Hi,
Le lundi 22 mai 2023 à 13:15 +0300, Andy Shevchenko a écrit :
> On Mon, May 22, 2023 at 1:59 AM Artur Rojek <contact@xxxxxxxxxxxxxx>
> wrote:
> >
> > Consumers expect the buffer to only contain enabled channels. While
> > preparing the buffer, the driver makes two mistakes:
> > 1) It inserts empty data for disabled channels.
> > 2) Each ADC readout contains samples for two 16-bit channels. If
> > either
> > of them is active, the whole 32-bit sample is pushed into the
> > buffer
> > as-is.
> >
> > Both of those issues cause the active channels to appear at the
> > wrong
> > offsets in the buffer. Fix the above by demuxing samples for active
> > channels only.
> >
> > This has remained unnoticed, as all the consumers so far were only
> > using
> > channels 0 and 1, leaving them unaffected by changes introduced in
> > this
> > commit.
>
> ...
>
> > + u16 tdat[6];
> > + u32 val;
> > +
> > + memset(tdat, 0, ARRAY_SIZE(tdat));
>
> Yeah, as LKP tells us this should be sizeof() instead of
> ARRAY_SIZE().
Probably "u16 tdat[6] = { 0 };" would work too?
Cheers,
-Paul
>
> > + 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));
> }
>
> > + 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;
> > + }
> > }
>
