MXS SSP controller may have up to three chip selects per port: SS0, SS1 and SS2.
Currently only SS0 is supported in the mxs_spi driver.
Allow all the three chip select to work by selecting the desired one in bits 20 and 21 of the HW_SSP_CTRL0 register.
Signed-off-by: Fabio Estevam fabio.estevam@freescale.com --- Changes since v1: - Check vor valid cs inside spi_cs_is_valid() (patch 1/2)
drivers/spi/mxs_spi.c | 10 ++++++++++ 1 files changed, 10 insertions(+), 0 deletions(-)
diff --git a/drivers/spi/mxs_spi.c b/drivers/spi/mxs_spi.c index e7237e7..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; @@ -65,6 +67,8 @@ struct spi_slave *spi_setup_slave(unsigned int bus, unsigned int cs, { struct mxs_spi_slave *mxs_slave; uint32_t addr; + struct mx28_ssp_regs *ssp_regs; + int reg;
if (!spi_cs_is_valid(bus, cs)) { printf("mxs_spi: invalid bus %d / chip select %d\n", bus, cs); @@ -82,7 +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; }