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spi: add SPI_MOSI_IDLE_LOW mode bit 

Merge series from Boerge Struempfel <boerge.struempfel@gmail.com>:

Some spi controller switch the mosi line to high, whenever they are
idle. This may not be desired in all use cases. For example neopixel
leds can get confused and flicker due to misinterpreting the idle state.
Therefore, we introduce a new spi-mode bit, with which the idle behaviour
can be overwritten on a per device basis.
This commit is contained in:
Mark Brown 2023-05-30 17:43:31 +01:00
parent 0bbb363f86 b229a7f530
commit fe73245592
No known key found for this signature in database
GPG Key ID: 24D68B725D5487D0
4 changed files with 76 additions and 46 deletions
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9
drivers/spi/spi-imx.c
View File

@ -281,6 +281,7 @@ static bool spi_imx_can_dma(struct spi_controller *controller, struct spi_device
#define MX51_ECSPI_CONFIG_SCLKPOL(cs) (1 << ((cs & 3) + 4))
#define MX51_ECSPI_CONFIG_SBBCTRL(cs) (1 << ((cs & 3) + 8))
#define MX51_ECSPI_CONFIG_SSBPOL(cs) (1 << ((cs & 3) + 12))
#define MX51_ECSPI_CONFIG_DATACTL(cs) (1 << ((cs & 3) + 16))
#define MX51_ECSPI_CONFIG_SCLKCTL(cs) (1 << ((cs & 3) + 20))
#define MX51_ECSPI_INT 0x10
@ -573,6 +574,11 @@ static int mx51_ecspi_prepare_message(struct spi_imx_data *spi_imx,
cfg &= ~MX51_ECSPI_CONFIG_SCLKCTL(spi_get_chipselect(spi, 0));
}
if (spi->mode & SPI_MOSI_IDLE_LOW)
cfg |= MX51_ECSPI_CONFIG_DATACTL(spi_get_chipselect(spi, 0));
else
cfg &= ~MX51_ECSPI_CONFIG_DATACTL(spi_get_chipselect(spi, 0));
if (spi->mode & SPI_CS_HIGH)
cfg |= MX51_ECSPI_CONFIG_SSBPOL(spi_get_chipselect(spi, 0));
else
@ -1743,7 +1749,8 @@ static int spi_imx_probe(struct platform_device *pdev)
controller->prepare_message = spi_imx_prepare_message;
controller->unprepare_message = spi_imx_unprepare_message;
controller->slave_abort = spi_imx_slave_abort;
controller->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH | SPI_NO_CS;
controller->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH | SPI_NO_CS |
SPI_MOSI_IDLE_LOW;
if (is_imx35_cspi(spi_imx) || is_imx51_ecspi(spi_imx) ||
is_imx53_ecspi(spi_imx))

3
drivers/spi/spidev.c
View File

@ -64,7 +64,8 @@ static_assert(N_SPI_MINORS > 0 && N_SPI_MINORS <= 256);
| SPI_NO_CS | SPI_READY | SPI_TX_DUAL \
| SPI_TX_QUAD | SPI_TX_OCTAL | SPI_RX_DUAL \
| SPI_RX_QUAD | SPI_RX_OCTAL \
| SPI_RX_CPHA_FLIP)
| SPI_RX_CPHA_FLIP | SPI_3WIRE_HIZ \
| SPI_MOSI_IDLE_LOW)
struct spidev_data {
dev_t devt;

3
include/uapi/linux/spi/spi.h
View File

@ -28,6 +28,7 @@
#define SPI_RX_OCTAL _BITUL(14) /* receive with 8 wires */
#define SPI_3WIRE_HIZ _BITUL(15) /* high impedance turnaround */
#define SPI_RX_CPHA_FLIP _BITUL(16) /* flip CPHA on Rx only xfer */
#define SPI_MOSI_IDLE_LOW _BITUL(17) /* leave mosi line low when idle */
/*
* All the bits defined above should be covered by SPI_MODE_USER_MASK.
@ -37,6 +38,6 @@
* These bits must not overlap. A static assert check should make sure of that.
* If adding extra bits, make sure to increase the bit index below as well.
*/
#define SPI_MODE_USER_MASK (_BITUL(17) - 1)
#define SPI_MODE_USER_MASK (_BITUL(18) - 1)
#endif /* _UAPI_SPI_H */

107
tools/spi/spidev_test.c
View File

@ -172,28 +172,37 @@ 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 [-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"
" -8 --octal octal transfer\n"
" -S --size transfer size\n"
" -I --iter iterations\n");
printf("Usage: %s [-2348CDFHILMNORSZbdilopsv]\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"
" -l --loop loopback\n"
"spi mode:\n"
" -H --cpha clock phase\n"
" -O --cpol clock polarity\n"
" -F --rx-cpha-flip flip CPHA on Rx only xfer\n"
"number of wires for transmission:\n"
" -2 --dual dual transfer\n"
" -4 --quad quad transfer\n"
" -8 --octal octal transfer\n"
" -3 --3wire SI/SO signals shared\n"
" -Z --3wire-hiz high impedance turnaround\n"
"data:\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"
" -p Send data (e.g. \"1234\\xde\\xad\")\n"
" -S --size transfer size\n"
" -I --iter iterations\n"
"additional parameters:\n"
" -b --bpw bits per word\n"
" -L --lsb least significant bit first\n"
" -C --cs-high chip select active high\n"
" -N --no-cs no chip select\n"
" -R --ready slave pulls low to pause\n"
" -M --mosi-idle-low leave mosi line low when idle\n"
"misc:\n"
" -v --verbose Verbose (show tx buffer)\n");
exit(1);
}
@ -201,31 +210,34 @@ 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' },
{ "octal", 0, 0, '8' },
{ "size", 1, 0, 'S' },
{ "iter", 1, 0, 'I' },
{ "device", 1, 0, 'D' },
{ "speed", 1, 0, 's' },
{ "delay", 1, 0, 'd' },
{ "loop", 0, 0, 'l' },
{ "cpha", 0, 0, 'H' },
{ "cpol", 0, 0, 'O' },
{ "rx-cpha-flip", 0, 0, 'F' },
{ "dual", 0, 0, '2' },
{ "quad", 0, 0, '4' },
{ "octal", 0, 0, '8' },
{ "3wire", 0, 0, '3' },
{ "3wire-hiz", 0, 0, 'Z' },
{ "input", 1, 0, 'i' },
{ "output", 1, 0, 'o' },
{ "size", 1, 0, 'S' },
{ "iter", 1, 0, 'I' },
{ "bpw", 1, 0, 'b' },
{ "lsb", 0, 0, 'L' },
{ "cs-high", 0, 0, 'C' },
{ "no-cs", 0, 0, 'N' },
{ "ready", 0, 0, 'R' },
{ "mosi-idle-low", 0, 0, 'M' },
{ "verbose", 0, 0, 'v' },
{ NULL, 0, 0, 0 },
};
int c;
c = getopt_long(argc, argv, "D:s:d:b:i:o:lHOLC3NR248p:vS:I:",
c = getopt_long(argc, argv, "D:s:d:b:i:o:lHOLC3ZFMNR248p:vS:I:",
lopts, NULL);
if (c == -1)
@ -268,6 +280,15 @@ static void parse_opts(int argc, char *argv[])
case '3':
mode |= SPI_3WIRE;
break;
case 'Z':
mode |= SPI_3WIRE_HIZ;
break;
case 'F':
mode |= SPI_RX_CPHA_FLIP;
break;
case 'M':
mode |= SPI_MOSI_IDLE_LOW;
break;
case 'N':
mode |= SPI_NO_CS;
break;