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Commit ee1cd515 authored by Andrzej Pietrasiewicz's avatar Andrzej Pietrasiewicz Committed by Felipe Balbi
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usb: gadget: printer: add configfs support 



Add support for configfs interface so that f_printer can be used as a
component of usb gadgets composed with it.

Signed-off-by: default avatarAndrzej Pietrasiewicz <andrzej.p@samsung.com>
Signed-off-by: default avatarFelipe Balbi <balbi@ti.com>
parent a2a8e48a

Documentation/ABI/testing/configfs-usb-gadget-printer

0 → 100644
+9 −0
Original line number Diff line number Diff line 
What:		/config/usb-gadget/gadget/functions/printer.name

Date:		Apr 2015

KernelVersion:	4.1

Description:

		The attributes:



		pnp_string	- Data to be passed to the host in pnp string

		q_len		- Number of requests per endpoint

Documentation/usb/gadget-testing.txt

+47 −0
Original line number Diff line number Diff line
@@ -19,6 +19,7 @@ provided by gadgets. 
16. UAC1 function

17. UAC2 function

18. UVC function

19. PRINTER function





1. ACM function
@@ -726,3 +727,49 @@ with these patches: 
http://www.spinics.net/lists/linux-usb/msg99220.html



host: luvcview -f yuv



19. PRINTER function

====================



The function is provided by usb_f_printer.ko module.



Function-specific configfs interface

------------------------------------



The function name to use when creating the function directory is "printer".

The printer function provides these attributes in its function directory:



	pnp_string	- Data to be passed to the host in pnp string

	q_len		- Number of requests per endpoint



Testing the PRINTER function

----------------------------



The most basic testing:



device: run the gadget

# ls -l /devices/virtual/usb_printer_gadget/



should show g_printer<number>.



If udev is active, then /dev/g_printer<number> should appear automatically.



host:



If udev is active, then e.g. /dev/usb/lp0 should appear.



host->device transmission:



device:

# cat /dev/g_printer<number>

host:

# cat > /dev/usb/lp0



device->host transmission:



# cat > /dev/g_printer<number>

host:

# cat /dev/usb/lp0



More advanced testing can be done with the prn_example

described in Documentation/usb/gadget-printer.txt.

drivers/usb/gadget/Kconfig

+13 −0
Original line number Diff line number Diff line
@@ -437,6 +437,19 @@ config USB_CONFIGFS_F_UVC 
	  device. It provides a userspace API to process UVC control requests

	  and stream video data to the host.



config USB_CONFIGFS_F_PRINTER

	bool "Printer function"

	select USB_F_PRINTER

	help

	  The Printer function channels data between the USB host and a

	  userspace program driving the print engine. The user space

	  program reads and writes the device file /dev/g_printer<X> to

	  receive or send printer data. It can use ioctl calls to

	  the device file to get or set printer status.



	  For more information, see Documentation/usb/gadget_printer.txt

	  which includes sample code for accessing the device file.



source "drivers/usb/gadget/legacy/Kconfig"



endchoice

drivers/usb/gadget/function/f_printer.c

+128 −2
Original line number Diff line number Diff line
@@ -1140,6 +1140,117 @@ static void printer_func_disable(struct usb_function *f) 
	spin_unlock_irqrestore(&dev->lock, flags);

}



static inline struct f_printer_opts

*to_f_printer_opts(struct config_item *item)

{

	return container_of(to_config_group(item), struct f_printer_opts,

			    func_inst.group);

}



CONFIGFS_ATTR_STRUCT(f_printer_opts);

CONFIGFS_ATTR_OPS(f_printer_opts);



static void printer_attr_release(struct config_item *item)

{

	struct f_printer_opts *opts = to_f_printer_opts(item);



	usb_put_function_instance(&opts->func_inst);

}



static struct configfs_item_operations printer_item_ops = {

	.release	= printer_attr_release,

	.show_attribute	= f_printer_opts_attr_show,

	.store_attribute = f_printer_opts_attr_store,

};



static ssize_t f_printer_opts_pnp_string_show(struct f_printer_opts *opts,

					      char *page)

{

	int result;



	mutex_lock(&opts->lock);

	result = strlcpy(page, opts->pnp_string + 2, PNP_STRING_LEN - 2);

	mutex_unlock(&opts->lock);



	return result;

}



static ssize_t f_printer_opts_pnp_string_store(struct f_printer_opts *opts,

					       const char *page, size_t len)

