Re: [PATCH v4 17/19] thermal/tegra: Do not enable the thermal zone, it is already enabled

Thierry Reding
2023-03-01T14:30:15Z

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On Tue, Feb 28, 2023 at 12:22:36PM +0100, Daniel Lezcano wrote:
> The code enables the thermal zone after setting it up. But the thermal
> zone is already enabled by thermal_of_zone_register() function.
>
> Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
> ---
> drivers/thermal/tegra/tegra30-tsensor.c | 8 +-------
> 1 file changed, 1 insertion(+), 7 deletions(-)
>
> diff --git a/drivers/thermal/tegra/tegra30-tsensor.c b/drivers/thermal/tegra/tegra30-tsensor.c
> index 3506c3f3c474..e38902abf207 100644
> --- a/drivers/thermal/tegra/tegra30-tsensor.c
> +++ b/drivers/thermal/tegra/tegra30-tsensor.c
> @@ -346,7 +346,7 @@ static int tegra_tsensor_enable_hw_channel(const struct tegra_tsensor *ts,
> {
> const struct tegra_tsensor_channel *tsc = &ts->ch[id];
> struct thermal_zone_device *tzd = tsc->tzd;
> - int err, hot_trip = 0, crit_trip = 0;
> + int hot_trip = 0, crit_trip = 0;
> u32 val;
>
> if (!tzd) {
> @@ -401,12 +401,6 @@ static int tegra_tsensor_enable_hw_channel(const struct tegra_tsensor *ts,
> val |= FIELD_PREP(TSENSOR_SENSOR0_CONFIG0_INTR_THERMAL_RST_EN, 1);
> writel_relaxed(val, tsc->regs + TSENSOR_SENSOR0_CONFIG0);
>
> - err = thermal_zone_device_enable(tzd);
> - if (err) {
> - dev_err(ts->dev, "ch%u: failed to enable zone: %d\n", id, err);
> - return err;
> - }
> -
> return 0;
> }

This function is called in tegra_tsensor_resume() and balances out the
tegra_tsensor_hw_channel() calls from tegra_tsensor_suspend(). If we
remove the call from here, we'll likely end up with the zones disabled
after a resume.

This ends up calling thermal_zone_device_set_mode(), which is a no-op,
basically, if the mode is unchanged, so this seems harmless.

If you need this to change anyway, I suppose we could move the calls to
thermal_zone_device_enable() and move them into suspend/resume instead.
That's a bit tricky to undo in the error recovery paths, but should be
doable.

Thierry

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