From 3d0e92aefdac58d2a2e5a731a402848cf3145b83 Mon Sep 17 00:00:00 2001
From: Sebastien Bourdeauducq <sb@m-labs.hk>
Date: Tue, 19 Jun 2018 23:49:17 +0800
Subject: [PATCH] hmc7043: check that chip is disabled at startup

---
 artiq/firmware/libboard_artiq/hmc830_7043.rs | 15 ++++++++++++---
 1 file changed, 12 insertions(+), 3 deletions(-)

diff --git a/artiq/firmware/libboard_artiq/hmc830_7043.rs b/artiq/firmware/libboard_artiq/hmc830_7043.rs
index 0e7f5a6ed..06292e831 100644
--- a/artiq/firmware/libboard_artiq/hmc830_7043.rs
+++ b/artiq/firmware/libboard_artiq/hmc830_7043.rs
@@ -227,10 +227,16 @@ pub mod hmc7043 {
         }
     }
 
-    pub fn detect() -> Result<(), &'static str> {
+    pub const CHIP_ID: u32 = 0xf17904;
+
+    pub fn get_id() -> u32 {
         spi_setup();
-        let id = (read(0x78) as u32) << 16 | (read(0x79) as u32) << 8 | read(0x7a) as u32;
-        if id != 0xf17904 {
+        (read(0x78) as u32) << 16 | (read(0x79) as u32) << 8 | read(0x7a) as u32
+    }
+
+    pub fn detect() -> Result<(), &'static str> {
+        let id = get_id();
+        if id != CHIP_ID {
             error!("invalid HMC7043 ID: 0x{:08x}", id);
             return Err("invalid HMC7043 identification");
         } else {
@@ -340,6 +346,9 @@ pub fn init() -> Result<(), &'static str> {
 
     hmc830::check_locked()?;
 
+    if hmc7043::get_id() == hmc7043::CHIP_ID {
+        error!("HMC7043 detected while in reset (board rework missing?)");
+    }
     hmc7043::enable();
     hmc7043::detect()?;
     hmc7043::init();