On 20-04-30 13:20, Sakari Ailus wrote:
> On Thu, Apr 30, 2020 at 12:11:57PM +0200, Marco Felsch wrote:
> > On 20-04-30 12:59, Sakari Ailus wrote:
> > > Hi Marco,
> > >
> > > On Thu, Apr 30, 2020 at 11:53:32AM +0200, Marco Felsch wrote:
> > > > Hi Sakari,
> > > >
> > > > On 20-04-30 12:45, Sakari Ailus wrote:
> > > > > Hi Marco,
> > > > >
> > > > > On Thu, Apr 30, 2020 at 11:35:24AM +0200, Marco Felsch wrote:
> >
> > ...
> >
> > > > > > > - if (mclk != OV8856_MCLK) {
> > > > > > > - dev_err(dev, "external clock %d is not supported", mclk);
> > > > > > > - return -EINVAL;
> > > > > > > + if (!is_acpi_node(fwnode)) {
> > > > > > > + ov8856->xvclk = devm_clk_get(dev, "xvclk");
> > > > > > > + if (IS_ERR(ov8856->xvclk)) {
> > > > > > > + dev_err(dev, "could not get xvclk clock (%pe)\n",
> > > > > > > + ov8856->xvclk);
> > > > > > > + return PTR_ERR(ov8856->xvclk);
> > > > > > > + }
> > > > > > > +
> > > > > > > + clk_set_rate(ov8856->xvclk, xvclk_rate);
> > > > > > > + xvclk_rate = clk_get_rate(ov8856->xvclk);
> > > > > > > }
> > > > > >
> > > > > > Why do we handle the clock only in DT case? Is there a problem with the
> > > > > > clock handling and ACPI?
> > > > >
> > > > > Not really, it's just that ACPI does not provide an interface to the clocks
> > > > > as such.
> > > >
> > > > But you will get a clk by devm_clk_get()?
> > >
> > > No, because ACPI does not expose one to drivers. Effectively the entire
> > > power sequences are implemented in ACPI, not in the driver.
> > >
> >
> > Ah okay, thanks for the explanation. I'm really not into the ACPI
> > stuff.. So this means the __power_off / power_on should only be done if
> > we are using DT's?
>
> Correct. That's why it bails out early. It could be yet earlier though,
> without doing anything.
Yes I see. For easier and error less prone handling I would prefer:
if (is_acpi_node())
return 0;
as first instruction for __power_off/on().
Also I would refator the ov8856_check_hwcfg() so the common part can be
used by this function and by a ov8856_parse_of() function. But thats
only my opinion.
Regards,
Marco
