_G1_SEL(gpct_index, bits));
 }
 
-/* negative mite_channel means no channel */
+static inline void ni_set_gpct_dma_no_channel(struct comedi_device *dev,
+                                             unsigned gpct_index)
+{
+       ni_set_bitfield(dev, NI_E_DMA_G0_G1_SEL_REG,
+                       NI_E_DMA_G0_G1_SEL_MASK(gpct_index), 0);
+}
+
 static inline void ni_set_cdo_dma_channel(struct comedi_device *dev,
-                                         int mite_channel)
+                                         unsigned mite_channel)
 {
        struct ni_private *devpriv = dev->private;
        unsigned long flags;
@@ -628,16 +634,26 @@ static inline void ni_set_cdo_dma_channel(struct comedi_device *dev,
 
        spin_lock_irqsave(&devpriv->soft_reg_copy_lock, flags);
        devpriv->cdio_dma_select_reg &= ~NI_M_CDIO_DMA_SEL_CDO_MASK;
-       if (mite_channel >= 0) {
-               /*
-                * XXX just guessing ni_stc_dma_channel_select_bitfield()
-                * returns the right bits, under the assumption the cdio dma
-                * selection works just like ai/ao/gpct.
-                * Definitely works for dma channels 0 and 1.
-                */
-               bits = ni_stc_dma_channel_select_bitfield(mite_channel);
-               devpriv->cdio_dma_select_reg |= NI_M_CDIO_DMA_SEL_CDO(bits);
-       }
+       /*
+        * XXX just guessing ni_stc_dma_channel_select_bitfield()
+        * returns the right bits, under the assumption the cdio dma
+        * selection works just like ai/ao/gpct.
+        * Definitely works for dma channels 0 and 1.
+        */
+       bits = ni_stc_dma_channel_select_bitfield(mite_channel);
+       devpriv->cdio_dma_select_reg |= NI_M_CDIO_DMA_SEL_CDO(bits);
+       ni_writeb(dev, devpriv->cdio_dma_select_reg, NI_M_CDIO_DMA_SEL_REG);
+       mmiowb();
+       spin_unlock_irqrestore(&devpriv->soft_reg_copy_lock, flags);
+}
+
+static inline void ni_set_cdo_dma_no_channel(struct comedi_device *dev)
+{
+       struct ni_private *devpriv = dev->private;
+       unsigned long flags;
+
+       spin_lock_irqsave(&devpriv->soft_reg_copy_lock, flags);
+       devpriv->cdio_dma_select_reg &= ~NI_M_CDIO_DMA_SEL_CDO_MASK;
        ni_writeb(dev, devpriv->cdio_dma_select_reg, NI_M_CDIO_DMA_SEL_REG);
        mmiowb();
        spin_unlock_irqrestore(&devpriv->soft_reg_copy_lock, flags);
@@ -745,7 +761,7 @@ static void ni_release_ai_mite_channel(struct comedi_device *dev)
 
        spin_lock_irqsave(&devpriv->mite_channel_lock, flags);
        if (devpriv->ai_mite_chan) {
-               ni_set_ai_dma_channel(dev, -1);
+               ni_set_ai_dma_no_channel(dev);
                mite_release_channel(devpriv->ai_mite_chan);
                devpriv->ai_mite_chan = NULL;
        }
@@ -761,7 +777,7 @@ static void ni_release_ao_mite_channel(struct comedi_device *dev)
 
        spin_lock_irqsave(&devpriv->mite_channel_lock, flags);
        if (devpriv->ao_mite_chan) {
-               ni_set_ao_dma_channel(dev, -1);
+               ni_set_ao_dma_no_channel(dev);
                mite_release_channel(devpriv->ao_mite_chan);
                devpriv->ao_mite_chan = NULL;
        }
@@ -781,7 +797,7 @@ static void ni_release_gpct_mite_channel(struct comedi_device *dev,
                struct mite_channel *mite_chan =
                    devpriv->counter_dev->counters[gpct_index].mite_chan;
 
-               ni_set_gpct_dma_channel(dev, gpct_index, -1);
+               ni_set_gpct_dma_no_channel(dev, gpct_index);
                ni_tio_set_mite_channel(&devpriv->
                                        counter_dev->counters[gpct_index],
                                        NULL);
@@ -799,7 +815,7 @@ static void ni_release_cdo_mite_channel(struct comedi_device *dev)
 
        spin_lock_irqsave(&devpriv->mite_channel_lock, flags);
        if (devpriv->cdo_mite_chan) {
-               ni_set_cdo_dma_channel(dev, -1);
+               ni_set_cdo_dma_no_channel(dev);
                mite_release_channel(devpriv->cdo_mite_chan);
                devpriv->cdo_mite_chan = NULL;
        }