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

Biju Das
2019-04-26T07:02:24Z

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?

> #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