Hi,
I am trying to use USART6 on STM32MP257F-DK development board. I have enabled it in the device tree, recompiled it and I now can see the /dev/ttySTM1 node. The problem is, that sometimes, after reboot, any access to the USART (even changing its baudrate using stty -F /dev/ttySTM1 command) causes SERC exception (with ID 36 which corresponds to USART6) to happen.
This does not happen all the time, but most of the time. Once and it doesn't happen after boot it won't happen again until next reboot and the UART works just fine.
here my device tree change:
&usart6 {
pinctrl-names = "default", "idle", "sleep";
pinctrl-0 = <&usart6_pins_a>;
pinctrl-1 = <&usart6_idle_pins_a>;
pinctrl-2 = <&usart6_sleep_pins_a>;
/delete-property/dmas;
/delete-property/dma-names;
status = "okay";
};
it seemed first that disabling the DMA helps, but I am not so sure now
usart6_pins_a: usart6-0 {
pins1 {
pinmux = <STM32_PINMUX('F', 13, AF3)>; /* USART6_TX */
bias-disable;
drive-push-pull;
slew-rate = <0>;
};
pins2 {
pinmux = <STM32_PINMUX('F', 14, AF3)>; /* USART6_RX */
bias-pull-up;
};
};
usart6_idle_pins_a: usart6-idle-0 {
pins1 {
pinmux = <STM32_PINMUX('F', 13, ANALOG)>; /* USART6_TX */
};
pins3 {
pinmux = <STM32_PINMUX('F', 14, AF3)>; /* USART6_RX */
bias-pull-up;
};
};
usart6_sleep_pins_a: usart6-sleep-0 {
pins {
pinmux = <STM32_PINMUX('F', 13, ANALOG)>, /* USART6_TX */
<STM32_PINMUX('F', 14, ANALOG)>; /* USART6_RX */
};
};
Thanks!
Alexey.
