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

Patrick DELAUNAY patrick.delaunay at foss.st.com
Wed Jan 13 11:00:59 CET 2021

> 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(-)
Applied to u-boot-stm/master, thanks!



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