zBusNet/zephyr-patches/0001-drivers-lora-sx126x-add-one-shot-IRQ-timestamp-peek.patch

From 4a7e9a77611d7a85a660e826c1dad97f355b0414 Mon Sep 17 00:00:00 2001
From: ZiB <zib@zi3.xyz>
Date: Mon, 2 Nov 2026 00:00:11 -0800
Subject: [PATCH 1/3] drivers: lora: sx126x: add one-shot IRQ timestamp peek

Expose higher-precision IRQ timestamp via sx126x_irq_timestamp_get()
by capturing a free-running cycle count at the DIO1 GPIO ISR, before
any SPI/workqueue latency, and resolving it in the IRQ handler to an
absolute timestamp directly comparable to k_uptime_get()/k_uptime_ticks().

Gated by CONFIG_LORA_SX126X_NATIVE_IRQ_TIMESTAMP (default y): the
cycle-counter/uptime reads, the conversions, and the extra struct
fields all compile out when disabled, and sx126x_irq_timestamp_get()
still links as a trivial false-returning stub so no caller needs its
own #ifdef. The added work (one more cycle-counter read in the ISR,
one k_uptime_ticks() read, two 64-bit fixed-point conversions) runs
per IRQ, reducing timestamp latency by about 450us in testing.

Signed-off-by: ZiB <zib@zi3.xyz>
---
 drivers/lora/native/sx126x/Kconfig      | 10 +++++
 drivers/lora/native/sx126x/sx126x.c     | 38 +++++++++++++++++
 drivers/lora/native/sx126x/sx126x.h     |  7 ++++
 drivers/lora/native/sx126x/sx126x_hal.c |  4 ++
 drivers/lora/native/sx126x/sx126x_hal.h |  3 ++
 include/zephyr/drivers/lora/sx126x.h    | 55 +++++++++++++++++++++++++
 6 files changed, 117 insertions(+)
 create mode 100644 include/zephyr/drivers/lora/sx126x.h

diff --git a/drivers/lora/native/sx126x/Kconfig b/drivers/lora/native/sx126x/Kconfig
index 2e59112419a..14d955302b3 100644
--- a/drivers/lora/native/sx126x/Kconfig
+++ b/drivers/lora/native/sx126x/Kconfig
@@ -39,3 +39,13 @@ config LORA_SX126X_NATIVE_STANDALONE
 	depends on DT_HAS_SEMTECH_SX1262_ENABLED || DT_HAS_SEMTECH_SX1261_ENABLED
 	help
 	  Standalone SX1261/SX1262 support for the native SX126x driver.
+
+config LORA_SX126X_NATIVE_IRQ_TIMESTAMP
+	bool "Radio-IRQ timestamp peek"
+	default y
+	depends on LORA_SX126X_NATIVE
+	help
+	  Expose higher-precision IRQ timestamp via sx126x_irq_timestamp_get()
+	  by capturing a free-running cycle count at the DIO1 GPIO ISR, before
+	  any SPI/workqueue latency, and resolve it in the IRQ handler to an
+	  absolute timestamp directly comparable to k_uptime_get()/k_uptime_ticks().
diff --git a/drivers/lora/native/sx126x/sx126x.c b/drivers/lora/native/sx126x/sx126x.c
index d3a7313e964..c3f9d63f3f5 100644
--- a/drivers/lora/native/sx126x/sx126x.c
+++ b/drivers/lora/native/sx126x/sx126x.c
@@ -6,6 +6,7 @@
 #include <zephyr/kernel.h>
 #include <zephyr/device.h>
 #include <zephyr/drivers/lora.h>
+#include <zephyr/drivers/lora/sx126x.h>
 #include <zephyr/pm/device.h>
 #include <zephyr/sys/byteorder.h>
 
@@ -847,6 +848,15 @@ static void sx126x_irq_work_handler(struct k_work *work)
 		return;
 	}
 
+#if IS_ENABLED(CONFIG_LORA_SX126X_NATIVE_IRQ_TIMESTAMP)
+	uint32_t delta_cycles = k_cycle_get_32() - data->hal.dio1_raw_cycles;
+	uint64_t delta_ns = k_cyc_to_ns_floor64(delta_cycles);
+	uint64_t now_ns = k_ticks_to_ns_floor64(k_uptime_ticks());
+
+	data->irq_ts.event_uptime_ns = now_ns - delta_ns;
+	data->irq_ts.irq_status = irq_status;
+#endif
+
 	LOG_DBG("IRQ status: 0x%04x", irq_status);
 
 	/* Clear handled IRQs */
@@ -870,6 +880,34 @@ static void sx126x_irq_work_handler(struct k_work *work)
 	}
 }
 
