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STM32 SPI: nbits interface extended to handle LSB- or MSB-first operation. From Teemu Pirinen

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This commit is contained in:
Gregory Nutt 2013-08-16 11:35:22 -06:00
parent 94bcdc66b0
commit ddc93e1da3
1 changed files with 13 additions and 3 deletions
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16
arch/arm/src/stm32/stm32_spi.c
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@ -200,7 +200,7 @@ struct stm32_spidev_s
sem_t exclsem; /* Held while chip is selected for mutual exclusion */ sem_t exclsem; /* Held while chip is selected for mutual exclusion */
uint32_t frequency; /* Requested clock frequency */ uint32_t frequency; /* Requested clock frequency */
uint32_t actual; /* Actual clock frequency */ uint32_t actual; /* Actual clock frequency */
uint8_t nbits; /* Width of word in bits (8 or 16) */ int8_t nbits; /* Width of word in bits (8 or 16) */
uint8_t mode; /* Mode 0,1,2,3 */ uint8_t mode; /* Mode 0,1,2,3 */
#endif #endif
}; };
@ -1153,14 +1153,24 @@ static void spi_setbits(FAR struct spi_dev_s *dev, int nbits)
switch (nbits) switch (nbits)
{ {
case -8:
setbits = SPI_CR1_LSBFIRST;
clrbits = SPI_CR1_DFF;
break;
case 8: case 8:
setbits = 0; setbits = 0;
clrbits = SPI_CR1_DFF; clrbits = SPI_CR1_DFF|SPI_CR1_LSBFIRST;
break;
case -16:
setbits = SPI_CR1_DFF|SPI_CR1_LSBFIRST;
clrbits = 0;
break; break;
case 16: case 16:
setbits = SPI_CR1_DFF; setbits = SPI_CR1_DFF;
clrbits = 0; clrbits = SPI_CR1_LSBFIRST;
break; break;
default: default: