[PATCH V3] ARM: shmobile: Rework the PMIC IRQ line quirk

[marek.vasut@gmail.com (Marek Vasut)]

On 06/11/2018 04:30 PM, Geert Uytterhoeven wrote:
> Hi Marek,
> 
> On Mon, Jun 11, 2018 at 4:19 PM Marek Vasut <marek.vasut@gmail.com> wrote:
>> On 06/11/2018 04:10 PM, Geert Uytterhoeven wrote:
>>> On Mon, Jun 11, 2018 at 4:04 PM Marek Vasut <marek.vasut@gmail.com> wrote:
>>>> On 06/11/2018 03:49 PM, Geert Uytterhoeven wrote:
>>>>> On Mon, Jun 11, 2018 at 3:39 PM Marek Vasut <marek.vasut@gmail.com> wrote:
>>>>>> On 06/11/2018 03:03 PM, Geert Uytterhoeven wrote:
>>>>>>> On Mon, Jun 11, 2018 at 2:15 PM Marek Vasut <marek.vasut@gmail.com> wrote:
>>>>>>>> On 06/11/2018 11:56 AM, Geert Uytterhoeven wrote:
>>>>>>>>> On Mon, Jun 4, 2018 at 7:59 PM Marek Vasut <marek.vasut@gmail.com> wrote:
>>>>>>>>>> Rather than hard-coding the quirk topology, which stopped scaling,
>>>>>>>>>> parse the information from DT. The code looks for all compatible
>>>>>>>>>> PMICs -- da9036 and da9210 -- and checks if their IRQ line is tied
>>>>>>>>>> to the same pin. If so, the code sends a matching sequence to the
>>>>>>>>>> PMIC to deassert the IRQ.
>>>>>
>>>>>>>>>> +               ret = of_property_read_u32(np, "reg", &addr);
>>>>>>>>>> +               if (ret)
>>>>>>>>>> +                       return ret;
>>>>>>>>>
>>>>>>>>> I think it's safer to skip this entry and continue, after calling
>>>>>>>>> kfree(quirk), of course.
>>>>>>>>>
>>>>>>>>>> +
>>>>>>>>>> +               quirk->id = id;
>>>>>>>>>> +               quirk->i2c_msg.addr = addr;
>>>>>>>>>> +               quirk->shared = false;
>>>>>>>>>> +
>>>>>>>>>> +               ret = of_irq_parse_one(np, 0, &quirk->irq_args);
>>>>>>>>>> +               if (ret)
>>>>>>>>>> +                       return ret;
>>>>>>>>>
>>>>>>>>> kfree(quirk) and continue...
>>>>>>>>
>>>>>>>> I wonder if it shouldn't rather free the entire list and abort ?
>>>>>>>
>>>>>>> "Be strict when sending, be liberal when receiving."
>>>>>>
>>>>>> Meaning ? I think "the language barrier is protecting me" (TM)
>>>>>
>>>>> Do the best you can, given the buggy DT you received.
>>>>> I.e. don't fail completely, just ignore the bad device node, and continue.
>>>>
>>>> But if you ignore node, you might as well ignore one which is shared and
>>>> then the system crashes due to IRQ storm anyway. So hum, what can we do ?
>>>
>>> Correct. If it's a critical node, it will crash regardless.
>>> If it's a non-critical node, you have the choice between aborting and crashing,
>>> or ignoring and keeping the system alive. Your call.
>>
>> But wait, since we control which machines this code runs on , can't we
>> assure they have valid DTs ? This situation with invalid DT starts to
>> look a bit hypothetical to me.
> 
> That assumes you keep the list of machines to check, and don't want to fix the
> issue automatically when detected (on any R-Car Gen2 or RZ/G1 platform, so
> you still need to check for r8a779[0-4] and r8a774[23457]).

Yes, I want to keep a list of machines to check, to be _sure_ some
machine doesn't randomly blow up.

> Anyway, as we care about booting old DTBs on new kernels (for a while), we
> have a few more release cycles to bikeshed ;-)

I was about to ask if this patch then makes any sense or not.

-- 
Best regards,
Marek Vasut