Hi Andy,
Le lundi 22 mai 2023 à 13:18 +0300, Andy Shevchenko a écrit :
> On Mon, May 22, 2023 at 1:15 PM Andy Shevchenko
> <andy.shevchenko@xxxxxxxxx> wrote:
> > On Mon, May 22, 2023 at 1:59 AM Artur Rojek
> > <contact@xxxxxxxxxxxxxx> wrote:
>
> ...
>
> > > + u16 tdat[6];
> > > + u32 val;
> > > +
> > > + memset(tdat, 0, ARRAY_SIZE(tdat));
> >
> > Yeah, as LKP tells us this should be sizeof() instead of
> > ARRAY_SIZE().
> >
> > > + for (i = 0; mask && i < ARRAY_SIZE(tdat); mask >>= 2) {
> > > + if (mask & 0x3) {
> >
> > (for the consistency it has to be GENMASK(), but see below)
> >
> > First of all, strictly speaking we should use the full mask without
> > limiting it to the 0 element in the array (I'm talking about
> > active_scan_mask).
> >
> > That said, we may actually use bit operations here in a better way,
> > i.e.
> >
> > unsigned long mask = active_scan_mask[0] & (active_scan_mask[0] -
> > 1);
> >
> > j = 0;
> > for_each_set_bit(i, active_scan_mask, ...) {
> > val = readl(...);
> > /* Two channels per sample. Demux active. */
> > tdat[j++] = val >> (16 * (i % 2));
>
> Alternatively
>
> /* Two channels per sample. Demux active. */
> if (i % 2)
> tdat[j++] = upper_16_bits(val);
> else
> tdat[j++] = lower_16_bits(val);
>
> which may be better to read.
It's not if/else though. You would check (i % 2) for the upper 16 bits,
and (i % 1) for the lower 16 bits. Both can be valid at the same time.
Cheers,
-Paul
>
> > }
> >
> > > + val = readl(adc->base +
> > > JZ_ADC_REG_ADTCH);
> > > + /* Two channels per sample. Demux active.
> > > */
> > > + if (mask & BIT(0))
> > > + tdat[i++] = val & 0xffff;
> > > + if (mask & BIT(1))
> > > + tdat[i++] = val >> 16;
> > > + }
> > > }
>
>
