[U-Boot] [PATCH] spi: soft_spi: Fix null ptr when probing soft_spi.

[Jagan Teki]

On Wed, Dec 19, 2018 at 8:40 PM Horatiu Vultur
<horatiu.vultur at microchip.com> wrote:
>
> When probing soft_spi the result of dev_get_parent_priv(dev) in probe
> function is null ptr because the spi is on the ahb bus which has
> per_child_auto_alloc_size set to 0. Therefore it would generate an Ooops
> messages when accessing spi_slave structure.
>
> The fix consist of delaying the read of dm_spi_slave_platdata until a
> child under the spi is probed, to be able to read SPI mode. Therefore
> implement .child_pre_probe in which updates soft_spi_platdata based on
> child dm_spi_slave_platdata.
>
> Signed-off-by: Horatiu Vultur <horatiu.vultur at microchip.com>
> ---
>  drivers/spi/soft_spi.c | 24 +++++++++++++++++-------
>  1 file changed, 17 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/spi/soft_spi.c b/drivers/spi/soft_spi.c
> index b06883f..e28591b 100644
> --- a/drivers/spi/soft_spi.c
> +++ b/drivers/spi/soft_spi.c
> @@ -210,18 +210,13 @@ static int soft_spi_ofdata_to_platdata(struct udevice *dev)
>
>  static int soft_spi_probe(struct udevice *dev)
>  {
> -       struct spi_slave *slave = dev_get_parent_priv(dev);
>         struct soft_spi_platdata *plat = dev->platdata;
> -       int cs_flags, clk_flags;
>         int ret;
>
> -       cs_flags = (slave->mode & SPI_CS_HIGH) ? 0 : GPIOD_ACTIVE_LOW;
> -       clk_flags = (slave->mode & SPI_CPOL) ? GPIOD_ACTIVE_LOW : 0;
> -
>         if (gpio_request_by_name(dev, "cs-gpios", 0, &plat->cs,
> -                                GPIOD_IS_OUT | cs_flags) ||
> +                                GPIOD_IS_OUT) ||
>             gpio_request_by_name(dev, "gpio-sck", 0, &plat->sclk,
> -                                GPIOD_IS_OUT | clk_flags))
> +                                GPIOD_IS_OUT))
>                 return -EINVAL;
>
>         ret = gpio_request_by_name(dev, "gpio-mosi", 0, &plat->mosi,
> @@ -241,6 +236,20 @@ static int soft_spi_probe(struct udevice *dev)
>         return 0;
>  }
>
> +static int soft_spi_child_pre_probe(struct udevice *dev)
> +{
> +       struct udevice *bus = dev_get_parent(dev);
> +       struct dm_spi_slave_platdata *slave = dev_get_parent_platdata(dev);
> +       struct soft_spi_platdata *plat = bus->platdata;
> +
> +       if (!(slave->mode & SPI_CS_HIGH))
> +               plat->cs.flags |= GPIOD_ACTIVE_LOW;
> +       if (slave->mode & SPI_CPOL)
> +               plat->sclk.flags |= GPIOD_ACTIVE_LOW;

Can't we update the flags during .set_mode? it set_mode would trigger
during initial probe time and modes were updated as part of that.