Re: [RFC PATCH 46/57] driver: Add variants of driver_find_device()

[Suzuki K Poulose]

On 03/06/2019 20:11, Greg KH wrote:
> On Mon, Jun 03, 2019 at 04:50:12PM +0100, Suzuki K Poulose wrote:
> > Add a wrappers to lookup a device by name for a given driver, by various
> > generic properties of a device. This can avoid the proliferation of custom
> > match functions throughout the drivers.
> >
> > Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
> > Cc: "Rafael J. Wysocki" <rafael@xxxxxxxxxx>
> > Signed-off-by: Suzuki K Poulose <suzuki.poulose@xxxxxxx>
> > ---
> >   include/linux/device.h | 44 ++++++++++++++++++++++++++++++++++++++++++++
> >   1 file changed, 44 insertions(+)
> >
> > diff --git a/include/linux/device.h b/include/linux/device.h
> > index 52d59d5..68d6e04 100644
> > --- a/include/linux/device.h
> > +++ b/include/linux/device.h
> > @@ -401,6 +401,50 @@ struct device *driver_find_device(struct device_driver *drv,
> >   				  struct device *start, void *data,
> >   				  int (*match)(struct device *dev, const void *data));
> >   
> > +/**
> > + * driver_find_device_by_name - device iterator for locating a particular device
> > + * of a specific name.
> > + * @driver: the driver we're iterating
> > + * @start: Device to begin with
> > + * @name: name of the device to match
> > + */
> > +static inline struct device *driver_find_device_by_name(struct device_driver *drv,
> > +							struct device *start,
> > +							const char *name)
> > +{
> > +	return driver_find_device(drv, start, (void *)name, device_match_name);
>
> Why is the cast needed?
>
> > +}
> > +
> > +/**
> > + * driver_find_device_by_of_node- device iterator for locating a particular device
> > + * by of_node pointer.
> > + * @driver: the driver we're iterating
> > + * @start: Device to begin with
> > + * @np: of_node pointer to match.
> > + */
> > +static inline struct device *
> > +driver_find_device_by_of_node(struct device_driver *drv,
> > +			      struct device *start,
> > +			      const struct device_node *np)
> > +{
> > +	return driver_find_device(drv, start, (void *)np, device_match_of_node);
>
> Same here.
>
> > +}
> > +
> > +/**
> > + * driver_find_device_by_fwnode- device iterator for locating a particular device
> > + * by fwnode pointer.
> > + * @driver: the driver we're iterating
> > + * @start: Device to begin with
> > + * @fwnode: fwnode pointer to match.
> > + */
> > +static inline struct device *
> > +driver_find_device_by_fwnode(struct device_driver *drv,
> > +			     struct device *start,
> > +			     const struct fwnode_handle *fwnode)
> > +{
> > +	return driver_find_device(drv, start, (void *)fwnode, device_match_fwnode);
>
> And here

Because the driver_find_device() expects a "void *" and not a "const void *".
May be we could promote that to "const void *" in the core API too, since we
have converted the "match" to const void * already. Thoughts ?

Suzuki