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stm32f1: add SPI support

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Add basic SPI support and associated documentation.

v2: remove baud rate check, fix baud rate calculations
v3: finish transaction with BSY check, disable SPI when not in use

Signed-off-by: Grigori Goronzy <greg@chown.ath.cx>
This commit is contained in:
Grigori Goronzy
2018-07-02 23:17:28 +02:00
committed by KevinOConnor
parent b0ee323e2e
commit 5c7c8c984b
5 changed files with 122 additions and 2 deletions
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101
src/stm32f1/gpio.c
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@@ -11,8 +11,10 @@
#include "compiler.h" // ARRAY_SIZE
#include "gpio.h" // gpio_out_setup
#include "stm32f1xx.h"
#include "stm32f1xx_ll_rcc.h"
#include "stm32f1xx_ll_gpio.h"
#include "stm32f1xx_ll_adc.h"
#include "stm32f1xx_ll_spi.h"
#include "sched.h" // sched_shutdown
#include "board/irq.h"
#include "board/io.h"
@@ -219,3 +221,102 @@ gpio_adc_cancel_sample(struct gpio_adc g)
LL_ADC_ClearFlag_EOS(ADC1);
}
}
/****************************************************************
* Serial Peripheral Interface (SPI) pins
****************************************************************/
void spi_set_mode(SPI_TypeDef *spi, uint8_t mode)
{
switch (mode) {
case 0:
LL_SPI_SetClockPolarity(spi, LL_SPI_POLARITY_LOW);
LL_SPI_SetClockPhase(spi, LL_SPI_PHASE_1EDGE);
break;
case 1:
LL_SPI_SetClockPolarity(spi, LL_SPI_POLARITY_LOW);
LL_SPI_SetClockPhase(spi, LL_SPI_PHASE_2EDGE);
break;
case 2:
LL_SPI_SetClockPolarity(spi, LL_SPI_POLARITY_HIGH);
LL_SPI_SetClockPhase(spi, LL_SPI_PHASE_1EDGE);
break;
case 3:
LL_SPI_SetClockPolarity(spi, LL_SPI_POLARITY_HIGH);
LL_SPI_SetClockPhase(spi, LL_SPI_PHASE_2EDGE);
break;
default:
shutdown("Invalid SPI mode");
}
}
void spi_set_baudrate(SPI_TypeDef *spi, uint32_t rate)
{
const uint32_t pclk = __LL_RCC_CALC_PCLK1_FREQ(SystemCoreClock, LL_RCC_GetAPB1Prescaler());
const uint32_t prescaler = pclk / rate;
uint32_t setting = LL_SPI_BAUDRATEPRESCALER_DIV256;
if (prescaler <= 2)
setting = LL_SPI_BAUDRATEPRESCALER_DIV2;
else if (prescaler <= 4)
setting = LL_SPI_BAUDRATEPRESCALER_DIV4;
else if (prescaler <= 8)
setting = LL_SPI_BAUDRATEPRESCALER_DIV8;
else if (prescaler <= 16)
setting = LL_SPI_BAUDRATEPRESCALER_DIV16;
else if (prescaler <= 32)
setting = LL_SPI_BAUDRATEPRESCALER_DIV32;
else if (prescaler <= 64)
setting = LL_SPI_BAUDRATEPRESCALER_DIV64;
else if (prescaler <= 128)
setting = LL_SPI_BAUDRATEPRESCALER_DIV128;
LL_SPI_SetBaudRatePrescaler(spi, setting);
}
void spi_init_pins(void)
{
LL_GPIO_SetPinMode(GPIOB, LL_GPIO_PIN_13, LL_GPIO_MODE_ALTERNATE);
LL_GPIO_SetPinMode(GPIOB, LL_GPIO_PIN_14, LL_GPIO_MODE_INPUT);
LL_GPIO_SetPinMode(GPIOB, LL_GPIO_PIN_15, LL_GPIO_MODE_ALTERNATE);
LL_GPIO_SetPinOutputType(GPIOB, LL_GPIO_PIN_13, LL_GPIO_OUTPUT_PUSHPULL);
LL_GPIO_SetPinPull(GPIOB, LL_GPIO_PIN_14, LL_GPIO_PULL_UP);
LL_GPIO_SetPinOutputType(GPIOB, LL_GPIO_PIN_15, LL_GPIO_OUTPUT_PUSHPULL);
}
struct spi_config
spi_setup(uint32_t bus, uint8_t mode, uint32_t rate)
{
struct spi_config config;
config.config = *SPI2;
if (bus > 0 || !rate)
shutdown("Invalid spi_setup parameters");
spi_init_pins();
spi_set_mode(&config.config, mode);
spi_set_baudrate(&config.config, rate);
return config;
}
void
spi_transfer(struct spi_config config, uint8_t receive_data,
uint8_t len, uint8_t *data)
{
*SPI2 = config.config;
LL_SPI_Enable(SPI2);
while (len--) {
LL_SPI_TransmitData8(SPI2, *data);
while (!LL_SPI_IsActiveFlag_TXE(SPI2));
if (receive_data) {
while (!LL_SPI_IsActiveFlag_RXNE(SPI2));
*data = LL_SPI_ReceiveData8(SPI2);
}
data++;
}
while (LL_SPI_IsActiveFlag_BSY(SPI2));
LL_SPI_Disable(SPI2);
}