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    SubjectRe: [PATCH] thermal: tegra: add get_trend ops
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    Hi all,
    Does there have any more comments for this patch?

    Thanks.
    Wei.

    On 21/11/2018 2:36 PM, Wei Ni wrote:
    >
    >
    > On 20/11/2018 11:38 PM, Thierry Reding wrote:
    >> On Tue, Nov 20, 2018 at 05:11:17PM +0800, Wei Ni wrote:
    >>> Add support for get_trend ops that allows soctherm
    >>> sensors to be used with the step-wise governor.
    >>>
    >>> Signed-off-by: Wei Ni <wni@nvidia.com>
    >>> ---
    >>> drivers/thermal/tegra/soctherm.c | 34 ++++++++++++++++++++++++++++++++++
    >>> 1 file changed, 34 insertions(+)
    >>>
    >>> diff --git a/drivers/thermal/tegra/soctherm.c b/drivers/thermal/tegra/soctherm.c
    >>> index ed28110a3535..d2951fbe2b7c 100644
    >>> --- a/drivers/thermal/tegra/soctherm.c
    >>> +++ b/drivers/thermal/tegra/soctherm.c
    >>> @@ -488,9 +488,43 @@ static int tegra_thermctl_set_trip_temp(void *data, int trip, int temp)
    >>> return 0;
    >>> }
    >>>
    >>> +static int tegra_thermctl_get_trend(void *data, int trip,
    >>> + enum thermal_trend *trend)
    >>> +{
    >>> + struct tegra_thermctl_zone *zone = data;
    >>> + struct thermal_zone_device *tz = zone->tz;
    >>> + int trip_temp, temp, last_temp, ret;
    >>> +
    >>> + if (!tz)
    >>> + return -EINVAL;
    >>> +
    >>> + ret = tz->ops->get_trip_temp(zone->tz, trip, &trip_temp);
    >>> + if (ret)
    >>> + return ret;
    >>> +
    >>> + mutex_lock(&tz->lock);
    >>> + temp = tz->temperature;
    >>> + last_temp = tz->last_temperature;
    >>> + mutex_unlock(&tz->lock);
    >>> +
    >>> + if (temp > trip_temp) {
    >>> + if (temp >= last_temp)
    >>> + *trend = THERMAL_TREND_RAISING;
    >>> + else
    >>> + *trend = THERMAL_TREND_STABLE;
    >>> + } else if (temp < trip_temp) {
    >>> + *trend = THERMAL_TREND_DROPPING;
    >>> + } else {
    >>> + *trend = THERMAL_TREND_STABLE;
    >>> + }
    >>> +
    >>> + return 0;
    >>> +}
    >>
    >> This looks like a reimplementation of the get_tz_trend() helper. Is
    >> seems like that helper already has everything we need. Perhaps this
    >> isn't working because of-thermal installs of_thermal_get_trend(), a
    >> function that returns -EINVAL if the driver doesn't implement the
    >> ->get_trend() callback.
    >
    > 1. The get_tz_trend() helper can work, because it has:
    > if (tz->emul_temperature || !tz->ops->get_trend ||
    > tz->ops->get_trend(tz, trip, &trend)) {
    > ...
    > }
    > the tz->ops->get_trend is of_thermal_get_trend(). If without special
    > get_trend(), it will return -EINVAL, so it will implement the if block
    > to get the "trend". If we have the special get_trend(), then the
    > of_thermal_get_trend() will return 0, so this helper will not implement
    > the if block, it will get the "trend" from the special get_trend().
    >
    > 2. There has a little difference between the helper and our special
    > callback. The tegra_thermctl_get_trend() consider the trip_temp, but the
    > get_tz_trend() helper didn't.
    >
    >>
    >> Perhaps a better way would be to do something like this in
    >> thermal_zone_of_add_sensor():
    >>
    >> if (ops->get_trend)
    >> tzd->ops->get_trend = of_thermal_get_trend;
    >>
    >> That's similar to how ->set_trips() and ->set_emul_temp() are set up
    >> and should make sure that get_tz_trend() will do the right thing for
    >> all drivers that don't implement a special ->get_trend().
    >
    > As above description, I think the of_thermal_get_trend() already can
    > handle this case, doesn't need to change.
    >
    > Wei.
    >
    >>
    >> Thierry
    >>

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