RE: [PATCH v4 4/6] usb: roles: add API to get usb_role_switch by node

Chunfeng Yun
2019-04-26T07:16:35Z

Hi Biju,
On Fri, 2019-04-26 at 07:02 +0000, Biju Das wrote:
> Hi Chunfeng Yun,
>
> Thanks for the patch.
>
> > Subject: [PATCH v4 4/6] usb: roles: add API to get usb_role_switch by node
> >
> > Add fwnode_usb_role_switch_get() to make easier to get usb_role_switch
> > by fwnode which register it.
> > It's useful when there is not device_connection registered between two
> > drivers and only knows the fwnode which register usb_role_switch.
> >
> > Signed-off-by: Chunfeng Yun <chunfeng.yun@mediatek.com>
> Tested-by: Biju Das <biju.das@bp.renesas.com>
> > ---
> > v4 changes:
> > 1. use switch_fwnode_match() to find fwnode suggested by Heikki
> > 2. this patch now depends on [1]
> >
> > [1] [v6,08/13] usb: roles: Introduce stubs for the exiting functions in role.h
> > https://patchwork.kernel.org/patch/10909971/
> >
> > v3 changes:
> > 1. use fwnodes instead of node suggested by Andy
> > 2. rebuild the API suggested by Heikki
> >
> > v2 no changes
> > ---
> > drivers/usb/roles/class.c | 25 +++++++++++++++++++++++++
> > include/linux/usb/role.h | 8 ++++++++
> > 2 files changed, 33 insertions(+)
> >
> > diff --git a/drivers/usb/roles/class.c b/drivers/usb/roles/class.c index
> > f45d8df5cfb8..994fcb979795 100644
> > --- a/drivers/usb/roles/class.c
> > +++ b/drivers/usb/roles/class.c
> > @@ -12,6 +12,7 @@
> > #include <linux/device.h>
> > #include <linux/module.h>
> > #include <linux/mutex.h>
> > +#include <linux/of.h>
>
> Is it required?
Forgot to remove it after using fwnode instead of node, will remove it
in next version

Thanks a lot

>
> > #include <linux/slab.h>
> >
> > static struct class *role_class;
> > @@ -135,6 +136,30 @@ struct usb_role_switch *usb_role_switch_get(struct
> > device *dev) } EXPORT_SYMBOL_GPL(usb_role_switch_get);
> >
> > +/**
> > + * fwnode_usb_role_switch_get - Find USB role switch by it's parent
> > +fwnode
> > + * @fwnode: The fwnode that register USB role switch
> > + *
> > + * Finds and returns role switch registered by @fwnode. The reference
> > +count
> > + * for the found switch is incremented.
> > + */
> > +struct usb_role_switch *
> > +fwnode_usb_role_switch_get(struct fwnode_handle *fwnode) {
> > + struct usb_role_switch *sw;
> > + struct device *dev;
> > +
> > + dev = class_find_device(role_class, NULL, fwnode,
> > switch_fwnode_match);
> > + if (!dev)
> > + return ERR_PTR(-EPROBE_DEFER);
> > +
> > + sw = to_role_switch(dev);
> > + WARN_ON(!try_module_get(sw->dev.parent->driver->owner));
> > +
> > + return sw;
> > +}
> > +EXPORT_SYMBOL_GPL(fwnode_usb_role_switch_get);
> > +
> > /**
> > * usb_role_switch_put - Release handle to a switch
> > * @sw: USB Role Switch
> > diff --git a/include/linux/usb/role.h b/include/linux/usb/role.h index
> > da2b9641b877..35d460f9ec40 100644
> > --- a/include/linux/usb/role.h
> > +++ b/include/linux/usb/role.h
> > @@ -48,6 +48,8 @@ int usb_role_switch_set_role(struct usb_role_switch
> > *sw, enum usb_role role); enum usb_role usb_role_switch_get_role(struct
> > usb_role_switch *sw); struct usb_role_switch *c(struct
> > device *dev); void usb_role_switch_put(struct usb_role_switch *sw);
> > +struct usb_role_switch *
> > +fwnode_usb_role_switch_get(struct fwnode_handle *fwnode);
>
> > struct usb_role_switch *
> > usb_role_switch_register(struct device *parent, @@ -72,6 +74,12 @@ static
> > inline struct usb_role_switch *usb_role_switch_get(struct device *dev)
> >
> > static inline void usb_role_switch_put(struct usb_role_switch *sw) { }
> >
> > +static inline struct usb_role_switch *
> > +fwnode_usb_role_switch_get(struct fwnode_handle *fwnode) {
> > + return ERR_PTR(-ENODEV);
> > +}
> > +
>
> > static inline struct usb_role_switch *
> > usb_role_switch_register(struct device *parent,
> > const struct usb_role_switch_desc *desc)
> > --
> > 2.21.0
>