[U-Boot] [PATCH] spi: mxs: Allow other chip selects to work

[Fabio Estevam]

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 at 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