samples: stm32: mco: Update sample to use dts instead of Kconfig

Update MCO board sample to use devicetree information instead of Kconfig
configurations.

Signed-off-by: Joakim Andersson <[email protected]>

Author: joerchan

samples/boards/st/mco/README.rst

@@ -14,7 +14,7 @@ Requirements
 ************
 
 The SoC should support MCO functionality and use a pin that has the MCO alternate function.
-To support another board, add an overlay in boards folder.
+To support another board, add a dts overlay file in boards folder.
 Make sure that the output clock is enabled in dts overlay file.
 
 

samples/boards/st/mco/boards/nucleo_u5a5zj_q.overlay

@@ -3,10 +3,20 @@
 	status = "okay";
 };
 
-/ {
-	zephyr,user {
-		/* Select MCO pin to use. */
-		pinctrl-0 = <&rcc_mco_pa8>;
-		pinctrl-names = "default";
-	};
+/* See reference manual (RM0456):
+ *   0b0111: LSE clock selected
+ */
+#define MCO1_SEL_LSE 7
+
+/* See reference manual (RM0456):
+ *   0b001: MCO divided by 2
+ */
+#define MCO1_PRE_DIV_2 1
+
+&mco1 {
+	status = "okay";
+	clocks = <&rcc STM32_SRC_LSE MCO1_SEL(MCO1_SEL_LSE)>;
+	prescaler = <MCO1_PRE(MCO1_PRE_DIV_2)>;
+	pinctrl-0 = <&rcc_mco_pa8>;
+	pinctrl-names = "default";
 };

samples/boards/st/mco/prj.conf

@@ -1,3 +1 @@
-# Set MCO1 source to desired clock.
-CONFIG_CLOCK_STM32_MCO1_SRC_LSE=y
-CONFIG_CLOCK_STM32_MCO1_DIV=1
+# Empty

samples/boards/st/mco/src/main.c

@@ -7,15 +7,24 @@
 #include <zephyr/kernel.h>
 #include <zephyr/drivers/pinctrl.h>
 
-/* Define the pinctrl information for the MCO pin. */
-PINCTRL_DT_DEFINE(DT_PATH(zephyr_user));
-
 int main(void)
 {
-	/* Configure the MCO pin using pinctrl in order to set the alternate function of the pin. */
-	const struct pinctrl_dev_config *pcfg = PINCTRL_DT_DEV_CONFIG_GET(DT_PATH(zephyr_user));
-	(void)pinctrl_apply_state(pcfg, PINCTRL_STATE_DEFAULT);
+	const struct device *dev;
+
+	/* This sample demonstrates MCO usage via Device Tree.
+	 * MCO configuration is performed in the Device Tree overlay files.
+	 * Each MCO will be enabled automatically by the driver during device
+	 * initialization. This sample checks that all MCOs are ready - if so,
+	 * the selected clock should be visible on the chosen GPIO pin.
+	 */
+	dev = DEVICE_DT_GET(DT_NODELABEL(mco1));
+	if (device_is_ready(dev)) {
+		printk("MCO1 device successfully configured\n");
+	} else {
+		printk("MCO1 device not ready\n");
+		return -1;
+	}
 
-	printk("\nMCO pin configured, end of example.\n");
+	printk("\nDisplayed the status of all MCO devices - end of example.\n");
 	return 0;
 }