使用Gadget 做usb鼠标键盘设备

感谢TI社区提供的好帮助啊！http://e2e.ti.com/support/arm/sitara_arm/f/791/p/571771/2103409?pi316653=2
虽然海思平台和TI平台不一样 ，但也大同小异。

具体的步骤如下：
转到内核目录：
//加载配置文件

cp xxx .config 
修改配置 
make xxxx menuconfig 
-> Device Drivers -> USB support -> USB Gadget Support 添加gadget， HID Gadget 
进到： 
-> Device Drivers -> USB support > USB Gadget Support-> USB Peripheral Controller 
->Device Drivers ->USB support > USB Gadget Support -> USB Peripheral Controller -> Hisilicon USB2.0 Device Controller SUPPORT 
+ [*] Hisilicon USB2.0 Device auto switch

打开自动切换！！！！
需要注意的是gadget子项的驱动依赖于udc模块和composite模块，而composite模块又依赖于udc模块，udc是硬件接口模块，直接操作USB寄存器等。composite为上层驱动提供操作UDC。

所以加载顺序必要是udc-hisi.ko 、libcomposite.ko 、g_hid.ko
加载发现出现问题，某些函数不能用，经过研究要打开

File systems > Pseudo filesystems 
+ {*} Userspace-driven configuration filesystem 

即可，加载g_hid.ko后出现： 
insmod: can’t insert ‘g_hid.ko’: No such device 
原因在于没有注册设备报告描述符！！！修改hid.c文件 
头文件：

+#include <linux/usb/g_hid.h>

+static struct hidg_func_descriptor keyboard_report_data =
+{
+   .subclass       = 0, /* No subclass */  
+   .protocol       = 1, /* Keyboard */
+   .report_length      = 8,
+   .report_desc_length = 63,
+   .report_desc        = {
+   0x05, 0x01, /* USAGE_PAGE (Generic Desktop)           */
+       0x09, 0x06, /* USAGE (Keyboard)                       */
+       0xa1, 0x01, /* COLLECTION (Application)               */
+       0x05, 0x07, /*   USAGE_PAGE (Keyboard)                */
+       0x19, 0xe0, /*   USAGE_MINIMUM (Keyboard LeftControl) */
+       0x29, 0xe7, /*   USAGE_MAXIMUM (Keyboard Right GUI)   */
+       0x15, 0x00, /*   LOGICAL_MINIMUM (0)                  */
+       0x25, 0x01, /*   LOGICAL_MAXIMUM (1)                  */
+       0x75, 0x01, /*   REPORT_SIZE (1)                      */
+       0x95, 0x08, /*   REPORT_COUNT (8)                     */
+       0x81, 0x02, /*   INPUT (Data,Var,Abs)                 */
    +   0x95, 0x01, /*   REPORT_COUNT (1)                     */
    +   0x75, 0x08, /*   REPORT_SIZE (8)                      */
    +   0x81, 0x03, /*   INPUT (Cnst,Var,Abs)                 */
    +   0x95, 0x05, /*   REPORT_COUNT (5)                     */
    +   0x75, 0x01, /*   REPORT_SIZE (1)                      */
    +   0x05, 0x08, /*   USAGE_PAGE (LEDs)                    */
    +   0x19, 0x01, /*   USAGE_MINIMUM (Num Lock)             */
    +   0x29, 0x05, /*   USAGE_MAXIMUM (Kana)                 */
    +   0x91, 0x02, /*   OUTPUT (Data,Var,Abs)                */
    +   0x95, 0x01, /*   REPORT_COUNT (1)                     */
    +   0x75, 0x03, /*   REPORT_SIZE (3)                      */
    +   0x91, 0x03, /*   OUTPUT (Cnst,Var,Abs)                */
    +   0x95, 0x06, /*   REPORT_COUNT (6)                     */
    +   0x75, 0x08, /*   REPORT_SIZE (8)                      */
    +   0x15, 0x00, /*   LOGICAL_MINIMUM (0)                  */
    +   0x25, 0x65, /*   LOGICAL_MAXIMUM (101)                */
    +   0x05, 0x07, /*   USAGE_PAGE (Keyboard)                */
    +   0x19, 0x00, /*   USAGE_MINIMUM (Reserved)             */
    +   0x29, 0x65, /*   USAGE_MAXIMUM (Keyboard Application) */
    +   0x81, 0x00, /*   INPUT (Data,Ary,Abs)                 */
    +   0xc0        /* END_COLLECTION                         */  
+};

