From a792fa11bea0bde00aa9aaf0aa6c2640bdb633a3 Mon Sep 17 00:00:00 2001
From: Yuval Adam <_@yuv.al>
Date: Fri, 3 Aug 2018 16:19:11 +0300
Subject: Implement r820t init

---
 src/usb.rs | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

(limited to 'src/usb.rs')

diff --git a/src/usb.rs b/src/usb.rs
index fdae356..035786e 100644
--- a/src/usb.rs
+++ b/src/usb.rs
@@ -28,6 +28,9 @@ const FIR_DEFAULT: [u8; FIR_LENGTH] = [
     0x9c, 0x0d, 0x71, 0x11, 0x14, 0x71, 0x74, 0x19, 0x41, 0xa5,
 ];
 
+const DEF_RTL_XTAL_FREQ: u32 = 28800000;
+const MIN_RTL_XTAL_FREQ: u32 = DEF_RTL_XTAL_FREQ - 1000;
+const MAX_RTL_XTAL_FREQ: u32 = DEF_RTL_XTAL_FREQ + 1000;
 
 const CTRL_TIMEOUT: Duration = Duration::from_millis(300);
 
@@ -181,6 +184,19 @@ impl<'a> Usb<'a> {
         self.demod_write_reg(0, 0x0d, 0x83, 1);
     }
 
+    pub fn set_if_freq(&self, freq: u32) {
+        let rtl_xtal: u32 = DEF_RTL_XTAL_FREQ; // need to apply PPM correction
+        let base = 1u32 << 22;
+        let if_freq: i32 = (freq as f64 * base as f64 / rtl_xtal as f64 * -1f64) as i32;
+
+        let tmp = ((if_freq >> 16) as u16) & 0x3f;
+        self.demod_write_reg(1, 0x19, tmp, 1);
+        let tmp = ((if_freq >> 8) as u16) & 0xff;
+        self.demod_write_reg(1, 0x1a, tmp, 1);
+        let tmp = if_freq as u16 & 0xff;
+        self.demod_write_reg(1, 0x1b, tmp, 1);
+    }
+
     pub fn deinit_baseband(&self) {
         // deinit tuner?
 
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