From 037c10ab4df4efb5faa8b504cd64f67fe82c665e Mon Sep 17 00:00:00 2001
From: Michael Ossmann <mike@ossmann.com>
Date: Tue, 24 Feb 2026 20:32:51 -0500
Subject: [PATCH] Use external callback to set radio sample rate

---
 firmware/common/hackrf_core.c |  4 +++-
 firmware/common/radio.c       | 27 ++++++++++++++++-----------
 firmware/common/radio.h       | 12 ++++++++++++
 3 files changed, 31 insertions(+), 12 deletions(-)

diff --git a/firmware/common/hackrf_core.c b/firmware/common/hackrf_core.c
index 8eaecfbc..081ca110 100644
--- a/firmware/common/hackrf_core.c
+++ b/firmware/common/hackrf_core.c
@@ -351,7 +351,9 @@ fpga_driver_t fpga = {
 };
 #endif
 
-radio_t radio;
+radio_t radio = {
+	.sample_rate_cb = sample_rate_set,
+};
 
 rf_path_t rf_path = {
 	.switchctrl = 0,
diff --git a/firmware/common/radio.c b/firmware/common/radio.c
index 01a7b05a..3f06867d 100644
--- a/firmware/common/radio.c
+++ b/firmware/common/radio.c
@@ -210,21 +210,26 @@ static bool radio_update_sample_rate(radio_t* const radio, uint64_t* bank)
 	}
 	new_n = (n != previous_n);
 
-	fp_40_24_t afe_rate = rate << n;
-	afe_rate = sample_rate_set(afe_rate, false);
-	new_afe_rate = (afe_rate != applied_afe_rate);
-	if (new_afe_rate) {
-		afe_rate = sample_rate_set(afe_rate, true);
-		applied_afe_rate = afe_rate;
-		rate = afe_rate >> n;
+	if (radio->sample_rate_cb) {
+		fp_40_24_t afe_rate = rate << n;
+		afe_rate = radio->sample_rate_cb(afe_rate, false);
+		new_afe_rate = (afe_rate != applied_afe_rate);
+		if (new_afe_rate) {
+			afe_rate = radio->sample_rate_cb(afe_rate, true);
+			applied_afe_rate = afe_rate;
+			rate = afe_rate >> n;
+		}
+	} else {
+		rate = RADIO_UNSET;
 	}
 	new_rate = (rate != radio->config[RADIO_BANK_APPLIED][RADIO_SAMPLE_RATE]);
 	if (new_rate) {
 		radio->config[RADIO_BANK_APPLIED][RADIO_SAMPLE_RATE] = rate;
-
-		/* Round to the nearest Hz for display. */
-		const uint32_t rate_hz = (rate + (FP_ONE_HZ >> 1)) / FP_ONE_HZ;
-		hackrf_ui()->set_sample_rate(rate_hz);
+		if (rate != RADIO_UNSET) {
+			/* Round to the nearest Hz for display. */
+			const uint32_t rate_hz = (rate + (FP_ONE_HZ >> 1)) / FP_ONE_HZ;
+			hackrf_ui()->set_sample_rate(rate_hz);
+		}
 	}
 
 	return (new_afe_rate || new_rate || new_n);
diff --git a/firmware/common/radio.h b/firmware/common/radio.h
index 59f9592a..13cd2626 100644
--- a/firmware/common/radio.h
+++ b/firmware/common/radio.h
@@ -27,6 +27,8 @@
 #include <stdint.h>
 #include <stdbool.h>
 
+#include "fixed_point.h"
+
 typedef enum {
 	RADIO_OK = 1,
 	RADIO_ERR_INVALID_PARAM = -2,
@@ -205,10 +207,20 @@ typedef enum {
 
 #define RADIO_NUM_BANKS (5)
 
+/**
+ * A callback function must be provided that configures clock generation to
+ * produce the requested sample clock frequency. The function must return the
+ * configured sample rate. A boolean program argument may be set to false to
+ * execute a dry run, returning the sample rate without configuring clock
+ * generation.
+ */
+typedef fp_40_24_t (*sample_rate_fn)(const fp_40_24_t sample_rate, const bool program);
+
 typedef struct radio_t {
 	radio_config_mode_t config_mode;
 	uint64_t config[RADIO_NUM_BANKS][RADIO_NUM_REGS];
 	volatile uint32_t regs_dirty;
+	sample_rate_fn sample_rate_cb;
 } radio_t;
 
 void radio_init(radio_t* const radio);