Re: [PATCH 2/3] media: i2c: ov9734: Add power on/off sequencing support

[Tin Posavec]

Hi Sakari,

On Mon, Nov 09, 2026 at 02:28:22PM +0200, Sakari Ailus wrote:
> > +     if (ov9734->reset || ov9734->powerdown) {
> > +             /*
> > +              * Keep reset/powerdown asserted for at least 2 ms on a
> > +              * back-to-back off-on cycle.
> > +              */
>
> The comment isn't useful. Please drop it.

I'll drop it in v2.

> > +             fsleep(2 * USEC_PER_MSEC);
> > +             gpiod_set_value_cansleep(ov9734->powerdown, 0);
> > +             gpiod_set_value_cansleep(ov9734->reset, 0);
>
> The sensor appears to need a single GPIO (xshutdown). I wonder what's the
> other one.

There isn't one that I know of. I based the GPIO handling on ov01a10,
which requests both a reset and a powerdown GPIO. On the NUC M15 the
INT3472 provides neither of them, and on the Surface Laptop 1 it
provides the reset GPIO, as Afonso reported. I'll keep only the reset
GPIO in v2.

> > +     /* Give the sensor time to start up before accessing it */
>
> Ditto.

I'll drop this one too.

> > +     fsleep(20 * USEC_PER_MSEC);
>
> 8192 external clock cycles are required for this.

I'll wait for 8192 external clock cycles in v2.

Thank you for the feedback.

Regards,

Tin Posavec