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Commit 31a16294 authored by Randy Dunlap's avatar Randy Dunlap Committed by Linus Torvalds
Browse files

documentation: move spidev_fdx example to its own source file 



Move sample source code to its own source file so that it can be used
easier and build-tested/check/maintained by anyone.

(Makefile changes are in a separate patch for all of Documentation/.)

Signed-off-by: default avatarRandy Dunlap <randy.dunlap@oracle.com>
Acked-by: default avatarDavid Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent cf43369d

Documentation/spi/spidev

+2 −166
Original line number Diff line number Diff line
@@ -126,8 +126,8 @@ NOTES: 
FULL DUPLEX CHARACTER DEVICE API

================================



See the sample program below for one example showing the use of the full

duplex programming interface.  (Although it doesn't perform a full duplex

See the spidev_fdx.c sample program for one example showing the use of the

full duplex programming interface.  (Although it doesn't perform a full duplex

transfer.)  The model is the same as that used in the kernel spi_sync()

request; the individual transfers offer the same capabilities as are

available to kernel drivers (except that it's not asynchronous).
@@ -141,167 +141,3 @@ and bitrate for each transfer segment.) 


To make a full duplex request, provide both rx_buf and tx_buf for the

same transfer.  It's even OK if those are the same buffer.
 




SAMPLE PROGRAM

==============



--------------------------------	CUT HERE

#include <stdio.h>

#include <unistd.h>

#include <stdlib.h>

#include <fcntl.h>

#include <string.h>



#include <sys/ioctl.h>

#include <sys/types.h>

#include <sys/stat.h>



#include <linux/types.h>

#include <linux/spi/spidev.h>





static int verbose;



static void do_read(int fd, int len)

{

	unsigned char	buf[32], *bp;

	int		status;



	/* read at least 2 bytes, no more than 32 */

	if (len < 2)

		len = 2;

	else if (len > sizeof(buf))

		len = sizeof(buf);

	memset(buf, 0, sizeof buf);



	status = read(fd, buf, len);

	if (status < 0) {

		perror("read");

		return;

	}

	if (status != len) {

		fprintf(stderr, "short read\n");

		return;

	}



	printf("read(%2d, %2d): %02x %02x,", len, status,

		buf[0], buf[1]);

	status -= 2;

	bp = buf + 2;

	while (status-- > 0)

		printf(" %02x", *bp++);

	printf("\n");

}



static void do_msg(int fd, int len)

{

	struct spi_ioc_transfer	xfer[2];

	unsigned char		buf[32], *bp;

	int			status;



	memset(xfer, 0, sizeof xfer);

	memset(buf, 0, sizeof buf);



	if (len > sizeof buf)

		len = sizeof buf;



	buf[0] = 0xaa;

	xfer[0].tx_buf = (__u64) buf;

	xfer[0].len = 1;



	xfer[1].rx_buf = (__u64) buf;

	xfer[1].len = len;



	status = ioctl(fd, SPI_IOC_MESSAGE(2), xfer);

	if (status < 0) {

		perror("SPI_IOC_MESSAGE");

		return;

	}



	printf("response(%2d, %2d): ", len, status);

	for (bp = buf; len; len--)

		printf(" %02x", *bp++);

	printf("\n");

}



static void dumpstat(const char *name, int fd)

{

	__u8	mode, lsb, bits;

	__u32	speed;



	if (ioctl(fd, SPI_IOC_RD_MODE, &mode) < 0) {

		perror("SPI rd_mode");

		return;

	}

	if (ioctl(fd, SPI_IOC_RD_LSB_FIRST, &lsb) < 0) {

		perror("SPI rd_lsb_fist");

		return;

	}

	if (ioctl(fd, SPI_IOC_RD_BITS_PER_WORD, &bits) < 0) {

		perror("SPI bits_per_word");

		return;

	}

	if (ioctl(fd, SPI_IOC_RD_MAX_SPEED_HZ, &speed) < 0) {

		perror("SPI max_speed_hz");

		return;

	}



	printf("%s: spi mode %d, %d bits %sper word, %d Hz max\n",

		name, mode, bits, lsb ? "(lsb first) " : "", speed);

}



int main(int argc, char **argv)

{

	int		c;

	int		readcount = 0;

	int		msglen = 0;

	int		fd;

	const char	*name;



	while ((c = getopt(argc, argv, "hm:r:v")) != EOF) {

		switch (c) {

		case 'm':

			msglen = atoi(optarg);

			if (msglen < 0)

				goto usage;

			continue;

		case 'r':

			readcount = atoi(optarg);

			if (readcount < 0)

				goto usage;

			continue;

		case 'v':

			verbose++;

			continue;

		case 'h':

		case '?':

usage:

			fprintf(stderr,

				"usage: %s [-h] [-m N] [-r N] /dev/spidevB.D\n",

				argv[0]);

			return 1;

