Here is a patch that will allow the soft SPI driver to support all different SPI modes (CPOL=0/1, CPHA=0/1).
Signed-off-by: Zach Sadecki zach.sadecki@ripcode.com
=================================================================== --- common/soft_spi.c +++ common/soft_spi.c @@ -39,7 +39,33 @@ #define PRINTD(fmt,args...) #endif
+#ifndef CONFIG_SPI_CPOL +#define CONFIG_SPI_CPOL 0 +#endif
+#ifndef CONFIG_SPI_CPHA +#define CONFIG_SPI_CPHA 0 +#endif + +#if (CONFIG_SPI_CPOL == 0) +#define SPI_CLOCK_IDLE 0 +#define SPI_CLOCK_ACTIVE 1 +#else +#define SPI_CLOCK_IDLE 1 +#define SPI_CLOCK_ACTIVE 0 +#endif + +#if (CONFIG_SPI_CPHA == 0) +/* Read on active (1st) edge */ +#define SPI_CLOCK_WRITE SPI_CLOCK_IDLE +#define SPI_CLOCK_READ SPI_CLOCK_ACTIVE +#else +/* Read on idle (2nd) edge */ +#define SPI_CLOCK_WRITE SPI_CLOCK_ACTIVE +#define SPI_CLOCK_READ SPI_CLOCK_IDLE +#endif + +
/*=====================================================================* / /* Public Functions */
/*=====================================================================* / @@ -87,10 +113,12 @@ PRINTD("spi_xfer: chipsel %08X dout %08X din %08X bitlen %d\n", (int)chipsel, *(uint *)dout, *(uint *)din, bitlen);
+ SPI_SCL(SPI_CLOCK_IDLE); /* Ensure SPI clock starts in idle state */ if(chipsel != NULL) { (*chipsel)(1); /* select the target chip */ } - + SPI_DELAY; /* half clock delay after SS */ + for(j = 0; j < bitlen; j++) { /* * Check if it is time to work on a new byte. @@ -102,14 +130,14 @@ } tmpdin = 0; } - SPI_SCL(0); + SPI_SCL(SPI_CLOCK_WRITE); SPI_SDA(tmpdout & 0x80); SPI_DELAY; - SPI_SCL(1); - SPI_DELAY; + SPI_SCL(SPI_CLOCK_READ); tmpdin <<= 1; tmpdin |= SPI_READ; tmpdout <<= 1; + SPI_DELAY; } /* * If the number of bits isn't a multiple of 8, shift the last @@ -120,7 +148,7 @@ tmpdin <<= 8 - (bitlen % 8); *din++ = tmpdin;
- SPI_SCL(0); /* SPI wants the clock left low for idle */ + SPI_SCL(SPI_CLOCK_IDLE); /* Leave SPI clock in idle state */
if(chipsel != NULL) { (*chipsel)(0); /* deselect the target chip */