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Allow for inverted SPI CS logic (#23699)
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@daskygit
daskygit authored Sep 9, 2024
1 parent 3aaa086 commit 2c7bf34
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Showing 4 changed files with 128 additions and 70 deletions.
84 changes: 52 additions & 32 deletions platforms/avr/drivers/spi_master.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -36,9 +36,18 @@
# define SPI_TIMEOUT 100
#endif

static pin_t currentSlavePin = NO_PIN;
static uint8_t currentSlaveConfig = 0;
static bool currentSlave2X = false;
static pin_t current_slave_pin = NO_PIN;
static bool current_cs_active_low = true;
static uint8_t current_slave_config = 0;
static bool current_slave_2x = false;

static inline void spi_select(void) {
gpio_write_pin(current_slave_pin, current_cs_active_low ? 0 : 1);
}

static inline void spi_unselect(void) {
gpio_write_pin(current_slave_pin, current_cs_active_low ? 1 : 0);
}

void spi_init(void) {
gpio_write_pin_high(SPI_SS_PIN);
Expand All @@ -50,63 +59,74 @@ void spi_init(void) {
}

bool spi_start(pin_t slavePin, bool lsbFirst, uint8_t mode, uint16_t divisor) {
if (currentSlavePin != NO_PIN || slavePin == NO_PIN) {
spi_start_config_t start_config = {0};
start_config.slave_pin = slavePin;
start_config.lsb_first = lsbFirst;
start_config.mode = mode;
start_config.divisor = divisor;
start_config.cs_active_low = true;
return spi_start_extended(&start_config);
}

bool spi_start_extended(spi_start_config_t *start_config) {
if (current_slave_pin != NO_PIN || start_config->slave_pin == NO_PIN) {
return false;
}

currentSlaveConfig = 0;
current_slave_config = 0;

if (lsbFirst) {
currentSlaveConfig |= _BV(DORD);
if (start_config->lsb_first) {
current_slave_config |= _BV(DORD);
}

switch (mode) {
switch (start_config->mode) {
case 1:
currentSlaveConfig |= _BV(CPHA);
current_slave_config |= _BV(CPHA);
break;
case 2:
currentSlaveConfig |= _BV(CPOL);
current_slave_config |= _BV(CPOL);
break;
case 3:
currentSlaveConfig |= (_BV(CPOL) | _BV(CPHA));
current_slave_config |= (_BV(CPOL) | _BV(CPHA));
break;
}

uint16_t roundedDivisor = 1;
while (roundedDivisor < divisor) {
while (roundedDivisor < start_config->divisor) {
roundedDivisor <<= 1;
}

switch (roundedDivisor) {
case 16:
currentSlaveConfig |= _BV(SPR0);
current_slave_config |= _BV(SPR0);
break;
case 64:
currentSlaveConfig |= _BV(SPR1);
current_slave_config |= _BV(SPR1);
break;
case 128:
currentSlaveConfig |= (_BV(SPR1) | _BV(SPR0));
current_slave_config |= (_BV(SPR1) | _BV(SPR0));
break;
case 2:
currentSlave2X = true;
current_slave_2x = true;
break;
case 8:
currentSlave2X = true;
currentSlaveConfig |= _BV(SPR0);
current_slave_2x = true;
current_slave_config |= _BV(SPR0);
break;
case 32:
currentSlave2X = true;
currentSlaveConfig |= _BV(SPR1);
current_slave_2x = true;
current_slave_config |= _BV(SPR1);
break;
}

SPCR |= currentSlaveConfig;
if (currentSlave2X) {
SPCR |= current_slave_config;
if (current_slave_2x) {
SPSR |= _BV(SPI2X);
}
currentSlavePin = slavePin;
gpio_set_pin_output(currentSlavePin);
gpio_write_pin_low(currentSlavePin);
current_slave_pin = start_config->slave_pin;
current_cs_active_low = start_config->cs_active_low;
gpio_set_pin_output(current_slave_pin);
spi_select();

return true;
}
Expand Down Expand Up @@ -168,13 +188,13 @@ spi_status_t spi_receive(uint8_t *data, uint16_t length) {
}

void spi_stop(void) {
if (currentSlavePin != NO_PIN) {
gpio_set_pin_output(currentSlavePin);
gpio_write_pin_high(currentSlavePin);
currentSlavePin = NO_PIN;
if (current_slave_pin != NO_PIN) {
gpio_set_pin_output(current_slave_pin);
spi_unselect();
current_slave_pin = NO_PIN;
SPSR &= ~(_BV(SPI2X));
SPCR &= ~(currentSlaveConfig);
currentSlaveConfig = 0;
currentSlave2X = false;
SPCR &= ~(current_slave_config);
current_slave_config = 0;
current_slave_2x = false;
}
}
9 changes: 9 additions & 0 deletions platforms/avr/drivers/spi_master.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -41,9 +41,18 @@ typedef int16_t spi_status_t;
#ifdef __cplusplus
extern "C" {
#endif
typedef struct spi_start_config_t {
pin_t slave_pin;
bool lsb_first;
uint8_t mode;
uint16_t divisor;
bool cs_active_low;
} spi_start_config_t;

void spi_init(void);

bool spi_start(pin_t slavePin, bool lsbFirst, uint8_t mode, uint16_t divisor);
bool spi_start_extended(spi_start_config_t *start_config);

spi_status_t spi_write(uint8_t data);

