Re: [PATCH v2 5/5] iio: mxs-lradc: add write_raw function to modifyscale

[Hector Palacios]

Hi Jonathan,

On 07/19/2013 10:32 PM, Jonathan Cameron wrote:
> > > > @@ -323,6 +326,54 @@ static int mxs_lradc_read_raw(struct iio_dev *iio_dev,
> > > >        return ret;
> > > >    }
> > > >
> > > > +static int mxs_lradc_write_raw(struct iio_dev *iio_dev,
> > > > +                   const struct iio_chan_spec *chan,
> > > > +                   int val, int val2, long m)
> > > > +{
> > > > +    struct mxs_lradc *lradc = iio_priv(iio_dev);
> > > > +    int ret;
> > > > +
> > > > +    ret = mutex_trylock(&lradc->lock);
> > > > +    if (!ret)
> > > > +        return -EBUSY;
> > > > +
> > > > +    switch (m) {
> > > > +    case IIO_CHAN_INFO_SCALE:
> > > > +        ret = -EINVAL;
> > > > +        if (val == lradc->scale_avail[chan->channel][0][0] &&
> > > > +            val2 == lradc->scale_avail[chan->channel][0][1]) {
> > > > +            /* [0] -> divider by two disabled */
> > >
> > > This comment is confusing, you use [0] in different dimensions of the array. So
> > > is the stuff below.
> > >
> > > Still, how does this even work, can you show me and example how to set the
> > > divider from userland ? Sorry, I'm a bit confused with this 3D-business here,
> > > even if the comment in previous patch made it a bit clearer. Actually you can
> > > use some #define to specify if you're accessing div/2 or div/1 portion of the
> > > array to make it more readable.
> > >
> > > Like ... scale_avail[chan->channel][LRADC_DIV_BY_2][LRADC_DECIMAL_PART] ...
> > > would by nice.
> >
> > Agreed.
> Could even make the int + nano part a structure then you could have
> scale_avail[chan->channel][LRADC_DIV_BY_2].integer / .nano
>
> might not be worth the hassel though for the slight gain in readability.
>
> I'm happy either way.

I prefer the struct approach, it removes one dimension to the array and I find it cleaner.

Best regards,
--
Hector Palacios
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