fix(llcc68): cache detected chip type

Store the detected chip type after the first successful version-register read so repeated radio operations do not keep querying the chip identity.

This preserves Unknown as uncached so transient read failures or unsupported responses can still be retried on a later call.

.clang-format

@@ -0,0 +1,25 @@
+# C++ specific configuration (akin to Google's C++ style)
+# https://clang.llvm.org/docs/ClangFormatStyleOptions.html#adding-additional-style-options
+---
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+BasedOnStyle: LLVM
+UseTab: ForContinuationAndIndentation
+IndentWidth: 4
+TabWidth: 4
+AccessModifierOffset: -4
+ColumnLimit: 0
+NamespaceIndentation: Inner
+FixNamespaceComments: false
+AllowShortIfStatementsOnASingleLine: WithoutElse
+AllowShortLoopsOnASingleLine: true
+AllowShortBlocksOnASingleLine: Empty
+IndentCaseLabels: false
+SortIncludes: Never
+AlignConsecutiveMacros: AcrossEmptyLines
+AlignConsecutiveAssignments: Consecutive
+BreakStringLiterals: true
+LineEnding: LF
+MaxEmptyLinesToKeep: 2
+BreakBeforeBraces: Attach
+InsertBraces: true
+BreakAfterAttributes: Always

include/llcc68.hpp

@@ -44,10 +44,10 @@ constexpr auto DEFAULT_BUSY_TIMEOUT_MS = 100;
  * @param ldro_on Low data rate optimization setting sent to the radio
  */
 constexpr airtime_t calc_time_on_air(uint8_t len, uint8_t sf, LoRaBandwidth bw,
-                                     LoRaCodingRate cr,
-                                     uint16_t preamble_length,
-                                     LoRaHeaderType header_type,
-                                     LoRaCrcType crc_type, bool ldro_on);
+									 LoRaCodingRate cr,
+									 uint16_t preamble_length,
+									 LoRaHeaderType header_type,
+									 LoRaCrcType crc_type, bool ldro_on);
 
 struct LLCC68 {
 	/** trivial getter */
@@ -253,7 +253,7 @@ struct LLCC68 {
 	expected<unit, error_code> set_rx_duty_cycle(uint32_t rx_period,
 												 uint32_t sleep_period);
 	expected<unit, error_code> set_rx_duty_cycle_ms(uint32_t rx_period_ms,
-												   uint32_t sleep_period_ms);
+													uint32_t sleep_period_ms);
 	expected<unit, error_code> set_sleep(sleep_config_t config);
 	expected<unit, error_code> set_tx_continuous_wave();
 	expected<unit, error_code> set_tx_infinite_preamble();
@@ -303,6 +303,7 @@ struct LLCC68 {
 
 	/** properties */
 	const struct device *dev;
+	std::optional<ChipType> cached_chip_type{};
 };
 } // namespace app::driver::llcc68
 

include/llcc68_raw.h

@@ -15,9 +15,9 @@ extern "C" {
 typedef void (*llcc68_user_dio1_handler_t)(const struct device *dev, void *user_data);
 
 enum llcc68_rf_switch_mode {
-	LLCC68_RF_SWITCH_NONE = 0,
+	LLCC68_RF_SWITCH_NONE               = 0,
 	LLCC68_RF_SWITCH_GPIO_COMPLEMENTARY = 1,
-	LLCC68_RF_SWITCH_DIO2_SINGLE = 2,
+	LLCC68_RF_SWITCH_DIO2_SINGLE        = 2,
 };
 
 struct llcc68_config {