Re: [PATCH v6 01/12] drivers: base: Unified device connection lookup

[Hans de Goede]

Hi all,

On 09-03-18 18:53, Greg Kroah-Hartman wrote:
> On Fri, Mar 02, 2018 at 11:20:46AM +0100, Hans de Goede wrote:
> > From: Heikki Krogerus <heikki.krogerus@xxxxxxxxxxxxxxx>
> >
> > Several frameworks - clk, gpio, phy, pmw, etc. - maintain
> > lookup tables for describing connections and provide custom
> > API for handling them. This introduces a single generic
> > lookup table and API for the connections.
> >
> > The motivation for this commit is centralizing the
> > connection lookup, but the goal is to ultimately extract the
> > connection descriptions also from firmware by using the
> > fwnode_graph_* functions and other mechanisms that are
> > available.
> >
> > Signed-off-by: Heikki Krogerus <heikki.krogerus@xxxxxxxxxxxxxxx>
> > Reviewed-by: Hans de Goede <hdegoede@xxxxxxxxxx>
> > Reviewed-by: Andy Shevchenko <andy.shevchenko@xxxxxxxxx>
> > Signed-off-by: Hans de Goede <hdegoede@xxxxxxxxxx>
>
> Sorry for the delay, just now reviewing this patch...
>
> The content is fine (if not scary for the obvious reason of passing
> around 'struct device' of different bus types, but ok...), but the api
> naming is "rough":


Heikki, I think it is best if you answer Greg's remarks. FWIW I'm
fine with the changes Greg proposes.

I currently have significantly less bandwidth for this due to
personal circumstances, so if a new version of this patch-set
is necessary it would be great if you (Heikki) can do a v7.

Regards,

Hans

> > --- /dev/null
> > +++ b/include/linux/connection.h
>
> "connection.h" is vague, why not just put this in device.h? >
> > @@ -0,0 +1,34 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +
> > +#ifndef _LINUX_CONNECTION_H_
> > +#define _LINUX_CONNECTION_H_
> > +
> > +#include <linux/list.h>
> > +
> > +struct device;
> > +
> > +/**
> > + * struct devcon - Device Connection Descriptor
> > + * @endpoint: The names of the two devices connected together
> > + * @id: Unique identifier for the connection
> > + * @list: List head, private for devcon internal use only
> > + */
> > +struct devcon {
>
> 'struct device_connection'?  Spell it out please, people might think
> this is a "developer conference" :)
>
> > +	const char		*endpoint[2];
> > +	const char		*id;
> > +	struct list_head	list;
> > +};
> > +
> > +void *__device_find_connection(struct device *dev, const char *con_id,
> > +			       void *data,
> > +			       void *(*match)(struct devcon *con, int ep,
> > +					      void *data));
>
> Ick, __* functions are usually "no lock needed", but here you are doing
> a lot "more" than the normal device_find_connection() call.  Why not
> make this:
> 	device_connection_find_match()?
>
> > +
> > +struct device *device_find_connection(struct device *dev, const char *con_id);
>
> device_connection_find()?
>
> > +
> > +#define DEVCON(_ep0, _ep1, _id)    (struct devcon) { { _ep0, _ep1 }, _id, }
>
> Can you use named identifiers here?
>
> > +
> > +void add_device_connection(struct devcon *con);
> > +void remove_device_connection(struct devcon *con);
>
> device_connection_add() and device_connection_remove()?
>
> I can make the api name changes in an add-on patch.
>
> thanks,
>
> greg k-h