[PATCH] clk: introduce u-boot,ignore-clk-defaults

[Peng Fan]

> Subject: Re: [PATCH] clk: introduce u-boot,ignore-clk-defaults
> 
> 
> On 10/13/21 5:37 AM, Peng Fan (OSS) wrote:
> > From: Peng Fan <peng.fan at nxp.com>
> >
> > Current code has a force clk_set_defaults in multiple stages, U-Boot
> > reuse the same device tree and Linux Kernel device tree, but we not
> > register all the clks as Linux Kernel, so clk_set_defaults will fail
> > and cause the clk provider registeration fail.
> >
> > So introduce a new property to ignore the default settings which could
> > be used by any node that wanna ignore default settings.
> >
> > Signed-off-by: Peng Fan <peng.fan at nxp.com>
> > ---
> >   doc/device-tree-bindings/device.txt | 3 +++
> >   drivers/clk/clk-uclass.c            | 3 +++
> >   2 files changed, 6 insertions(+)
> >
> > diff --git a/doc/device-tree-bindings/device.txt
> > b/doc/device-tree-bindings/device.txt
> > index 73ce2a3b5b..fe34ced268 100644
> > --- a/doc/device-tree-bindings/device.txt
> > +++ b/doc/device-tree-bindings/device.txt
> > @@ -28,6 +28,9 @@ the acpi,compatible property.
> >       Linux will only load the driver if the device can be detected (e.g. on
> I2C
> >       bus). Note that this is an out-of-tree Linux feature.
> >
> > +Common device bindings that could be shared listed below:
> > + - u-boot,ignore-clk-defaults : ignore the assigned-clock-parents
> > +   and assigned-clock-rates for a device that has the property.
> >
> >   Example
> >   -------
> > diff --git a/drivers/clk/clk-uclass.c b/drivers/clk/clk-uclass.c index
> > 493018b33e..6bf3179e7b 100644
> > --- a/drivers/clk/clk-uclass.c
> > +++ b/drivers/clk/clk-uclass.c
> > @@ -376,6 +376,9 @@ int clk_set_defaults(struct udevice *dev, enum
> clk_defaults_stage stage)
> >   	if (!dev_has_ofnode(dev))
> >   		return 0;
> >
> > +	if (ofnode_get_property(dev_ofnode(dev), "u-boot,ignore-clk-defaults",
> NULL))
> > +		return 0;
> > +
> >   	/*
> >   	 * To avoid setting defaults twice, don't set them before relocation.
> >   	 * However, still set them for SPL. And still set them if
> > explicitly
> >
> 
> Why not just have the property ignore errors?

I think the force err return was done by Simon?

> 
> In the long term, it may be better to standardize that e.g. ENOENT means that
> the clock doesn't exist. That way we can skip setting the defaults.
> ENOSYS should probably be treated the same way (warn, but don't fail).

I am not sure whether people expect force error for ENOENT/ENOSYS in U-Boot.
For i.MX, I not expect force error.

Regards,
Peng.

> 
> --Sean