drivers: ieee802154_nrf5: cabability IEE802154_OPENTHREAD_HW_CST

The new Kconfig option `IEEE802154_NRF5_CST_ENDPOINT` is added.
When it is enabled, then capability `IEE802154_OPENTHREAD_HW_CST`
is supported by the ieee802154_nrf5 driver and allows to set the
CST period and CST expected transmission time point.
This feature is an OpenThread-specific extention to the
ieee802154_nrf5 driver.

Signed-off-by: Damian Krolik <damian.krolik@nordicsemi.no>
Co-authored-by: Andrzej Kuroś <andrzej.kuros@nordicsemi.no>

drivers/ieee802154/Kconfig.nrf5

@@ -94,4 +94,12 @@ config IEEE802154_NRF5_MULTIPLE_CCA
 	  When this option is enabled the OpenThread capability
 	  IEEE802154_OPENTHREAD_HW_MULTIPLE_CCA is supported by the ieee802154_nrf5.
 
+config IEEE802154_NRF5_CST_ENDPOINT
+	bool "Support for OpenThread CST Endpoint extension in the ieee802154_nrf5."
+	help
+	  Enable support for OpenThread CST (Coordinated Sampled Transmitter) Endpoint
+	  with CST IE injection as an extension to ieee802154_nrf5 driver.
+	  When this option is enabled, the ieee802154_nrf5 driver supports the
+	  IEEE802154_OPENTHREAD_HW_CST capability.
+
 endif

drivers/ieee802154/ieee802154_nrf5.c

@@ -258,6 +258,9 @@ static void nrf5_get_capabilities_at_boot(void)
 #endif
 #if defined(CONFIG_IEEE802154_SELECTIVE_TXCHANNEL)
 		| IEEE802154_HW_SELECTIVE_TXCHANNEL
+#endif
+#if defined(CONFIG_IEEE802154_NRF5_CST_ENDPOINT)
+		| IEEE802154_OPENTHREAD_HW_CST
 #endif
 		;
 }
@@ -1028,6 +1031,17 @@ static int nrf5_configure(const struct device *dev,
 		}
 		break;
 
+#if defined(CONFIG_IEEE802154_NRF5_CST_ENDPOINT)
+	case IEEE802154_OPENTHREAD_CONFIG_CST_PERIOD:
+		nrf_802154_cst_writer_period_set(config->cst_period);
+		break;
+
+	case IEEE802154_OPENTHREAD_CONFIG_EXPECTED_TX_TIME:
+		nrf_802154_cst_writer_anchor_time_set(nrf_802154_timestamp_phr_to_mhr_convert(
+			config->expected_tx_time / NSEC_PER_USEC));
+		break;
+#endif /* CONFIG_IEEE802154_NRF5_CST_ENDPOINT */
+
 	default:
 		return -EINVAL;
 	}