forked from Minki/linux
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: Randy Dunlap <randy.dunlap@oracle.com> Acked-by: David Brownell <dbrownell@users.sourceforge.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Randy Dunlap
Linus Torvalds
parent
cf43369d55
commit
31a1629426
@ -126,8 +126,8 @@ NOTES:
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FULL DUPLEX CHARACTER DEVICE API
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================================
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See the sample program below for one example showing the use of the full
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duplex programming interface. (Although it doesn't perform a full duplex
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See the spidev_fdx.c sample program for one example showing the use of the
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full duplex programming interface. (Although it doesn't perform a full duplex
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transfer.) The model is the same as that used in the kernel spi_sync()
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request; the individual transfers offer the same capabilities as are
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available to kernel drivers (except that it's not asynchronous).
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@ -141,167 +141,3 @@ and bitrate for each transfer segment.)
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To make a full duplex request, provide both rx_buf and tx_buf for the
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same transfer. It's even OK if those are the same buffer.
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SAMPLE PROGRAM
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==============
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-------------------------------- CUT HERE
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#include <stdio.h>
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#include <unistd.h>
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#include <stdlib.h>
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#include <fcntl.h>
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#include <string.h>
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#include <sys/ioctl.h>
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#include <sys/types.h>
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#include <sys/stat.h>
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#include <linux/types.h>
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#include <linux/spi/spidev.h>
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static int verbose;
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static void do_read(int fd, int len)
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{
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unsigned char buf[32], *bp;
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int status;
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/* read at least 2 bytes, no more than 32 */
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if (len < 2)
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len = 2;
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else if (len > sizeof(buf))
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len = sizeof(buf);
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memset(buf, 0, sizeof buf);
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status = read(fd, buf, len);
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if (status < 0) {
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perror("read");
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return;
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}
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if (status != len) {
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fprintf(stderr, "short read\n");
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return;
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}
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printf("read(%2d, %2d): %02x %02x,", len, status,
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buf[0], buf[1]);
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status -= 2;
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bp = buf + 2;
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while (status-- > 0)
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printf(" %02x", *bp++);
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printf("\n");
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}
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static void do_msg(int fd, int len)
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{
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struct spi_ioc_transfer xfer[2];
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unsigned char buf[32], *bp;
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int status;
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memset(xfer, 0, sizeof xfer);
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memset(buf, 0, sizeof buf);
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if (len > sizeof buf)
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len = sizeof buf;
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buf[0] = 0xaa;
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xfer[0].tx_buf = (__u64) buf;
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xfer[0].len = 1;
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xfer[1].rx_buf = (__u64) buf;
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xfer[1].len = len;
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status = ioctl(fd, SPI_IOC_MESSAGE(2), xfer);
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if (status < 0) {
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perror("SPI_IOC_MESSAGE");
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return;
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}
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printf("response(%2d, %2d): ", len, status);
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for (bp = buf; len; len--)
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printf(" %02x", *bp++);
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printf("\n");
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}
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static void dumpstat(const char *name, int fd)
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{
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__u8 mode, lsb, bits;
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__u32 speed;
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if (ioctl(fd, SPI_IOC_RD_MODE, &mode) < 0) {
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perror("SPI rd_mode");
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return;
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}
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if (ioctl(fd, SPI_IOC_RD_LSB_FIRST, &lsb) < 0) {
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perror("SPI rd_lsb_fist");
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return;
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}
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if (ioctl(fd, SPI_IOC_RD_BITS_PER_WORD, &bits) < 0) {
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perror("SPI bits_per_word");
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return;
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}
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if (ioctl(fd, SPI_IOC_RD_MAX_SPEED_HZ, &speed) < 0) {
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perror("SPI max_speed_hz");
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return;
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}
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printf("%s: spi mode %d, %d bits %sper word, %d Hz max\n",
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name, mode, bits, lsb ? "(lsb first) " : "", speed);
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}
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int main(int argc, char **argv)
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{
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int c;
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int readcount = 0;
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int msglen = 0;
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int fd;
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const char *name;
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while ((c = getopt(argc, argv, "hm:r:v")) != EOF) {
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switch (c) {
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case 'm':
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msglen = atoi(optarg);
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if (msglen < 0)
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goto usage;
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continue;
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case 'r':
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readcount = atoi(optarg);
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if (readcount < 0)
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goto usage;
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continue;
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case 'v':
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verbose++;
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continue;
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case 'h':
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case '?':
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usage:
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fprintf(stderr,
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"usage: %s [-h] [-m N] [-r N] /dev/spidevB.D\n",
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argv[0]);
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return 1;
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}
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}
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if ((optind + 1) != argc)
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goto usage;
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name = argv[optind];
