On 05/09/2016 06:33 PM, Chen-Yu Tsai wrote:
>> +
>> + power->supply = devm_power_supply_register(&pdev->dev,
>> + &axp20x_ac_power_desc, &psy_cfg);
>> + if (IS_ERR(power->supply))
>> + return PTR_ERR(power->supply);
>> +
>> + /* Request irqs after registering, as irqs may trigger immediately */
>> + for (i = 0; i < ARRAY_SIZE(irq_names); i++) {
>> + irq = platform_get_irq_byname(pdev, irq_names[i]);
>> + if (irq < 0) {
>> + dev_warn(&pdev->dev, "No IRQ for %s: %d\n",
>> + irq_names[i], irq);
>> + continue;
>> + }
>> + irq = regmap_irq_get_virq(axp20x->regmap_irqc, irq);
>> + r = devm_request_any_context_irq(&pdev->dev, irq,
>> + axp20x_irq_ac_handler, 0, DRVNAME, power);
>> + if (r < 0)
>> + dev_warn(&pdev->dev, "Error requesting %s IRQ: %d\n",
>> + irq_names[i], r);
>
> Won't missing IRQs hinder the usage of this driver / hardware?
> A power supply isn't much use if the system isn't told when
> it's gone.
>
That's a good point. The real question is: how would you handle missing
IRQs? I have looked at other uses of devm_request_any_context_irq, e.g.
in rtc-pm8xxx.c [0]. These other users often return an error code in the
probe function. That doesn't help the system, though: it still won't
notice if the power is unplugged in addition to missing the driver
completely.
It's probably best to provide the remaining (functional) parts of the
driver (reading from /sys/class..) even if the IRQs cannot be
registered. The code is pretty much the same in the axp20x-usb-power.
Michael
[0] http://lxr.free-electrons.com/source/drivers/rtc/rtc-pm8xxx.c#L490
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