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Diffstat (limited to 'Documentation/usb/gadget_hid.txt')
| -rw-r--r-- | Documentation/usb/gadget_hid.txt | 175 |
1 files changed, 90 insertions, 85 deletions
diff --git a/Documentation/usb/gadget_hid.txt b/Documentation/usb/gadget_hid.txt index 7a0fb8e16e27..098d563040cc 100644 --- a/Documentation/usb/gadget_hid.txt +++ b/Documentation/usb/gadget_hid.txt @@ -1,28 +1,31 @@ - - Linux USB HID gadget driver +=========================== +Linux USB HID gadget driver +=========================== Introduction +============ - The HID Gadget driver provides emulation of USB Human Interface - Devices (HID). The basic HID handling is done in the kernel, - and HID reports can be sent/received through I/O on the - /dev/hidgX character devices. +The HID Gadget driver provides emulation of USB Human Interface +Devices (HID). The basic HID handling is done in the kernel, +and HID reports can be sent/received through I/O on the +/dev/hidgX character devices. - For more details about HID, see the developer page on - http://www.usb.org/developers/hidpage/ +For more details about HID, see the developer page on +http://www.usb.org/developers/hidpage/ Configuration +============= - g_hid is a platform driver, so to use it you need to add - struct platform_device(s) to your platform code defining the - HID function descriptors you want to use - E.G. something - like: +g_hid is a platform driver, so to use it you need to add +struct platform_device(s) to your platform code defining the +HID function descriptors you want to use - E.G. something +like:: -#include <linux/platform_device.h> -#include <linux/usb/g_hid.h> + #include <linux/platform_device.h> + #include <linux/usb/g_hid.h> -/* hid descriptor for a keyboard */ -static struct hidg_func_descriptor my_hid_data = { + /* hid descriptor for a keyboard */ + static struct hidg_func_descriptor my_hid_data = { .subclass = 0, /* No subclass */ .protocol = 1, /* Keyboard */ .report_length = 8, @@ -61,85 +64,87 @@ static struct hidg_func_descriptor my_hid_data = { 0x81, 0x00, /* INPUT (Data,Ary,Abs) */ 0xc0 /* END_COLLECTION */ } -}; + }; -static struct platform_device my_hid = { + static struct platform_device my_hid = { .name = "hidg", .id = 0, .num_resources = 0, .resource = 0, .dev.platform_data = &my_hid_data, -}; + }; - You can add as many HID functions as you want, only limited by - the amount of interrupt endpoints your gadget driver supports. +You can add as many HID functions as you want, only limited by +the amount of interrupt endpoints your gadget driver supports. Configuration with configfs +=========================== - Instead of adding fake platform devices and drivers in order to pass - some data to the kernel, if HID is a part of a gadget composed with - configfs the hidg_func_descriptor.report_desc is passed to the kernel - by writing the appropriate stream of bytes to a configfs attribute. +Instead of adding fake platform devices and drivers in order to pass +some data to the kernel, if HID is a part of a gadget composed with +configfs the hidg_func_descriptor.report_desc is passed to the kernel +by writing the appropriate stream of bytes to a configfs attribute. Send and receive HID reports +============================ - HID reports can be sent/received using read/write on the - /dev/hidgX character devices. See below for an example program - to do this. +HID reports can be sent/received using read/write on the +/dev/hidgX character devices. See below for an example program +to do this. - hid_gadget_test is a small interactive program to test the HID - gadget driver. To use, point it at a hidg device and set the - device type (keyboard / mouse / joystick) - E.G.: +hid_gadget_test is a small interactive program to test the HID +gadget driver. To use, point it at a hidg device and set the +device type (keyboard / mouse / joystick) - E.G.:: - # hid_gadget_test /dev/hidg0 keyboard + # hid_gadget_test /dev/hidg0 keyboard - You are now in the prompt of hid_gadget_test. You can type any - combination of options and values. Available options and - values are listed at program start. In keyboard mode you can - send up to six values. +You are now in the prompt of hid_gadget_test. You can type any +combination of options and