定义键盘设备：
+static struct platform_device keyboard_device = {  
+   .name           = "hidg",  
+   .id         = 0,  
+   .num_resources      = 0,  
+   .resource       = 0,  
+   .dev.platform_data  = &keyboard_report_data,  
+};  

 

在static int __init hidg_init(void)函数开始处注册键盘设备

+status = platform_device_register(&keyboard_device);  
+   if (status < 0) {
+       printk("____ reg failed\n");
+       platform_device_unregister(&keyboard_device);
+       return status;  
+   }   

在驱动卸载处释放键盘设备

platform_driver_unregister(&hidg_plat_driver); 
+platform_device_unregister(&keyboard_device); 
usb_composite_unregister(&hidg_driver);

添加后即可识别为键盘设别如下图所示：



单个键盘和鼠标没有任何问题，然而同时设置鼠标和键盘加载后出现如下错误：
------------[ cut here ]------------
WARNING: CPU: 1 PID: 139 at fs/sysfs/dir.c:31 sysfs_warn_dup+0x60/0x70()
sysfs: cannot create duplicate filename '/devices/platform/hidg.0'
Modules linked in: g_hid(+) libcomposite udc_hisi [last unloaded: g_hid]
CPU: 1 PID: 139 Comm: insmod Tainted: G        W      3.18.20 #14
[<c001487c>] (unwind_backtrace) from [<c0011964>] (show_stack+0x10/0x14)
[<c0011964>] (show_stack) from [<c041e220>] (dump_stack+0x88/0x98)
[<c041e220>] (dump_stack) from [<c001e2d0>] (warn_slowpath_common+0x6c/0x88)
[<c001e2d0>] (warn_slowpath_common) from [<c001e31c>] (warn_slowpath_fmt+0x30/0x40)
[<c001e31c>] (warn_slowpath_fmt) from [<c012b4b8>] (sysfs_warn_dup+0x60/0x70)
[<c012b4b8>] (sysfs_warn_dup) from [<c012b550>] (sysfs_create_dir_ns+0x88/0x98)
[<c012b550>] (sysfs_create_dir_ns) from [<c01f94b0>] (kobject_add_internal+0xb0/0x300)
[<c01f94b0>] (kobject_add_internal) from [<c01f98bc>] (kobject_add+0x48/0x94)
[<c01f98bc>] (kobject_add) from [<c024eac4>] (device_add+0xd8/0x53c)
[<c024eac4>] (device_add) from [<c0252924>] (platform_device_add+0xb4/0x21c)
[<c0252924>] (platform_device_add) from [<bf0625bc>] (hidg_init+0x38/0xc8 [g_hid])
[<bf0625bc>] (hidg_init [g_hid]) from [<c00088d0>] (do_one_initcall+0x8c/0x1c8)
[<c00088d0>] (do_one_initcall) from [<c0085298>] (load_module+0x1740/0x1e88)
[<c0085298>] (load_module) from [<c0085ab8>] (SyS_init_module+0xd8/0xec)
[<c0085ab8>] (SyS_init_module) from [<c000e4a0>] (ret_fast_syscall+0x0/0x38)
---[ end trace c7b2846a724052eb ]---

static struct platform_device mouse_device = {  
   .name           = "hidg",  
   .id         = 0,  
   .num_resources      = 0,  
   .resource       = 0,  
   .dev.platform_data  = &mouse_report_desc,  
};

id和keyboard的id相同了冲突了！！
经过这样子做，鼠标键盘在dev对应的是hidg0(键盘id 0) hidg1(鼠标id 1),只要打开这两个设备，往这两个设备发送键盘和鼠标报告就可以了

经过如此的配置只要按照顺序加载udc-hisi.ko、libcomposite.ko、以及g_hid.ko即可使用gadget鼠标键盘设备了，卸载这些驱动后，host又可以正常使用。