Hi Patrice,
From: Patrice CHOTARD patrice.chotard@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@st.com
board/st/stm32mp1/stm32mp1.c | 106 +++++++++++++++++++++-------------- 1 file changed, 63 insertions(+), 43 deletions(-)
Reviewed-by: Patrick Delaunay patrick.delaunay@st.com
Thanks
Patrick