[PATCH 03/22] dm: core: add support for device re-parenting

[Simon Glass]

Hi Claudiu,

On Wed, 29 Jul 2020 at 08:51, Claudiu Beznea
<claudiu.beznea at microchip.com> wrote:
>
> In common clock framework the relation b/w parent and child clocks is
> determined based on the udevice parent/child information. A clock
> parent could be changed based on devices needs. In case this is happen
> the functionalities for clock who's parent is changed are broken. Add
> a function that reparent a device. This will be used in clk-uclass.c
> to reparent a clock device.
>
> Signed-off-by: Claudiu Beznea <claudiu.beznea at microchip.com>
> ---
>  drivers/core/device.c        | 26 ++++++++++++++++++++++++++
>  include/dm/device-internal.h |  9 +++++++++
>  2 files changed, 35 insertions(+)

Please add a sandbox test for this function.

>
> diff --git a/drivers/core/device.c b/drivers/core/device.c
> index a7408d9c76c6..f149d55ac1e1 100644
> --- a/drivers/core/device.c
> +++ b/drivers/core/device.c
> @@ -267,6 +267,32 @@ int device_bind_by_name(struct udevice *parent, bool pre_reloc_only,
>                         devp);
>  }
>
> +int device_reparent(struct udevice *dev, struct udevice *new_parent)
> +{
> +       struct udevice *cparent;
> +       struct udevice *pos, *n;
> +
> +       if (!dev || !new_parent)
> +               return -EINVAL;
> +

This is an error by the caller and would not be present in production
code. Perhaps use assert()?

> +       if (!dev->parent)
> +               return -ENODEV;

This can't happen. Every device except for the root one has a parent.

> +
> +       list_for_each_entry_safe(pos, n, &dev->parent->child_head,
> +                                sibling_node) {
> +               if (pos->driver != dev->driver)
> +                       continue;
> +
> +               list_del(&dev->sibling_node);
> +               list_add_tail(&dev->sibling_node, &new_parent->child_head);
> +               dev->parent = new_parent;
> +
> +               return 0;
> +       }
> +
> +       return -ENODEV;

What does this error mean?

> +}
> +
>  static void *alloc_priv(int size, uint flags)
>  {
>         void *priv;
> diff --git a/include/dm/device-internal.h b/include/dm/device-internal.h
> index 294d6c18105a..c5d7ec0650f9 100644
> --- a/include/dm/device-internal.h
> +++ b/include/dm/device-internal.h
> @@ -84,6 +84,15 @@ int device_bind_by_name(struct udevice *parent, bool pre_reloc_only,
>                         const struct driver_info *info, struct udevice **devp);
>
>  /**
> + * device_reparent: reparent the device to a new parent
> + *
> + * @dev: pointer to device to be reparented
> + * @new_parent: pointer to new parent device
> + * @return 0 if OK, -ve on error
> + */
> +int device_reparent(struct udevice *dev, struct udevice *new_parent);
> +
> +/**
>   * device_ofdata_to_platdata() - Read platform data for a device
>   *
>   * Read platform data for a device (typically from the device tree) so that
> --
> 2.7.4
>

Regards,
Simon