configuring UART1 using pinctrl for two UARTs

Question

Hi,

I am migrating a project to NRF Connect SDK and an having an issue changing the RX/TX pins so that I can talk to s different device via same UART instance.

On previous SDK, this was quite simple and worked fine using nrf_libuarte_async_uninit(&libuarte);

However with NRF Connect SDK (I'm using 2.4.0), it is more complex. I have looked at the documentation here: https://developer.nordicsemi.com/nRF_Connect_SDK/doc/latest/zephyr/hardware/pinctrl/index.html#

And also posts such as:

How to switch uart pins while runtime using pinctrl (Zephyr) (nrf52832) ?

However, I am still unable to progress.

One issue is that when I try and define additional pinctrl states as per docs:

periph0: periph@0 {
    ...
    /* state 0 ("default") */
    pinctrl-0 = <...>;
    ...
    /* state N ("mystate") */
    pinctrl-N = <...>;
    /* names for state 0 up to state N */
    pinctrl-names = "default", ..., "mystate";
    ...
};

I get compilation errors.

For example the following works:

modem_uart: &uart1 {
	status = "okay";
	current-speed = <115200>;
	// pinctrl-0 = <&uart1_default_alt>;
	// pinctrl-1 = <&uart1_sleep_alt>;
	pinctrl-0 = <&uart1_default>;
	pinctrl-1 = <&uart1_sleep>;
	pinctrl-names = "default","sleep";
	//pinctrl-names = "default-alt","sleep-alt","default","sleep";
};

&pinctrl {
	compatible = "nordic,nrf-pinctrl";
	uart1_default_alt: uart1_default_alt {
		group1 {
			psels = <NRF_PSEL(UART_RX, 0, 30)>, <NRF_PSEL(UART_TX, 0, 31)>;
		};
	};
	uart1_sleep_alt: uart1_sleep_alt {
		group1 {
			psels = <NRF_PSEL(UART_RX, 0, 30)>, <NRF_PSEL(UART_TX, 0, 31)>;
		};
	};
	uart1_default: uart1_default {
		group1 {
			psels = <NRF_PSEL(UART_RX, 0, 8)>, <NRF_PSEL(UART_TX, 0, 7)>;
		};
	};
	uart1_sleep: uart1_sleep {
		group1 {
			psels = <NRF_PSEL(UART_RX, 0, 8)>, <NRF_PSEL(UART_TX, 0, 7)>;
		};
	};
};

But if I try and add two more pinctrl states, the code no longer compiles:

modem_uart: &uart1 {
	status = "okay";
	current-speed = <115200>;
	pinctrl-0 = <&uart1_default_alt>;
	pinctrl-1 = <&uart1_sleep_alt>;
	pinctrl-2 = <&uart1_default>;
	pinctrl-3 = <&uart1_sleep>;
	//pinctrl-names = "default","sleep";
	pinctrl-names = "default-alt","sleep-alt","default","sleep";
};

&pinctrl {
	compatible = "nordic,nrf-pinctrl";
	uart1_default_alt: uart1_default_alt {
		group1 {
			psels = <NRF_PSEL(UART_RX, 0, 30)>, <NRF_PSEL(UART_TX, 0, 31)>;
		};
	};
	uart1_sleep_alt: uart1_sleep_alt {
		group1 {
			psels = <NRF_PSEL(UART_RX, 0, 30)>, <NRF_PSEL(UART_TX, 0, 31)>;
		};
	};
	uart1_default: uart1_default {
		group1 {
			psels = <NRF_PSEL(UART_RX, 0, 8)>, <NRF_PSEL(UART_TX, 0, 7)>;
		};
	};
	uart1_sleep: uart1_sleep {
		group1 {
			psels = <NRF_PSEL(UART_RX, 0, 8)>, <NRF_PSEL(UART_TX, 0, 7)>;
		};
	};
};

The error is:
/opt/nordic/ncs/v2.4.0/zephyr/include/zephyr/drivers/pinctrl.h:93:17: error: 'PINCTRL_STATE_DEFAULT_ALT' undeclared here (not in a function);

I have also tried using groups which compiles OK but unfortunately, only the last group is ever referenced - this seems to be a known limitation.

Pinctrl multiple group issue

My plan (if I can get more than two states to work) is use the pause/resume approach:

// Suspend UART
pm_device_action_run(modem_uart, PM_DEVICE_ACTION_SUSPEND);

// Select state > 1U which hopefully maps to my new pin configs
pinctrl_apply_state(config->pcfg, PINCTRL_STATE_PRIV_START);

// Resume UART
pm_device_action_run(modem_uart, PM_DEVICE_ACTION_RESUME);

Any help would be appreciated as I am out of ideas...

Nick

configuring UART1 using pinctrl for two UARTs

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