[PATCH] board: stm32pm1: update USB-C power detection algorithm on DK boards

[Patrick DELAUNAY]

Hi Patrice,

> From: Patrice CHOTARD <patrice.chotard at st.com>
> Sent: vendredi 16 octobre 2020 09:29
> 
> USB-C power supply which are Power Delivery compliant (USB-PD) are able to
> provide different voltage/current (for example 5V/3A 9V/3A 12V/2.25A...)
> 
> In this case, the power supply need to negotiate the voltage/current to use with
> the device using CC1/CC2 USB-C signals.
> 
> If this negotiation occurs during ADC measurement (done also on CC1/CC2 USB-
> C signals) some ADC acquisition can be corrupted which cause wrong power
> supply current detection.
> 
> To avoid this, the power supply current detection algorithm is updated as
> following:
>   - perform an ADC measurement, if a 3A current is detected, continue the
>     boot process.
>   - else, wait 20ms (max tPDDebounce duration) to ensure that USB-PD
>     negotiation is done and perform another ADC measurement.
> 
> Signed-off-by: Patrice Chotard <patrice.chotard at st.com>
> ---
> 
>  board/st/stm32mp1/stm32mp1.c | 106 +++++++++++++++++++++--------------
>  1 file changed, 63 insertions(+), 43 deletions(-)
> 

Reviewed-by: Patrick Delaunay <patrick.delaunay at st.com>

Thanks

Patrick