[U-Boot] [PATCH v2 3/4] dm: spi: Check cs number before accessing slaves

[Jagan Teki]

Hi Bin,

On Mon, Sep 9, 2019 at 6:30 PM Bin Meng <bmeng.cn at gmail.com> wrote:
>
> Add chip select number check in spi_find_chip_select().
>
> Signed-off-by: Bin Meng <bmeng.cn at gmail.com>
>
> ---
>
> Changes in v2:
> - move the chip select number check to spi_find_chip_select()
>
>  drivers/spi/spi-uclass.c | 45 ++++++++++++++++++++++++++-------------------
>  include/spi.h            |  3 ++-
>  2 files changed, 28 insertions(+), 20 deletions(-)
>
> diff --git a/drivers/spi/spi-uclass.c b/drivers/spi/spi-uclass.c
> index 24de0b5..cdeceb5 100644
> --- a/drivers/spi/spi-uclass.c
> +++ b/drivers/spi/spi-uclass.c
> @@ -179,7 +179,32 @@ int spi_chip_select(struct udevice *dev)
>
>  int spi_find_chip_select(struct udevice *bus, int cs, struct udevice **devp)
>  {
> +       struct dm_spi_ops *ops;
> +       struct spi_cs_info info;
>         struct udevice *dev;
> +       int ret;
> +
> +       /*
> +        * Ask the driver. For the moment we don't have CS info.
> +        * When we do we could provide the driver with a helper function
> +        * to figure out what chip selects are valid, or just handle the
> +        * request.
> +        */
> +       ops = spi_get_ops(bus);
> +       if (ops->cs_info) {
> +               ret = ops->cs_info(bus, cs, &info);
> +       } else {
> +               /*
> +                * We could assume there is at least one valid chip select.
> +                * The driver didn't care enough to tell us.
> +                */
> +               ret = 0;
> +       }
> +
> +       if (ret) {
> +               printf("Invalid cs %d (err=%d)\n", cs, ret);
> +               return ret;
> +       }
>

This is breaking 'sf probe' with associated bus and cs on SiFive.