linux-kernel - Re: [PATCH] regmap-irq: Update interrupt clear register for proper reset

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Date:   Wed, 16 Feb 2022 16:58:58 +0000
From:   Mark Brown <broonie@...nel.org>
To:     Prasad Kumpatla <quic_pkumpatl@...cinc.com>
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        "Rafael J. Wysocki" <rafael@...nel.org>,
        linux-kernel@...r.kernel.org,
        Charles Keepax <ckeepax@...nsource.cirrus.com>,
        "Srinivas Kandagatla  . [ 
         B. [  B. [
        B" <srinivas.kandagatla@...aro.org>
Subject: Re: [PATCH] regmap-irq: Update interrupt clear register for proper
 reset

On Wed, Feb 16, 2022 at 03:30:26PM +0530, Prasad Kumpatla wrote:
> With the existing logic where clear_ack is true, interrupt clear register
> reset is not handled properly. Due to this only the first interrupts get
> processed properly and further interrupts are blocked due to interrupt
> clear register is not reset. So writing 0x00 and 0xff(when ack_invert is
> true) should have no effect, other than clearing the ACKs just set.

This commit log still has the problem that it's not clearly describing
the problem and I've forgotten again - in what way is the interrupt
clear reset not handled properly?  What should happen and what does
happen?

>  				if (d->chip->ack_invert && !ret)
> -					ret = regmap_write(map, reg,
> -							   d->mask_buf[i]);
> +					ret = regmap_write(map, reg, 0xff);

Why only 0xff and not UINT_MAX?

>  				else if (!ret)
> -					ret = regmap_write(map, reg,
> -							   ~d->mask_buf[i]);
> +					ret = regmap_write(map, reg, 0x00);

Please write 0 normally, no need for 00.

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