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

[Ahmad Fatoum <a.fatoum@pengutronix.de>]

On 10.03.23 15:46, Michael Riesch wrote:
> 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?

Not sure. I'd need to reproduce. Is there an easy way to adjust a mainline
board to get the same behavior? Is your downstream board code inside a
board driver probe function or is it raw in an initcall?

Cheers,
Ahmad

> 
> 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);
> 

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