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EFM32: Fix issues associated with SPI bi order. From Pierre

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This commit is contained in:
Gregory Nutt 2014-11-09 07:15:48 -06:00
parent b96654347b
commit 6ea107784d
1 changed files with 32 additions and 11 deletions
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43
arch/arm/src/efm32/efm32_spi.c
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@ -159,6 +159,7 @@ struct efm32_spidev_s
#endif #endif
uint8_t nbits; /* Width of word in bits (4-16) */ uint8_t nbits; /* Width of word in bits (4-16) */
bool lsbfirst; /* True: Bit order is LSB first */
bool initialized; /* True: Already initialized */ bool initialized; /* True: Already initialized */
}; };
@ -1007,32 +1008,50 @@ static void spi_setbits(struct spi_dev_s *dev, int nbits)
const struct efm32_spiconfig_s *config; const struct efm32_spiconfig_s *config;
uint32_t regval; uint32_t regval;
uint32_t setting; uint32_t setting;
unsigned int truebits; bool lsbfirst;
spivdbg("nbits=%d\n", nbits); spivdbg("nbits=%d\n", nbits);
DEBUGASSERT(priv && priv->config); DEBUGASSERT(priv && priv->config);
config = priv->config; config = priv->config;
/* Has the number of bits changed? */ /* Bit order is encoded by the sign of nbits */
if (nbits != priv->nbits) if (nbits < 0)
{ {
/* LSB first */
lsbfirst = true;
nbits = -nbits;
}
else
{
/* MSH first */
lsbfirst = false;
}
/* Has the number of bits or the bit order changed? */
if (nbits != priv->nbits || lsbfirst != priv->lsbfirst)
{
/* Set the new bit order */
regval = spi_getreg(config, EFM32_USART_CTRL_OFFSET); regval = spi_getreg(config, EFM32_USART_CTRL_OFFSET);
if (nbits < 0) if (lsbfirst)
{ {
regval &= ~USART_CTRL_MSBF; regval &= ~USART_CTRL_MSBF;
truebits = -nbits;
} }
else else
{ {
regval |= USART_CTRL_MSBF; regval |= USART_CTRL_MSBF;
truebits = nbits;
} }
spi_putreg(config, EFM32_USART_CLKDIV_OFFSET, regval); spi_putreg(config, EFM32_USART_CTRL_OFFSET, regval);
switch (truebits) /* Select the new number of bits */
switch (nbits)
{ {
case 4: case 4:
setting = USART_FRAME_DATABITS_FOUR; setting = USART_FRAME_DATABITS_FOUR;
@ -1099,7 +1118,8 @@ static void spi_setbits(struct spi_dev_s *dev, int nbits)
* faster * faster
*/ */
priv->nbits = nbits; priv->nbits = nbits;
priv->lsbfirst = lsbfirst;
} }
} }
@ -1556,9 +1576,9 @@ static int spi_portinitialize(struct efm32_spidev_s *priv)
USART_CTRL_CLKPHA_SAMPLELEADING; USART_CTRL_CLKPHA_SAMPLELEADING;
spi_putreg(config, EFM32_USART_CTRL_OFFSET, regval); spi_putreg(config, EFM32_USART_CTRL_OFFSET, regval);
/* LSB First */ /* MSB First */
regval &= ~USART_CTRL_MSBF; regval |= USART_CTRL_MSBF;
spi_putreg(config, EFM32_USART_CTRL_OFFSET, regval); spi_putreg(config, EFM32_USART_CTRL_OFFSET, regval);
#ifndef CONFIG_SPI_OWNBUS #ifndef CONFIG_SPI_OWNBUS
@ -1566,6 +1586,7 @@ static int spi_portinitialize(struct efm32_spidev_s *priv)
priv->mode = SPIDEV_MODE0; priv->mode = SPIDEV_MODE0;
#endif #endif
priv->nbits = 8; priv->nbits = 8;
priv->lsbfirst = false;
/* 8 bits */ /* 8 bits */