Re: [PATCH v4 2/2] iio: light: vcnl4000: add support for Capella CM36686 and CM36672P

[Erikas Bitovtas <xerikasxx@gmail.com>]

On 2/14/26 8:09 PM, Jonathan Cameron wrote:
>> ---
>>  drivers/iio/light/vcnl4000.c | 40 ++++++++++++++++++++++++++++++++++++++++
>>  1 file changed, 40 insertions(+)
>>
>> diff --git a/drivers/iio/light/vcnl4000.c b/drivers/iio/light/vcnl4000.c
>> index a36c23813679..1f8f4e4586f4 100644
>> --- a/drivers/iio/light/vcnl4000.c
>> +++ b/drivers/iio/light/vcnl4000.c
>> @@ -185,6 +185,7 @@ static const int vcnl4040_ps_oversampling_ratio[] = {1, 2, 4, 8};
>>  #define VCNL4000_SLEEP_DELAY_MS	2000 /* before we enter pm_runtime_suspend */
>>  
>>  enum vcnl4000_device_ids {
>> +	CM36672P,
>>  	VCNL4000,
>>  	VCNL4010,
>>  	VCNL4040,
>> @@ -235,6 +236,8 @@ struct vcnl4000_chip_spec {
>>  };
>>  
>>  static const struct i2c_device_id vcnl4000_id[] = {
>> +	{ "cm36672p", CM36672P },
>> +	{ "cm36686", VCNL4040 },
>>  	{ "vcnl4000", VCNL4000 },
>>  	{ "vcnl4010", VCNL4010 },
>>  	{ "vcnl4020", VCNL4010 },
>> @@ -1842,6 +1845,22 @@ static const struct iio_chan_spec vcnl4040_channels[] = {
>>  	}
>>  };
> 
> ...
> 
>>  	[VCNL4000] = {
>>  		.prod = "VCNL4000",
>>  		.init = vcnl4000_init,
>> @@ -2033,6 +2065,14 @@ static int vcnl4000_probe(struct i2c_client *client)
>>  }
>>  
>>  static const struct of_device_id vcnl_4000_of_match[] = {
>> +	{
>> +		.compatible = "capella,cm36672p",
>> +		.data = (void *)CM36672P,
>> +	},
>> +	{
>> +		.compatible = "capella,cm36686",
>> +		.data = (void *)VCNL4040,
> 
> Is this necessary? I 'think' if you drop it we'll match instead
> on the vcnl4040 fallback and then the access to the data will be
> through the stripped name only bit of the compatible (first entry, not
> the fallback so cm36686 in this case). So you do need the cm36686
> entry in the i2c_device_id table above. Probably better to keep
> this here to avoid having to reason this out - but perhaps a
> comment to that affect would be useful (assuming you verify my
> reasoning).
>
After I removed the entry for "capella,cm36686", I received the "Unable
to handle kernel NULL pointer dereference" error in dmesg. And at least
stk3310 driver includes a compatible entry both for the device (stk3013)
and for the fallback (stk3310). So my assumption is that this entry is
needed.
I could include a comment explaining that cm36686 is fully compatible
with vcnl4040, however, if that is necessary.
> As Andy suggested moving away from enum values an towards
> direct pointers to the chip_info structures + drop the
> i2c_client_get_device_id() in favour of i2c_get_match_data() which
> uses the right firmware entry to get the data in all cases is the
> right long term solution and avoids an association being necessary
> between the two tables.
> 
> Jonathan
> 
> 
> 
> 
>> +	},
>>  	{
>>  		.compatible = "vishay,vcnl4000",
>>  		.data = (void *)VCNL4000,
>>
>