linux-kernel - Re: [PATCH] pinctrl: qcom: Add intr_target_width to define intr_target

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Date:   Fri, 14 Jul 2023 13:51:22 -0700
From:   Bjorn Andersson <quic_bjorande@...cinc.com>
To:     Andrew Halaney <ahalaney@...hat.com>
CC:     Ninad Naik <quic_ninanaik@...cinc.com>, <andersson@...nel.org>,
        <agross@...nel.org>, <konrad.dybcio@...aro.org>,
        <linux-arm-msm@...r.kernel.org>, <linux-gpio@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>, <quic_ppareek@...cinc.com>,
        <psodagud@...cinc.com>, <quic_kprasan@...cinc.com>
Subject: Re: [PATCH] pinctrl: qcom: Add intr_target_width to define
 intr_target_bit field width

On Fri, Jul 14, 2023 at 01:17:12PM -0500, Andrew Halaney wrote:
> On Fri, Jul 14, 2023 at 11:40:09AM +0530, Ninad Naik wrote:
> > SA8775 and newer target have added support for an increased number of
> > interrupt targets. To implement this change, the intr_target field, which
> > is used to configure the interrupt target in the interrupt configuration
> > register is increased from 3 bits to 4 bits.
> > 
> > In accordance to these updates, a new intr_target_width member is
> > introduced in msm_pingroup structure. This member stores the value of
> > width of intr_target field in the interrupt configuration register. This
> > value is used to dynamically calculate and generate mask for setting the
> > intr_target field. By default, this mask is set to 3 bit wide, to ensure
> > backward compatibility with the older targets.
> > 
> > Signed-off-by: Ninad Naik <quic_ninanaik@...cinc.com>
> 
> Thanks for the patch. Naive question (without really reading the code),
> but what practical affect does this have?
> 
> i.e. does this change behavior of how IRQs were handled before this
> patch vs after on this platform?
> 

Yes, the affected field denotes where interrupts should be routed and
without this patch not all the bits where updated.

> To shed some light on the question, there's a GPIO IRQ for the ethernet
> phy on this platform that is purposely _not_ described because it didn't
> ever trigger, resulting in the interface staying down. Things work
> fine without the IRQ (the driver goes into polling mode).
> The explanation I got was very brief and attributed it to a "hardware issue".
> 
> I'm wondering if I should re-evaluate that, and if this was the
> "hardware issue".
> 

It's plausible that your interrupt fired elsewhere. Definitely worth
giving that scenario another test run.

Regards,
Bjorn