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@xxxxxxxxx>
> > ---
> > 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);
> >
> >
>
>
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