Hi,
On 3/16/23 15:07, Krzysztof Kozlowski wrote:
> On 16/03/2023 13:50, Hans de Goede wrote:
>> Hi Krzysztof,
>>
>> On 3/12/23 14:26, Krzysztof Kozlowski wrote:
>>> The driver can be compile tested as built-in making certain data unused:
>>>
>>> drivers/platform/olpc/olpc-xo175-ec.c:737:35: error: ‘olpc_xo175_ec_id_table’ defined but not used [-Werror=unused-const-variable=]
>>>
>>> Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@xxxxxxxxxx>
>>> ---
>>> drivers/platform/olpc/olpc-xo175-ec.c | 2 +-
>>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>>
>>> diff --git a/drivers/platform/olpc/olpc-xo175-ec.c b/drivers/platform/olpc/olpc-xo175-ec.c
>>> index 4823bd2819f6..04573495ef5a 100644
>>> --- a/drivers/platform/olpc/olpc-xo175-ec.c
>>> +++ b/drivers/platform/olpc/olpc-xo175-ec.c
>>> @@ -734,7 +734,7 @@ static const struct of_device_id olpc_xo175_ec_of_match[] = {
>>> };
>>> MODULE_DEVICE_TABLE(of, olpc_xo175_ec_of_match);
>>>
>>> -static const struct spi_device_id olpc_xo175_ec_id_table[] = {
>>> +static const struct spi_device_id olpc_xo175_ec_id_table[] __maybe_unused = {
>>> { "xo1.75-ec", 0 },
>>> {}
>>> };
>>> MODULE_DEVICE_TABLE(spi, olpc_xo175_ec_id_table);
>>
>> The whole presence of the olpc_xo175_ec_id_table[] seems to make little sense.
>>
>> This should be referenced by:
>>
>> static struct spi_driver olpc_xo175_ec_spi_driver = {
>>
>> Like this:
>>
>> .probe = olpc_xo175_ec_probe,
>> .remove = olpc_xo175_ec_remove,
>> + .id_table = olpc_xo175_ec_id_table,
>
> Yes, it should.
>
>>
>> Otherwise those ids cannot be used to load the driver the non DT/of way. Since the driver assumingly does actually bind already this means that it is only used the DT/of way and it seems to me that the whole olpc_xo175_ec_id_table[] can be removed entirely.
>>
>> Exposing modaliases for a non supported way of binding the driver does not really seem useful ?
>
> However binding the device and module loading (uevent) uses sometimes
> different pieces. Maybe something changed in kernel, but sometime ago
> certain buses where sending uevent for module loading with one ID (e.g.
> platform or spi bus) but device matching would be according to OF. Thus
> if you did not have entries in spi_device_id, the module would not autoload.
>
> It was exactly the case for example here:
> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=c46ed2281bbe4b84e6f3d4bdfb0e4e9ab813fa9d&context=30&ignorews=0&dt=0
>
> You needed spi_device_id for proper module autoloading.
>
> Unless something change in between in the kernel?
Looks like your right, the spi_uevent() code always emits "spi:xxxxxxx" style modalias even for dt/of enumerated devices:
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/spi/spi.c#n398
So the table needs to stay.
Can you do a v2 (of just this patch) adding an id_table entry to olpc_xo175_ec_spi_driver rather then using __maybe_unused ?
Regards,
Hans
