Re: [RESEND PATCH v6 17/17] media: qcom: camss: Comment CSID dt_id field

[Bryan O'Donoghue]

On 27/09/2023 12:42, Hans Verkuil wrote:
> > +		/*
> > +		 * DT_ID is a two bit bitfield that is concatenated with
> > +		 * the four least significant bits of the six bit VC
> > +		 * bitfield to generate an internal CID value.
> > +		 *
> > +		 * CSID_RDI_CFG0(vc)
> > +		 * DT_ID : 28:27
> > +		 * VC    : 26:22
> This is 5 bits, not 6 bits as the comment above says. Which is right?

Yes you're right I had "DT" which is six bits in my head when I wrote 
this. The VC bitfield is five.

> > +		 * DT    : 21:16
> > +		 *
> > +		 * CID   : VC 3:0 << 2 | DT_ID 1:0
> > +		 */
> >   		u8 dt_id = vc;
> So if dt_id is 2 bits, and vc can be more than 2 bits in the future,
> shouldn't this read "vc & 3"?

Hmm...

val |= dt_id << RDI_CFG0_DT_ID;

yes that would overrun otherwise.

---
bod