linux-kernel - Re: [PATCH v8] mfd: Add Cherry Trail Whiskey Cove PMIC driver

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Date:   Sun, 4 Jun 2017 14:52:59 +0200
From:   Hans de Goede <hdegoede@...hat.com>
To:     Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
        Lee Jones <lee.jones@...aro.org>,
        Andy Shevchenko <andy.shevchenko@...il.com>
Cc:     Wolfram Sang <wsa@...-dreams.de>,
        Paul Gortmaker <paul.gortmaker@...driver.com>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        Bin Gao <bin.gao@...el.com>,
        Felipe Balbi <felipe.balbi@...ux.intel.com>
Subject: Re: [PATCH v8] mfd: Add Cherry Trail Whiskey Cove PMIC driver

Hi,

On 30-05-17 15:05, Andy Shevchenko wrote:
> On Tue, 2017-05-30 at 13:20 +0100, Lee Jones wrote:
>> On Tue, 30 May 2017, Andy Shevchenko wrote:
>>
>>> On Tue, May 30, 2017 at 12:02 PM, Lee Jones <lee.jones@...aro.org>
>>> wrote:
>>>> On Tue, 23 May 2017, Hans de Goede wrote:
>>>>> +static const struct i2c_device_id cht_wc_i2c_id[] = {
>>>>> +     { }
>>>>> +};
>>>>
>>>> What's the point in this empty table?
>>>
>>> This is artifact of I2C framework, otherwise if will be not
>>> enumerated.
>>>
>>> +Wolfram.
>>>
>>> Wolfram, can we fix this? (In case we have either ACPI table or OF
>>> table there is no need to oblige providing empty legacy table)
>>
>> I think I fixed this already.
>>
>> Hint: `git grep probe_new -- drivers/i2c` >
> Indeed.
> Thanks for a hint!

Unfortunately switching to probe_new (which I've done for
the upcoming v9 of the MFD CHT Whiskey Cove driver) is not enough,
as i2c_device_probe() (from drivers/i2c/i2c-core) still has:

         /*
          * An I2C ID table is not mandatory, if and only if, a suitable Device
          * Tree match table entry is supplied for the probing device.
          */
         if (!driver->id_table &&
             !i2c_of_match_device(dev->driver->of_match_table, client))
                 return -ENODEV;

So before we can remove the empty id tables from various ACPI
drivers we first need to extend this check to also work with
ACPI device matching.

Regards,

Hans