啥也不说了,先上代码:
由于linux中的list.h不能直接用,所以单独提取了出来使用:
//listop.h
/*it is from linux list */ #ifndef LISTOP_H #define LISTOP_H struct list_head { struct list_head *next, *prev; }; typedef struct list_head list_t; #define LIST_HEAD_INIT(name) { &(name), &(name) } #define LIST_HEAD(name) \ struct list_head name = LIST_HEAD_INIT(name) #define INIT_LIST_HEAD(ptr) do { \ (ptr)->next = (ptr); (ptr)->prev = (ptr); \ } while (0) /** * list_add - add a new entry * @new: new entry to be added * @head: list head to add it after * * Insert a new entry after the specified head. * This is good for implementing stacks. */ void list_add(struct list_head *new, struct list_head *head); /** * list_add_tail - add a new entry * @new: new entry to be added * @head: list head to add it before * * Insert a new entry before the specified head. * This is useful for implementing queues. */ void list_add_tail(struct list_head *new, struct list_head *head); /** * list_del - deletes entry from list. * @entry: the element to delete from the list. * Note: list_empty on entry does not return true after this, the entry is in an undefined state. */ void list_del(struct list_head *entry); /** * list_del_init - deletes entry from list and reinitialize it. * @entry: the element to delete from the list. */ void list_del_init(struct list_head *entry); /** * list_move - delete from one list and add as another's head * @list: the entry to move * @head: the head that will precede our entry */ void list_move(struct list_head *list, struct list_head *head); /** * list_move_tail - delete from one list and add as another's tail * @list: the entry to move * @head: the head that will follow our entry */ void list_move_tail(struct list_head *list, struct list_head *head); /** * list_splice - join two lists * @list: the new list to add. * @head: the place to add it in the first list. */ void list_splice(struct list_head *list, struct list_head *head); /** * list_empty - tests whether a list is empty * @head: the list to test. */ static int list_empty(struct list_head *head) { return head->next == head; } /** * list_dequeue - dequeue the head of the list if there are more than one entry * @list: the list to dequeue */ struct list_head * list_dequeue( struct list_head *list ); /** * list_entry - get the struct for this entry * @ptr: the &struct list_head pointer. * @type: the type of the struct this is embedded in. * @member: the name of the list_struct within the struct. */ #define list_entry(ptr, type, member) \ ((type *)((char *)(ptr)-(unsigned long)(&((type *)0)->member))) /** * list_for_each - iterate over a list * @pos: the &struct list_head to use as a loop counter. * @head: the head for your list. */ #define list_for_each(pos, head) \ for (pos = (head)->next; pos != (head); \ pos = pos->next) /** * list_for_each_safe - iterate over a list safe against removal of list entry * @pos: the &struct list_head to use as a loop counter. * @n: another &struct list_head to use as temporary storage * @head: the head for your list. */ #define list_for_each_safe(pos, n, head) \ for (pos = (head)->next, n = pos->next; pos != (head); \ pos = n, n = pos->next) /** * list_for_each_prev - iterate over a list in reverse order * @pos: the &struct list_head to use as a loop counter. * @head: the head for your list. */ #define list_for_each_prev(pos, head) \ for (pos = (head)->prev; pos != (head); \ pos = pos->prev) /** * list_for_each_entry - iterate over list of given type * @pos: the type * to use as a loop counter. * @head: the head for your list. * @member: the name of the list_struct within the struct. */ #define list_for_each_entry(pos, head, member) \ for (pos = list_entry((head)->next, typeof(*pos), member); \ &pos->member != (head); \ pos = list_entry(pos->member.next, typeof(*pos), member)) #endif
