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

[Marek Vasut <marex@denx.de>]

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