Re: [PATCH v3] mfd: syscon: Add hardware spinlock support

[Baolin Wang]

Hi Arnd,

On 29 November 2017 at 18:07, Arnd Bergmann <arnd@xxxxxxxx> wrote:
> On Mon, Nov 20, 2017 at 7:54 AM, Baolin Wang <baolin.wang@xxxxxxxxxx> wrote:
>> Some system control registers need hardware spinlock to synchronize
>> between the multiple subsystems, so we should add hardware spinlock
>> support for syscon.
>>
>
>> @@ -87,6 +88,12 @@ static struct syscon *of_syscon_register(struct device_node *np)
>>         if (ret)
>>                 reg_io_width = 4;
>>
>> +       ret = of_hwspin_lock_get_id(np, 0);
>> +       if (ret > 0) {
>> +               syscon_config.hwlock_id = ret;
>> +               syscon_config.hwlock_mode = HWLOCK_IRQSTATE;
>> +       }
>
> Hi Baolin,
>
> The error handling here seems insufficient, I think we have to treat
> the following cases separately:
>
> - ret>0 (this is fine)
> - no spinlock in DT: of_hwspin_lock_get_id currently returns -EINVAL,
>   we probably want to use a different return code (maybe -ESRCH ?)
>   here so we can tell the difference beween no spinlock, and an
>   invalid spinlock
> - deferred probing: if the spinlock is there but the driver is not
>   yet available, we may need to propagate the -EPROBE_DEFER
>   here
> - other error: this would probably be a fatal condition here, and
>   we should print a warning and clean up.

You are correct and I will add some error handling. Thanks for your comments.

-- 
Baolin.wang
Best Regards