#include "listop.h" static void __check_head(struct list_head* head) { if ((head->next == 0) && (head->prev == 0)) { INIT_LIST_HEAD(head); } } /* * Insert a new entry between two known consecutive entries. * * This is only for internal list manipulation where we know * the prev/next entries already! */ static void __list_add(struct list_head* new, struct list_head* prev, struct list_head* next) { next->prev = new; new->next = next; new->prev = prev; prev->next = new; } /* * Delete a list entry by making the prev/next entries * point to each other. * * This is only for internal list manipulation where we know * the prev/next entries already! */ static void __list_del(struct list_head* prev, struct list_head* next) { next->prev = prev; prev->next = next; } /** * list_add - add a new entry * @new: new entry to be added * @head: list head to add it after * * Insert a new entry after the specified head. * This is good for implementing stacks. */ void list_add(struct list_head* new, struct list_head* head) { __check_head(head); __list_add(new, head, head->next); } /** * list_add_tail - add a new entry * @new: new entry to be added * @head: list head to add it before * * Insert a new entry before the specified head. * This is useful for implementing queues. */ void list_add_tail(struct list_head* new, struct list_head* head) { __check_head(head); __list_add(new, head->prev, head); } /** * list_del - deletes entry from list. * @entry: the element to delete from the list. * Note: list_empty on entry does not return true after this, the entry is in an undefined state. */ void list_del(struct list_head* entry) { __list_del(entry->prev, entry->next); } /** * list_del_init - deletes entry from list and reinitialize it. * @entry: the element to delete from the list. */ void list_del_init(struct list_head* entry) { __list_del(entry->prev, entry->next); INIT_LIST_HEAD(entry); } /** * list_move - delete from one list and add as another's head * @list: the entry to move * @head: the head that will precede our entry */ void list_move(struct list_head* list, struct list_head* head) { __check_head(head); __list_del(list->prev, list->next); list_add(list, head); } /** * list_move_tail - delete from one list and add as another's tail * @list: the entry to move * @head: the head that will follow our entry */ void list_move_tail(struct list_head* list, struct list_head* head) { __check_head(head); __list_del(list->prev, list->next); list_add_tail(list, head); } /** * list_splice - join two lists * @list: the new list to add. * @head: the place to add it in the first list. */ void list_splice(struct list_head* list, struct list_head* head) { struct list_head* first = list; struct list_head* last = list->prev; struct list_head* at = head->next; first->prev = head; head->next = first; last->next = at; at->prev = last; } struct list_head* list_dequeue( struct list_head* list ) { struct list_head* next, *prev, *result = ((void*)0); prev = list; next = prev->next; if ( next != prev ) { result = next; next = next->next; next->prev = prev; prev->next = next; result->prev = result->next = result; } return result; }
主要的文件在这里:
//my_joystick.c
