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modified post 226d8e2 by Anonymous on Fri 13th Dec 2019 14:55
original post 8c4e by Anonymous on Wed 11th Dec 2019 15:56
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/*

1	1		/*
2	2		* qaweep1.c - Quantron beeper-weeper demo V0.0.1
3	3		*
4	4		* Written by Roland Mainz <r.mainz@eckelmann.de>
5	5		*/
6	6
7	7		/*
8	8		* Compile with
9	9		* $ /opt/OSELAS.Toolchain-2012.12.0/arm-v5te-linux-gnueabi/gcc-4.7.2-glibc-2.16.0-binutils-2.22-kernel-3.6-sanitized/bin/arm-v5te-linux-gnueabi-gcc -std=gnu99 -g -Wall -fno-use-linker-plugin qaweep1.c
10	10		*/
11	11		#include <errno.h>
12	12		#include <fcntl.h>
13	13		#include <stdio.h>
14	14		#include <stdlib.h>
15	15		#include <sys/stat.h>
16	16		#include <sys/types.h>
17	17		#include <unistd.h>
18	18
19	19		#define NUM_ELEMENTS_IN_ARRAY(ar) (sizeof(ar) / sizeof (ar[0]))
20	20		const double freqs[] = {
21	21		440.0000,
22	22		466.1638,
23	23		493.8833,
24	24		523.2511,
25	25		554.3653,
26	26		587.3295,
27	27		622.2540,
28	28		659.2551,
29	29		698.4565,
30	30		739.9888,
31	31		783.9909,
32	32		830.6094,
33	33		880.0000,
34	34		932.3275,
35	35		987.7666,
36	36		1046.502,
37	37		1108.731,
38	38		1174.659,
39	39		1244.508
40	40		};
41	41
42	42		#define MICROSECONDS_PER_SEC (1000000L)
43	43
44		-	int main(int ac, char *av[])
	44	+	static
	45	+	int cycle_loop(int fd, long cycles, long low_delay, long high_delay)
45	46		{
46		-	int retval = EXIT_FAILURE;
	47	+	int retval = 0;
47		-	int fd,
	48	+	int i;
49	49
50		-	fd = open("/sys/class/gpio/export", O_WRONLY);
	50	+	for (i = 0; i < cycles; i++) {
51		-	if (fd == -1) {
	51	+	if (write(fd, "1", 1) != 1) {
53	52		goto exit_ioerr;
54	53		}
55	54
56		-	if (write(fd, "11", 2) != 2) {
	55	+	(void)usleep(low_delay);
60	56
61		-	(void)close(fd);
	57	+	if (write(fd, "0", 1) != 1) {
	58	+	goto exit_ioerr;
62	60
63		-	gpiodirfd = open("/sys/class/gpio/gpio11/", O_DIRECTORY);
	61	+	(void)usleep(high_delay);
67	62		}
68	63
69		-	fd = openat(gpiodirfd, "direction", O_WRONLY);
	64	+	retval = 1;
70		-	if (fd == -1) {
	65	+	exit_ioerr:
74	66
75		-	if (write(fd, "out", 3) != 3) {
	67	+	return retval;
78	68		}
79	69
80		-	(void)close(fd);
	70	+	int main(int ac, char *av[])
	71	+	{
81	75
82		-	fd = openat(gpiodirfd, "value", O_WRONLY);
	76	+	fd = open("/sys/class/gpio/export", O_WRONLY);
83	77		if (fd == -1) {
84		-	perror("Unable to open value");
	78	+	perror("Unable to open /sys/class/gpio/export");
85	79		goto exit_ioerr;
86	80		}
87	81
88		-	int i, j;
	82	+	if (write(fd, "11", 2) != 2) {
89		-	for (j=0 ; j < NUM_ELEMENTS_IN_ARRAY(freqs) ; j++)
	83	+	perror("Error writing to /sys/class/gpio/export");
90		-	{
	84	+	goto exit_ioerr;
91		-	double f = freqs[j];
	85	+	}
94	86
95		-	(void)printf("freq=%4.4f\tdelay=%ld\tcycles=%ld\n",
	87	+	(void)close(fd);
99	88
100		-	for (i = 0; i < cycles; i++) {
	89	+	gpiodirfd = open("/sys/class/gpio/gpio11/", O_DIRECTORY);
101		-	if (write(fd, "1", 1) != 1) {
	90	+	if (gpiodirfd == -1) {
102		-	perror("Error writing 0 to value");
	91	+	perror("Unable to open /sys/class/gpio/gpio11/");
103	92		goto exit_ioerr;
104	93		}
105	94
106		-	(void)usleep(delay/2);
	95	+	fd = openat(gpiodirfd, "direction", O_WRONLY);
	96	+	if (fd == -1) {
107	100
108		-	if (write(fd, "0", 1) != 1) {
	101	+	if (write(fd, "out", 3) != 3) {
109		-	perror("Error writing 1 to value");
	102	+	perror("Error writing to /sys/class/gpio/gpio11/direction");
110	103		goto exit_ioerr;
111	104		}
112	105
119		-
	106	+	(void)close(fd);
115	107
116		-	/* Wait 1/10 second */
	108	+	fd = openat(gpiodirfd, "value", O_WRONLY);
	109	+	if (fd == -1) {
118	112		}
119	113
120		-	(void)close(fd);
	114	+	int j;
	115	+	for (j=0 ; j < NUM_ELEMENTS_IN_ARRAY(freqs) ; j++)
121	120
122		-	fd = open("/sys/class/gpio/unexport", O_WRONLY);
	121	+	(void)printf("freq=%4.4f\tdelay=%ld\tcycles=%ld\n",
123		-	if (fd == -1) {
	122	+	f,
124		-	perror("Unable to open /sys/class/gpio/unexport");
	123	+	delay,
	124	+	cycles);
127	125
128		-	if (write(fd, "11", 2) != 2) {
	126	+	if (!cycle_loop(fd, cycles, delay/2, delay/2))
129		-	perror("Error writing to /sys/class/gpio/unexport");
	127	+	{
	128	+	perror("Error writing 0 to value");
130	129		goto exit_ioerr;
131	130		}
132	131
133		-	retval = EXIT_SUCCESS;
	132	+	/* Wait 1/4 second */
134		-	exit_ioerr:
	133	+	(void)usleep(MICROSECONDS_PER_SEC/4);
	134	+	}
136	136		(void)close(fd);
139	137
140		-	return retval;
	138	+	fd = open("/sys/class/gpio/unexport", O_WRONLY);
141		-	}
	139	+	if (fd == -1) {
142		-
	140	+	perror("Unable to open /sys/class/gpio/unexport");
143		-
	141	+	goto exit_ioerr;
144		-
	142	+	}
145	143
146		-
	144	+	if (write(fd, "11", 2) != 2) {
147		-
	145	+	perror("Error writing to /sys/class/gpio/unexport");
148		-
	146	+	goto exit_ioerr;
149		-
	147	+	}
150	148
151		-
	149	+	retval = EXIT_SUCCESS;
152		-
	150	+	exit_ioerr:
153		-
	151	+	if (fd >=0)
154		-
	152	+	(void)close(fd);
155		-
	153	+	if (gpiodirfd >=0)
156		-
	154	+	(void)close(gpiodirfd);
157	155
158		-
	156	+	return retval;
159		-
	157	+	}
160	158