[PATCH v7 07/13] spi: spidev_test: add compare mode

[Jonas Rebmann <jre@pengutronix.de>]

From: Marc Kleine-Budde <mkl@pengutronix.de>

Check whether the received data correspond to the transferred data but
without enabling loopback mode in the controller.

This is for testing with TX physically bridged to RX which is useful if
a loopback mode is unavailable or insufficient.

Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
Signed-off-by: Jonas Rebmann <jre@pengutronix.de>
---
 tools/spi/spidev_test.c | 15 ++++++++++++---
 1 file changed, 12 insertions(+), 3 deletions(-)

diff --git a/tools/spi/spidev_test.c b/tools/spi/spidev_test.c
index e46eaef4d2ab..7b343803903e 100644
--- a/tools/spi/spidev_test.c
+++ b/tools/spi/spidev_test.c
@@ -44,6 +44,7 @@ static int verbose;
 static int transfer_size = -1;
 static int iterations;
 static int interval = 5; /* interval in seconds for showing transfer rate */
+static int compare;
 static int random_input;
 static int input_choices;
 
@@ -174,7 +175,7 @@ static void transfer(int fd, uint8_t const *tx, uint8_t const *rx, size_t len)
 	if (verbose)
 		hex_dump(rx, len, 32, "RX");
 
-	if (mode & SPI_LOOP) {
+	if (compare || mode & SPI_LOOP) {
 		if (memcmp(tx, rx, len)) {
 			fprintf(stderr, "transfer error !\n");
 			hex_dump(tx, len, 32, "TX");
@@ -186,13 +187,14 @@ static void transfer(int fd, uint8_t const *tx, uint8_t const *rx, size_t len)
 
 static void print_usage(const char *prog)
 {
-	printf("Usage: %s [-2348CDFHILMNORSZbdilopsvw]\n", prog);
+	printf("Usage: %s [-2348CDFHILMNORSZbcdilopsvw]\n", prog);
 	puts("general device settings:\n"
 		 "  -D --device         device to use (default /dev/spidev1.1)\n"
 		 "  -s --speed          max speed (Hz)\n"
 		 "  -d --delay          delay (usec)\n"
 		 "  -w --word-delay     word delay (usec)\n"
 		 "  -l --loop           loopback\n"
+		 "  -c --compare        compare RX'ed and TX'ed data\n"
 		 "spi mode:\n"
 		 "  -H --cpha           clock phase\n"
 		 "  -O --cpol           clock polarity\n"
@@ -230,6 +232,7 @@ static void parse_opts(int argc, char *argv[])
 			{ "delay",         1, 0, 'd' },
 			{ "word-delay",    1, 0, 'w' },
 			{ "loop",          0, 0, 'l' },
+			{ "compare",       0, 0, 'c' },
 			{ "cpha",          0, 0, 'H' },
 			{ "cpol",          0, 0, 'O' },
 			{ "rx-cpha-flip",  0, 0, 'F' },
@@ -253,7 +256,7 @@ static void parse_opts(int argc, char *argv[])
 		};
 		int c;
 
-		c = getopt_long(argc, argv, "D:s:d:w:b:i:o:lHOLC3ZFMNR248p:vS:I:",
+		c = getopt_long(argc, argv, "D:s:d:w:b:i:o:lcHOLC3ZFMNR248p:vS:I:",
 				lopts, NULL);
 
 		if (c == -1)
@@ -285,6 +288,9 @@ static void parse_opts(int argc, char *argv[])
 		case 'l':
 			mode |= SPI_LOOP;
 			break;
+		case 'c':
+			compare = 1;
+			break;
 		case 'H':
 			mode |= SPI_CPHA;
 			break;
@@ -466,6 +472,9 @@ int main(int argc, char *argv[])
 	if (iterations && transfer_size < 0)
 		pabort("-I (--iter) is only implemented for -S (--size)");
 
+	if (compare && mode & (SPI_TX_OCTAL | SPI_TX_QUAD | SPI_TX_DUAL))
+		pabort("-c (--compare) conflicts with -2 (--dual), -4 (--quad) or -8 (--octal)");
+
 	fd = open(device, O_RDWR);
 	if (fd < 0)
 		pabort("can't open device");

-- 
2.56.0.rc0.108.gf0ef1b96a0