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SPI Reference table
| SPI | Pin | Pin name | GPIO name | DT overlay node | Device node | |
|---|---|---|---|---|---|---|
| VIM3/3L | SPI_B | 15 | SPIB_SS | GPIOH_6 | spi1 | /dev/spidev2.1 |
| 16 | SPIB_SCLK | GPIOH_7 | ||||
| 35 | SPIB_MISO | GPIOH_5 | ||||
| 37 | SPIB_MOSI | GPIOH_4 | ||||
| VIM4 | SPI_A | 25 | SPI_A_SCLK | GPIOT_20 | spi0 | /dev/spidev1.0 |
| 26 | SPI_A_SS0 | GPIOT_21 | ||||
| 36 | SPI_A_MOSI | GPIOT_18 | ||||
| 37 | SPI_A_MISO | GPIOT_19 | ||||
| VIM1S | SPI_A | 29 | SPI_A_MOSI | GPIOZ_1 | ||
| 31 | SPI_A_CLK | GPIOZ_2 | ||||
| 32 | SPI_A_MISO | GPIOZ_0 | ||||
| 33 | SPI_A_SS0 | GPIOZ_3 | ||||
| VIM 5 | SPI_C | 26 | SPI_C_MOSI | GPIOM_0 | spi1 | /dev/spidev1.0 |
| 36 | SPI_C_SCLK | GPIOM_2 | ||||
| 25 | SPI_C_MISO | GPIOM_1 | ||||
| 37 | SPI_C_SS0 | GPIOM_3 |
Enable SPI
In order to use the SPI, you need to enable the SPI function via Device Tree Overlay.
VIM3/3L/Edge1
Edit /boot/env.txt to add the SPI node to overlays node if it doesn't exist.
Take VIM3 as an example to enable SPI_B, you need to add spi1 node to overlays node if it doesn't exist.
overlays=spi1
As SPI pins are also used for other function, e.g. UART_C, PWM_F, so that you also need to remove node uart3 and pwm_f.
After reboot, you will see the spi device node.
$ ls /dev/spidev1.1
/dev/spidev1.1
VIM3 with 5.15 kernel
Edit /boot/dtb/amlogic/kvim3.dtb.overlay.env to add spi node to fdt_overlays node if it doesn't exist.
e.g. Enable SPI_B, you need to add spi1 to node fdt_overlays if it doesn't exist.
fdt_overlays=spi1
After reboot, you will see the SPI device node.
$ ls /dev/spidev2.1
/dev/spidev2.1
VIM3L with 5.15 kernel
Edit /boot/dtb/amlogic/kvim3l.dtb.overlay.env to add spi node to fdt_overlays node if it doesn't exist.
e.g. Enable SPI_B, you need to add spi1 to node fdt_overlays if it doesn't exist.
fdt_overlays=spi1
After reboot, you will see the SPI device node.
$ ls /dev/spidev2.1
/dev/spidev2.1
VIM4
Edit /boot/dtb/amlogic/kvim4.dtb.overlay.env to add spi node to fdt_overlays node if it doesn't exist.
e.g. Enable SPI_A, you need to add spi0 to node fdt_overlays if it doesn't exist.
fdt_overlays=spi0
After reboot, you will see the SPI device node.
$ ls /dev/spidev1.0
/dev/spidev1.0
VIM1S
Edit /boot/dtb/amlogic/kvim1s.dtb.overlay.env to add spi node to fdt_overlays node if it doesn't exist.
e.g. Enable SPI_A, you need to add spi0 to node fdt_overlays if it doesn't exist.
fdt_overlays=spi0
After reboot, you will see the SPI device node.
$ ls /dev/spidev1.0
/dev/spidev1.0
VIM 4
Edit /boot/dtb/amlogic/kvim-5.dtb.overlay.env to add spi node to fdt_overlays node if it doesn't exist.
e.g. Enable SPI_C, you need to add spi1 to node fdt_overlays if it doesn't exist.
fdt_overlays=spi1
After reboot, you will see the SPI device node.
$ ls /dev/spidev1.0
/dev/spidev1.0
</tabbox>
===== Disable SPI =====
If you want to use normal GPIO instead of SPI, you can remove the SPI node in [[products:sbc:common:configurations:device-tree-overlay|Device Tree Overlay]].
