stm32/rtc: more rtc cleanup

embassy-stm32/src/rtc/datetime.rs

@@ -4,8 +4,60 @@ use core::convert::From;
 #[cfg(feature = "chrono")]
 use chrono::{self, Datelike, NaiveDate, Timelike, Weekday};
 
-use super::byte_to_bcd2;
-use crate::pac::rtc::Rtc;
+#[cfg(any(feature = "defmt", feature = "time"))]
+use crate::peripherals::RTC;
+#[cfg(any(feature = "defmt", feature = "time"))]
+use crate::rtc::sealed::Instance;
+
+/// Represents an instant in time that can be substracted to compute a duration
+pub struct RtcInstant {
+    /// 0..59
+    pub second: u8,
+    /// 0..256
+    pub subsecond: u16,
+}
+
+impl RtcInstant {
+    #[allow(dead_code)]
+    pub(super) fn from(second: u8, subsecond: u16) -> Result<Self, super::RtcError> {
+        Ok(Self { second, subsecond })
+    }
+}
+
+#[cfg(feature = "defmt")]
+impl defmt::Format for RtcInstant {
+    fn format(&self, fmt: defmt::Formatter) {
+        defmt::write!(
+            fmt,
+            "{}:{}",
+            self.second,
+            RTC::regs().prer().read().prediv_s() - self.subsecond,
+        )
+    }
+}
+
+#[cfg(feature = "time")]
+impl core::ops::Sub for RtcInstant {
+    type Output = embassy_time::Duration;
+
+    fn sub(self, rhs: Self) -> Self::Output {
+        use embassy_time::{Duration, TICK_HZ};
+
+        let second = if self.second < rhs.second {
+            self.second + 60
+        } else {
+            self.second
+        };
+
+        let psc = RTC::regs().prer().read().prediv_s() as u32;
+
+        let self_ticks = second as u32 * (psc + 1) + (psc - self.subsecond as u32);
+        let other_ticks = rhs.second as u32 * (psc + 1) + (psc - rhs.subsecond as u32);
+        let rtc_ticks = self_ticks - other_ticks;
+
+        Duration::from_ticks(((rtc_ticks * TICK_HZ as u32) / (psc + 1)) as u64)
+    }
+}
 
 /// Errors regarding the [`DateTime`] struct.
 #[derive(Clone, Debug, PartialEq, Eq)]
@@ -32,19 +84,85 @@ pub enum Error {
 /// Structure containing date and time information
 pub struct DateTime {
     /// 0..4095
-    pub year: u16,
+    year: u16,
     /// 1..12, 1 is January
-    pub month: u8,
+    month: u8,
     /// 1..28,29,30,31 depending on month
-    pub day: u8,
+    day: u8,
     ///
-    pub day_of_week: DayOfWeek,
+    day_of_week: DayOfWeek,
     /// 0..23
-    pub hour: u8,
+    hour: u8,
     /// 0..59
-    pub minute: u8,
+    minute: u8,
     /// 0..59
-    pub second: u8,
+    second: u8,
+}
+
+impl DateTime {
+    pub const fn year(&self) -> u16 {
+        self.year
+    }
+
+    pub const fn month(&self) -> u8 {
+        self.month
+    }
+
+    pub const fn day(&self) -> u8 {
+        self.day
+    }
+
+    pub const fn day_of_week(&self) -> DayOfWeek {
+        self.day_of_week
+    }
+
+    pub const fn hour(&self) -> u8 {
+        self.hour
+    }
+
+    pub const fn minute(&self) -> u8 {
+        self.minute
+    }
+
+    pub const fn second(&self) -> u8 {
+        self.second
+    }
+
+    pub fn from(
+        year: u16,
+        month: u8,
+        day: u8,
+        day_of_week: u8,
+        hour: u8,
+        minute: u8,
+        second: u8,
+    ) -> Result<Self, Error> {
+        let day_of_week = day_of_week_from_u8(day_of_week)?;
+
+        if year > 4095 {
+            Err(Error::InvalidYear)
+        } else if month < 1 || month > 12 {
+            Err(Error::InvalidMonth)
+        } else if day < 1 || day > 31 {
+            Err(Error::InvalidDay)
+        } else if hour > 23 {
+            Err(Error::InvalidHour)
+        } else if minute > 59 {
+            Err(Error::InvalidMinute)
+        } else if second > 59 {
+            Err(Error::InvalidSecond)
+        } else {
+            Ok(Self {
+                year,
+                month,
+                day,
+                day_of_week,
+                hour,
+                minute,
+                second,
+            })
+        }
+    }
 }
 
 #[cfg(feature = "chrono")]
@@ -142,58 +260,3 @@ pub(super) fn validate_datetime(dt: &DateTime) -> Result<(), Error> {
         Ok(())
     }
 }
-
-pub(super) fn write_date_time(rtc: &Rtc, t: DateTime) {
-    let (ht, hu) = byte_to_bcd2(t.hour as u8);
-    let (mnt, mnu) = byte_to_bcd2(t.minute as u8);
-    let (st, su) = byte_to_bcd2(t.second as u8);
-
-    let (dt, du) = byte_to_bcd2(t.day as u8);
-    let (mt, mu) = byte_to_bcd2(t.month as u8);
-    let yr = t.year as u16;
-    let yr_offset = (yr - 1970_u16) as u8;
-    let (yt, yu) = byte_to_bcd2(yr_offset);
-
-    use crate::pac::rtc::vals::Ampm;
-
-    rtc.tr().write(|w| {
-        w.set_ht(ht);
-        w.set_hu(hu);
-        w.set_mnt(mnt);
-        w.set_mnu(mnu);
-        w.set_st(st);
-        w.set_su(su);
-        w.set_pm(Ampm::AM);
-    });
-
-    rtc.dr().write(|w| {
-        w.set_dt(dt);
-        w.set_du(du);
-        w.set_mt(mt > 0);
-        w.set_mu(mu);
-        w.set_yt(yt);
-        w.set_yu(yu);
-        w.set_wdu(day_of_week_to_u8(t.day_of_week));
-    });
-}
-
-pub(super) fn datetime(
-    year: u16,
-    month: u8,
-    day: u8,
-    day_of_week: u8,
-    hour: u8,
-    minute: u8,
-    second: u8,
-) -> Result<DateTime, Error> {
-    let day_of_week = day_of_week_from_u8(day_of_week)?;
-    Ok(DateTime {
-        year,
-        month,
-        day,
-        day_of_week,
-        hour,
-        minute,
-        second,
-    })
-}