Re: [PATCH] i2c: implement detect callback for virtual adapter device as well

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

On 25.01.23 10:27, Marco Felsch wrote:
> Hi Ahmad,
> 
> On 23-01-25, Ahmad Fatoum wrote:
>> For MMCs, we already support detect on both the hardware device and the
>> mmcX virtual device. Let's do the same for i2c, so users have the option
>> to do `detect i2c0` instead of `detect 30a30000.i2c@30a30000.of`.
> 
> nice :)

Glad you like it. Only usecase I have for this is detecting an I2C device
tat was added by an overlay to a bus that was already probed beforehand.

I2C bus probe is still on-by-default, though we could change
that in future.

I still need to wire this into the overlay code to call bus detect automatically.

> 
>> `detect -a` still works as expected, as the detect callback is a no-op
>> if everything on the bus is already registered.
>>
>> Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
> 
> Reviewed-by: Marco Felsch <m.felsch@pengutronix.de>
> 
>> ---
>>  drivers/i2c/i2c.c | 13 +++++++++++--
>>  1 file changed, 11 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/i2c/i2c.c b/drivers/i2c/i2c.c
>> index 7e1cea49f3b6..4ecf7bb163e6 100644
>> --- a/drivers/i2c/i2c.c
>> +++ b/drivers/i2c/i2c.c
>> @@ -472,6 +472,14 @@ int of_i2c_register_devices_by_node(struct device_node *node)
>>  }
>>  
>>  static int i2c_bus_detect(struct device *dev)
>> +{
>> +	struct i2c_adapter *adap = container_of(dev, struct i2c_adapter, dev);
>> +
>> +	of_i2c_register_devices(adap);
>> +	return 0;
>> +}
>> +
>> +static int i2c_hw_detect(struct device *dev)
>>  {
>>  	struct i2c_adapter *adap;
>>  
>> @@ -712,6 +720,7 @@ int i2c_add_numbered_adapter(struct i2c_adapter *adapter)
>>  	}
>>  
>>  	adapter->dev.id = adapter->nr;
>> +	adapter->dev.detect = i2c_bus_detect;
>>  	dev_set_name(&adapter->dev, "i2c");
>>  
>>  	ret = register_device(&adapter->dev);
>> @@ -726,8 +735,8 @@ int i2c_add_numbered_adapter(struct i2c_adapter *adapter)
>>  	hw_dev = adapter->dev.parent;
>>  	if (hw_dev && dev_of_node(hw_dev)) {
>>  		if (!hw_dev->detect)
>> -			hw_dev->detect = i2c_bus_detect;
>> -		i2c_bus_detect(hw_dev);
>> +			hw_dev->detect = i2c_hw_detect;
>> +		i2c_hw_detect(hw_dev);
>>  	}
>>  
>>  	return 0;
>> -- 
>> 2.30.2
>>
>>
>>
> 

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