drtio: reset Si5324 at each boot

artiq/firmware/libboard/si5324.rs

@@ -1,6 +1,7 @@
 use core::result;
 use i2c;
 use clock;
+use csr;
 
 type Result<T> = result::Result<T, &'static str>;
 
@@ -20,6 +21,12 @@ fn pca9548_select(channel: u8) -> Result<()> {
     Ok(())
 }
 
+fn reset(en: bool) {
+    unsafe {
+        csr::si5324_rst_n::out_write(if en { 0 } else { 1 })
+    }
+}
+
 // NOTE: the logical parameters DO NOT MAP to physical values written
 // into registers. They have to be mapped; see the datasheet.
 // DSPLLsim reports the logical parameters in the design summary, not
@@ -126,6 +133,11 @@ fn locked() -> Result<bool> {
 pub fn setup_hitless_clock_switching(settings: &FrequencySettings) -> Result<()> {
     let s = map_frequency_settings(settings)?;
 
+    reset(true);
+    clock::spin_us(1_000);
+    reset(false);
+    clock::spin_us(10_000);
+
     #[cfg(soc_platform = "kc705")]
     pca9548_select(7)?;
 

artiq/gateware/targets/kc705_drtio_satellite.py

@@ -92,7 +92,8 @@ class Satellite(BaseSoC):
                 i_I=ClockSignal("rtio_rx"),
                 o_O=si5324_clkin.p, o_OB=si5324_clkin.n
             )
-        self.comb += platform.request("si5324").rst_n.eq(1)
+        self.submodules.si5324_rst_n = gpio.GPIOOut(platform.request("si5324").rst_n)
+        self.csr_devices.append("si5324_rst_n")
         i2c = self.platform.request("i2c")
         self.submodules.i2c = gpio.GPIOTristate([i2c.scl, i2c.sda])
         self.csr_devices.append("i2c")