From: Ansuel Smith <ansuelsmth@gmail.com>
To: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: Andy Gross <agross@kernel.org>,
Bjorn Andersson <bjorn.andersson@linaro.org>,
Amit Kucheria <amitk@kernel.org>,
Thara Gopinath <thara.gopinath@linaro.org>,
Zhang Rui <rui.zhang@intel.com>,
linux-arm-msm@vger.kernel.org, linux-pm@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 2/2] drivers: thermal: tsens: add timeout to get_tem_tsens_valid
Date: Fri, 17 Sep 2021 13:06:42 +0200 [thread overview]
Message-ID: <YUR2wmcMMWtoLDGB@Ansuel-xps.localdomain> (raw)
In-Reply-To: <f06f6d13-e659-16e9-5900-2d82596f139c@linaro.org>
On Fri, Sep 17, 2021 at 11:08:15AM +0200, Daniel Lezcano wrote:
> On 07/09/2021 23:25, Ansuel Smith wrote:
> > The function can loop and lock the system if for whatever reason the bit
> > for the target sensor is NEVER valid. This is the case if a sensor is
> > disabled by the factory and the valid bit is never reported as actually
> > valid. Add a timeout check and exit if a timeout occurs. As this is
> > a very rare condition, handle the timeout only if the first read fails.
> > While at it also rework the function to improve readability.
> >
> > Signed-off-by: Ansuel Smith <ansuelsmth@gmail.com>
> > ---
> > drivers/thermal/qcom/tsens.c | 40 +++++++++++++++++++++++-------------
> > 1 file changed, 26 insertions(+), 14 deletions(-)
> >
> > diff --git a/drivers/thermal/qcom/tsens.c b/drivers/thermal/qcom/tsens.c
> > index b1162e566a70..1ff244176beb 100644
> > --- a/drivers/thermal/qcom/tsens.c
> > +++ b/drivers/thermal/qcom/tsens.c
> > @@ -599,26 +599,38 @@ int get_temp_tsens_valid(const struct tsens_sensor *s, int *temp)
> > int hw_id = s->hw_id;
> > u32 temp_idx = LAST_TEMP_0 + hw_id;
> > u32 valid_idx = VALID_0 + hw_id;
> > + unsigned long timeout;
> > u32 valid;
> > int ret;
> >
> > /* VER_0 doesn't have VALID bit */
> > - if (tsens_version(priv) >= VER_0_1) {
> > + if (tsens_version(priv) == VER_0)
> > + goto get_temp;
> > +
> > + ret = regmap_field_read(priv->rf[valid_idx], &valid);
> > + if (ret || valid)
> > + goto check_valid;
> > +
> > + timeout = jiffies + msecs_to_jiffies(20);
>
> Why not use regmap_field_read_poll_timeout() ?
>
Ok will convert this to pool_timeout and send v3.
Thx for the review.
> > + do {
> > + /* Valid bit is 0 for 6 AHB clock cycles.
> > + * At 19.2MHz, 1 AHB clock is ~60ns.
> > + * We should enter this loop very, very rarely.
> > + */
> > + ndelay(400);
> > ret = regmap_field_read(priv->rf[valid_idx], &valid);
> > - if (ret)
> > - return ret;
> > - while (!valid) {
> > - /* Valid bit is 0 for 6 AHB clock cycles.
> > - * At 19.2MHz, 1 AHB clock is ~60ns.
> > - * We should enter this loop very, very rarely.
> > - */
> > - ndelay(400);
> > - ret = regmap_field_read(priv->rf[valid_idx], &valid);
> > - if (ret)
> > - return ret;
> > - }
> > - }
> > + if (ret || valid)
> > + goto check_valid;
> > + } while (time_before(jiffies, timeout));
> > +
> > + return -ETIMEDOUT;
> > +
> > +check_valid:
> > + /* Check ret of valid bit read */
> > + if (ret)
> > + return ret;
> >
> > +get_temp:
> > /* Valid bit is set, OK to read the temperature */
> > *temp = tsens_hw_to_mC(s, temp_idx);
> >
> >
>
>
> --
> <http://www.linaro.org/> Linaro.org │ Open source software for ARM SoCs
>
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next prev parent reply other threads:[~2021-09-17 11:06 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-07 21:25 [PATCH v2 1/2] drivers: thermal: tsens: fix wrong check for tzd in irq handlers Ansuel Smith
2021-09-07 21:25 ` [PATCH v2 2/2] drivers: thermal: tsens: add timeout to get_tem_tsens_valid Ansuel Smith
2021-09-07 21:57 ` Matthias Kaehlcke
2021-09-17 9:08 ` Daniel Lezcano
2021-09-17 11:06 ` Ansuel Smith [this message]
2021-09-17 9:08 ` [PATCH v2 1/2] drivers: thermal: tsens: fix wrong check for tzd in irq handlers Daniel Lezcano
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