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

login
register
mail settings
Submitter Fabio Estevam
Date April 23, 2012, 12:43 p.m.
Message ID <1335184992-2381-1-git-send-email-fabio.estevam@freescale.com>
Download mbox | patch
Permalink /patch/154421/
State Changes Requested
Headers show

Comments

Fabio Estevam - April 23, 2012, 12:43 p.m.
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>
---
 drivers/spi/mxs_spi.c |   17 +++++++++++++++++
 1 files changed, 17 insertions(+), 0 deletions(-)
Marek Vasut - April 23, 2012, 1:12 p.m.
Dear 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@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;
>  }

Acked-by: Marek Vasut <marex@denx.de>

Best regards,
Marek Vasut
Mike Frysinger - April 23, 2012, 5:43 p.m.
On Monday 23 April 2012 08:43:12 Fabio Estevam wrote:
> --- a/drivers/spi/mxs_spi.c
> +++ b/drivers/spi/mxs_spi.c
> @@ -56,12 +58,19 @@ struct spi_slave *spi_setup_slave(unsigned int bus,
> 
>  	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;
> +	}

this stuff really belongs in spi_cs_is_valid(), sans the printf's.
-mike

Patch

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;
 }