Expand Down
96 changes: 58 additions & 38 deletions platforms/chibios/drivers/spi_master.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -19,13 +19,33 @@
#include "timer.h"

static bool spiStarted = false;

#if SPI_SELECT_MODE == SPI_SELECT_MODE_NONE
static pin_t currentSlavePin;
static pin_t current_slave_pin = NO_PIN;
static bool current_cs_active_low = true;
#endif

static SPIConfig spiConfig;

static inline void spi_select(void) {
spiSelect(&SPI_DRIVER);

#if SPI_SELECT_MODE == SPI_SELECT_MODE_NONE
if (current_slave_pin != NO_PIN) {
gpio_write_pin(current_slave_pin, current_cs_active_low ? 0 : 1);
}
#endif
}

static inline void spi_unselect(void) {
#if SPI_SELECT_MODE == SPI_SELECT_MODE_NONE
if (current_slave_pin != NO_PIN) {
gpio_write_pin(current_slave_pin, current_cs_active_low ? 1 : 0);
}
#endif

spiUnselect(&SPI_DRIVER);
}

__attribute__((weak)) void spi_init(void) {
static bool is_initialised = false;
if (!is_initialised) {
Expand Down Expand Up @@ -63,24 +83,23 @@ __attribute__((weak)) void spi_init(void) {
}
}

bool spi_start(pin_t slavePin, bool lsbFirst, uint8_t mode, uint16_t divisor) {
bool spi_start_extended(spi_start_config_t *start_config) {
#if (SPI_USE_MUTUAL_EXCLUSION == TRUE)
spiAcquireBus(&SPI_DRIVER);
#endif // (SPI_USE_MUTUAL_EXCLUSION == TRUE)

if (spiStarted) {
return false;
}

#if SPI_SELECT_MODE != SPI_SELECT_MODE_NONE
if (slavePin == NO_PIN) {
if (start_config->slave_pin == NO_PIN) {
return false;
}
#endif

#if !(defined(WB32F3G71xx) || defined(WB32FQ95xx))
uint16_t roundedDivisor = 2;
while (roundedDivisor < divisor) {
while (roundedDivisor < start_config->divisor) {
roundedDivisor <<= 1;
}

Expand All @@ -92,11 +111,11 @@ bool spi_start(pin_t slavePin, bool lsbFirst, uint8_t mode, uint16_t divisor) {
#if defined(K20x) || defined(KL2x)
spiConfig.tar0 = SPIx_CTARn_FMSZ(7) | SPIx_CTARn_ASC(1);

if (lsbFirst) {
if (start_config->lsb_first) {
spiConfig.tar0 |= SPIx_CTARn_LSBFE;
}

switch (mode) {
switch (start_config->mode) {
case 0:
break;
case 1:
Expand Down Expand Up @@ -141,11 +160,11 @@ bool spi_start(pin_t slavePin, bool lsbFirst, uint8_t mode, uint16_t divisor) {
spiConfig.cr0 = SPI_CR0_SELOEN;
spiConfig.cr1 = SPI_CR1_MODE | 8; // 8 bits and in master mode

if (lsbFirst) {
if (start_config->lsb_first) {
spiConfig.cr1 |= SPI_CR1_FIRSTBIT;
}

switch (mode) {
switch (start_config->mode) {
case 0:
spiConfig.cr1 |= SPI_CR1_FORMAT_MODE0;
break;
Expand All @@ -163,17 +182,17 @@ bool spi_start(pin_t slavePin, bool lsbFirst, uint8_t mode, uint16_t divisor) {
spiConfig.cpr = (roundedDivisor - 1) >> 1;

#elif defined(WB32F3G71xx) || defined(WB32FQ95xx)
if (!lsbFirst) {
osalDbgAssert(lsbFirst != FALSE, "unsupported lsbFirst");
if (!start_config->lsb_first) {
osalDbgAssert(start_config->lsb_first != FALSE, "unsupported lsb_first");
}

if (divisor < 1) {
if (start_config->divisor < 1) {
return false;
}

spiConfig.SPI_BaudRatePrescaler = (divisor << 2);
spiConfig.SPI_BaudRatePrescaler = (start_config->divisor << 2);

switch (mode) {
switch (start_config->mode) {
case 0:
spiConfig.SPI_CPHA = SPI_CPHA_1Edge;
spiConfig.SPI_CPOL = SPI_CPOL_Low;
Expand All @@ -192,8 +211,8 @@ bool spi_start(pin_t slavePin, bool lsbFirst, uint8_t mode, uint16_t divisor) {
break;
}
#elif defined(MCU_RP)
if (lsbFirst) {
osalDbgAssert(lsbFirst == false, "RP2040s PrimeCell SPI implementation does not support sending LSB first.");
if (start_config->lsb_first) {
osalDbgAssert(start_config->lsb_first == false, "RP2040s PrimeCell SPI implementation does not support sending LSB first.");
}