===== Demo Source Code =====
SPDX-License-Identifier: GPL-2.0-only /* * SPI testing utility (using spidev driver) * * Copyright © 2007 MontaVista Software, Inc. * Copyright © 2007 Anton Vorontsov avorontsov@ru.mvista.com * * Cross-compile with cross-gcc -I/path/to/cross-kernel/include */ #include <stdint.h> #include <unistd.h> #include <stdio.h> #include <stdlib.h> #include <string.h> #include <getopt.h> #include <fcntl.h> #include <time.h> #include <sys/ioctl.h> #include <linux/ioctl.h> #include <sys/stat.h> #include <linux/types.h> #include <linux/spi/spidev.h> #define ARRAY_SIZE(a) (sizeof(a) / sizeof1) static void pabort(const char *s) { perror(s); abort(); } static const char *device = “/dev/spidev1.0”; 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; static int transfer_size; static int iterations; static int interval = 5; /* interval in seconds for showing transfer rate */ uint8_t default_tx[] = { 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0x40, 0x00, 0x00, 0x00, 0x00, 0x95, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xF0, 0x0D, }; uint8_t default_rx[ARRAY_SIZE(default_tx)] = {0, }; char *input_tx; static void hex_dump(const void *src, size_t length, size_t line_size, char *prefix) { int i = 0; const unsigned char *address = src; const unsigned char *line = address; unsigned char c; printf(“%s | ”, prefix); while (length– > 0) { printf(“%02X ”, *address++); if (!(++i % line_size) || (length == 0 && i % line_size)) { if (length == 0) { while (i++ % line_size) printf(“__ ”); } printf(“ |”); while (line < address) { c = *line++; printf(“%c”, (c < 32 || c > 126) ? '.' : c); } printf(“|\n”); if (length > 0) printf(“%s | ”, prefix); } } } /* * Unescape - process hexadecimal escape character * converts shell input “\x23” → 0x23 */ static int unescape(char *_dst, char *_src, size_t len) { int ret = 0; int match; char *src = _src; char *dst = _dst; unsigned int ch; while (*src) { if (*src == '\\' && *(src+1) == 'x') { match = sscanf(src + 2, “%2x”, &ch); if (!match) pabort(“malformed input string”); src += 4; *dst++ = (unsigned char)ch; } else { *dst++ = *src++; } ret++; } return ret; } 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, .len = len, .delay_usecs = delay, .speed_hz = speed, .bits_per_word = bits, }; if (mode & SPI_TX_QUAD) tr.tx_nbits = 4; else if (mode & SPI_TX_DUAL) tr.tx_nbits = 2; if (mode & SPI_RX_QUAD) tr.rx_nbits = 4; else if (mode & SPI_RX_DUAL) tr.rx_nbits = 2; if (!(mode & SPI_LOOP)) { if (mode & (SPI_TX_QUAD | SPI_TX_DUAL)) tr.rx_buf = 0; else if (mode & (SPI_RX_QUAD | SPI_RX_DUAL)) tr.tx_buf = 0; } ret = ioctl(fd, SPI_IOC_MESSAGE(1), &tr); if (ret < 1) pabort(“can't send spi message”); if (verbose) hex_dump(tx, len, 32, “TX”); 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 output file”); close(out_fd); } if (verbose) hex_dump(rx, len, 32, “RX”); } static void print_usage(const char *prog) { printf(“Usage: %s [-DsbdlHOLC3vpNR24SI]\n”, prog); puts(“ -D –device device to use (default /dev/spidev1.1)\n” “ -s –speed max speed (Hz)\n” “ -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” “ -L –lsb least significant bit first\n” “ -C –cs-high chip select active high\n” “ -3 –3wire SI/SO signals shared\n” “ -v –verbose Verbose (show tx buffer)\n” “ -p Send data (e.g. \”1234\\xde\\xad\“)\n” “ -N –no-cs no chip select\n” “ -R –ready slave pulls low to pause\n” “ -2 –dual dual transfer\n” “ -4 –quad quad transfer\n” “ -S –size transfer size\n” “ -I –iter iterations\n”); exit(1); } static void parse_opts(int argc, char *argv[]) { while (1) { static const struct option lopts[] = { { “device”, 1, 0, 'D' }, { “speed”, 1, 0, 's' }, { “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' }, { “lsb”, 0, 0, 'L' }, { “cs-high”, 0, 0, 'C' }, { “3wire”, 0, 0, '3' }, { “no-cs”, 0, 0, 'N' }, { “ready”, 0, 0, 'R' }, { “dual”, 0, 0, '2' }, { “verbose”, 0, 0, 'v' }, { “quad”, 0, 0, '4' }, { “size”, 1, 0, 'S' }, { “iter”, 1, 0, 'I' }, { NULL, 0, 0, 0 }, }; int c; c = getopt_long(argc, argv, “D:s:d:b:i:o:lHOLC3NR24p:vS:I:”, lopts, NULL); if (c == -1) break; switch © { case 'D': device = optarg; break; case 's': speed = atoi(optarg); break; case 'd': delay = atoi(optarg); break; case 'b': bits = atoi(optarg); break; case 'i': input_file = optarg; break; case 'o': output_file = optarg; break; case 'l': mode |= SPI_LOOP; break; case 'H': mode |= SPI_CPHA; break; case 'O': mode |= SPI_CPOL; break; case 'L': mode |= SPI_LSB_FIRST; break; case 'C': mode |= SPI_CS_HIGH; break; case '3': mode |= SPI_3WIRE; break; case 'N': mode |= SPI_NO_CS; break; case 'v': verbose = 1; break; case 'R': mode |= SPI_READY; break; case 'p': input_tx = optarg; break; case '2': mode |= SPI_TX_DUAL; break; case '4': mode |= SPI_TX_QUAD; break; case 'S': transfer_size = atoi(optarg); break; case 'I': iterations = atoi(optarg); break; default: print_usage(argv[0]); break; } } if (mode & SPI_LOOP) { if (mode & SPI_TX_DUAL) mode |= SPI_RX_DUAL; if (mode & SPI_TX_QUAD) mode |= SPI_RX_QUAD; } } static void transfer_escaped_string(int fd, char *str) { size_t size = strlen(str); uint8_t *tx; uint8_t *rx; tx = malloc(size); if (!tx) pabort(“can't allocate tx buffer”); rx = malloc(size); if (!rx) pabort(“can't allocate rx buffer”); size = unescape2)
transfer(fd, tx, rx, size); free(rx); free(tx);} static void transfer_file(int fd, char *filename) {
ssize_t bytes; struct stat sb; int tx_fd; uint8_t *tx; uint8_t *rx;
if (stat(filename, &sb) == -1)
pabort("can't stat input file");
tx_fd = open(filename, O_RDONLY);
if (tx_fd < 0)
pabort("can't open input file");
tx = malloc(sb.st_size);
if (!tx)
pabort("can't allocate tx buffer");
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)
pabort("failed to read input file");
transfer(fd, tx, rx, sb.st_size); free(rx); free(tx); close(tx_fd);} static uint64_t _read_count; static uint64_t _write_count; static void show_transfer_rate(void) {
static uint64_t prev_read_count, prev_write_count; double rx_rate, tx_rate;
rx_rate = ((_read_count - prev_read_count) * 8) / (interval*1000.0); tx_rate = ((_write_count - prev_write_count) * 8) / (interval*1000.0);
printf("rate: tx %.1fkbps, rx %.1fkbps\n", rx_rate, tx_rate);
prev_read_count = _read_count; prev_write_count = _write_count;} static void transfer_buf(int fd, int len) {
uint8_t *tx; uint8_t *rx; int i;
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");
transfer(fd, tx, rx, len);
_write_count += len; _read_count += len;
if (mode & SPI_LOOP) {
if (memcmp(tx, rx, len)) {
fprintf(stderr, "transfer error !\n");
hex_dump(tx, len, 32, "TX");
hex_dump(rx, len, 32, "RX");
exit(1);
}
}
free(rx); free(tx);} int main(int argc, char *argv[]) {
int ret = 0; int fd;
parse_opts(argc, argv);
fd = open(device, O_RDWR);
if (fd < 0)
pabort("can't open device");
/*
* spi mode
*/
ret = ioctl(fd, SPI_IOC_WR_MODE32, &mode);
if (ret == -1)
pabort("can't set spi mode");
ret = ioctl(fd, SPI_IOC_RD_MODE32, &mode);
if (ret == -1)
pabort("can't get spi mode");
/*
* bits per word
*/
ret = ioctl(fd, SPI_IOC_WR_BITS_PER_WORD, &bits);
if (ret == -1)
pabort("can't set bits per word");
ret = ioctl(fd, SPI_IOC_RD_BITS_PER_WORD, &bits);
if (ret == -1)
pabort("can't get bits per word");
/*
* max speed hz
*/
ret = ioctl(fd, SPI_IOC_WR_MAX_SPEED_HZ, &speed);
if (ret == -1)
pabort("can't set max speed hz");
ret = ioctl(fd, SPI_IOC_RD_MAX_SPEED_HZ, &speed);
if (ret == -1)
pabort("can't get max speed hz");
printf("spi mode: 0x%x\n", mode);
printf("bits per word: %d\n", bits);
printf("max speed: %d Hz (%d KHz)\n", speed, speed/1000);
if (input_tx && input_file)
pabort("only one of -p and --input may be selected");
if (input_tx)
transfer_escaped_string(fd, input_tx);
else if (input_file)
transfer_file(fd, input_file);
else if (transfer_size) {
struct timespec last_stat;
clock_gettime(CLOCK_MONOTONIC, &last_stat);
while (iterations-- > 0) {
struct timespec current;
transfer_buf(fd, transfer_size);
clock_gettime(CLOCK_MONOTONIC, ¤t);
if (current.tv_sec - last_stat.tv_sec > interval) {
show_transfer_rate();
last_stat = current;
}
}
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));
close(fd);
return ret;}
Compile test code:$ gcc -o spidev_test spidev_test.c
===== Test demonstration ===== Prepare input text file:$ echo “Amazing Khadas!” > ./spi_in.txt
Connect PIN36(MOSI), PIN37(MISO) then run ''spidev_test'':$ ./spidev_test -D /dev/spidev1.1 -i spi_in.txt -o ./spi_out.txt spi mode: 0x0 bits per word: 8 max speed: 500000 Hz (500 KHz)
<WRAP important > Please choose the correct spi device node. </WRAP> Check output data:$ cat ./spi_out.txt Amazing Khadas! ```