From 4f97d00e7932cd12f9bc613c90a4238ec3efb72b Mon Sep 17 00:00:00 2001
From: Sebastien Bourdeauducq <sb@m-labs.hk>
Date: Thu, 5 Jan 2017 14:54:48 +0100
Subject: [PATCH] firmware: make i2c busno u8

---
 artiq/firmware/libboard/i2c.rs         | 25 +++++++++++++------------
 artiq/firmware/libboard/si5324.rs      |  2 +-
 artiq/firmware/libksupport/lib.rs      |  8 ++++----
 artiq/firmware/runtime/kernel_proto.rs |  8 ++++----
 4 files changed, 22 insertions(+), 21 deletions(-)

diff --git a/artiq/firmware/libboard/i2c.rs b/artiq/firmware/libboard/i2c.rs
index 811f065bd..6a2fb61c8 100644
--- a/artiq/firmware/libboard/i2c.rs
+++ b/artiq/firmware/libboard/i2c.rs
@@ -2,16 +2,16 @@ use csr;
 use clock;
 
 fn half_period() { clock::spin_us(100) }
-fn sda_bit(busno: u32) -> u8 { 1 << (2 * busno + 1) }
-fn scl_bit(busno: u32) -> u8 { 1 << (2 * busno) }
+fn sda_bit(busno: u8) -> u8 { 1 << (2 * busno + 1) }
+fn scl_bit(busno: u8) -> u8 { 1 << (2 * busno) }
 
-fn sda_i(busno: u32) -> bool {
+fn sda_i(busno: u8) -> bool {
     unsafe {
         csr::i2c::in_read() & sda_bit(busno) != 0
     }
 }
 
-fn sda_oe(busno: u32, oe: bool) {
+fn sda_oe(busno: u8, oe: bool) {
     unsafe {
         let reg = csr::i2c::oe_read();
         let reg = if oe { reg | sda_bit(busno) } else { reg & !sda_bit(busno) };
@@ -19,7 +19,7 @@ fn sda_oe(busno: u32, oe: bool) {
     }
 }
 
-fn sda_o(busno: u32, o: bool) {
+fn sda_o(busno: u8, o: bool) {
     unsafe {
         let reg = csr::i2c::out_read();
         let reg = if o  { reg | sda_bit(busno) } else { reg & !sda_bit(busno) };
@@ -27,7 +27,7 @@ fn sda_o(busno: u32, o: bool) {
     }
 }
 
-fn scl_oe(busno: u32, oe: bool) {
+fn scl_oe(busno: u8, oe: bool) {
     unsafe {
         let reg = csr::i2c::oe_read();
         let reg = if oe { reg | scl_bit(busno) } else { reg & !scl_bit(busno) };
@@ -35,7 +35,7 @@ fn scl_oe(busno: u32, oe: bool) {
     }
 }
 
-fn scl_o(busno: u32, o: bool) {
+fn scl_o(busno: u8, o: bool) {
     unsafe {
         let reg = csr::i2c::out_read();
         let reg = if o  { reg | scl_bit(busno) } else { reg & !scl_bit(busno) };
@@ -45,6 +45,7 @@ fn scl_o(busno: u32, o: bool) {
 
 pub fn init() {
     for busno in 0..csr::CONFIG_I2C_BUS_COUNT {
+        let busno = busno as u8;
         // Set SCL as output, and high level
         scl_o(busno, true);
         scl_oe(busno, true);
@@ -62,7 +63,7 @@ pub fn init() {
     }
 }
 
-pub fn start(busno: u32) {
+pub fn start(busno: u8) {
     // Set SCL high then SDA low
     scl_o(busno, true);
     half_period();
@@ -70,7 +71,7 @@ pub fn start(busno: u32) {
     half_period();
 }
 
-pub fn restart(busno: u32) {
+pub fn restart(busno: u8) {
     // Set SCL low then SDA high */
     scl_o(busno, false);
     half_period();
@@ -80,7 +81,7 @@ pub fn restart(busno: u32) {
     start(busno);
 }
 
