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:

quoted

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@mediatek.com>
---
 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,

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