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cpu/sam0_common: SPI: add support for SAMD20

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This commit is contained in:
Benjamin Valentin 2020-06-17 17:59:48 +02:00
parent fb2a6b7024
commit 94c7f40b9c
1 changed files with 38 additions and 9 deletions
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47
cpu/sam0_common/periph/spi.c
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@ -69,6 +69,40 @@ static inline void poweroff(spi_t bus)
sercom_clk_dis(dev(bus));
}
static void _reset(SercomSpi *dev)
{
dev->CTRLA.reg |= SERCOM_SPI_CTRLA_SWRST;
while (dev->CTRLA.reg & SERCOM_SPI_CTRLA_SWRST) {}
#ifdef SERCOM_SPI_STATUS_SYNCBUSY
while (dev->STATUS.bit.SYNCBUSY) {}
#else
while (dev->SYNCBUSY.bit.SWRST) {}
#endif
}
static inline void _disable(SercomSpi *dev)
{
dev->CTRLA.reg = 0;
#ifdef SERCOM_SPI_STATUS_SYNCBUSY
while (dev->STATUS.bit.SYNCBUSY) {}
#else
while (dev->SYNCBUSY.reg) {}
#endif
}
static inline void _enable(SercomSpi *dev)
{
dev->CTRLA.bit.ENABLE = 1;
#ifdef SERCOM_SPI_STATUS_SYNCBUSY
while (dev->STATUS.bit.SYNCBUSY) {}
#else
while (dev->SYNCBUSY.reg) {}
#endif
}
static inline bool _use_dma(spi_t bus)
{
#ifdef MODULE_PERIPH_DMA
@ -120,9 +154,7 @@ void spi_init(spi_t bus)
poweron(bus);
/* reset all device configuration */
dev(bus)->CTRLA.reg |= SERCOM_SPI_CTRLA_SWRST;
while ((dev(bus)->CTRLA.reg & SERCOM_SPI_CTRLA_SWRST) ||
(dev(bus)->SYNCBUSY.reg & SERCOM_SPI_SYNCBUSY_SWRST)) {}
_reset(dev(bus));
/* configure base clock */
sercom_set_gen(dev(bus), spi_config[bus].gclk_src);
@ -191,8 +223,7 @@ int spi_acquire(spi_t bus, spi_cs_t cs, spi_mode_t mode, spi_clk_t clk)
/* first configuration or reconfiguration after altered device usage */
if (dev(bus)->BAUD.reg != baud || dev(bus)->CTRLA.reg != ctrla) {
/* disable the device */
dev(bus)->CTRLA.reg &= ~(SERCOM_SPI_CTRLA_ENABLE);
while (dev(bus)->SYNCBUSY.reg & SERCOM_SPI_SYNCBUSY_ENABLE) {}
_disable(dev(bus));
dev(bus)->BAUD.reg = baud;
dev(bus)->CTRLA.reg = ctrla;
@ -201,8 +232,7 @@ int spi_acquire(spi_t bus, spi_cs_t cs, spi_mode_t mode, spi_clk_t clk)
}
/* finally enable the device */
dev(bus)->CTRLA.reg |= SERCOM_SPI_CTRLA_ENABLE;
while (dev(bus)->SYNCBUSY.reg & SERCOM_SPI_SYNCBUSY_ENABLE) {}
_enable(dev(bus));
/* mux clk_pin to SPI peripheral */
gpio_init_mux(spi_config[bus].clk_pin, spi_config[bus].clk_mux);
@ -217,8 +247,7 @@ void spi_release(spi_t bus)
gpio_disable_mux(spi_config[bus].clk_pin);
/* disable the device */
dev(bus)->CTRLA.reg &= ~(SERCOM_SPI_CTRLA_ENABLE);
while (dev(bus)->SYNCBUSY.reg & SERCOM_SPI_SYNCBUSY_ENABLE) {}
_disable(dev(bus));
/* power off the device */
poweroff(bus);