Re: [PATCH v2 2/4] of: support of_ensure_probed for top-level machine device

[Michael Riesch <michael.riesch@wolfvision.net>]

Hi Ahmad,

On 2/10/23 17:53, Ahmad Fatoum wrote:
> Creation of a machine device for the top-level node has special casing
> in of_probe(). Export of_platform_device_create_root(), so it's possible
> to ensure probe of the machine device. This is required when doing
> of_devices_ensure_probed_by_dev_id with the machine compatible.
> 
> Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>

This patch breaks my board code that calls
of_device_ensure_probed_by_alias() in the probe() of the board driver.
The function always returns -ENODEV.

Do I have to adjust my (downstream) board code somehow?

Thanks and best regards,
Michael

> ---
> v1 -> v2:
>   - new patch to facilitate patch 3/4
> ---
>  drivers/of/base.c     | 10 +++++++---
>  drivers/of/platform.c |  2 +-
>  include/of.h          |  1 +
>  3 files changed, 9 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/of/base.c b/drivers/of/base.c
> index 1221cd316cdf..7ba0655401cc 100644
> --- a/drivers/of/base.c
> +++ b/drivers/of/base.c
> @@ -2512,13 +2512,13 @@ static int of_probe_memory(void)
>  }
>  mem_initcall(of_probe_memory);
>  
> -static void of_platform_device_create_root(struct device_node *np)
> +struct device *of_platform_device_create_root(struct device_node *np)
>  {
>  	static struct device *dev;
>  	int ret;
>  
>  	if (dev)
> -		return;
> +		return dev;
>  
>  	dev = xzalloc(sizeof(*dev));
>  	dev->id = DEVICE_ID_SINGLE;
> @@ -2526,8 +2526,12 @@ static void of_platform_device_create_root(struct device_node *np)
>  	dev_set_name(dev, "machine");
>  
>  	ret = platform_device_register(dev);
> -	if (ret)
> +	if (ret) {
>  		free_device(dev);
> +		return ERR_PTR(ret);
> +	}
> +
> +	return dev;
>  }
>  
>  static const struct of_device_id reserved_mem_matches[] = {
> diff --git a/drivers/of/platform.c b/drivers/of/platform.c
> index 69f9ddec50ca..11cde8924f94 100644
> --- a/drivers/of/platform.c
> +++ b/drivers/of/platform.c
> @@ -421,7 +421,7 @@ static struct device *of_device_create_on_demand(struct device_node *np)
>  
>  	parent = of_get_parent(np);
>  	if (!parent)
> -		return NULL;
> +		return of_platform_device_create_root(np);
>  
>  	if (!np->dev && parent->dev) {
>  		ret = device_detect(parent->dev);
> diff --git a/include/of.h b/include/of.h
> index 1a38774615a4..63c90255cd64 100644
> --- a/include/of.h
> +++ b/include/of.h
> @@ -298,6 +298,7 @@ extern void of_platform_device_dummy_drv(struct device *dev);
>  extern int of_platform_populate(struct device_node *root,
>  				const struct of_device_id *matches,
>  				struct device *parent);
> +extern struct device *of_platform_device_create_root(struct device_node *np);
>  extern struct device *of_find_device_by_node(struct device_node *np);
>  extern struct device *of_device_enable_and_register(struct device_node *np);
>  extern struct device *of_device_enable_and_register_by_name(const char *name);