RE: [PATCH v4 2/4] device property: Add fwnode_is_compatible() and device_is_compatible() helpers

[Jun Li <jun.li@nxp.com>]

> -----Original Message-----
> From: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
> Sent: Monday, October 19, 2020 8:25 PM
> To: Jun Li <jun.li@nxp.com>
> Cc: heikki.krogerus@linux.intel.com; robh+dt@kernel.org;
> rafael@kernel.org; gregkh@linuxfoundation.org; hdegoede@redhat.com;
> lee.jones@linaro.org; mika.westerberg@linux.intel.com;
> dmitry.torokhov@gmail.com; prabhakar.mahadev-lad.rj@bp.renesas.com;
> laurent.pinchart+renesas@ideasonboard.com; linux-usb@vger.kernel.org;
> devicetree@vger.kernel.org; dl-linux-imx <linux-imx@nxp.com>; Peter Chen
> <peter.chen@nxp.com>
> Subject: Re: [PATCH v4 2/4] device property: Add fwnode_is_compatible() and
> device_is_compatible() helpers
> 
> On Mon, Oct 19, 2020 at 05:03:13PM +0800, Li Jun wrote:
> > From: Heikki Krogerus <heikki.krogerus@linux.intel.com>
> >
> > Since there are also some ACPI platforms where the "compatible"
> > property is used, introducing a generic helper function
> > fwnode_is_compatible() that can be used with DT, ACPI and swnodes, and
> > a wrapper function
> > device_is_compatible() with it.
> >
> > The function calls of_device_is_comaptible() with OF nodes, and with
> > ACPI and swnodes it matches the given string against the "compatible"
> > string property array.
> 
> ...
> 
> > + * Match the compatible strings of @fwnode against @compat. Returns
> > + positive
> > + * value on match, and 0 when no matching compatible string is found.
> 
> Please move Returns... to a separate paragraph.

OK, will change.

> 
> Btw, this is not true...
> 
> > +int fwnode_is_compatible(struct fwnode_handle *fwnode, const char
> > +*compat) {
> > +	int ret;
> > +
> > +	if (is_of_node(fwnode))
> > +		return of_device_is_compatible(to_of_node(fwnode), compat);
> > +
> > +	ret = fwnode_property_match_string(fwnode, "compatible", compat);
> > +
> 
> > +	return ret < 0 ? 0 : 1;
> 
> ...and this is at least strange after all.

of_device_is_compatible() will return positive value on match, and 0
when no matching,
fwnode_property_match_string() will return 0 if the property was found
(success); and negative error code on failure. so the return conversion
of fwnode_property_match_string () should work here.

> 
> > +}
> 
> > + * Match the compatible strings of @dev against @compat. Returns
> > + positive value
> > + * on match, and 0 when no matching compatible string is found.
> 
> So does this.

Yes, will change.

> 
> ...
> 
> > +int fwnode_is_compatible(struct fwnode_handle *fwnode, const char
> > +*compat); int device_is_compatible(struct device *dev, const char
> > +*compat);
> 
> Please, group them rather device_is_compatible() with device_* and fwnode_*
> ones respectively.

Ok, will move them in next version.

Thanks
Li Jun

> 
> --
> With Best Regards,
> Andy Shevchenko
>