#include <stdio.h> #include <sys/types.h> #include <sys/time.h> #include <sys/stat.h> #include <fcntl.h> #include <unistd.h> #include <errno.h> #include <stdlib.h> #include <string.h> #include <linux/joystick.h> //#include <linux/list.h> /*郁闷,不能直接使用linux自带的list链表,需要单独提取出来,见前面的code*/ #include "listop.h" #if 1 #define LOG_DBG(fmt, ...) fprintf(stdout, fmt, ##__VA_ARGS__) #else #define LOG_DBG(fmt, ...) #endif #define LOG_ERR(fmt, ...) fprintf(stderr, fmt, ##__VA_ARGS__) typedef struct _joy_stick_ctx { struct list_head list; int i4_js_fd; unsigned int i4_op_block; } JOYSTICK_CTX_T; LIST_HEAD(_t_js_ctx_head); /*==> struct list_head _t_js_ctx_head = {&_t_js_ctx_head, &_t_js_ctx_head};*/ int joystick_open(char* cp_js_dev_name, int i4_block) { int i4_open_flags = O_RDONLY; JOYSTICK_CTX_T* pt_joystick_ctx = NULL; if (!cp_js_dev_name) { LOG_ERR("[%s] js device name is NULL\n", __func__); return -1; } pt_joystick_ctx = (JOYSTICK_CTX_T*)calloc(sizeof(JOYSTICK_CTX_T), 1); if (!pt_joystick_ctx) { LOG_ERR("[%s] no memory!!\n", __func__); return -1; } pt_joystick_ctx->i4_op_block = i4_block ? 1 : 0; if (pt_joystick_ctx->i4_op_block == 0) { i4_open_flags |= O_NONBLOCK; } pt_joystick_ctx->i4_js_fd = open(cp_js_dev_name, i4_open_flags); if (pt_joystick_ctx->i4_js_fd < 0) { LOG_ERR("[%s] open device %s error\n", __func__, cp_js_dev_name); free(pt_joystick_ctx); return -1; } list_add_tail(&pt_joystick_ctx->list, &_t_js_ctx_head); return pt_joystick_ctx->i4_js_fd; } int joystick_close(int i4_fd) { struct list_head* pt_entry; struct list_head* pt_next; JOYSTICK_CTX_T* pt_node; if (list_empty(&_t_js_ctx_head)) { LOG_ERR("[%s] device not opened\n", __func__); return -1; } list_for_each_safe(pt_entry, pt_next, &_t_js_ctx_head) { pt_node = list_entry(pt_entry, JOYSTICK_CTX_T, list); if (pt_node->i4_js_fd == i4_fd) { list_del_init(&pt_node->list); free(pt_node); return close(i4_fd); } } LOG_ERR("[%s] i4_fd=%d invalid\n", __func__, i4_fd); return -1; } int joystick_read_one_event(int i4_fd, struct js_event* tp_jse) { int i4_rd_bytes; /*do not check i4_fd again*/ i4_rd_bytes = read(i4_fd, tp_jse, sizeof(struct js_event)); if (i4_rd_bytes == -1) { if (errno == EAGAIN) { /*when no block, it is not error*/ return 0; } else { return -1; } } return i4_rd_bytes; } int joystick_read_ready(int i4_fd) { int i4_block = 2; struct list_head* pt_entry; JOYSTICK_CTX_T* pt_node; if (list_empty(&_t_js_ctx_head)) { LOG_ERR("[%s] device not opened\n", __func__); return -1; } list_for_each(pt_entry, &_t_js_ctx_head) { pt_node = list_entry(pt_entry, JOYSTICK_CTX_T, list); if (pt_node->i4_js_fd == i4_fd) { i4_block = pt_node->i4_op_block; break; } } if (i4_block == 2) { LOG_ERR("[%s] i4_fd=%d invalid\n", __func__, i4_fd); return 0; } else if (i4_block == 1) { fd_set readfd; int i4_ret = 0; struct timeval timeout = {0, 0}; FD_ZERO(&readfd); FD_SET(i4_fd, &readfd); i4_ret = select(i4_fd + 1, &readfd, NULL, NULL, &timeout); if (i4_ret > 0 && FD_ISSET(i4_fd, &readfd)) { return 1; } else { return 0; } } return 1; /*noblock read, aways ready*/ } void debug_list(void) { if (! list_empty(&_t_js_ctx_head)) { struct list_head* pt_entry; JOYSTICK_CTX_T* pt_node; list_for_each(pt_entry, &_t_js_ctx_head) { pt_node = list_entry(pt_entry, JOYSTICK_CTX_T, list); LOG_DBG("fd:%d--block:%d\n", pt_node->i4_js_fd, pt_node->i4_op_block); } } else { LOG_DBG("-----------> EMPTY NOW\n"); } } #if 1 typedef struct _axes_t { int x; int y; } AXES_T; int main(int argc, char* argv[]) { int fd, rc; int op_times = 0; char number_of_axes = 0; char number_of_btns = 0; char js_name_str[128]; unsigned int buttons_state = 0; AXES_T* tp_axes = NULL; int i, print_init_stat = 0; struct js_event jse; fd = joystick_open("/dev/input/js0", 1); if (fd < 0) { LOG_ERR("open failed.