From 24f2c1d073a5b932ed0b532c0c50a330f0992c07 Mon Sep 17 00:00:00 2001
From: Michael Ossmann <mike@ossmann.com>
Date: Sun, 9 Oct 2022 05:58:26 -0400
Subject: [PATCH] h1r9: MAX2839: always use the low LNA band

---
 firmware/common/max2839.c        | 13 +++++++------
 firmware/common/max2839_regs.def | 10 +++++++++-
 2 files changed, 16 insertions(+), 7 deletions(-)

diff --git a/firmware/common/max2839.c b/firmware/common/max2839.c
index 23b64629..a8c69f8c 100644
--- a/firmware/common/max2839.c
+++ b/firmware/common/max2839.c
@@ -117,6 +117,13 @@ void max2839_setup(max2839_driver_t* const drv)
 	/* set HPF corner frequency to 1 kHz */
 	set_MAX2839_HPC_STOP(drv, MAX2839_STOP_1K);
 
+	/*
+	 * There are two LNA band settings, but we only use one of them.
+	 * Switching to the other one doesn't make the overall spectrum any
+	 * flatter but adds a surprise step in the middle.
+	 */
+	set_MAX2839_LNAband(drv, MAX2839_LNAband_2_4);
+
 	max2839_regs_commit(drv);
 }
 
@@ -207,7 +214,6 @@ void max2839_stop(max2839_driver_t* const drv)
 void max2839_set_frequency(max2839_driver_t* const drv, uint32_t freq)
 {
 	uint8_t band;
-	uint8_t lna_band;
 	uint32_t div_frac;
 	uint32_t div_int;
 	uint32_t div_rem;
@@ -217,16 +223,12 @@ void max2839_set_frequency(max2839_driver_t* const drv, uint32_t freq)
 	/* Select band. Allow tuning outside specified bands. */
 	if (freq < 2400000000U) {
 		band = MAX2839_LOGEN_BSW_2_3;
-		lna_band = MAX2839_LNAband_2_4;
 	} else if (freq < 2500000000U) {
 		band = MAX2839_LOGEN_BSW_2_4;
-		lna_band = MAX2839_LNAband_2_4;
 	} else if (freq < 2600000000U) {
 		band = MAX2839_LOGEN_BSW_2_5;
-		lna_band = MAX2839_LNAband_2_6;
 	} else {
 		band = MAX2839_LOGEN_BSW_2_6;
-		lna_band = MAX2839_LNAband_2_6;
 	}
 
 	/* ASSUME 40MHz PLL. Ratio = F*(4/3)/40,000,000 = F/30,000,000 */
@@ -245,7 +247,6 @@ void max2839_set_frequency(max2839_driver_t* const drv, uint32_t freq)
 
 	/* Band settings */
 	set_MAX2839_LOGEN_BSW(drv, band);
-	set_MAX2839_LNAband(drv, lna_band);
 
 	/* Write order matters here, so commit INT and FRAC_HI before
 	 * committing FRAC_LO, which is the trigger for VCO
diff --git a/firmware/common/max2839_regs.def b/firmware/common/max2839_regs.def
index 8cd578cf..bee66846 100644
--- a/firmware/common/max2839_regs.def
+++ b/firmware/common/max2839_regs.def
@@ -119,7 +119,15 @@ __MREG__(MAX2839_Temperature_Clk_En,9,1,1)
 __MREG__(MAX2839_RESERVED_9_2,9,2,1)
 __MREG__(MAX2839_DOUT_Drive_Sel,9,3,1)
 __MREG__(MAX2839_DOUT_3state_Ctrl,9,4,1)
-__MREG__(MAX2839_DOUT_Pin_Sel,9,7,3)
+__MREG__(MAX2839_DOUT_SEL,9,7,3)
+#define MAX2839_DOUT_SEL_SPI             0 // default, SPI comm
+#define MAX2839_DOUT_SEL_PLL_LOCK_DETECT 1
+#define MAX2839_DOUT_SEL_VAS_TEST_OUT    2
+#define MAX2839_DOUT_SEL_HPFSM_TEST_OUT  3
+#define MAX2839_DOUT_SEL_LOGEN_TRIM_OUT  4
+#define MAX2839_DOUT_SEL_RX_FUSE_GASKET  5
+#define MAX2839_DOUT_SEL_TX_FUSE_GASKET  6
+#define MAX2839_DOUT_SEL_ZERO            7
 __MREG__(MAX2839_RESERVED_9_9,9,9,2)
 
 /* REG 10 */