+bool sx126x_irq_timestamp_get(const struct device *dev, uint16_t irq_bit, uint64_t *ns_out)
+{
+#if IS_ENABLED(CONFIG_LORA_SX126X_NATIVE_IRQ_TIMESTAMP)
+	struct sx126x_data *data = dev->data;
+	unsigned int key;
+	uint64_t event_uptime_ns;
+	uint16_t irq_status;
+
+	key = irq_lock();
+	event_uptime_ns = data->irq_ts.event_uptime_ns;
+	irq_status = data->irq_ts.irq_status;
+	irq_unlock(key);
+
+	if (!(irq_status & irq_bit)) {
+		return false;
+	}
+
+	*ns_out = event_uptime_ns;
+
+	return true;
+#else
+	ARG_UNUSED(dev);
+	ARG_UNUSED(irq_bit);
+	ARG_UNUSED(ns_out);
+	return false;
+#endif
+}
+
 static int sx126x_set_configured_packet_params(const struct device *dev, uint8_t payload_len)
 {
 	struct sx126x_data *data = dev->data;
diff --git a/drivers/lora/native/sx126x/sx126x.h b/drivers/lora/native/sx126x/sx126x.h
index 07c50f0044d..0ea5154e901 100644
--- a/drivers/lora/native/sx126x/sx126x.h
+++ b/drivers/lora/native/sx126x/sx126x.h
@@ -75,6 +75,13 @@ struct sx126x_data {
 	/* Deferred work for interrupt handling */
 	struct k_work irq_work;
 	const struct device *dev;
+
+#if IS_ENABLED(CONFIG_LORA_SX126X_NATIVE_IRQ_TIMESTAMP)
+	struct {
+		uint64_t event_uptime_ns;
+		uint16_t irq_status;
+	} irq_ts;
+#endif
 };
 
 int sx126x_set_packet_type(const struct device *dev, uint8_t type);
diff --git a/drivers/lora/native/sx126x/sx126x_hal.c b/drivers/lora/native/sx126x/sx126x_hal.c
index 34f7089584f..2bc86251fc0 100644
--- a/drivers/lora/native/sx126x/sx126x_hal.c
+++ b/drivers/lora/native/sx126x/sx126x_hal.c
@@ -76,6 +76,10 @@ static void dio1_isr(const struct device *gpio, struct gpio_callback *cb,
 {
 	struct sx126x_hal_data *data = CONTAINER_OF(cb, struct sx126x_hal_data, dio1_cb);
 
+#if IS_ENABLED(CONFIG_LORA_SX126X_NATIVE_IRQ_TIMESTAMP)
+	data->dio1_raw_cycles = k_cycle_get_32();
+#endif
+
 	if (data->dio1_callback != NULL) {
 		data->dio1_callback(data->dev);
 	}
diff --git a/drivers/lora/native/sx126x/sx126x_hal.h b/drivers/lora/native/sx126x/sx126x_hal.h
index e4b26ba60bd..b7d8d30922e 100644
--- a/drivers/lora/native/sx126x/sx126x_hal.h
+++ b/drivers/lora/native/sx126x/sx126x_hal.h
@@ -42,6 +42,9 @@ struct sx126x_hal_data {
 	struct gpio_callback dio1_cb;
 	void (*dio1_callback)(const struct device *dev);
 	const struct device *dev;
+#if IS_ENABLED(CONFIG_LORA_SX126X_NATIVE_IRQ_TIMESTAMP)
+	uint32_t dio1_raw_cycles;
+#endif
 };
 
 int sx126x_hal_init(const struct device *dev);
diff --git a/include/zephyr/drivers/lora/sx126x.h b/include/zephyr/drivers/lora/sx126x.h
new file mode 100644
index 00000000000..7e134f434af
--- /dev/null
+++ b/include/zephyr/drivers/lora/sx126x.h
@@ -0,0 +1,55 @@
+/**
+ * @file
+ * @brief SX126x-specific extensions to the LoRa driver API.
+ *
+ * Not part of the generic @ref lora_interface API: these expose a hardware
+ * capability (radio-internal IRQ timing) specific to the SX126x family.
+ */
+#ifndef ZEPHYR_INCLUDE_DRIVERS_LORA_SX126X_H_
+#define ZEPHYR_INCLUDE_DRIVERS_LORA_SX126X_H_
+
+#include <zephyr/device.h>
+#include <zephyr/sys/util.h>
+#include <stdint.h>
+#include <stdbool.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/**
+ * @name SX126x IRQ source bits
+ *
+ * Mirror the chip's GetIrqStatus bit positions (DS.SX1261-2.W.APP,
+ * 13.3.1), for use with @ref sx126x_irq_timestamp_get.
+ * @{
+ */
+#define SX126X_IRQ_TS_TX_DONE           BIT(0)
+#define SX126X_IRQ_TS_RX_DONE           BIT(1)
+#define SX126X_IRQ_TS_PREAMBLE_DETECTED BIT(2)
+#define SX126X_IRQ_TS_SYNC_WORD_VALID   BIT(3)
+#define SX126X_IRQ_TS_HEADER_VALID      BIT(4)
+#define SX126X_IRQ_TS_HEADER_ERR        BIT(5)
+#define SX126X_IRQ_TS_CRC_ERR           BIT(6)
+#define SX126X_IRQ_TS_RX_TX_TIMEOUT     BIT(9)
+/** @} */
+
+/**
+ * @brief Get a precise timestamp for the most recent occurrence of one
+ * SX126x radio IRQ.
+ *
+ * @param dev      SX126x LoRa device
+ * @param irq_bit  Single @c SX126X_IRQ_TS_* bit to query
+ * @param ns_out   Set to the absolute event timestamp, in nanoseconds,
+ *                 on the same timebase as @ref k_uptime_ticks
+ * @return true if @p irq_bit was set in the most recent IRQ status read,
+ *         and @p ns_out was written; false otherwise (including when
+ *         @kconfig{CONFIG_LORA_SX126X_NATIVE_IRQ_TIMESTAMP} is disabled)
+ */
+bool sx126x_irq_timestamp_get(const struct device *dev, uint16_t irq_bit, uint64_t *ns_out);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* ZEPHYR_INCLUDE_DRIVERS_LORA_SX126X_H_ */
-- 
2.54.0 (Apple Git-157)