On Tue, May 03, 2022 at 11:48:33AM -0400, Alan Stern wrote:
> On Tue, May 03, 2022 at 05:27:08PM +0200, Geert Uytterhoeven wrote:
> > Hi Alan,
> >
> > On Tue, May 3, 2022 at 5:14 PM Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> wrote:
> > > On Tue, May 03, 2022 at 12:14:30PM +0200, Geert Uytterhoeven wrote:
> > > > On Sat, 23 Apr 2022, Alan Stern wrote:
> > > > > This patch adds a "gadget" bus and uses it for registering gadgets and
> > > > > their drivers. From now on, bindings will be managed by the driver
> > > > > core rather than through ad-hoc manipulations in the UDC core.
> > > > >
> > > > > As part of this change, the driver_pending_list is removed. The UDC
> > > > > core won't need to keep track of unbound drivers for later binding,
> > > > > because the driver core handles all of that for us.
> > > > >
> > > > > However, we do need one new feature: a way to prevent gadget drivers
> > > > > from being bound to more than one gadget at a time. The existing code
> > > > > does this automatically, but the driver core doesn't -- it's perfectly
> > > > > happy to bind a single driver to all the matching devices on the bus.
> > > > > The patch adds a new bitflag to the usb_gadget_driver structure for
> > > > > this purpose.
> > > > >
> > > > > A nice side effect of this change is a reduction in the total lines of
> > > > > code, since now the driver core will do part of the work that the UDC
> > > > > used to do.
> > > > >
> > > > > A possible future patch could add udc devices to the gadget bus, say
> > > > > as a separate device type.
> > > > >
> > > > > Signed-off-by: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx>
> > > >
> > > > Thanks for your patch, which is now commit fc274c1e997314bf ("USB:
> > > > gadget: Add a new bus for gadgets") in usb-next.
> > > >
> > > > This patch cause a regression on the Renesas Salvator-XS development
> > > > board, as R-Car H3 has multiple USB gadget devices:
> > >
> > > Then these gadgets ought to have distinct names in order to avoid the
> > > conflict below:
Geert:
Can you test the patch below? It ought to fix the problem (although it
might end up causing other problems down the line...)
Alan Stern
Index: usb-devel/drivers/usb/gadget/udc/core.c
===================================================================
--- usb-devel.orig/drivers/usb/gadget/udc/core.c
+++ usb-devel/drivers/usb/gadget/udc/core.c
@@ -12,6 +12,7 @@
#include <linux/module.h>
#include <linux/device.h>
#include <linux/list.h>
+#include <linux/idr.h>
#include <linux/err.h>
#include <linux/dma-mapping.h>
#include <linux/sched/task_stack.h>
@@ -23,6 +24,8 @@
#include "trace.h"
+static DEFINE_IDA(gadget_id_numbers);
+
static struct bus_type gadget_bus_type;
/**
@@ -1248,7 +1251,6 @@ static void usb_udc_nop_release(struct d
void usb_initialize_gadget(struct device *parent, struct usb_gadget *gadget,
void (*release)(struct device *dev))
{
- dev_set_name(&gadget->dev, "gadget");
INIT_WORK(&gadget->work, usb_gadget_state_work);
gadget->dev.parent = parent;
@@ -1304,12 +1306,21 @@ int usb_add_gadget(struct usb_gadget *ga
usb_gadget_set_state(gadget, USB_STATE_NOTATTACHED);
udc->vbus = true;
+ ret = ida_alloc(&gadget_id_numbers, GFP_KERNEL);
+ if (ret < 0)
+ goto err_del_udc;
+ gadget->id_number = ret;
+ dev_set_name(&gadget->dev, "gadget.%d", ret);
+
ret = device_add(&gadget->dev);
if (ret)
- goto err_del_udc;
+ goto err_free_id;
return 0;
+ err_free_id:
+ ida_free(&gadget_id_numbers, gadget->id_number);
+
err_del_udc:
flush_work(&gadget->work);
device_del(&udc->dev);
@@ -1417,6 +1428,7 @@ void usb_del_gadget(struct usb_gadget *g
kobject_uevent(&udc->dev.kobj, KOBJ_REMOVE);
flush_work(&gadget->work);
device_del(&gadget->dev);
+ ida_free(&gadget_id_numbers, gadget->id_number);
device_unregister(&udc->dev);
}
EXPORT_SYMBOL_GPL(usb_del_gadget);
Index: usb-devel/include/linux/usb/gadget.h
===================================================================
--- usb-devel.orig/include/linux/usb/gadget.h
+++ usb-devel/include/linux/usb/gadget.h
@@ -386,6 +386,7 @@ struct usb_gadget_ops {
* @lpm_capable: If the gadget max_speed is FULL or HIGH, this flag
* indicates that it supports LPM as per the LPM ECN & errata.
* @irq: the interrupt number for device controller.
+ * @id_number: a unique ID number for ensuring that gadget names are distinct
*
* Gadgets have a mostly-portable "gadget driver" implementing device
* functions, handling all usb configurations and interfaces. Gadget
@@ -446,6 +447,7 @@ struct usb_gadget {
unsigned connected:1;
unsigned lpm_capable:1;
int irq;
+ int id_number;
};
#define work_to_gadget(w) (container_of((w), struct usb_gadget, work))
