[PATCH 3/7] spi: spidev_test: allow disabling rx or tx buffers

[Jonas Rebmann]

From: Marc Kleine-Budde <mkl@xxxxxxxxxxxxxx>

Allow not providing rx or tx buffers. This is useful to check if drivers
that don't use SPI_CONTROLLER_MUST_RX (or -TX respectively) handle their
operations correctly without a buffer.

Signed-off-by: Marc Kleine-Budde <mkl@xxxxxxxxxxxxxx>
Signed-off-by: Jonas Rebmann <jre@xxxxxxxxxxxxxx>
---
 tools/spi/spidev_test.c | 61 ++++++++++++++++++++++++++++++++-----------------
 1 file changed, 40 insertions(+), 21 deletions(-)

diff --git a/tools/spi/spidev_test.c b/tools/spi/spidev_test.c
index 05c585ea71b2..6b0e839e6c33 100644
--- a/tools/spi/spidev_test.c
+++ b/tools/spi/spidev_test.c
@@ -47,6 +47,7 @@ static int transfer_size;
 static int iterations;
 static int interval = 5; /* interval in seconds for showing transfer rate */
 static int compare;
+static int do_tx = 1, do_rx = 1;
 
 static uint8_t default_tx[] = {
 	0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
@@ -153,10 +154,10 @@ static void transfer(int fd, uint8_t const *tx, uint8_t const *rx, size_t len)
 	if (ret < 1)
 		pabort("can't send spi message");
 
-	if (verbose)
+	if (verbose && tx)
 		hex_dump(tx, len, 32, "TX");
 
-	if (output_file) {
+	if (rx && output_file) {
 		out_fd = open(output_file, O_WRONLY | O_CREAT | O_TRUNC, 0666);
 		if (out_fd < 0)
 			pabort("could not open output file");
@@ -168,13 +169,13 @@ static void transfer(int fd, uint8_t const *tx, uint8_t const *rx, size_t len)
 		close(out_fd);
 	}
 
-	if (verbose)
+	if (verbose && rx)
 		hex_dump(rx, len, 32, "RX");
 }
 
 static void print_usage(const char *prog)
 {
-	printf("Usage: %s [-2348CDFHILMNORSZbdilcopsvw]\n", prog);
+	printf("Usage: %s [-2348CDFHILMNORSZbdilctropsvw]\n", prog);
 	puts("general device settings:\n"
 		 "  -D --device         device to use (default /dev/spidev1.1)\n"
 		 "  -s --speed          max speed (Hz)\n"
@@ -182,6 +183,8 @@ static void print_usage(const char *prog)
 		 "  -w --word-delay     word delay (usec)\n"
 		 "  -l --loop           loopback\n"
 		 "  -c --compare        compare RX'ed and TX'ed data\n"
+		 "  -t --no-tx          don't send data\n"
+		 "  -r --no-rx          don't receive data\n"
 		 "spi mode:\n"
 		 "  -H --cpha           clock phase\n"
 		 "  -O --cpol           clock polarity\n"
@@ -220,6 +223,8 @@ static void parse_opts(int argc, char *argv[])
 			{ "word-delay",    1, 0, 'w' },
 			{ "loop",          0, 0, 'l' },
 			{ "compare",       0, 0, 'c' },
+			{ "no-tx",         0, 0, 't' },
+			{ "no-rx",         0, 0, 'r' },
 			{ "cpha",          0, 0, 'H' },
 			{ "cpol",          0, 0, 'O' },
 			{ "rx-cpha-flip",  0, 0, 'F' },
@@ -243,7 +248,7 @@ static void parse_opts(int argc, char *argv[])
 		};
 		int c;
 
-		c = getopt_long(argc, argv, "D:s:d:w:b:i:o:lcHOLC3ZFMNR248p:vS:I:",
+		c = getopt_long(argc, argv, "D:s:d:w:b:i:o:lctrHOLC3ZFMNR248p:vS:I:",
 				lopts, NULL);
 
 		if (c == -1)
@@ -278,6 +283,12 @@ static void parse_opts(int argc, char *argv[])
 		case 'c':
 			compare = 1;
 			break;
+		case 't':
+			do_tx = 0;
+			break;
+		case 'r':
+			do_rx = 0;
+			break;
 		case 'H':
 			mode |= SPI_CPHA;
 			break;
@@ -415,26 +426,31 @@ static void show_transfer_rate(void)
 
 static void transfer_buf(int fd, int len)
 {
-	uint8_t *tx;
-	uint8_t *rx;
+	uint8_t *tx = NULL;
+	uint8_t *rx = NULL;
 	int i;
 
-	tx = malloc(len);
-	if (!tx)
-		pabort("can't allocate tx buffer");
-	for (i = 0; i < len; i++)
-		tx[i] = random();
+	if (do_tx) {
+		tx = malloc(len);
+		if (!tx)
+			pabort("can't allocate tx buffer");
+		for (i = 0; i < len; i++)
+			tx[i] = random();
+	}
 
-	rx = malloc(len);
-	if (!rx)
-		pabort("can't allocate rx buffer");
+	if (do_rx) {
+		rx = malloc(len);
+		if (!rx)
+			pabort("can't allocate rx buffer");
+	}
 
 	transfer(fd, tx, rx, len);
+	if (do_tx)
+		_write_count += len;
+	if (do_rx)
+		_read_count += len;
 
-	_write_count += len;
-	_read_count += len;
-
-	if (compare) {
+	if (tx && rx && compare) {
 		if (memcmp(tx, rx, len)) {
 			fprintf(stderr, "transfer error !\n");
 			hex_dump(tx, len, 32, "TX");
@@ -455,8 +471,11 @@ int main(int argc, char *argv[])
 
 	parse_opts(argc, argv);
 
-	if (input_tx && input_file)
-		pabort("only one of -p and --input may be selected");
+	if (!!input_tx + !!input_file + !do_tx > 0)
+		pabort("only one of -p, -i (--input), -t (--no-tx) may be selected");
+
+	if (compare && (!do_tx || !do_rx))
+		pabort("-l/-c conflict with -t or -r");
 
 	fd = open(device, O_RDWR);
 	if (fd < 0)

-- 
2.55.0.806.gb8242b093d