spi: spidev_test: output to a file

For testing of larger data transfers, output unmodified data
directly to a file.
Signed-off-by: Joshua Clayton <stillcompiling@gmail.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

tools/spi/spidev_test.c

@@ -35,6 +35,7 @@ static const char *device = "/dev/spidev1.1";
 static uint32_t mode;
 static uint8_t bits = 8;
 static char *input_file;
+static char *output_file;
 static uint32_t speed = 500000;
 static uint16_t delay;
 static int verbose;
@@ -105,7 +106,7 @@ static int unescape(char *_dst, char *_src, size_t len)
 static void transfer(int fd, uint8_t const *tx, uint8_t const *rx, size_t len)
 {
 	int ret;
-
+	int out_fd;
 	struct spi_ioc_transfer tr = {
 		.tx_buf = (unsigned long)tx,
 		.rx_buf = (unsigned long)rx,
@@ -136,7 +137,21 @@ static void transfer(int fd, uint8_t const *tx, uint8_t const *rx, size_t len)
 
 	if (verbose)
 		hex_dump(tx, len, 32, "TX");
-	hex_dump(rx, len, 32, "RX");
+
+	if (output_file) {
+		out_fd = open(output_file, O_WRONLY | O_CREAT | O_TRUNC, 0666);
+		if (out_fd < 0)
+			pabort("could not open output file");
+
+		ret = write(out_fd, rx, len);
+		if (ret != len)
+			pabort("not all bytes written to utput file");
+
+		close(out_fd);
+	}
+
+	if (verbose || !output_file)
+		hex_dump(rx, len, 32, "RX");
 }
 
 static void print_usage(const char *prog)
@@ -147,6 +162,7 @@ static void print_usage(const char *prog)
 	     "  -d --delay    delay (usec)\n"
 	     "  -b --bpw      bits per word \n"
 	     "  -i --input    input data from a file (e.g. \"test.bin\")\n"
+	     "  -o --output   output data to a file (e.g. \"results.bin\")\n"
 	     "  -l --loop     loopback\n"
 	     "  -H --cpha     clock phase\n"
 	     "  -O --cpol     clock polarity\n"
@@ -171,6 +187,7 @@ static void parse_opts(int argc, char *argv[])
 			{ "delay",   1, 0, 'd' },
 			{ "bpw",     1, 0, 'b' },
 			{ "input",   1, 0, 'i' },
+			{ "output",  1, 0, 'o' },
 			{ "loop",    0, 0, 'l' },
 			{ "cpha",    0, 0, 'H' },
 			{ "cpol",    0, 0, 'O' },
@@ -186,7 +203,7 @@ static void parse_opts(int argc, char *argv[])
 		};
 		int c;
 
-		c = getopt_long(argc, argv, "D:s:d:b:i:lHOLC3NR24p:v",
+		c = getopt_long(argc, argv, "D:s:d:b:i:o:lHOLC3NR24p:v",
 				lopts, NULL);
 
 		if (c == -1)
@@ -208,6 +225,9 @@ static void parse_opts(int argc, char *argv[])
 		case 'i':
 			input_file = optarg;
 			break;
+		case 'o':
+			output_file = optarg;
+			break;
 		case 'l':
 			mode |= SPI_LOOP;
 			break;