The `DAS08_MUX_MASK` macro is a bitmask for the control register corresponding to the analog input multiplexor channel selection bits. Rename it to `DAS08_CONTROL_MUX_MASK` and add a comment. Note that the current setting of the multiplexor can also be read from the same bit positions in the status register, but the driver does not use it. Add a comment to that effect. The `DAS08_MUX(x)` macro takes an analog input channel number and returns the corresponding analog input multiplexor channel selection bits for the control register. Rename it to `DAS08_CONTROL_MUX(x)` and add a comment. Signed-off-by: Ian Abbott <abbotti@xxxxxxxxx> --- drivers/staging/comedi/drivers/das08.c | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-) diff --git a/drivers/staging/comedi/drivers/das08.c b/drivers/staging/comedi/drivers/das08.c index b43bc2d..f0ee617 100644 --- a/drivers/staging/comedi/drivers/das08.c +++ b/drivers/staging/comedi/drivers/das08.c @@ -68,8 +68,12 @@ /* digital inputs (not "JR" boards) */ #define DAS08_STATUS_DI(x) (((x) & 0x70) >> 4) #define DAS08_CONTROL_REG 0x02 /* (W) control */ -#define DAS08_MUX_MASK 0x7 -#define DAS08_MUX(x) ((x) & DAS08_MUX_MASK) +/* + * Note: The AI multiplexor channel can also be read from status register using + * the same mask. + */ +#define DAS08_CONTROL_MUX_MASK 0x7 /* multiplexor channel mask */ +#define DAS08_CONTROL_MUX(x) ((x) & DAS08_CONTROL_MUX_MASK) /* mux channel */ #define DAS08_INTE (1<<3) #define DAS08_DO_MASK 0xf0 #define DAS08_OP(x) (((x) << 4) & DAS08_DO_MASK) @@ -238,8 +242,8 @@ static int das08_ai_rinsn(struct comedi_device *dev, struct comedi_subdevice *s, /* set multiplexer */ /* lock to prevent race with digital output */ spin_lock(&dev->spinlock); - devpriv->do_mux_bits &= ~DAS08_MUX_MASK; - devpriv->do_mux_bits |= DAS08_MUX(chan); + devpriv->do_mux_bits &= ~DAS08_CONTROL_MUX_MASK; + devpriv->do_mux_bits |= DAS08_CONTROL_MUX(chan); outb(devpriv->do_mux_bits, dev->iobase + DAS08_CONTROL_REG); spin_unlock(&dev->spinlock); -- 2.1.4 _______________________________________________ devel mailing list devel@xxxxxxxxxxxxxxxxxxxxxx http://driverdev.linuxdriverproject.org/mailman/listinfo/driverdev-devel
