thermal: stm32: Fix low threshold interrupt flood
authorPascal Paillet <p.paillet@st.com>
Fri, 10 Jan 2020 10:16:05 +0000 (11:16 +0100)
committerDaniel Lezcano <daniel.lezcano@linaro.org>
Mon, 27 Jan 2020 14:40:26 +0000 (15:40 +0100)
commit2f23e319b133c7392493e77f515a237c8e1e6dd6
treea07cb8fa782dfa87304e6fbf6704b67528331fac
parent9d8593f22ea33a88f89075b14fc58a95fc15b8ae
thermal: stm32: Fix low threshold interrupt flood

With the STM32 thermal peripheral, it is not possible to dump the
temperature that has caused the interrupt.
When the temperature reaches the low threshold, we generally read
a temperature that is a little bit higher than the low threshold.
This maybe due to sampling precision, and also because the CPU becomes
hotter when it quits WFI mode.
In that case, the framework does not change the trip points. This leads
to a lot of low threshold interrupts.

The fix is to set the low threshold value 0.5 degrees Celsius
below the actual request.

The problem is not so frequent with the high threshold and it would
no be a good idea to set the threshold value higher than the request.

Signed-off-by: Pascal Paillet <p.paillet@st.com>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Link: https://lore.kernel.org/r/20200110101605.24984-7-p.paillet@st.com
drivers/thermal/st/stm_thermal.c