values. Available options and +values are listed at program start. In keyboard mode you can +send up to six values. - For example type: g i s t r --left-shift +For example type: g i s t r --left-shift - Hit return and the corresponding report will be sent by the - HID gadget. +Hit return and the corresponding report will be sent by the +HID gadget. - Another interesting example is the caps lock test. Type - --caps-lock and hit return. A report is then sent by the - gadget and you should receive the host answer, corresponding - to the caps lock LED status. +Another interesting example is the caps lock test. Type +--caps-lock and hit return. A report is then sent by the +gadget and you should receive the host answer, corresponding +to the caps lock LED status:: - --caps-lock - recv report:2 + --caps-lock + recv report:2 - With this command: +With this command:: - # hid_gadget_test /dev/hidg1 mouse + # hid_gadget_test /dev/hidg1 mouse - You can test the mouse emulation. Values are two signed numbers. +You can test the mouse emulation. Values are two signed numbers. -Sample code +Sample code:: -/* hid_gadget_test */ + /* hid_gadget_test */ -#include <pthread.h> -#include <string.h> -#include <stdio.h> -#include <ctype.h> -#include <fcntl.h> -#include <errno.h> -#include <stdio.h> -#include <stdlib.h> -#include <unistd.h> + #include <pthread.h> + #include <string.h> + #include <stdio.h> + #include <ctype.h> + #include <fcntl.h> + #include <errno.h> + #include <stdio.h> + #include <stdlib.h> + #include <unistd.h> -#define BUF_LEN 512 + #define BUF_LEN 512 -struct options { + struct options { const char *opt; unsigned char val; -}; + }; -static struct options kmod[] = { + static struct options kmod[] = { {.opt = "--left-ctrl", .val = 0x01}, {.opt = "--right-ctrl", .val = 0x10}, {.opt = "--left-shift", .val = 0x02}, @@ -149,9 +154,9 @@ static struct options kmod[] = { {.opt = "--left-meta", .val = 0x08}, {.opt = "--right-meta", .val = 0x80}, {.opt = NULL} -}; + }; -static struct options kval[] = { + static struct options kval[] = { {.opt = "--return", .val = 0x28}, {.opt = "--esc", .val = 0x29}, {.opt = "--bckspc", .val = 0x2a}, @@ -183,10 +188,10 @@ static struct options kval[] = { {.opt = "--up", .val = 0x52}, {.opt = "--num-lock", .val = 0x53}, {.opt = NULL} -}; + }; -int keyboard_fill_report(char report[8], char buf[BUF_LEN], int *hold) -{ + int keyboard_fill_report(char report[8], char buf[BUF_LEN], int *hold) + { char *tok = strtok(buf, " "); int key = 0; int i = 0; @@ -229,17 +234,17 @@ int keyboard_fill_report(char report[8], char buf[BUF_LEN], int *hold) fprintf(stderr, "unknown option: %s\n", tok); } return 8; -} + } -static struct options mmod[] = { + static struct options mmod[] = { {.opt = "--b1", .val = 0x01}, {.opt = "--b2", .val = 0x02}, {.opt = "--b3", .val = 0x04}, {.opt = NULL} -}; + }; -int mouse_fill_report(char report[8], char buf[BUF_LEN], int *hold) -{ + int mouse_fill_report(char report[8], char buf[BUF_LEN], int *hold) + { char *tok = strtok(buf, " "); int mvt = 0; int i = 0; @@ -274,9 +279,9 @@ int mouse_fill_report(char report[8], char buf[BUF_LEN], int *hold) fprintf(stderr, "unknown option: %s\n", tok); } return 3; -} + } -static struct options jmod[] = { + static struct options jmod[] = { {.opt = "--b1", .val = 0x10}, {.opt = "--b2", .val = 0x20}, {.opt = "--b3", .val = 0x40}, @@ -287,10 +292,10 @@ static struct options jmod[] = { {.opt = "--hat4", .val = 0x03}, {.opt = "--hatneutral", .val = 0x04}, {.opt = NULL} -}; + }; -int joystick_fill_report(char report[8], char buf[BUF_LEN], int *hold) -{ + int joystick_fill_report(char report[8], char buf[BUF_LEN], int *hold) + { char *tok = strtok(buf, " "); int mvt = 0; int i = 0; @@ -326,10 +331,10 @@ int joystick_fill_report(char report[8], char buf[BUF_LEN], int *hold) fprintf(stderr, "unknown option: %s\n", tok); } return 4; -} + } -void print_options(char c) -{ + void print_options(char c) + { int i = 0; if (c == 'k') { @@ -358,10 +363,10 @@ void print_options(char c) " three signed numbers\n" "--quit to close\n"); } -} + } -int main(int argc, const char *argv[]) -{ + int main(int argc, const char *argv[]) + { const char *filename = NULL; int fd = 0; char buf[BUF_LEN]; @@ -449,4 +454,4 @@ int main(int argc, const char *argv[]) close(fd); return 0; -} + } |