[U-Boot] [PATCH] spi: mxs: Allow other chip selects to work
Marek Vasut
marex at denx.de
Mon Apr 23 15:12:38 CEST 2012
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 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;
> }
Acked-by: Marek Vasut <marex at denx.de>
Best regards,
Marek Vasut
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