{

	int result, l;



	mutex_lock(&opts->lock);

	result = strlcpy(opts->pnp_string + 2, page, PNP_STRING_LEN - 2);

	l = strlen(opts->pnp_string + 2) + 2;

	opts->pnp_string[0] = (l >> 8) & 0xFF;

	opts->pnp_string[1] = l & 0xFF;

	mutex_unlock(&opts->lock);



	return result;

}



static struct f_printer_opts_attribute f_printer_opts_pnp_string =

	__CONFIGFS_ATTR(pnp_string, S_IRUGO | S_IWUSR,

			f_printer_opts_pnp_string_show,

			f_printer_opts_pnp_string_store);



static ssize_t f_printer_opts_q_len_show(struct f_printer_opts *opts,

					 char *page)

{

	int result;



	mutex_lock(&opts->lock);

	result = sprintf(page, "%d\n", opts->q_len);

	mutex_unlock(&opts->lock);



	return result;

}



static ssize_t f_printer_opts_q_len_store(struct f_printer_opts *opts,

					  const char *page, size_t len)

{

	int ret;

	u16 num;



	mutex_lock(&opts->lock);

	if (opts->refcnt) {

		ret = -EBUSY;

		goto end;

	}



	ret = kstrtou16(page, 0, &num);

	if (ret)

		goto end;



	if (num > 65535) {

		ret = -EINVAL;

		goto end;

	}



	opts->q_len = (unsigned)num;

	ret = len;

end:

	mutex_unlock(&opts->lock);

	return ret;

}



static struct f_printer_opts_attribute f_printer_opts_q_len =

	__CONFIGFS_ATTR(q_len, S_IRUGO | S_IWUSR, f_printer_opts_q_len_show,

			f_printer_opts_q_len_store);



static struct configfs_attribute *printer_attrs[] = {

	&f_printer_opts_pnp_string.attr,

	&f_printer_opts_q_len.attr,

	NULL,

};



static struct config_item_type printer_func_type = {

	.ct_item_ops	= &printer_item_ops,

	.ct_attrs	= printer_attrs,

	.ct_owner	= THIS_MODULE,

};



static inline int gprinter_get_minor(void)

{

	return ida_simple_get(&printer_ida, 0, 0, GFP_KERNEL);
@@ -1180,6 +1291,7 @@ static struct usb_function_instance *gprinter_alloc_inst(void) 
	if (!opts)

		return ERR_PTR(-ENOMEM);



	mutex_init(&opts->lock);

	opts->func_inst.free_func_inst = gprinter_free_inst;

	ret = &opts->func_inst;
@@ -1201,6 +1313,8 @@ static struct usb_function_instance *gprinter_alloc_inst(void) 
		if (idr_is_empty(&printer_ida.idr))

			gprinter_cleanup();

	}

	config_group_init_type_name(&opts->func_inst.group, "",

				    &printer_func_type);



unlock:

	mutex_unlock(&printer_ida_lock);
@@ -1210,8 +1324,13 @@ unlock: 
static void gprinter_free(struct usb_function *f)

{

	struct printer_dev *dev = func_to_printer(f);

	struct f_printer_opts *opts;



	opts = container_of(f->fi, struct f_printer_opts, func_inst);

	kfree(dev);

	mutex_lock(&opts->lock);

	--opts->refcnt;

	mutex_unlock(&opts->lock);

}



static void printer_func_unbind(struct usb_configuration *c,
@@ -1265,16 +1384,23 @@ static struct usb_function *gprinter_alloc(struct usb_function_instance *fi) 


	opts = container_of(fi, struct f_printer_opts, func_inst);



	if (opts->minor >= minors)

	mutex_lock(&opts->lock);

	if (opts->minor >= minors) {

		mutex_unlock(&opts->lock);

		return ERR_PTR(-ENOENT);

	}



	dev = kzalloc(sizeof(*dev), GFP_KERNEL);

	if (!dev)

	if (!dev) {

		mutex_unlock(&opts->lock);

		return ERR_PTR(-ENOMEM);

	}



	++opts->refcnt;

	dev->minor = opts->minor;

	dev->pnp_string = opts->pnp_string;

	dev->q_len = opts->q_len;

	mutex_unlock(&opts->lock);



	dev->function.name = "printer";

	dev->function.bind = printer_func_bind;

drivers/usb/gadget/function/u_printer.h

+7 −0
Original line number Diff line number Diff line
@@ -25,6 +25,13 @@ struct f_printer_opts { 
	int				minor;

	char				pnp_string[PNP_STRING_LEN];

	unsigned			q_len;



	/*

	 * Protect the data from concurrent access by read/write

	 * and create symlink/remove symlink

	 */

	struct mutex			lock;

	int				refcnt;

};



#endif /* U_PRINTER_H */