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.este...@freescale.com>
---
drivers/spi/mxs_spi.c | 17 +++++++++++++++++
1 files changed, 17 insertions(+), 0 deletions(-)
diff --git a/drivers/spi/mxs_spi.c b/drivers/spi/mxs_spi.c
index 4e6f14e..c0bfd25 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;
@@ -56,12 +58,19 @@ 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 (bus > 3) {
printf("MXS SPI: Max bus number is 3\n");
return NULL;
}
+ if (cs > 2) {
+ printf("MXS SPI: Invalid chip select number: %d\n", cs);
+ return NULL;
+ }
+
mxs_slave = malloc(sizeof(struct mxs_spi_slave));
if (!mxs_slave)
return NULL;
@@ -74,6 +83,14 @@ struct spi_slave *spi_setup_slave(unsigned int bus, unsigned
int cs,
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;
}
--
1.7.1
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