[PATCH 01/11] staging: comedi: hwdrv_apci1500: introduce z8536_read()

[Ian Abbott]

On 02/12/14 17:19, H Hartley Sweeten wrote:
> The Z8536 CIO registers are indirectly read by writing the register value
> to the control register then reading the control register. Introduce a helper
> function to read the Z8536 CIO registers.
>
> Signed-off-by: H Hartley Sweeten <hsweeten at visionengravers.com>
> Cc: Ian Abbott <abbotti at mev.co.uk>
> Cc: Greg Kroah-Hartman <gregkh at linuxfoundation.org>
> ---
>   .../comedi/drivers/addi-data/hwdrv_apci1500.c      | 216 +++++----------------
>   1 file changed, 52 insertions(+), 164 deletions(-)
>
> diff --git a/drivers/staging/comedi/drivers/addi-data/hwdrv_apci1500.c b/drivers/staging/comedi/drivers/addi-data/hwdrv_apci1500.c
> index bfa9228..5d4d35b 100644
> --- a/drivers/staging/comedi/drivers/addi-data/hwdrv_apci1500.c
> +++ b/drivers/staging/comedi/drivers/addi-data/hwdrv_apci1500.c
> @@ -129,6 +129,14 @@ static int i_InputChannel;
>   static int i_TimerCounter1Enabled, i_TimerCounter2Enabled,
>   	   i_WatchdogCounter3Enabled;
>
> +static unsigned int z8536_read(struct comedi_device *dev, unsigned int reg)
> +{
> +	struct apci1500_private *devpriv = dev->private;
> +
> +	outb(reg, devpriv->iobase + APCI1500_Z8536_CONTROL_REGISTER);
> +	return inb(devpriv->iobase + APCI1500_Z8536_CONTROL_REGISTER);
> +}
> +

Since this is used by both the interrupt handler and "normal" code, it 
should use a spin-lock (e.g. dev->spinlock could be used).  That also 
applies to z8536_write() in patch 2 and probably the "reset" sequence at 
the start of z8536_reset() in patch 3.

-- 
-=( Ian Abbott @ MEV Ltd.    E-mail: <abbotti at mev.co.uk> )=-
-=(                          Web: http://www.mev.co.uk/  )=-