[PATCH v4 4/9] spi: spidev_test: allow disabling rx or tx buffers
From: Jonas Rebmann
Date: Fri Sep 18 2026 - 12:42:38 EST
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 | 90 +++++++++++++++++++++++++++++++++----------------
1 file changed, 61 insertions(+), 29 deletions(-)
diff --git a/tools/spi/spidev_test.c b/tools/spi/spidev_test.c
index 7993eae88c44..906f9997b10a 100644
--- a/tools/spi/spidev_test.c
+++ b/tools/spi/spidev_test.c
@@ -45,6 +45,8 @@ 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 int input_choices;
static uint8_t default_tx[] = {
0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
@@ -151,7 +153,7 @@ 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) {
@@ -166,13 +168,13 @@ 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 [-2348CDFHILMNORSZbcdilopsvw]\n", prog);
+ printf("Usage: %s [-2348CDFHILMNORSZbcdiloprstvw]\n", prog);
puts("general device settings:\n"
" -D --device device to use (default /dev/spidev1.1)\n"
" -s --speed max speed (Hz)\n"
@@ -180,6 +182,8 @@ 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"
@@ -218,6 +222,8 @@ 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' },
@@ -241,7 +247,7 @@ 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)
@@ -265,6 +271,7 @@ static void parse_opts(int argc, char *argv[])
break;
case 'i':
input_file = optarg;
+ input_choices++;
break;
case 'o':
output_file = optarg;
@@ -275,6 +282,13 @@ static void parse_opts(int argc, char *argv[])
case 'c':
compare = 1;
break;
+ case 't':
+ do_tx = 0;
+ input_choices++;
+ break;
+ case 'r':
+ do_rx = 0;
+ break;
case 'H':
mode |= SPI_CPHA;
break;
@@ -310,6 +324,7 @@ static void parse_opts(int argc, char *argv[])
break;
case 'p':
input_tx = optarg;
+ input_choices++;
break;
case '2':
mode |= SPI_TX_DUAL;
@@ -322,6 +337,7 @@ static void parse_opts(int argc, char *argv[])
break;
case 'S':
transfer_size = atoi(optarg);
+ input_choices++;
break;
case 'I':
iterations = atoi(optarg);
@@ -344,15 +360,17 @@ static void transfer_escaped_string(int fd, char *str)
{
size_t size = strlen(str);
uint8_t *tx;
- uint8_t *rx;
+ uint8_t *rx = NULL;
tx = malloc(size);
if (!tx)
pabort("can't allocate tx buffer");
- rx = malloc(size);
- if (!rx)
- pabort("can't allocate rx buffer");
+ if (do_rx) {
+ rx = malloc(size);
+ if (!rx)
+ pabort("can't allocate rx buffer");
+ }
size = unescape((char *)tx, str, size);
transfer(fd, tx, rx, size);
@@ -366,7 +384,7 @@ static void transfer_file(int fd, char *filename)
struct stat sb;
int tx_fd;
uint8_t *tx;
- uint8_t *rx;
+ uint8_t *rx = NULL;
if (stat(filename, &sb) == -1)
pabort("can't stat input file");
@@ -379,9 +397,12 @@ static void transfer_file(int fd, char *filename)
if (!tx)
pabort("can't allocate tx buffer");
- rx = malloc(sb.st_size);
- if (!rx)
- pabort("can't allocate rx buffer");
+
+ if (do_rx) {
+ rx = malloc(sb.st_size);
+ if (!rx)
+ pabort("can't allocate rx buffer");
+ }
bytes = read(tx_fd, tx, sb.st_size);
if (bytes != sb.st_size)
@@ -412,26 +433,31 @@ 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 || mode & SPI_LOOP) {
+ if (tx && rx && (compare || mode & SPI_LOOP)) {
if (memcmp(tx, rx, len)) {
fprintf(stderr, "transfer error !\n");
hex_dump(tx, len, 32, "TX");
@@ -452,8 +478,14 @@ 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_choices > 1)
+ pabort("only one of -S (--size), -p, -i (--input), -t (--no-tx) may be selected");
+
+ if (compare && (!do_tx || !do_rx))
+ pabort("-c (--compare) conflicts with -t (--no-tx) or -r (--no-rx)");
+
+ if (!do_rx && output_file)
+ pabort("-r (--no-rx) conflicts with -o (--output)");
if (compare && mode & (SPI_TX_OCTAL | SPI_TX_QUAD | SPI_TX_DUAL))
pabort("-c (--compare) conflicts with -2 (--dual), -4 (--quad) or -8 (--octal)");
@@ -532,7 +564,7 @@ int main(int argc, char *argv[])
printf("total: tx %.1fKB, rx %.1fKB\n",
_write_count/1024.0, _read_count/1024.0);
} else
- transfer(fd, default_tx, default_rx, sizeof(default_tx));
+ transfer(fd, do_tx ? default_tx : NULL, do_rx ? default_rx : NULL, sizeof(default_tx));
close(fd);
--
2.56.0.rc0.108.gf0ef1b96a0