\n"); exit(1); } rc = ioctl(fd, JSIOCGAXES, &number_of_axes); if (rc != -1) { LOG_DBG("number_of_axes:%d\n", number_of_axes); if (number_of_axes > 0) { tp_axes = (AXES_T*)calloc(sizeof(AXES_T), 1); } } rc = ioctl(fd, JSIOCGBUTTONS, &number_of_btns); if (rc != -1) { LOG_DBG("number_of_btns:%d\n", number_of_btns); } if (ioctl(fd, JSIOCGNAME(sizeof(js_name_str)), js_name_str) < 0) { LOG_DBG(js_name_str, "Unknown", sizeof(js_name_str)); } LOG_DBG("joystick Name: %s\n", js_name_str); for (;;) { if (joystick_read_ready(fd)) { rc = joystick_read_one_event(fd, &jse); if (rc > 0) { if ((jse.type & JS_EVENT_INIT) == JS_EVENT_INIT) { if ((jse.type & ~JS_EVENT_INIT) == JS_EVENT_BUTTON) { if (jse.value) { buttons_state |= (1 << jse.number); } else { buttons_state &= ~(1 << jse.number); } } else if ((jse.type & ~JS_EVENT_INIT) == JS_EVENT_AXIS) { if (tp_axes) { if ((jse.number & 1) == 0) { tp_axes[jse.number / 2].x = jse.value; } else { tp_axes[jse.number / 2].y = jse.value; } } } } else { op_times++; if (print_init_stat == 0) { for (i = 0; i < number_of_btns; i++) { LOG_DBG("joystick init state: button %d is %s.\n", i, ((buttons_state & (1 << i)) == (1 << i)) ? "DOWN" : "UP"); } if (tp_axes) for (i = 0; i < number_of_axes; i++) { LOG_DBG("joystick init state: axes %d is x=%d y=%d.\n", i, tp_axes[i].x, tp_axes[i].y); } print_init_stat = 1; } if (jse.type == JS_EVENT_BUTTON) { if (jse.value) { buttons_state |= (1 << jse.number); } else { buttons_state &= ~(1 << jse.number); } LOG_DBG("joystick state: button %d is %s.\n", jse.number, ((buttons_state & (1 << jse.number)) == (1 << jse.number)) ? "DOWN" : "UP"); } else if (jse.type == JS_EVENT_AXIS) { if (tp_axes) { if ((jse.number & 1) == 0) { tp_axes[jse.number / 2].x = jse.value; } else { tp_axes[jse.number / 2].y = jse.value; } LOG_DBG("joystick state: axes %d is x=%d y=%d.\n", jse.number / 2, tp_axes[jse.number / 2].x, tp_axes[jse.number / 2].y); } else { LOG_DBG("joystick state: axes %d is %s=%d.\n", jse.number / 2, ((jse.number & 1) == 0) ? "x" : "y", jse.value); } } } if (op_times >= 18) { break; } } } usleep(1000); } joystick_close(fd); if (tp_axes) { free(tp_axes); } return 0; } #endif
编译: gcc -o my_joystick my_joystick.c listop.c
运行:
mayer@mayer-ubuntu:hid$ ./my_joystick
number_of_axes:2
number_of_btns:10
joystick Name: BETOP GAMEPAD
joystick init state: button 0 is UP.
joystick init state: button 1 is UP.
joystick init state: button 2 is UP.
joystick init state: button 3 is UP.
joystick init state: button 4 is UP.
joystick init state: button 5 is UP.
joystick init state: button 6 is UP.
joystick init state: button 7 is UP.
joystick init state: button 8 is UP.
joystick init state: button 9 is UP.
joystick init state: axes 0 is x=0 y=0.
joystick init state: axes 1 is x=0 y=135129.
joystick state: button 0 is DOWN.
joystick state: button 0 is UP.
joystick state: button 1 is DOWN.
joystick state: button 1 is UP.
joystick state: button 3 is DOWN.
joystick state: button 3 is UP.
joystick state: button 2 is DOWN.
joystick state: button 2 is UP.
joystick state: button 7 is DOWN.
joystick state: button 7 is UP.
joystick state: button 5 is DOWN.
joystick state: button 5 is UP.
joystick state: button 6 is DOWN.
joystick state: button 6 is UP.
joystick state: button 4 is DOWN.
joystick state: button 4 is UP.
joystick state: button 5 is DOWN.
joystick state: button 5 is UP.
不明白的地方可以参考linux kernel中的说明文件:Documentation/input/joystick-api.txt