		}

	}



	if ((optind + 1) != argc)

		goto usage;

	name = argv[optind];



	fd = open(name, O_RDWR);

	if (fd < 0) {

		perror("open");

		return 1;

	}



	dumpstat(name, fd);



	if (msglen)

		do_msg(fd, msglen);



	if (readcount)

		do_read(fd, readcount);



	close(fd);

	return 0;

}

Documentation/spi/spidev_fdx.c

0 → 100644
+158 −0
Original line number Diff line number Diff line 
#include <stdio.h>

#include <unistd.h>

#include <stdlib.h>

#include <fcntl.h>

#include <string.h>



#include <sys/ioctl.h>

#include <sys/types.h>

#include <sys/stat.h>



#include <linux/types.h>

#include <linux/spi/spidev.h>





static int verbose;



static void do_read(int fd, int len)

{

	unsigned char	buf[32], *bp;

	int		status;



	/* read at least 2 bytes, no more than 32 */

	if (len < 2)

		len = 2;

	else if (len > sizeof(buf))

		len = sizeof(buf);

	memset(buf, 0, sizeof buf);



	status = read(fd, buf, len);

	if (status < 0) {

		perror("read");

		return;

	}

	if (status != len) {

		fprintf(stderr, "short read\n");

		return;

	}



	printf("read(%2d, %2d): %02x %02x,", len, status,

		buf[0], buf[1]);

	status -= 2;

	bp = buf + 2;

	while (status-- > 0)

		printf(" %02x", *bp++);

	printf("\n");

}



static void do_msg(int fd, int len)

{

	struct spi_ioc_transfer	xfer[2];

	unsigned char		buf[32], *bp;

	int			status;



	memset(xfer, 0, sizeof xfer);

	memset(buf, 0, sizeof buf);



	if (len > sizeof buf)

		len = sizeof buf;



	buf[0] = 0xaa;

	xfer[0].tx_buf = (__u64) buf;

	xfer[0].len = 1;



	xfer[1].rx_buf = (__u64) buf;

	xfer[1].len = len;



	status = ioctl(fd, SPI_IOC_MESSAGE(2), xfer);

	if (status < 0) {

		perror("SPI_IOC_MESSAGE");

		return;

	}



	printf("response(%2d, %2d): ", len, status);

	for (bp = buf; len; len--)

		printf(" %02x", *bp++);

	printf("\n");

}



static void dumpstat(const char *name, int fd)

{

	__u8	mode, lsb, bits;

	__u32	speed;



	if (ioctl(fd, SPI_IOC_RD_MODE, &mode) < 0) {

		perror("SPI rd_mode");

		return;

	}

	if (ioctl(fd, SPI_IOC_RD_LSB_FIRST, &lsb) < 0) {

		perror("SPI rd_lsb_fist");

		return;

	}

	if (ioctl(fd, SPI_IOC_RD_BITS_PER_WORD, &bits) < 0) {

		perror("SPI bits_per_word");

		return;

	}

	if (ioctl(fd, SPI_IOC_RD_MAX_SPEED_HZ, &speed) < 0) {

		perror("SPI max_speed_hz");

		return;

	}



	printf("%s: spi mode %d, %d bits %sper word, %d Hz max\n",

		name, mode, bits, lsb ? "(lsb first) " : "", speed);

}



int main(int argc, char **argv)

{

	int		c;

	int		readcount = 0;

	int		msglen = 0;

	int		fd;

	const char	*name;



	while ((c = getopt(argc, argv, "hm:r:v")) != EOF) {

		switch (c) {

		case 'm':

			msglen = atoi(optarg);

			if (msglen < 0)

				goto usage;

			continue;

		case 'r':

			readcount = atoi(optarg);

			if (readcount < 0)

				goto usage;

			continue;

		case 'v':

			verbose++;

			continue;

		case 'h':

		case '?':

usage:

			fprintf(stderr,

				"usage: %s [-h] [-m N] [-r N] /dev/spidevB.D\n",

				argv[0]);

			return 1;

		}

	}



	if ((optind + 1) != argc)

		goto usage;

	name = argv[optind];



	fd = open(name, O_RDWR);

	if (fd < 0) {

		perror("open");

		return 1;

	}



	dumpstat(name, fd);



	if (msglen)

		do_msg(fd, msglen);



	if (readcount)

		do_read(fd, readcount);



	close(fd);

	return 0;

}