[nrf fromlist] drivers: clock_control: nrf54h-common: add utility to obtain LFOSC acc

Add a utility function to obtain LFOSC accuracy in PPM from BICR.

Upstream PR #: 81122

Signed-off-by: Gerard Marull-Paretas <[email protected]>
(cherry picked from commit af7dba707626e5a09046dcac1d626ef61086bd77)

Author: gmarull

drivers/clock_control/clock_control_nrf2_common.c

@@ -4,6 +4,7 @@
  */
 
 #include "clock_control_nrf2_common.h"
+#include <hal/nrf_bicr.h>
 
 #include <zephyr/logging/log.h>
 LOG_MODULE_REGISTER(clock_control_nrf2, CONFIG_CLOCK_CONTROL_LOG_LEVEL);
@@ -24,6 +25,8 @@ LOG_MODULE_REGISTER(clock_control_nrf2, CONFIG_CLOCK_CONTROL_LOG_LEVEL);
  */
 STRUCT_CLOCK_CONFIG(generic, ONOFF_CNT_MAX);
 
+#define BICR (NRF_BICR_Type *)DT_REG_ADDR(DT_NODELABEL(bicr))
+
 static void update_config(struct clock_config_generic *cfg)
 {
 	atomic_val_t prev_flags = atomic_or(&cfg->flags, FLAG_UPDATE_NEEDED);
@@ -75,6 +78,40 @@ static inline uint8_t get_index_of_highest_bit(uint32_t value)
 	return value ? (uint8_t)(31 - __builtin_clz(value)) : 0;
 }
 
+int lfosc_get_accuracy(uint16_t *accuracy)
+{
+	switch (nrf_bicr_lfosc_accuracy_get(BICR)) {
+	case NRF_BICR_LFOSC_ACCURACY_500PPM:
+		*accuracy = 500U;
+		break;
+	case NRF_BICR_LFOSC_ACCURACY_250PPM:
+		*accuracy = 250U;
+		break;
+	case NRF_BICR_LFOSC_ACCURACY_150PPM:
+		*accuracy = 150U;
+		break;
+	case NRF_BICR_LFOSC_ACCURACY_100PPM:
+		*accuracy = 100U;
+		break;
+	case NRF_BICR_LFOSC_ACCURACY_75PPM:
+		*accuracy = 75U;
+		break;
+	case NRF_BICR_LFOSC_ACCURACY_50PPM:
+		*accuracy = 50U;
+		break;
+	case NRF_BICR_LFOSC_ACCURACY_30PPM:
+		*accuracy = 30U;
+		break;
+	case NRF_BICR_LFOSC_ACCURACY_20PPM:
+		*accuracy = 20U;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
 int clock_config_init(void *clk_cfg, uint8_t onoff_cnt, k_work_handler_t update_work_handler)
 {
 	struct clock_config_generic *cfg = clk_cfg;

drivers/clock_control/clock_control_nrf2_common.h

@@ -36,6 +36,16 @@ struct clock_onoff {
 		struct clock_onoff onoff[_onoff_cnt]; \
 	}
 
+/**
+ * @brief Obtain LFOSC accuracy in ppm.
+ *
+ * @param[out] accuracy Accuracy in ppm.
+ *
+ * @retval 0 On success
+ * @retval -EINVAL If accuracy is not configured.
+ */
+int lfosc_get_accuracy(uint16_t *accuracy);
+
 /**
  * @brief Initializes a clock configuration structure.
  *