dts: arm: adi: Enable RTC counter for MAX32657

boards/adi/max32657evkit/max32657evkit_max32657.yaml

@@ -14,6 +14,7 @@ supported:
   - dma
   - counter
   - pwm
+  - rtc_counter
   - spi
 ram: 256
 flash: 960

boards/adi/max32657evkit/max32657evkit_max32657_common.dtsi

@@ -71,3 +71,8 @@
 	pinctrl-0 = <&spi0_mosi_p0_2 &spi0_miso_p0_4 &spi0_sck_p0_6 &spi0_ss0_p0_3>;
 	pinctrl-names = "default";
 };
+
+&rtc_counter {
+	status = "okay";
+	clock-source = <ADI_MAX32_PRPH_CLK_SRC_INRO>;
+};

boards/adi/max32657evkit/max32657evkit_max32657_ns.yaml

@@ -13,6 +13,7 @@ supported:
   - dma
   - counter
   - pwm
+  - rtc_counter
   - spi
 ram: 192
 flash: 576

drivers/counter/counter_max32_rtc.c

@@ -10,9 +10,13 @@
 #include <zephyr/drivers/clock_control/adi_max32_clock_control.h>
 #include <zephyr/drivers/pinctrl.h>
 #include <zephyr/irq.h>
+#include <zephyr/logging/log.h>
 
 #include <rtc.h>
 #include <wrap_max32_lp.h>
+#include <wrap_max32_rtc.h>
+
+LOG_MODULE_REGISTER(max32_counter_rtc, CONFIG_COUNTER_LOG_LEVEL);
 
 /* Resoultion is 1sec for time of day alarm*/
 #define MAX32_RTC_COUNTER_FREQ 1
@@ -34,6 +38,7 @@ struct max32_rtc_config {
 	struct counter_config_info info;
 	mxc_rtc_regs_t *regs;
 	void (*irq_func)(void);
+	struct max32_perclk perclk;
 };
 
 static int api_start(const struct device *dev)
@@ -207,10 +212,14 @@ static void rtc_max32_isr(const struct device *dev)
 
 static int rtc_max32_init(const struct device *dev)
 {
+	int ret;
 	const struct max32_rtc_config *cfg = dev->config;
 
-	while (MXC_RTC_Init(0, 0) == E_BUSY) {
-		;
+	while ((ret = Wrap_MXC_RTC_Init(0, 0, cfg->perclk.clk_src)) != E_SUCCESS) {
+		if (ret < 0) {
+			LOG_ERR("RTC does not support this clock source.");
+			return -ENOTSUP;
+		}
 	}
 
 	api_stop(dev);
@@ -252,6 +261,8 @@ static DEVICE_API(counter, counter_rtc_max32_driver_api) = {
 			},                                                                         \
 		.regs = (mxc_rtc_regs_t *)DT_INST_REG_ADDR(_num),                                  \
 		.irq_func = max32_rtc_irq_init_##_num,                                             \
+		.perclk.clk_src =                                                                  \
+			DT_INST_PROP_OR(_num, clock_source, ADI_MAX32_PRPH_CLK_SRC_ERTCO),         \
 	};                                                                                         \
                                                                                                    \
 	DEVICE_DT_INST_DEFINE(_num, &rtc_max32_init, NULL, &rtc_max32_data_##_num,                 \

dts/arm/adi/max32/max32657_common.dtsi

@@ -269,6 +269,13 @@
 		};
 	};
 
+	rtc_counter: rtc_counter@6000 {
+		compatible = "adi,max32-rtc-counter";
+		reg = <0x6000 0x400>;
+		interrupts = <2 0>;
+		status = "disabled";
+	};
+
 	spi0: spi@46000 {
 		compatible = "adi,max32-spi";
 		reg = <0x46000 0x1000>;

dts/bindings/counter/adi,max32-rtc-counter.yaml

@@ -7,3 +7,18 @@ description: ADI MAX32 compatible Counter RTC
 compatible: "adi,max32-rtc-counter"
 
 include: [base.yaml]
+
+properties:
+  reg:
+    required: true
+
+  clock-source:
+    type: int
+    enum: [4, 5]
+    description: |
+      Clock source to be used by the RTC peripheral. The following options
+      are available:
+      - 4: "ADI_MAX32_PRPH_CLK_SRC_ERTCO" External Real-Time Clock Oscillator
+      - 5: "ADI_MAX32_PRPH_CLK_SRC_INRO" Internal Ring Oscillator
+      The target device might not support all option please take a look on
+      target device user guide