[U-Boot] [PATCH v3 05/16] spi: Add support for dual and quad mode

[Jagan Teki]

On 19 November 2015 at 12:35, Mugunthan V N <mugunthanvnm at ti.com> wrote:
> spi bus can support dual and quad wire data transfers for tx and
> rx. So defining dual and quad modes for both tx and rx. Also add
> support to parse bus width used for spi tx and rx transfers.
>
> Signed-off-by: Mugunthan V N <mugunthanvnm at ti.com>
> Reviewed-by: Simon Glass <sjg at chromium.org>
> Reviewed-by: Tom Rini <trini at konsulko.com>
> ---
>  drivers/spi/spi-uclass.c | 33 +++++++++++++++++++++++++++++++++
>  include/spi.h            |  4 ++++
>  2 files changed, 37 insertions(+)
>
> diff --git a/drivers/spi/spi-uclass.c b/drivers/spi/spi-uclass.c
> index 58388ef..62d8da7 100644
> --- a/drivers/spi/spi-uclass.c
> +++ b/drivers/spi/spi-uclass.c
> @@ -349,6 +349,7 @@ int spi_slave_ofdata_to_platdata(const void *blob, int node,
>                                  struct dm_spi_slave_platdata *plat)
>  {
>         int mode = 0;
> +       int value;
>
>         plat->cs = fdtdec_get_int(blob, node, "reg", -1);
>         plat->max_hz = fdtdec_get_int(blob, node, "spi-max-frequency", 0);
> @@ -360,6 +361,38 @@ int spi_slave_ofdata_to_platdata(const void *blob, int node,
>                 mode |= SPI_CS_HIGH;
>         if (fdtdec_get_bool(blob, node, "spi-half-duplex"))
>                 mode |= SPI_PREAMBLE;
> +
> +       /* Device DUAL/QUAD mode */
> +       value = fdtdec_get_uint(blob, node, "spi-tx-bus-width", 1);
> +       switch (value) {
> +       case 1:
> +               break;
> +       case 2:
> +               mode |= SPI_TX_DUAL;
> +               break;
> +       case 4:
> +               mode |= SPI_TX_QUAD;
> +               break;
> +       default:
> +               error("spi-tx-bus-width %d not supported\n", value);
> +               break;
> +       }
> +
> +       value = fdtdec_get_uint(blob, node, "spi-rx-bus-width", 1);
> +       switch (value) {
> +       case 1:
> +               break;
> +       case 2:
> +               mode |= SPI_RX_DUAL;
> +               break;
> +       case 4:
> +               mode |= SPI_RX_QUAD;
> +               break;
> +       default:
> +               error("spi-rx-bus-width %d not supported\n", value);
> +               break;
> +       }
> +

I think these are similar to SPI TX/RX operation modes in spi.h and I
understand this is similar approach as with Linux but before this we
need to do many changes on u-boot as well.

>         plat->mode = mode;
>
>         return 0;
> diff --git a/include/spi.h b/include/spi.h
> index b4d2723..40dbb4d 100644
> --- a/include/spi.h
> +++ b/include/spi.h
> @@ -23,6 +23,10 @@
>  #define        SPI_LOOP        0x20                    /* loopback mode */
>  #define        SPI_SLAVE       0x40                    /* slave mode */
>  #define        SPI_PREAMBLE    0x80                    /* Skip preamble bytes */
> +#define        SPI_TX_DUAL     0x100                   /* transmit with 2 wires */
> +#define        SPI_TX_QUAD     0x200                   /* transmit with 4 wires */
> +#define        SPI_RX_DUAL     0x400                   /* receive with 2 wires */
> +#define        SPI_RX_QUAD     0x800                   /* receive with 4 wires */
>
>  /* SPI transfer flags */
>  #define SPI_XFER_BEGIN         0x01    /* Assert CS before transfer */
> --
> 2.6.2.280.g74301d6
>
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-- 
Jagan | openedev.