Re: [PATCH 1/2] genirq: add chip_{suspend,resume} PM support to irq_chip

[Florian Fainelli <f.fainelli@gmail.com>]

On 20/06/15 07:11, Thomas Gleixner wrote:
> On Fri, 19 Jun 2015, Brian Norris wrote:
>> This patch adds a second set of suspend/resume hooks to irq_chip, this
>> time to represent *chip* suspend/resume, rather than IRQ suspend/resume.
>> These callbacks will always be called for an irqchip and are based on
>> the per-chip irq_chip_generic struct, rather than the per-IRQ irq_data
>> struct.
> 
> There is no per-chip irq_chip_generic struct. It's only there if the
> irq chip has been instantiated as a generic chip.
>  
>>  /**
>>   * struct irq_chip - hardware interrupt chip descriptor
>>   *
>> @@ -317,6 +319,12 @@ static inline irq_hw_number_t irqd_to_hwirq(struct irq_data *d)
>>   * @irq_suspend:	function called from core code on suspend once per chip
>>   * @irq_resume:		function called from core code on resume once per chip
>>   * @irq_pm_shutdown:	function called from core code on shutdown once per chip
>> + * @chip_suspend:	function called from core code on suspend once per
>> + *			chip; for handling chip details even when no interrupts
>> + *			are in use
>> + * @chip_resume:	function called from core code on resume once per chip;
>> + *			for handling chip details even when no interrupts are
>> + *			in use
>>   * @irq_calc_mask:	Optional function to set irq_data.mask for special cases
>>   * @irq_print_chip:	optional to print special chip info in show_interrupts
>>   * @irq_request_resources:	optional to request resources before calling
>> @@ -357,6 +365,8 @@ struct irq_chip {
>>  	void		(*irq_suspend)(struct irq_data *data);
>>  	void		(*irq_resume)(struct irq_data *data);
>>  	void		(*irq_pm_shutdown)(struct irq_data *data);
>> +	void		(*chip_suspend)(struct irq_chip_generic *gc);
>> +	void		(*chip_resume)(struct irq_chip_generic *gc);
> 
> I really don't want to set a precedent for random (*foo)(*bar)
> callbacks.
>  
>> +
>> +		if (ct->chip.chip_suspend)
>> +			ct->chip.chip_suspend(gc);
> 
> So wouldn't it be the more intuitive solution to make this a callback
> in the struct gc itself?

Brian can correct me, but his approach is more generic, if there is
another irqchip driver needing a similar infrastructure, this would be
already there, and directly usable. Maybe all we need to is to change
the chip_suspend/resume arguments to pass a reference to irq_chip instead?

I can go ahead and rewrite that part of the patch to make this is
exclusively located to the irq_chip_generic structure instead.
--
Florian