Messages in this thread | | | From | Andy Shevchenko <> | Date | Wed, 4 Jul 2018 13:19:26 +0300 | Subject | Re: [PATCH v2 2/2] IIO: st_accel_i2c.c: Use probe_new() instead of probe() |
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Summon Javier to the discussion. For my opinion he is an expert in this topic.
On Wed, Jul 4, 2018 at 12:42 PM, Nikolaus Voss <nikolaus.voss@loewensteinmedical.de> wrote: > On Wed, 4 Jul 2018, Andy Shevchenko wrote: >> On Wed, Jul 4, 2018 at 12:09 PM, Nikolaus Voss >> <nikolaus.voss@loewensteinmedical.de> wrote: >>> On Wed, 4 Jul 2018, Andy Shevchenko wrote: >>>> On Wed, Jul 4, 2018 at 9:37 AM, Nikolaus Voss >>>> <nikolaus.voss@loewensteinmedical.de> wrote: >>>>> On Wed, 4 Jul 2018, Andy Shevchenko wrote: >>>>>> On Tue, Jul 3, 2018 at 9:06 AM, Nikolaus Voss >>>>>> <nikolaus.voss@loewensteinmedical.de> wrote:
>>>>>>> struct i2c_device_id argument of probe() is not used, so use >>>>>>> probe_new() >>>>>>> instead.
>>>>>> This makes... >>>>>> >>>>>>> MODULE_DEVICE_TABLE(i2c, st_accel_id_table);
>>>>>> ...this table obsolete IIUC. At least that's what I did when switched >>>>>> to ->probe_new() in some drivers. >>>>>> >>>>>> If I'm mistaken (again? :-) ) I would hear from someone to point me >>>>>> how it can be used after a switch.
>>>>> It is still used by the i2c-core in i2c_device_match() if DT and ACPI >>>>> matching fails.
>>>>> And it is used to create the corresponding modaliases for >>>>> driver loading.
>>>> My question is "How?!" >>>> I don't really see any points to match against it after switching to >>>> ->probe_new(). >>>> >>>> Could you point me to the code path in i2c (or OF?) core for that?
>>> As written above in i2c-core-base.c: i2c_device_match() -> >>> i2c_match_id(driver->id_table,... >>> >>> This is used for driver matching before probe() or probe_new() of the >>> device >>> driver can be called. probe_new() actually is a function signature change >>> only.
>> Okay, IIUC we got a match. What should we do with it? The table is not >> used in ->probe_new() (in i2c core), so, you can't say which line >> matched there.
> The table is not used by the driver, but is necessary to > > a) bind an i2c device declared via i2c_board_info with type field set > to one of the names of the i2c_device_id table to this driver > b) bind an i2c device declared via DT or ACPI but with no match in of_id/ > acpi_id table but an i2c_device_id table match to this driver (fallback > matching) > c) create the right modaliases at compile time for this driver to make > module auto-loading work in case of a) and b)
Javier, just a summary of the above. Nikolaus switched one driver to use ->probe_new() hook and left i2c ID table at the same time. My understanding that this table is not anymore in use.
But I have to admit I didn't see entire picture of this. Can you shed a light?
-- With Best Regards, Andy Shevchenko
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