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

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Message-ID: <20170531175330.GE20170@codeaurora.org>
Date:   Wed, 31 May 2017 10:53:30 -0700
From:   Stephen Boyd <sboyd@...eaurora.org>
To:     Kiran Gunda <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
Subject: Re: [PATCH V1 14/15] spmi: pmic-arb: do not ack and clear peripheral
 interrupts in cleanup_irq

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.

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