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libraries/SPI: Add support for peripheral mode. #200

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100 changes: 44 additions & 56 deletions libraries/SPI/SPI.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -12,66 +12,42 @@ arduino::ZephyrSPI::ZephyrSPI(const struct device *spi) : spi_dev(spi) {
}

uint8_t arduino::ZephyrSPI::transfer(uint8_t data) {
int ret;
uint8_t rx;
const struct spi_buf tx_buf = {.buf = &data, .len = sizeof(data)};
const struct spi_buf_set tx_buf_set = {
.buffers = &tx_buf,
.count = 1,
};
const struct spi_buf rx_buf = {.buf = &rx, .len = sizeof(rx)};
const struct spi_buf_set rx_buf_set = {
.buffers = &rx_buf,
.count = 1,
};

ret = spi_transceive(spi_dev, &config, &tx_buf_set, &rx_buf_set);
if (ret < 0) {
uint8_t rx = data;
if (transfer(&rx, sizeof(rx), &config) < 0) {
return 0;
}

return rx;
}

uint16_t arduino::ZephyrSPI::transfer16(uint16_t data) {
int ret;
uint16_t rx;
const struct spi_buf tx_buf = {.buf = &data, .len = sizeof(data)};
const struct spi_buf_set tx_buf_set = {
.buffers = &tx_buf,
.count = 1,
};
const struct spi_buf rx_buf = {.buf = &rx, .len = sizeof(rx)};
const struct spi_buf_set rx_buf_set = {
.buffers = &rx_buf,
.count = 1,
};

ret = spi_transceive(spi_dev, &config16, &tx_buf_set, &rx_buf_set);
if (ret < 0) {
uint16_t rx = data;
if (transfer(&rx, sizeof(rx), &config16) < 0) {
return 0;
}

return rx;
}

void arduino::ZephyrSPI::transfer(void *buf, size_t count) {
int ret = transfer(buf, count, &config);
(void)ret;
}

int arduino::ZephyrSPI::transfer(void *buf, size_t len, const struct spi_config *config) {
int ret;
const struct spi_buf tx_buf = {.buf = buf, .len = count};

const struct spi_buf tx_buf = {.buf = buf, .len = len};
const struct spi_buf_set tx_buf_set = {
.buffers = &tx_buf,
.count = 1,
};

uint8_t rx[count];
const struct spi_buf rx_buf = {.buf = &rx, .len = count};
const struct spi_buf rx_buf = {.buf = buf, .len = len};
const struct spi_buf_set rx_buf_set = {
.buffers = &rx_buf,
.count = 1,
};

spi_transceive(spi_dev, &config, &tx_buf_set, &rx_buf_set);
memcpy(buf, rx, count);
return spi_transceive(spi_dev, config, &tx_buf_set, &rx_buf_set);
}

void arduino::ZephyrSPI::usingInterrupt(int interruptNumber) {
Expand All @@ -80,21 +56,31 @@ void arduino::ZephyrSPI::usingInterrupt(int interruptNumber) {
void arduino::ZephyrSPI::notUsingInterrupt(int interruptNumber) {
}

#ifndef SPI_MIN_CLOCK_FEQUENCY
#define SPI_MIN_CLOCK_FEQUENCY 1000000
#endif

void arduino::ZephyrSPI::beginTransaction(SPISettings settings) {
memset(&config, 0, sizeof(config));
memset(&config16, 0, sizeof(config16));
config.frequency = settings.getClockFreq() > SPI_MIN_CLOCK_FEQUENCY ? settings.getClockFreq() :
SPI_MIN_CLOCK_FEQUENCY;
config16.frequency = config.frequency;
uint32_t mode = 0;

// Set bus mode
switch (settings.getBusMode()) {
case SPI_CONTROLLER:
break;
case SPI_PERIPHERAL:
mode |= SPI_OP_MODE_SLAVE;
break;
}

auto mode = SPI_MODE_CPOL | SPI_MODE_CPHA;
// Set data format
switch (settings.getBitOrder()) {
case LSBFIRST:
mode |= SPI_TRANSFER_LSB;
break;
case MSBFIRST:
mode |= SPI_TRANSFER_MSB;
break;
}

// Set data mode
switch (settings.getDataMode()) {
case SPI_MODE0:
mode = 0;
break;
case SPI_MODE1:
mode = SPI_MODE_CPHA;
Expand All @@ -106,12 +92,16 @@ void arduino::ZephyrSPI::beginTransaction(SPISettings settings) {
mode = SPI_MODE_CPOL | SPI_MODE_CPHA;
break;
}
config.operation = SPI_WORD_SET(8) |
(settings.getBitOrder() == MSBFIRST ? SPI_TRANSFER_MSB : SPI_TRANSFER_LSB) |
mode;
config16.operation =
SPI_WORD_SET(16) |
(settings.getBitOrder() == MSBFIRST ? SPI_TRANSFER_MSB : SPI_TRANSFER_LSB) | mode;

// Set SPI configuration structure for 8-bit transfers
memset(&config, 0, sizeof(struct spi_config));
config.operation = mode | SPI_WORD_SET(8);
config.frequency = max(SPI_MIN_CLOCK_FEQUENCY, settings.getClockFreq());

// Set SPI configuration structure for 16-bit transfers
memset(&config16, 0, sizeof(struct spi_config));
config16.operation = mode | SPI_WORD_SET(16);
config16.frequency = max(SPI_MIN_CLOCK_FEQUENCY, settings.getClockFreq());
}

void arduino::ZephyrSPI::endTransaction(void) {
Expand All @@ -125,8 +115,6 @@ void arduino::ZephyrSPI::detachInterrupt() {
}

void arduino::ZephyrSPI::begin() {
beginTransaction(SPISettings());
endTransaction();
}

void arduino::ZephyrSPI::end() {
Expand Down
9 changes: 9 additions & 0 deletions libraries/SPI/SPI.h
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Original file line number Diff line number Diff line change
Expand Up @@ -22,6 +22,12 @@
#define SPE 6
#define SPIE 7

// TODO:
// This depends on the clock settings, can't be used for all boards.
#ifndef SPI_MIN_CLOCK_FEQUENCY
#define SPI_MIN_CLOCK_FEQUENCY 1000000
#endif

/* Count the number of GPIOs for limit of number of interrupts */
#define INTERRUPT_HELPER(n, p, i) 1
#define INTERRUPT_COUNT \
Expand Down Expand Up @@ -50,6 +56,9 @@ class ZephyrSPI : public HardwareSPI {
virtual void begin();
virtual void end();

private:
int transfer(void *buf, size_t len, const struct spi_config *config);

protected:
const struct device *spi_dev;
struct spi_config config;
Expand Down
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