arch/arm64/src/imx9/imx9_lpi2c.c: Fix bus reset #16900
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imx9_lpi2c_reset didn't quite work. It tried to toggle scl line as GPIO, but the line was not even muxed properly. Instead, set the bus to relaxed mode, and drive address 0 to the bus. This toggles the clock, and also generates start and stop sequences on the bus. "Relaxed mode" is a new feature on the LPI2C block used in imx93. Signed-off-by: Jukka Laitinen <jukkax@ssrc.tii.ae>
xiaoxiang781216
approved these changes
Aug 25, 2025
acassis
approved these changes
Aug 25, 2025
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Summary
imx9_lpi2c_reset didn't quite work. It tried to toggle scl line as GPIO, but the line was not even muxed properly.
Instead, set the bus to relaxed mode, and drive address 0 to the bus. This toggles the clock, and also generates start and stop sequences on the bus.
"Relaxed mode" is a new feature on the LPI2C block used in imx93.
Impact
Only imx9 lpspi. Improves i2c bus error recovery.
Testing
Tested on imx93 board with a broken i2c led driver device which causes bus to get stuck occasionally.