在组件的基础属性栏中将 width 设置为 4，确保 Direction
为 Input。在 Edge capture register 属性栏中，选中 Synchronously capture，
并将 Edge Type 设置为 FALLING。在 Interrupt 属性栏中，选中 Generate IRQ，
并将 IRQ Type 设置为 Edge。点击 Finish 完成 Button 组件的配置
1 #include <linux/kernel.h> 2 #include <linux/module.h> 3 #include <linux/init.h> 4 #include <linux/interrupt.h> 5 #include <asm/io.h> 6 #include "../address_map_arm.h" 7 #include "../interrupt_ID.h" 8 void * LW_virtual; // Lightweight bridge base address 9 volatile int *LEDR_ptr, *KEY_ptr; // virtual addresses 10 11 irq_handler_t irq_handler(int irq, void *dev_id, struct pt_regs *regs) 12 { 13 *LEDR_ptr = *LEDR_ptr + 1; 14 // Clear the Edgecapture register (clears current interrupt) 15 *(KEY_ptr + 3) = 0xF; 16 return (irq_handler_t) IRQ_HANDLED; 17 } 18 static int __init initialize_pushbutton_handler(void) 19 { 20 int value; 21 // generate a virtual address for the FPGA lightweight bridge 22 LW_virtual = ioremap_nocache (LW_BRIDGE_BASE, LW_BRIDGE_SPAN); 23 24 LEDR_ptr = LW_virtual + LEDR_BASE; // virtual address for LEDR port 25 *LEDR_ptr = 0x200; // turn on the leftmost light 26 27 KEY_ptr = LW_virtual + KEY_BASE; // virtual address for KEY port 28 *(KEY_ptr + 3) = 0xF; // Clear the Edgecapture register 29 *(KEY_ptr + 2) = 0xF; // Enable IRQ generation for the 4 buttons 30 31 // Register the interrupt handler. 32 value = request_irq (KEYS_IRQ, (irq_handler_t) irq_handler, IRQF_SHARED, 33 "pushbutton_irq_handler", (void *) (irq_handler)); 34 return value; 35 } 36 static void __exit cleanup_pushbutton_handler(void) 37 { 38 *LEDR_ptr = 0; // Turn off LEDs and de-register irq handler 39 iounmap (LW_virtual); 40 free_irq (KEYS_IRQ, (void*) irq_handler); 41 } 42 module_init(initialize_pushbutton_handler); 43 module_exit(cleanup_pushbutton_handler);