linux-kernel - Re: [PATCH v2 15/15] drivers: thermal: tsens: Add interrupt support

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Message-ID: <5d67e71e.1c69fb81.6f885.6391@mx.google.com>
Date:   Thu, 29 Aug 2019 07:54:21 -0700
From:   Stephen Boyd <swboyd@...omium.org>
To:     Amit Kucheria <amit.kucheria@...aro.org>
Cc:     Daniel Lezcano <daniel.lezcano@...aro.org>,
        Mark Rutland <mark.rutland@....com>,
        Rob Herring <robh+dt@...nel.org>,
        Zhang Rui <rui.zhang@...el.com>,
        Andy Gross <agross@...nel.org>,
        Bjorn Andersson <bjorn.andersson@...aro.org>,
        Eduardo Valentin <edubezval@...il.com>,
        linux-arm-msm <linux-arm-msm@...r.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Marc Gonzalez <marc.w.gonzalez@...e.fr>,
        Brian Masney <masneyb@...tation.org>,
        Linux PM list <linux-pm@...r.kernel.org>
Subject: Re: [PATCH v2 15/15] drivers: thermal: tsens: Add interrupt support

Quoting Amit Kucheria (2019-08-29 05:30:59)
> On Thu, Aug 29, 2019 at 3:12 AM Stephen Boyd <swboyd@...omium.org> wrote:
> >
> > Quoting Amit Kucheria (2019-08-27 05:14:11)
> > > +                       thermal_zone_device_update(priv->sensor[i].tzd,
> > > +                                                  THERMAL_EVENT_UNSPECIFIED);
> > > +               } else {
> > > +                       dev_dbg(priv->dev, "[%u] %s: no violation:  %d\n",
> > > +                               hw_id, __func__, temp);
> > > +               }
> > > +       }
> > > +
> > > +       return IRQ_HANDLED;
> >
> > Should we return IRQ_NONE in the case that the above for loop didn't
> > find anything in those if/else-ifs?
> 
> The upper/lower interrupts are non-sticky, level-triggered. So if the
> temp returns to within the thresholds in the time that a IRQ was
> triggered and the handler scheduled, we might not see any threshold
> violations/interrupt bits set.
> 
> It feels to me that this is a case of the IRQ being handled
> (automagically) instead of IRQ_NONE. The definition of IRQ_NONE[1]
> also seems to suggest that it should be used when the IRQ wasn't
> handled. But it was handled in this case (although, automatically),
> wasn't it?

Ok I see. Sounds fine then to always return IRQ_HANDLED. Maybe you can
add a comment to this effect right above the return statement.