Subject: Re: [PATCH -next v2 1/2] device property: Return -ENXIO if there is no suitable FW interface

From: Guenter Roeck <[email-masked]>
Date: Wed, 26 Aug 2015 16:25:59 -0700

On 08/26/2015 04:37 PM, Rafael J. Wysocki wrote:
> On Wednesday, August 26, 2015 01:20:44 PM Guenter Roeck wrote:
>> Return -ENXIO if device property array access functions don't find
>> a suitable firmware interface.
>>
>> This lets drivers decide if they should use available platform data
>> instead.
>>
>> Cc: Rafael J. Wysocki <[email-masked]>
>> Signed-off-by: Guenter Roeck <[email-masked]>
>> ---
>> v2: Added patch
>>
>>   drivers/base/property.c | 7 +++++++
>>   1 file changed, 7 insertions(+)
>>
>> diff --git a/drivers/base/property.c b/drivers/base/property.c
>> index 287704d680bf..9600b824d138 100644
>> --- a/drivers/base/property.c
>> +++ b/drivers/base/property.c
>> @@ -69,6 +69,9 @@ static int pset_prop_read_array(struct property_set *pset, const char *name,
>>   	struct property_entry *prop;
>>   	unsigned int item_size;
>>
>> +	if (!pset)
>> +		return -ENXIO;
>> +
>
> This isn't exactly straightforward, because it relies on the fact that
> pset_prop_read_array() is the last thing tried by FWNODE_PROP_READ_ARRAY()
> and fwnode_property_read_string_array().  A comment about that might be
> helpful.
>
I see two options: Add a comment above, or change the calling code to

	...
	else if (is_pset(fwnode))
		return pset_prop_read_array(to_pset(fwnode), propname,
                          	            DEV_PROP_STRING, val, nval);
	return -ENXIO;

which would make it obvious and avoid side effects if the code is changed
later on. Would you be ok with this ?

Thanks,
Guenter