[U-Boot] [PATCH 3/3] core: Add dev_{disable,enable}_by_path

[Simon Glass]

Hi Mario,

On 28 March 2018 at 20:37, Mario Six <mario.six at gdsys.cc> wrote:
> We cannot use device structures to disable devices, since getting
> them with the API functions would bind and activate the device, which
> would fail if the underlying device does not exist.
>
> Hence, add a function to disable devices by path in a live device tree.

What is the use case here? Is it to disable something after it has
already been bound / probed? Why can this not be done in the device
tree before U-Boot starts?

Also this needs a test.

>
> Signed-off-by: Mario Six <mario.six at gdsys.cc>
> ---
>  drivers/core/device.c | 36 ++++++++++++++++++++++++++++++++++++
>  include/dm/device.h   | 20 ++++++++++++++++++++
>  2 files changed, 56 insertions(+)
>
> diff --git a/drivers/core/device.c b/drivers/core/device.c
> index 940a153c58..c627453bb9 100644
> --- a/drivers/core/device.c
> +++ b/drivers/core/device.c
> @@ -724,3 +724,39 @@ bool of_machine_is_compatible(const char *compat)
>
>         return !fdt_node_check_compatible(fdt, 0, compat);
>  }
> +
> +#ifdef CONFIG_OF_LIVE
> +int dev_disable_by_path(const char *path)
> +{
> +       ofnode node = np_to_ofnode(of_find_node_by_path(path));

Please see ofnode_path()

> +       struct udevice *dev = ofnode_dev(node);
> +       int res;
> +
> +       res = device_remove(dev, DM_REMOVE_NORMAL);
> +       if (res)
> +               return res;
> +
> +       res = device_unbind(dev);
> +       if (res)
> +               return res;
> +
> +       return ofnode_disable(node);
> +}
> +
> +int dev_enable_by_path(const char *path)
> +{
> +       ofnode node = np_to_ofnode(of_find_node_by_path(path));
> +       ofnode pnode = ofnode_get_parent(node);
> +       struct udevice *parent = ofnode_dev(pnode);
> +       int res;
> +
> +       if (!parent)
> +               return -EINVAL;
> +
> +       res = ofnode_enable(node);
> +       if (res)
> +               return res;
> +
> +       return lists_bind_fdt(parent, node, NULL);
> +}
> +#endif /* CONFIG_OF_LIVE */
> diff --git a/include/dm/device.h b/include/dm/device.h
> index 7786b1cf4e..f55907966a 100644
> --- a/include/dm/device.h
> +++ b/include/dm/device.h
> @@ -586,6 +586,26 @@ bool device_is_compatible(struct udevice *dev, const char *compat);
>   */
>  bool of_machine_is_compatible(const char *compat);
>
> +#ifdef CONFIG_OF_LIVE
> +
> +/**
> + * dev_disable_by_path() - Disable a device given its device tree path
> + *
> + * @path:      The device tree path identifying the device to be disabled
> + * @return 0 on success, -ve on error
> + */
> +int dev_disable_by_path(const char *path);
> +
> +/**
> + * dev_enable_by_path() - Enable a device given its device tree path
> + *
> + * @path:      The device tree path identifying the device to be enabled
> + * @return 0 on success, -ve on error
> + */
> +int dev_enable_by_path(const char *path);
> +
> +#endif /* CONFIG_OF_LIVE */
> +
>  /**
>   * device_is_on_pci_bus - Test if a device is on a PCI bus
>   *
> --
> 2.16.1
>

Regards,
Simon