Re: [PATCH v2 2/7] driver: Add rescan hook to struct device

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

On 09.03.23 13:54, Ahmad Fatoum wrote:
> On 09.03.23 12:52, Sascha Hauer wrote:
>> When devices are enabled with a device tree overlay the newly enabled
>> devices can be probed by doing a of_probe(). This works fine for the
>> regular platform devices, but doesn't work for devices which are not
>> probed by the core, but by the subsystem. Prominent examples are I2C or
>> SPI devices.
>>
>> This patch adds a struct device::rescan hook that subsystems can
>> implement to trigger rescanning the device nodes.
>>
>> Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
> 
> Reviewed-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
> 
>> ---
>>  drivers/of/platform.c | 11 +++++------
>>  include/driver.h      |  6 ++++++
>>  2 files changed, 11 insertions(+), 6 deletions(-)
>>
>> diff --git a/drivers/of/platform.c b/drivers/of/platform.c
>> index edb082b106..2e9abe32bc 100644
>> --- a/drivers/of/platform.c
>> +++ b/drivers/of/platform.c
>> @@ -153,8 +153,10 @@ struct device *of_platform_device_create(struct device_node *np,
>>  	 * Linux uses the OF_POPULATED flag to skip already populated/created
>>  	 * devices.
>>  	 */
>> -	if (np->dev)
>> +	if (np->dev) {
>> +		device_rescan(np->dev);
>>  		return np->dev;
>> +	}
>>  
>>  	/* count the io resources */
>>  	if (of_can_translate_address(np))
>> @@ -420,11 +422,8 @@ static struct device *of_device_create_on_demand(struct device_node *np)
>>  	if (!parent)
>>  		return NULL;
>>  
>> -	if (!np->dev && parent->dev) {
>> -		ret = device_detect(parent->dev);
>> -		if (ret && ret != -ENOSYS)
>> -			return ERR_PTR(ret);
>> -	}
>> +	if (!np->dev && parent->dev)
>> +		device_rescan(parent->dev);
>>  
>>  	if (!np->dev)
>>  		pr_debug("Creating device for %s\n", np->full_name);
>> diff --git a/include/driver.h b/include/driver.h
>> index f53668711b..91e1f01974 100644
>> --- a/include/driver.h
>> +++ b/include/driver.h
>> @@ -91,6 +91,7 @@ struct device {
>>  	 * when the driver should actually detect client devices
>>  	 */
>>  	int     (*detect) (struct device *);
>> +	void	(*rescan) (struct device *);
>>  
>>  	/*
>>  	 * if a driver probe is deferred, this stores the last error
>> @@ -158,7 +159,12 @@ static inline void put_device(struct device *dev) {}
>>  void free_device_res(struct device *dev);
>>  void free_device(struct device *dev);
>>  
>> +static inline void device_rescan(struct device *dev)
>> +{
>> +	if (dev->rescan)
>> +		dev->rescan(dev);
>>  
>> +}

Nitpick: add brace a liner higher, so the blank line is after it

>>  /* Iterate over a devices children
>>   */
>>  #define device_for_each_child(dev, child) \
> 

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