[PATCH] clk: introduce u-boot,ignore-clk-defaults

[Sean Anderson]

On 10/13/21 5:37 AM, Peng Fan (OSS) wrote:
> From: Peng Fan <peng.fan at nxp.com>
> 
> Current code has a force clk_set_defaults in multiple stages,
> U-Boot reuse the same device tree and Linux Kernel device tree,
> but we not register all the clks as Linux Kernel, so clk_set_defaults
> will fail and cause the clk provider registeration fail.
> 
> So introduce a new property to ignore the default settings which could
> be used by any node that wanna ignore default settings.
> 
> Signed-off-by: Peng Fan <peng.fan at nxp.com>
> ---
>   doc/device-tree-bindings/device.txt | 3 +++
>   drivers/clk/clk-uclass.c            | 3 +++
>   2 files changed, 6 insertions(+)
> 
> diff --git a/doc/device-tree-bindings/device.txt b/doc/device-tree-bindings/device.txt
> index 73ce2a3b5b..fe34ced268 100644
> --- a/doc/device-tree-bindings/device.txt
> +++ b/doc/device-tree-bindings/device.txt
> @@ -28,6 +28,9 @@ the acpi,compatible property.
>       Linux will only load the driver if the device can be detected (e.g. on I2C
>       bus). Note that this is an out-of-tree Linux feature.
>   
> +Common device bindings that could be shared listed below:
> + - u-boot,ignore-clk-defaults : ignore the assigned-clock-parents
> +   and assigned-clock-rates for a device that has the property.
>   
>   Example
>   -------
> diff --git a/drivers/clk/clk-uclass.c b/drivers/clk/clk-uclass.c
> index 493018b33e..6bf3179e7b 100644
> --- a/drivers/clk/clk-uclass.c
> +++ b/drivers/clk/clk-uclass.c
> @@ -376,6 +376,9 @@ int clk_set_defaults(struct udevice *dev, enum clk_defaults_stage stage)
>   	if (!dev_has_ofnode(dev))
>   		return 0;
>   
> +	if (ofnode_get_property(dev_ofnode(dev), "u-boot,ignore-clk-defaults", NULL))
> +		return 0;
> +
>   	/*
>   	 * To avoid setting defaults twice, don't set them before relocation.
>   	 * However, still set them for SPL. And still set them if explicitly
> 

Why not just have the property ignore errors?

In the long term, it may be better to standardize that e.g. ENOENT means
that the clock doesn't exist. That way we can skip setting the defaults.
ENOSYS should probably be treated the same way (warn, but don't fail).

--Sean