From 77f4308a7cc7b3c5e7a236c306b0c82f4f3d0fe0 Mon Sep 17 00:00:00 2001
From: David Wood <code@dtwood.co.uk>
Date: Sun, 19 Jul 2020 21:21:00 +0100
Subject: [PATCH] Add support for RTC from the HIB peripheral

---
 tm4c123x-hal/src/hib.rs | 72 ++++++++++++++++++++++++++++++++++++++
 tm4c123x-hal/src/lib.rs |  1 +
 tm4c129x-hal/src/hib.rs | 76 +++++++++++++++++++++++++++++++++++++++++
 tm4c129x-hal/src/lib.rs |  1 +
 4 files changed, 150 insertions(+)
 create mode 100644 tm4c123x-hal/src/hib.rs
 create mode 100644 tm4c129x-hal/src/hib.rs

diff --git a/tm4c123x-hal/src/hib.rs b/tm4c123x-hal/src/hib.rs
new file mode 100644
index 0000000..3cf7f25
--- /dev/null
+++ b/tm4c123x-hal/src/hib.rs
@@ -0,0 +1,72 @@
+//! A wrapper for the HIB (Hibernation) peripheral
+
+use crate::sysctl;
+
+/// Which source to use for the HIB clock
+pub enum Source {
+    /// HIB clock is from an external oscillator
+    ExternalOscillator,
+    /// HIB clock is from the internal low-frequency oscillator
+    LowFrequencyInternalOscillator,
+}
+
+/// A wrapper around the HIB (Hibernation) peripheral
+pub struct Hib {
+    hib: tm4c123x::HIB,
+}
+
+impl Hib {
+    /// Initialize the HIB peripheral, using a clock from `source`
+    pub fn hib(hib: tm4c123x::HIB, source: Source, _pc: &sysctl::PowerControl) -> Self {
+        hib.ctl.write(|w| {
+            match source {
+                Source::ExternalOscillator => w.oscbyp().set_bit(),
+                Source::LowFrequencyInternalOscillator => w.oscbyp().clear_bit(),
+            };
+
+            w.clk32en().set_bit();
+
+            w
+        });
+
+        while hib.ctl.read().wrc().bit_is_clear() {}
+        hib.ctl.write(|w| {
+            match source {
+                Source::ExternalOscillator => w.oscbyp().set_bit(),
+                Source::LowFrequencyInternalOscillator => w.oscbyp().clear_bit(),
+            };
+
+            w.oscdrv().set_bit();
+            w.clk32en().set_bit();
+            w.rtcen().set_bit();
+
+            w
+        });
+        while hib.ctl.read().wrc().bit_is_clear() {}
+
+        Hib { hib }
+    }
+
+    /// Get the current time, in units of (seconds, subseconds), where a
+    /// subsecond is 1/32768 seconds
+    pub fn get_time(&self) -> (u32, u16) {
+        loop {
+            let seconds = self.hib.rtcc.read().bits();
+            let subsec = self.hib.rtcss.read().rtcssc().bits();
+
+            if seconds == self.hib.rtcc.read().bits() {
+                return (seconds, subsec);
+            }
+        }
+    }
+
+    /// Get the current time in milliseconds
+    pub fn get_millis(&self) -> u64 {
+        let (seconds, subsec) = self.get_time();
+        let seconds: u64 = seconds.into();
+        let subsec: u64 = subsec.into();
+
+        let millis: u64 = subsec * 1000 / 32_768;
+        return seconds * 1000 + millis;
+    }
+}
diff --git a/tm4c123x-hal/src/lib.rs b/tm4c123x-hal/src/lib.rs
index 3772060..12137ba 100644
--- a/tm4c123x-hal/src/lib.rs
+++ b/tm4c123x-hal/src/lib.rs
@@ -33,6 +33,7 @@ pub use crate::tm4c123x::interrupt;
 use embedded_hal as hal;
 
 pub mod gpio;
+pub mod hib;
 pub mod i2c;
 pub mod prelude;
 pub mod pwm;
diff --git a/tm4c129x-hal/src/hib.rs b/tm4c129x-hal/src/hib.rs
new file mode 100644
index 0000000..2516d4d
--- /dev/null
+++ b/tm4c129x-hal/src/hib.rs
@@ -0,0 +1,76 @@
+//! A wrapper for the HIB (Hibernation) peripheral
+
+use crate::sysctl;
+
+/// Which source to use for the HIB clock
+pub enum Source {
+    /// HIB clock is from an external crystal
+    ExternalCrystal,
+    /// HIB clock is from an external oscillator
+    ExternalOscillator,
+    /// HIB clock is from the internal low-frequency oscillator
+    LowFrequencyInternalOscillator,
+}
+
+/// A wrapper around the HIB (Hibernation) peripheral
+pub struct Hib {
+    hib: tm4c129x::HIB,
+}
+
+impl Hib {
+    /// Initialize the HIB peripheral, using a clock from `source`
+    pub fn hib(hib: tm4c129x::HIB, source: Source, _pc: &sysctl::PowerControl) -> Self {
+        hib.ctl.write(|w| {
+            match source {
+                Source::ExternalCrystal => w.oscsel().clear_bit().oscbyp().clear_bit(),
+                Source::ExternalOscillator => w.oscsel().clear_bit().oscbyp().set_bit(),
+                Source::LowFrequencyInternalOscillator => w.oscsel().set_bit().oscbyp().clear_bit(),
+            };
+
+            w.clk32en().set_bit();
+
+            w
+        });
+
+        while hib.ctl.read().wrc().bit_is_clear() {}
+        hib.ctl.write(|w| {
+            match source {
+                Source::ExternalCrystal => w.oscsel().clear_bit().oscbyp().clear_bit(),
+                Source::ExternalOscillator => w.oscsel().clear_bit().oscbyp().set_bit(),
+                Source::LowFrequencyInternalOscillator => w.oscsel().set_bit().oscbyp().clear_bit(),
+            };
+
+            w.oscdrv().set_bit();
+            w.clk32en().set_bit();
+            w.rtcen().set_bit();
+
+            w
+        });
+        while hib.ctl.read().wrc().bit_is_clear() {}
+
+        Hib { hib }
+    }
+
+    /// Get the current time, in units of (seconds, subseconds), where a
+    /// subsecond is 1/32768 seconds
+    pub fn get_time(&self) -> (u32, u16) {
+        loop {
+            let seconds = self.hib.rtcc.read().bits();
+            let subsec = self.hib.rtcss.read().rtcssc().bits();
+
+            if seconds == self.hib.rtcc.read().bits() {
+                return (seconds, subsec);
+            }
+        }
+    }
+
+    /// Get the current time in milliseconds
+    pub fn get_millis(&self) -> u64 {
+        let (seconds, subsec) = self.get_time();
+        let seconds: u64 = seconds.into();
+        let subsec: u64 = subsec.into();
+
+        let millis: u64 = subsec * 1000 / 32_768;
+        return seconds * 1000 + millis;
+    }
+}
diff --git a/tm4c129x-hal/src/lib.rs b/tm4c129x-hal/src/lib.rs
index 618752c..73a6de0 100644
--- a/tm4c129x-hal/src/lib.rs
+++ b/tm4c129x-hal/src/lib.rs
@@ -33,6 +33,7 @@ pub use tm4c_hal::{bb, delay, time};
 pub use crate::tm4c129x::interrupt;
 
 pub mod gpio;
+pub mod hib;
 pub mod i2c;
 pub mod prelude;
 pub mod serial;