linux-kernel - Re: [PATCH V1 14/15] spmi: pmic-arb: do not ack and clear peripheral interrupts in cleanup

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Date:   Mon, 12 Jun 2017 19:10:21 -0700
From:   Stephen Boyd <sboyd@...eaurora.org>
To:     kgunda@...eaurora.org
Cc:     Abhijeet Dharmapurikar <adharmap@...eaurora.org>,
        David Collins <collinsd@...eaurora.org>,
        Christophe JAILLET <christophe.jaillet@...adoo.fr>,
        Subbaraman Narayanamurthy <subbaram@...eaurora.org>,
        linux-kernel@...r.kernel.org, linux-arm-msm@...r.kernel.org,
        adharmap@...cinc.com, aghayal@....qualcomm.com,
        linux-arm-msm-owner@...r.kernel.org
Subject: Re: [PATCH V1 14/15] spmi: pmic-arb: do not ack and clear peripheral
 interrupts in cleanup_irq

On 06/06, kgunda@...eaurora.org wrote:
> On 2017-06-02 12:56, kgunda@...eaurora.org wrote:
> >On 2017-05-31 23:23, Stephen Boyd wrote:
> >>On 05/30, Kiran Gunda wrote:
> >>>From: Subbaraman Narayanamurthy <subbaram@...eaurora.org>
> >>>
> >>>Currently, cleanup_irq() is invoked when a peripheral's interrupt
> >>>fires and there is no mapping present in the interrupt domain of
> >>>spmi interrupt controller.
> >>>
> >>>The cleanup_irq clears the arbiter bit, clears the pmic interrupt
> >>>and disables it at the pmic in that order. The last disable in
> >>>cleanup_irq races with request_irq() in that it stomps over the
> >>>enable issued by request_irq. Fix this by not writing to the pmic
> >>>in cleanup_irq. The latched bit will be left set in the pmic,
> >>>which will not send us more interrupts even if the enable bit
> >>>stays enabled.
> >>>
> >>>When a client wants to request an interrupt, use the activate
> >>>callback on the irq_domain to clear latched bit. This ensures
> >>>that the latched, if set due to the above changes in cleanup_irq
> >>>or when the bootloader leaves it set, gets cleaned up, paving way
> >>>for upcoming interrupts to trigger.
> >>>
> >>>With this, there is a possibility of unwanted triggering of
> >>>interrupt right after the latched bit is cleared - the interrupt
> >>>may be left enabled too. To avoid that, clear the enable first
> >>>followed by clearing the latched bit in the activate callback.
> >>>
> >>>Signed-off-by: Subbaraman Narayanamurthy <subbaram@...eaurora.org>
> >>>Signed-off-by: Kiran Gunda <kgunda@...eaurora.org>
> >>
> >>Please squash this with the patch that adds cleanup_irq() and
> >>rewrite the commit text to combine details from both.
> >Sure. Will squash it in the next patch submission.
> Patch that adds cleanup_irq is already taken in to the tree.
> Lets have this patch as is now.

Is this the one with the kbuild error? IRQ domains are not always
there, so I don't know how this is expected to work.

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