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fd = open(name, O_RDWR);
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if (fd < 0) {
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perror("open");
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return 1;
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}
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dumpstat(name, fd);
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if (msglen)
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do_msg(fd, msglen);
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if (readcount)
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do_read(fd, readcount);
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close(fd);
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return 0;
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}
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158
Documentation/spi/spidev_fdx.c
Normal file
158
Documentation/spi/spidev_fdx.c
Normal file
@ -0,0 +1,158 @@
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#include <stdio.h>
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#include <unistd.h>
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#include <stdlib.h>
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#include <fcntl.h>
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#include <string.h>
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#include <sys/ioctl.h>
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#include <sys/types.h>
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#include <sys/stat.h>
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#include <linux/types.h>
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#include <linux/spi/spidev.h>
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static int verbose;
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static void do_read(int fd, int len)
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{
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unsigned char buf[32], *bp;
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int status;
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/* read at least 2 bytes, no more than 32 */
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if (len < 2)
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len = 2;
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else if (len > sizeof(buf))
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len = sizeof(buf);
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memset(buf, 0, sizeof buf);
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status = read(fd, buf, len);
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if (status < 0) {
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perror("read");
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return;
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}
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if (status != len) {
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fprintf(stderr, "short read\n");
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return;
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}
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printf("read(%2d, %2d): %02x %02x,", len, status,
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buf[0], buf[1]);
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status -= 2;
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bp = buf + 2;
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while (status-- > 0)
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printf(" %02x", *bp++);
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printf("\n");
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}
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static void do_msg(int fd, int len)
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{
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struct spi_ioc_transfer xfer[2];
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unsigned char buf[32], *bp;
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int status;
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memset(xfer, 0, sizeof xfer);
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memset(buf, 0, sizeof buf);
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if (len > sizeof buf)
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len = sizeof buf;
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buf[0] = 0xaa;
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xfer[0].tx_buf = (__u64) buf;
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xfer[0].len = 1;
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xfer[1].rx_buf = (__u64) buf;
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xfer[1].len = len;
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status = ioctl(fd, SPI_IOC_MESSAGE(2), xfer);
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if (status < 0) {
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perror("SPI_IOC_MESSAGE");
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return;
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}
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printf("response(%2d, %2d): ", len, status);
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for (bp = buf; len; len--)
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printf(" %02x", *bp++);
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printf("\n");
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}
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static void dumpstat(const char *name, int fd)
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{
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__u8 mode, lsb, bits;
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__u32 speed;
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if (ioctl(fd, SPI_IOC_RD_MODE, &mode) < 0) {
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perror("SPI rd_mode");
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return;
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}
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if (ioctl(fd, SPI_IOC_RD_LSB_FIRST, &lsb) < 0) {
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perror("SPI rd_lsb_fist");
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return;
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}
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if (ioctl(fd, SPI_IOC_RD_BITS_PER_WORD, &bits) < 0) {
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perror("SPI bits_per_word");
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return;
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}
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if (ioctl(fd, SPI_IOC_RD_MAX_SPEED_HZ, &speed) < 0) {
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perror("SPI max_speed_hz");
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return;
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}
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printf("%s: spi mode %d, %d bits %sper word, %d Hz max\n",
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name, mode, bits, lsb ? "(lsb first) " : "", speed);
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}
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int main(int argc, char **argv)
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{
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int c;
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int readcount = 0;
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int msglen = 0;
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int fd;
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const char *name;
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while ((c = getopt(argc, argv, "hm:r:v")) != EOF) {
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switch (c) {
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case 'm':
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msglen = atoi(optarg);
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if (msglen < 0)
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goto usage;
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continue;
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case 'r':
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readcount = atoi(optarg);
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if (readcount < 0)
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goto usage;
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continue;
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case 'v':
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verbose++;
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continue;
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case 'h':
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case '?':
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usage:
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fprintf(stderr,
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"usage: %s [-h] [-m N] [-r N] /dev/spidevB.D\n",
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argv[0]);
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return 1;
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}
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}
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if ((optind + 1) != argc)
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goto usage;
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name = argv[optind];
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fd = open(name, O_RDWR);
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if (fd < 0) {
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perror("open");
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return 1;
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}
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dumpstat(name, fd);
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if (msglen)
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do_msg(fd, msglen);
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if (readcount)
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do_read(fd, readcount);
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close(fd);
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return 0;
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}
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