-pub fn stop(busno: u32) {
+pub fn stop(busno: u8) {
     // First, make sure SCL is low, so that the target releases the SDA line
     scl_o(busno, false);
     half_period();
@@ -92,7 +93,7 @@ pub fn stop(busno: u32) {
     half_period();
 }
 
-pub fn write(busno: u32, data: u8) -> bool {
+pub fn write(busno: u8, data: u8) -> bool {
     // MSB first
     for bit in (0..8).rev() {
         // Set SCL low and set our bit on SDA
@@ -115,7 +116,7 @@ pub fn write(busno: u32, data: u8) -> bool {
     !sda_i(busno)
 }
 
-pub fn read(busno: u32, ack: bool) -> u8 {
+pub fn read(busno: u8, ack: bool) -> u8 {
     // Set SCL low first, otherwise setting SDA as input may cause a transition
     // on SDA with SCL high which will be interpreted as START/STOP condition.
     scl_o(busno, false);
diff --git a/artiq/firmware/libboard/si5324.rs b/artiq/firmware/libboard/si5324.rs
index 41bbb050e..c58f20b41 100644
--- a/artiq/firmware/libboard/si5324.rs
+++ b/artiq/firmware/libboard/si5324.rs
@@ -1,7 +1,7 @@
 use i2c;
 use clock;
 
-const BUSNO: u32 = 0;
+const BUSNO: u8 = 0;
 const ADDRESS: u8 = 0x68;
 
 #[cfg(soc_platform = "kc705")]
diff --git a/artiq/firmware/libksupport/lib.rs b/artiq/firmware/libksupport/lib.rs
index dbca35b54..eb2423136 100644
--- a/artiq/firmware/libksupport/lib.rs
+++ b/artiq/firmware/libksupport/lib.rs
@@ -242,20 +242,20 @@ extern fn cache_put(key: *const u8, list: ArtiqList<i32>) {
 }
 
 extern fn i2c_start(busno: i32) {
-    send(&I2CStartRequest { busno: busno as u32 });
+    send(&I2CStartRequest { busno: busno as u8 });
 }
 
 extern fn i2c_stop(busno: i32) {
-    send(&I2CStopRequest { busno: busno as u32 });
+    send(&I2CStopRequest { busno: busno as u8 });
 }
 
 extern fn i2c_write(busno: i32, data: i8) -> bool {
-    send(&I2CWriteRequest { busno: busno as u32, data: data as u8 });
+    send(&I2CWriteRequest { busno: busno as u8, data: data as u8 });
     recv!(&I2CWriteReply { ack } => ack)
 }
 
 extern fn i2c_read(busno: i32, ack: bool) -> i8 {
-    send(&I2CReadRequest { busno: busno as u32, ack: ack });
+    send(&I2CReadRequest { busno: busno as u8, ack: ack });
     recv!(&I2CReadReply { data } => data) as i8
 }
 
diff --git a/artiq/firmware/runtime/kernel_proto.rs b/artiq/firmware/runtime/kernel_proto.rs
index d32750648..c4699b708 100644
--- a/artiq/firmware/runtime/kernel_proto.rs
+++ b/artiq/firmware/runtime/kernel_proto.rs
@@ -57,11 +57,11 @@ pub enum Message<'a> {
     CachePutRequest { key: &'a str, value: &'a [i32] },
     CachePutReply   { succeeded: bool },
 
-    I2CStartRequest { busno: u32 },
-    I2CStopRequest { busno: u32 },
-    I2CWriteRequest { busno: u32, data: u8 },
+    I2CStartRequest { busno: u8 },
+    I2CStopRequest { busno: u8 },
+    I2CWriteRequest { busno: u8, data: u8 },
     I2CWriteReply { ack: bool },
-    I2CReadRequest { busno: u32, ack: bool },
+    I2CReadRequest { busno: u8, ack: bool },
     I2CReadReply { data: u8 },
 
     Log(fmt::Arguments<'a>),