/*********************************************************************************
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* Copyright: (C) 2025 LingYun IoT System Studio
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* All rights reserved.
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*
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* Filename: buzzer.c
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* Description: This file is linux kernel pwm-beeper driver test code.
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*
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* Version: 1.0.0(12/17/2025)
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* Author: Guo Wenxue <guowenxue@gmail.com>
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* ChangeLog: 1, Release initial version on "12/17/2025 09:44:08 PM"
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*
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********************************************************************************/
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#include <stdio.h>
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#include <stdlib.h>
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#include <fcntl.h>
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#include <unistd.h>
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#include <string.h>
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#include <linux/input.h>
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#include <sys/time.h>
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int main(int argc, char *argv[]) {
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int fd;
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struct input_event ev;
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int frequency = 10000; // Default: 10kHz
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float duration = 0.5; // Default: 0.5 seconds
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// Parse command line arguments
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if (argc >= 2) {
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frequency = atoi(argv[1]);
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}
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if (argc >= 3) {
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duration = atof(argv[2]);
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}
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// Open buzzer device
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fd = open("/dev/input/event0", O_WRONLY);
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if (fd < 0) {
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perror("Failed to open /dev/input/event0");
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return 1;
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}
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printf("=== PWM Buzzer Control ===\n");
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printf("Device: /dev/input/event0\n");
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printf("Frequency: %d Hz\n", frequency);
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printf("Duration: %.2f seconds\n", duration);
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// Clear event structure
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memset(&ev, 0, sizeof(ev));
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ev.type = EV_SND; // 0x12 = Sound event
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ev.code = SND_TONE; // 0x02 = Tone control
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ev.value = frequency; // Frequency in Hz
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printf("\nStarting beep...\n");
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if (write(fd, &ev, sizeof(ev)) != sizeof(ev)) {
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perror("Failed to write start event");
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close(fd);
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return 1;
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}
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// Wait for specified duration
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usleep(duration * 1000000);
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// Stop beeping
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ev.value = 0; // 0 Hz = stop
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printf("Stopping beep...\n");
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if (write(fd, &ev, sizeof(ev)) != sizeof(ev)) {
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perror("Failed to write stop event");
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}
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// Close device
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close(fd);
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printf("\nTest completed!\n");
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return 0;
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}
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