diff options
Diffstat (limited to 'drivers/spi/mxs_spi.c')
| -rw-r--r-- | drivers/spi/mxs_spi.c | 23 |
1 files changed, 21 insertions, 2 deletions
diff --git a/drivers/spi/mxs_spi.c b/drivers/spi/mxs_spi.c index 4e6f14e..7859536 100644 --- a/drivers/spi/mxs_spi.c +++ b/drivers/spi/mxs_spi.c @@ -34,6 +34,8 @@ #define MXS_SPI_MAX_TIMEOUT 1000000 #define MXS_SPI_PORT_OFFSET 0x2000 +#define MXS_SSP_CHIPSELECT_MASK 0x00300000 +#define MXS_SSP_CHIPSELECT_SHIFT 20 struct mxs_spi_slave { struct spi_slave slave; @@ -51,14 +53,25 @@ void spi_init(void) { } +int spi_cs_is_valid(unsigned int bus, unsigned int cs) +{ + /* MXS SPI: 4 ports and 3 chip selects maximum */ + if (bus > 3 || cs > 2) + return 0; + else + return 1; +} + struct spi_slave *spi_setup_slave(unsigned int bus, unsigned int cs, unsigned int max_hz, unsigned int mode) { struct mxs_spi_slave *mxs_slave; uint32_t addr; + struct mx28_ssp_regs *ssp_regs; + int reg; - if (bus > 3) { - printf("MXS SPI: Max bus number is 3\n"); + if (!spi_cs_is_valid(bus, cs)) { + printf("mxs_spi: invalid bus %d / chip select %d\n", bus, cs); return NULL; } @@ -73,7 +86,13 @@ struct spi_slave *spi_setup_slave(unsigned int bus, unsigned int cs, mxs_slave->max_khz = max_hz / 1000; mxs_slave->mode = mode; mxs_slave->regs = (struct mx28_ssp_regs *)addr; + ssp_regs = mxs_slave->regs; + + reg = readl(&ssp_regs->hw_ssp_ctrl0); + reg &= ~(MXS_SSP_CHIPSELECT_MASK); + reg |= cs << MXS_SSP_CHIPSELECT_SHIFT; + writel(reg, &ssp_regs->hw_ssp_ctrl0); return &mxs_slave->slave; } |