[PATCH 05/46] staging: comedi: me4000: remove 'board' from me4000_ai_insn_read()

Ian Abbott abbotti at mev.co.uk
Wed Aug 5 11:38:26 UTC 2015


On 04/08/15 18:57, H Hartley Sweeten wrote:
> The 'board' pointer is only used in this function to verify that the
> 'chan' is valid for an aref of AREF_DIFF. The comedi core ensures that
> that aref is only possible if the subdevice has the SDF_DIFF subdevice_flag
> set. If so, the maximum channel is half the subdevice 'n_chan'. Use that
> instead and remove the 'board' variable.
>
> Signed-off-by: H Hartley Sweeten <hsweeten at visionengravers.com>
> ---
>   drivers/staging/comedi/drivers/me4000.c | 8 ++++----
>   1 file changed, 4 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/staging/comedi/drivers/me4000.c b/drivers/staging/comedi/drivers/me4000.c
> index d6b7adc..a1b30f9 100644
> --- a/drivers/staging/comedi/drivers/me4000.c
> +++ b/drivers/staging/comedi/drivers/me4000.c
> @@ -436,10 +436,10 @@ static void me4000_reset(struct comedi_device *dev)
>     ===========================================================================*/
>
>   static int me4000_ai_insn_read(struct comedi_device *dev,
> -			       struct comedi_subdevice *subdevice,
> -			       struct comedi_insn *insn, unsigned int *data)
> +			       struct comedi_subdevice *s,
> +			       struct comedi_insn *insn,
> +			       unsigned int *data)
>   {
> -	const struct me4000_board *board = dev->board_ptr;
>   	int chan = CR_CHAN(insn->chanspec);
>   	int rang = CR_RANGE(insn->chanspec);
>   	int aref = CR_AREF(insn->chanspec);
> @@ -487,7 +487,7 @@ static int me4000_ai_insn_read(struct comedi_device *dev,
>   			return -EINVAL;
>   		}
>
> -		if (chan >= board->ai_diff_nchan) {
> +		if (chan >= (s->n_chan / 2)) {

You also need to check that differential input mode is supported because 
the comedi core doesn't verify the aref flags.  Since you are removing 
the 'board' variable, that can be done by checking 's->subdev_flags & 
SDF_DIFF' (since patch 03 ensures that is only set if differential mode 
supported).

>   			dev_err(dev->class_dev,
>   				"Analog input is not available\n");
>   			return -EINVAL;
>


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


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