Re: [PATCH] iio: mma8452: Fix 'mma8452_dt_ids' defined but not used compiler warning

[Hans de Goede <hdegoede@redhat.com>]

Hi,

On 2/14/22 11:54, Jonathan Cameron wrote:
> On Mon, 14 Feb 2022 10:18:50 +0100
> Hans de Goede <hdegoede@redhat.com> wrote:
> 
>> Commit 90adc57bd55a ("iio: mma8452: Fix probe failing when an
>> i2c_device_id is used") introduces a new: "'mma8452_dt_ids' defined
>> but not used" compiler warning.
>>
>> This is caused by the switch from of_match_device() (which takes a
>> pointer to this) to device_get_match_data(), combined with the use of
>> of_match_ptr() when setting of_match_table.
>>
>> We actually want mma8452_dt_ids to get optmized away when CONFIG_OF is
>> not set, so mark it as __maybe_unused to silence the warning.
>>
>> Fixes: 90adc57bd55a ("iio: mma8452: Fix probe failing when an i2c_device_id is used")
>> Reported-by: kernel test robot <lkp@intel.com>
>> Signed-off-by: Hans de Goede <hdegoede@redhat.com>
> 
> For this I'd rather drop the of_match_ptr() protection.

Ok, that is fine with me.

> We will need to do that anyway shortly as part of converting this
> to fully device properties and allowing ACPI PRP0001 which uses
> the of_match_table from ACPI.
> 
> We can now easily make that transition as (via Andy)
> https://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux.git/commit/?h=i2c/alert-for-acpi&id=ca0acb511c21738b32386ce0f85c284b351d919e
> 
> Anyhow, I can just fix it up on the original patch once I'm on the
> right computer.

Great thank you.

> I might also post patches to get rid
> of the of dependency completely if no one else gets there
> before me.

Regards,

Hans


>> ---
>> Note the 90adc57bd55a hash is from the jic23/iio.git testing branch, not
>> sure of it is stable. It is probably best to just squash this into the
>> original commit.
>> ---
>>  drivers/iio/accel/mma8452.c | 2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/drivers/iio/accel/mma8452.c b/drivers/iio/accel/mma8452.c
>> index 590d9431e1bd..1324bd515377 100644
>> --- a/drivers/iio/accel/mma8452.c
>> +++ b/drivers/iio/accel/mma8452.c
>> @@ -1529,7 +1529,7 @@ static int mma8452_reset(struct i2c_client *client)
>>  	return -ETIMEDOUT;
>>  }
>>  
>> -static const struct of_device_id mma8452_dt_ids[] = {
>> +static const struct of_device_id __maybe_unused mma8452_dt_ids[] = {
>>  	{ .compatible = "fsl,mma8451", .data = &mma_chip_info_table[mma8451] },
>>  	{ .compatible = "fsl,mma8452", .data = &mma_chip_info_table[mma8452] },
>>  	{ .compatible = "fsl,mma8453", .data = &mma_chip_info_table[mma8453] },
>