usb: gadget: add some infracture to register/unregister functions
This patch provides an infrastructure to register & unregister a USB
function. This allows to turn a function into a module and avoid the
'#include "f_.*.c"' magic and we get a clear API / cut between the bare
gadget and its functions.
The concept is simple:
Each function defines the DECLARE_USB_FUNCTION_INIT macro whith an unique
name of the function and two allocation functions.
- one to create an "instance". The instance holds the current configuration
set. In case there are two usb_configudations with one function there will
be one instance and two usb_functions
- one to create an "function" from the instance.
The name of the instance is used to automaticaly load the module if it the
instance is not yet available.
The usb_function callbacks are slightly modified and extended:
- usb_get_function()
creates a struct usb_function inclunding all pointers (bind,
unbind,…). It uses the "instance" to map its configuration. So we can
have _two_ struct usb_function, one for each usb_configuration.
- ->unbind()
Since the struct usb_function was not allocated in ->bind() it should
not kfree()d here. This function should only reverse what happens in
->bind() that is request cleanup and the cleanup of allocated
descriptors.
- ->free_func()
a simple kfree() of the struct usb_function
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Felipe Balbi <balbi@ti.com>
diff --git a/drivers/usb/gadget/composite.c b/drivers/usb/gadget/composite.c
index 9db0000..4aa0e46 100644
--- a/drivers/usb/gadget/composite.c
+++ b/drivers/usb/gadget/composite.c
@@ -683,6 +683,31 @@
return result;
}
+int usb_add_config_only(struct usb_composite_dev *cdev,
+ struct usb_configuration *config)
+{
+ struct usb_configuration *c;
+
+ if (!config->bConfigurationValue)
+ return -EINVAL;
+
+ /* Prevent duplicate configuration identifiers */
+ list_for_each_entry(c, &cdev->configs, list) {
+ if (c->bConfigurationValue == config->bConfigurationValue)
+ return -EBUSY;
+ }
+
+ config->cdev = cdev;
+ list_add_tail(&config->list, &cdev->configs);
+
+ INIT_LIST_HEAD(&config->functions);
+ config->next_interface_id = 0;
+ memset(config->interface, 0, sizeof(config->interface));
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(usb_add_config_only);
+
/**
* usb_add_config() - add a configuration to a device.
* @cdev: wraps the USB gadget
@@ -703,30 +728,18 @@
int (*bind)(struct usb_configuration *))
{
int status = -EINVAL;
- struct usb_configuration *c;
+
+ if (!bind)
+ goto done;
DBG(cdev, "adding config #%u '%s'/%p\n",
config->bConfigurationValue,
config->label, config);
- if (!config->bConfigurationValue || !bind)
+ status = usb_add_config_only(cdev, config);
+ if (status)
goto done;
- /* Prevent duplicate configuration identifiers */
- list_for_each_entry(c, &cdev->configs, list) {
- if (c->bConfigurationValue == config->bConfigurationValue) {
- status = -EBUSY;
- goto done;
- }
- }
-
- config->cdev = cdev;
- list_add_tail(&config->list, &cdev->configs);
-
- INIT_LIST_HEAD(&config->functions);
- config->next_interface_id = 0;
- memset(config->interface, 0, sizeof(config->interface));
-
status = bind(config);
if (status < 0) {
while (!list_empty(&config->functions)) {