linux-kernel - Re: [PATCH] regmap: irq: clear status when disable irq

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Message-ID: <CAK=oMXfMAafBcFOF=Ct2_ZfYNY6eYW7oHV4kBeQA=hUSf5VnPw@mail.gmail.com>
Date:	Tue, 15 Oct 2013 20:03:28 +0800
From:	Yi Zhang <yizhang.mrvl@...il.com>
To:	Mark Brown <broonie@...nel.org>
Cc:	Yi Zhang <yizhang@...vell.com>, zhouqiao@...vell.com,
	zhangwm@...vell.com, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] regmap: irq: clear status when disable irq

2013/10/15 Mark Brown <broonie@...nel.org>:
> On Tue, Oct 15, 2013 at 01:03:58PM +0800, Yi Zhang wrote:
>
>> +                     bits_length = d->map->format.val_bytes * BITS_PER_BYTE;
>> +                     for (j = 0; j < bits_length; j++) {
>> +                             d->mask_buf[i] &= (0x1 << j);
Yes, this line is wrong, I shouldn't change the mask_buf; I'll change it;
my fault; sorry;
>> +                             if (!d->mask_buf[i])
>> +                                     ret = regmap_update_bits(d->map, reg,
>> +                                                              (0x1 << j), 0);
>> +                             if (ret != 0)
>> +                                     dev_err(d->map->dev, "Failed to ack 0x%x: %d\n",
>> +                                             reg, ret);
>
> I don't entirely understand this code - what's the loop doing?  It
> looks like it's trying to acknowledge things bit by bit but it's doing
> this by updating mask_buf so it looks like it'll corrupt the set of
> masked interrupts.  After the zeroth iteration any bits other than bit 0
> should get cleared by the &= (0x1 << j).  I'd have expected to just
> write mask_buf back or something similar.
>
> It's possible I'm missing something here but if that is the case perhaps
> some comments would be good.
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