On Wed, 5 Feb 2025 15:58:18 +0200
Matti Vaittinen <mazziesaccount@xxxxxxxxx> wrote:
> On 31/01/2025 19:41, Jonathan Cameron wrote:
> > On Fri, 31 Jan 2025 15:37:48 +0200
> > Matti Vaittinen <mazziesaccount@xxxxxxxxx> wrote:
> >
> >> The ROHM BD79124 is a 12-bit, 8-channel, SAR ADC. The ADC supports
> >> an automatic measurement mode, with an alarm interrupt for out-of-window
> >> measurements. The window is configurable for each channel.
> >>
>
> Hi Jonathan,
>
> I just sent the v2, where I (think I) addressed all comments except ones
> below. Just wanted to point out what was not changed and why :)
>
> ...
>
> >
> >> +struct bd79124_raw {
> >> + u8 bit0_3; /* Is set in high bits of the byte */
> >> + u8 bit4_11;
> >> +};
> >> +#define BD79124_RAW_TO_INT(r) ((r.bit4_11 << 4) | (r.bit0_3 >> 4))
> > You could do this as an endian conversion and a single shift I think.
> > Might be slightly simpler.
>
> I kept this struct with bytes matching the register spec. Doing the
> endian conversion and then shifting would probably have worked, but my
> head hurts when I try thinking how the bits settle there. Especially if
> this is done on a big-endian machine. I can rework this for v3 if you
> feel very strongly about this.
The key is that an endian conversion is always the same as OR + SHIFT
because that is being done in the system endiannes.
Doesn't matter that much, but we may see follow up patches switching
this over to the endian handlers.
