From mboxrd@z Thu Jan  1 00:00:00 1970
From: Gregory CLEMENT <gregory.clement@bootlin.com>
Date: Wed, 26 Dec 2018 16:37:36 +0100
Subject: [U-Boot] [PATCH] spi: soft_spi: Fix null ptr when probing
	soft_spi.
In-Reply-To: <1545231209-32505-1-git-send-email-horatiu.vultur@microchip.com>
 (Horatiu Vultur's message of "Wed, 19 Dec 2018 15:53:29 +0100")
References: <1545231209-32505-1-git-send-email-horatiu.vultur@microchip.com>
Message-ID: <877efwb8ov.fsf@bootlin.com>
List-Id: <u-boot.lists.denx.de>
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To: u-boot@lists.denx.de

Hi Horatiu,

I am adding Daniel because actually this patch is needed to be able to
boot the Luton MIPS based platform. It is on this platform that we find
this issue.

Gregory
=20
 On mer., d=C3=A9c. 19 2018, Horatiu Vultur <horatiu.vultur@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@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 udevi=
ce *dev)
> =20
>  static int soft_spi_probe(struct udevice *dev)
>  {
> -	struct spi_slave *slave =3D dev_get_parent_priv(dev);
>  	struct soft_spi_platdata *plat =3D dev->platdata;
> -	int cs_flags, clk_flags;
>  	int ret;
> =20
> -	cs_flags =3D (slave->mode & SPI_CS_HIGH) ? 0 : GPIOD_ACTIVE_LOW;
> -	clk_flags =3D (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;
> =20
>  	ret =3D gpio_request_by_name(dev, "gpio-mosi", 0, &plat->mosi,
> @@ -241,6 +236,20 @@ static int soft_spi_probe(struct udevice *dev)
>  	return 0;
>  }
> =20
> +static int soft_spi_child_pre_probe(struct udevice *dev)
> +{
> +	struct udevice *bus =3D dev_get_parent(dev);
> +	struct dm_spi_slave_platdata *slave =3D dev_get_parent_platdata(dev);
> +	struct soft_spi_platdata *plat =3D bus->platdata;
> +
> +	if (!(slave->mode & SPI_CS_HIGH))
> +		plat->cs.flags |=3D GPIOD_ACTIVE_LOW;
> +	if (slave->mode & SPI_CPOL)
> +		plat->sclk.flags |=3D GPIOD_ACTIVE_LOW;
> +
> +	return 0;
> +}
> +
>  static const struct udevice_id soft_spi_ids[] =3D {
>  	{ .compatible =3D "spi-gpio" },
>  	{ }
> @@ -254,5 +263,6 @@ U_BOOT_DRIVER(soft_spi) =3D {
>  	.ofdata_to_platdata =3D soft_spi_ofdata_to_platdata,
>  	.platdata_auto_alloc_size =3D sizeof(struct soft_spi_platdata),
>  	.priv_auto_alloc_size =3D sizeof(struct soft_spi_priv),
> +	.child_pre_probe =3D soft_spi_child_pre_probe,
>  	.probe	=3D soft_spi_probe,
>  };
> --=20
> 2.7.4
>

--=20
Gregory Clement, Bootlin
Embedded Linux and Kernel engineering
http://bootlin.com