// Motorola frame format and 8bit transfer data size.
Expand All @@ -203,7 +222,7 @@ bool spi_start(pin_t slavePin, bool lsbFirst, uint8_t mode, uint16_t divisor) {
// passed divisor to be the only value to divide the input clock by.
spiConfig.SSPCPSR = roundedDivisor; // Even number from 2 to 254

switch (mode) {
switch (start_config->mode) {
case 0:
spiConfig.SSPCR0 &= ~SPI_SSPCR0_SPO; // Clock polarity: low
spiConfig.SSPCR0 &= ~SPI_SSPCR0_SPH; // Clock phase: sample on first edge
Expand All @@ -224,11 +243,11 @@ bool spi_start(pin_t slavePin, bool lsbFirst, uint8_t mode, uint16_t divisor) {
#else
spiConfig.cr1 = 0;

if (lsbFirst) {
if (start_config->lsb_first) {
spiConfig.cr1 |= SPI_CR1_LSBFIRST;
}

switch (mode) {
switch (start_config->mode) {
case 0:
break;
case 1:
Expand Down Expand Up @@ -271,31 +290,37 @@ bool spi_start(pin_t slavePin, bool lsbFirst, uint8_t mode, uint16_t divisor) {

spiStarted = true;
#if SPI_SELECT_MODE == SPI_SELECT_MODE_NONE
currentSlavePin = slavePin;
current_slave_pin = start_config->slave_pin;
current_cs_active_low = start_config->cs_active_low;
#endif
#if SPI_SELECT_MODE == SPI_SELECT_MODE_PAD
spiConfig.ssport = PAL_PORT(slavePin);
spiConfig.sspad = PAL_PAD(slavePin);
gpio_set_pin_output(slavePin);
spiConfig.ssport = PAL_PORT(start_config->slave_pin);
spiConfig.sspad = PAL_PAD(start_config->slave_pin);
gpio_set_pin_output(start_config->slave_pin);
#elif SPI_SELECT_MODE == SPI_SELECT_MODE_NONE
if (slavePin != NO_PIN) {
gpio_set_pin_output(slavePin);
if (start_config->slave_pin != NO_PIN) {
gpio_set_pin_output(start_config->slave_pin);
}
#else
# error "Unsupported SPI_SELECT_MODE"
#endif

spiStart(&SPI_DRIVER, &spiConfig);
spiSelect(&SPI_DRIVER);
#if SPI_SELECT_MODE == SPI_SELECT_MODE_NONE
if (slavePin != NO_PIN) {
gpio_write_pin_low(slavePin);
}
#endif
spi_select();

return true;
}

bool spi_start(pin_t slavePin, bool lsbFirst, uint8_t mode, uint16_t divisor) {
spi_start_config_t start_config = {0};
start_config.slave_pin = slavePin;
start_config.lsb_first = lsbFirst;
start_config.mode = mode;
start_config.divisor = divisor;
start_config.cs_active_low = true;
return spi_start_extended(&start_config);
}

spi_status_t spi_write(uint8_t data) {
uint8_t rxData;
spiExchange(&SPI_DRIVER, 1, &data, &rxData);
Expand All @@ -322,12 +347,7 @@ spi_status_t spi_receive(uint8_t *data, uint16_t length) {

void spi_stop(void) {
if (spiStarted) {
#if SPI_SELECT_MODE == SPI_SELECT_MODE_NONE
if (currentSlavePin != NO_PIN) {
gpio_write_pin_high(currentSlavePin);
}
#endif
spiUnselect(&SPI_DRIVER);
spi_unselect();
spiStop(&SPI_DRIVER);
spiStarted = false;
}
Expand Down
9 changes: 9 additions & 0 deletions platforms/chibios/drivers/spi_master.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -75,9 +75,18 @@ typedef int16_t spi_status_t;
#ifdef __cplusplus
extern "C" {
#endif
typedef struct spi_start_config_t {
pin_t slave_pin;
bool lsb_first;
uint8_t mode;
uint16_t divisor;
bool cs_active_low;
} spi_start_config_t;

void spi_init(void);

bool spi_start(pin_t slavePin, bool lsbFirst, uint8_t mode, uint16_t divisor);
bool spi_start_extended(spi_start_config_t *start_config);

spi_status_t spi_write(uint8_t data);

Expand Down

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