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author | Sebastian Andrzej Siewior <bigeasy@linutronix.de> | 2012-12-23 21:10:15 +0100 |
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committer | Felipe Balbi <balbi@ti.com> | 2013-01-21 20:52:46 +0200 |
commit | 0062f6e56f70bd2230ba1ebd1667d1b32a1af3b2 (patch) | |
tree | 4240e27149c844f61cc718dd0458d400ecd33847 /drivers/usb/gadget/functions.c | |
parent | 59835ad727876f6ce5c18ce075e144a8fa989461 (diff) | |
download | linux-0062f6e56f70bd2230ba1ebd1667d1b32a1af3b2.tar.bz2 |
usb: gadget: add a forward pointer from usb_function to its "instance"
We can have multiple usb_functions which origin is the same "instance".
Within one USB configuration there should be only one function of an
instance. This back pointer helps configfs to recoginze to which
instance a given usb_function belongs.
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Felipe Balbi <balbi@ti.com>
Diffstat (limited to 'drivers/usb/gadget/functions.c')
-rw-r--r-- | drivers/usb/gadget/functions.c | 116 |
1 files changed, 116 insertions, 0 deletions
diff --git a/drivers/usb/gadget/functions.c b/drivers/usb/gadget/functions.c new file mode 100644 index 000000000000..b13f839e7368 --- /dev/null +++ b/drivers/usb/gadget/functions.c @@ -0,0 +1,116 @@ +#include <linux/kernel.h> +#include <linux/slab.h> +#include <linux/module.h> +#include <linux/err.h> + +#include <linux/usb/composite.h> + +static LIST_HEAD(func_list); +static DEFINE_MUTEX(func_lock); + +static struct usb_function_instance *try_get_usb_function_instance(const char *name) +{ + struct usb_function_driver *fd; + struct usb_function_instance *fi; + + fi = ERR_PTR(-ENOENT); + mutex_lock(&func_lock); + list_for_each_entry(fd, &func_list, list) { + + if (strcmp(name, fd->name)) + continue; + + if (!try_module_get(fd->mod)) { + fi = ERR_PTR(-EBUSY); + break; + } + fi = fd->alloc_inst(); + if (IS_ERR(fi)) + module_put(fd->mod); + else + fi->fd = fd; + break; + } + mutex_unlock(&func_lock); + return fi; +} + +struct usb_function_instance *usb_get_function_instance(const char *name) +{ + struct usb_function_instance *fi; + int ret; + + fi = try_get_usb_function_instance(name); + if (!IS_ERR(fi)) + return fi; + ret = PTR_ERR(fi); + if (ret != -ENOENT) + return fi; + ret = request_module("usbfunc:%s", name); + if (ret < 0) + return ERR_PTR(ret); + return try_get_usb_function_instance(name); +} +EXPORT_SYMBOL_GPL(usb_get_function_instance); + +struct usb_function *usb_get_function(struct usb_function_instance *fi) +{ + struct usb_function *f; + + f = fi->fd->alloc_func(fi); + if (IS_ERR(f)) + return f; + f->fi = fi; + return f; +} +EXPORT_SYMBOL_GPL(usb_get_function); + +void usb_put_function_instance(struct usb_function_instance *fi) +{ + struct module *mod; + + if (!fi) + return; + + mod = fi->fd->mod; + fi->free_func_inst(fi); + module_put(mod); +} +EXPORT_SYMBOL_GPL(usb_put_function_instance); + +void usb_put_function(struct usb_function *f) +{ + if (!f) + return; + + f->free_func(f); +} +EXPORT_SYMBOL_GPL(usb_put_function); + +int usb_function_register(struct usb_function_driver *newf) +{ + struct usb_function_driver *fd; + int ret; + + ret = -EEXIST; + + mutex_lock(&func_lock); + list_for_each_entry(fd, &func_list, list) { + if (!strcmp(fd->name, newf->name)) + goto out; + } + ret = 0; + list_add_tail(&newf->list, &func_list); +out: + mutex_unlock(&func_lock); + return ret; +} +EXPORT_SYMBOL_GPL(usb_function_register); + +void usb_function_unregister(struct usb_function_driver *fd) +{ + mutex_lock(&func_lock); + list_del(&fd->list); + mutex_unlock(&func_lock); +} +EXPORT_SYMBOL_GPL(usb_function_unregister); |