Hi, On Fri, 2019-03-15 at 10:18 +0200, Heikki Krogerus wrote: > On Fri, Mar 15, 2019 at 03:38:31PM +0800, Chunfeng Yun wrote: > > Add usb_role_switch_get_by_node() to make easier to get > > usb_role_switch by node which register it. > > It's useful when there is not device_connection registered > > between two drivers and only knows the node which register > > usb_role_switch. > > > > Signed-off-by: Chunfeng Yun <chunfeng.yun@xxxxxxxxxxxx> > > --- > > drivers/usb/roles/class.c | 30 ++++++++++++++++++++++++++++++ > > include/linux/usb/role.h | 1 + > > 2 files changed, 31 insertions(+) > > > > diff --git a/drivers/usb/roles/class.c b/drivers/usb/roles/class.c > > index 99116af07f1d..284b19856dc4 100644 > > --- a/drivers/usb/roles/class.c > > +++ b/drivers/usb/roles/class.c > > @@ -11,6 +11,7 @@ > > #include <linux/device.h> > > #include <linux/module.h> > > #include <linux/mutex.h> > > +#include <linux/of.h> > > #include <linux/slab.h> > > > > static struct class *role_class; > > @@ -121,6 +122,35 @@ struct usb_role_switch *usb_role_switch_get(struct device *dev) > > } > > EXPORT_SYMBOL_GPL(usb_role_switch_get); > > > > +static int __switch_match_node(struct device *dev, const void *node) > > +{ > > + return dev->parent->of_node == (const struct device_node *)node; > > +} > > Andy already pointed out that you need to use fwnodes. > > Rule of thumb: You always use fwnodes. Only if there is something that > can't be done with fwnodes you use DT or ACPI nodes directly. > > In this case there is absolutely nothing that would prevent you from > using fwnodes. > Got it, will fix it in next version. BTW: I encounter a build error when CONFIG_USB_ROLE_SWITCH is not enabled, drivers/usb/mtu3/mtu3_dr.o: In function `ssusb_role_sw_register': ./drivers/usb/mtu3/mtu3_dr.c:460: undefined reference to `usb_role_switch_register' drivers/usb/mtu3/mtu3_dr.o: In function `ssusb_otg_switch_exit': ./drivers/usb/mtu3/mtu3_dr.c:491: undefined reference to `usb_role_switch_unregister' the following patch has fixed the issue, but seems not get into kernel, [v3,08/12] usb: roles: Add usb role switch notifier. https://patchwork.kernel.org/patch/10836525/ What should I do if I add a new API? Thanks > > thanks, >