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

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Date:   Tue, 06 Jun 2017 16:57:40 +0530
From:   kgunda@...eaurora.org
To:     Stephen Boyd <sboyd@...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 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.