16. UAC1 function
17. UAC2 function
18. UVC function
+19. PRINTER function
1. ACM function
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.
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);
if (!opts)
return ERR_PTR(-ENOMEM);
+ mutex_init(&opts->lock);
opts->func_inst.free_func_inst = gprinter_free_inst;
ret = &opts->func_inst;
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);
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,
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;
projects / GitHub / exynos8895 / android_kernel_samsung_universal8895.git / commitdiff