Implement RTC peripheral for all stm32 families with rtc

embassy-stm32/src/rtc/mod.rs

@@ -0,0 +1,238 @@
+//! RTC peripheral abstraction
+use core::marker::PhantomData;
+
+#[cfg_attr(feature = "chrono", path = "datetime_chrono.rs")]
+#[cfg_attr(not(feature = "chrono"), path = "datetime_no_deps.rs")]
+mod datetime;
+
+pub use self::datetime::{DateTime, DayOfWeek, Error as DateTimeError};
+
+/// refer to AN4759 to compare features of RTC2 and RTC3
+#[cfg_attr(any(rtc_v1), path = "v1.rs")]
+#[cfg_attr(
+    any(
+        rtc_v2f0, rtc_v2f2, rtc_v2f3, rtc_v2f4, rtc_v2f7, rtc_v2h7, rtc_v2l0, rtc_v2l1, rtc_v2l4, rtc_v2wb
+    ),
+    path = "v2/mod.rs"
+)]
+#[cfg_attr(any(rtc_v3, rtc_v3u5), path = "v3.rs")]
+mod versions;
+use embassy_hal_common::Peripheral;
+pub use versions::*;
+
+/// Errors that can occur on methods on [RtcClock]
+#[derive(Clone, Debug, PartialEq, Eq)]
+pub enum RtcError {
+    /// An invalid DateTime was given or stored on the hardware.
+    InvalidDateTime(DateTimeError),
+
+    /// The RTC clock is not running
+    NotRunning,
+}
+
+/// RTC Abstraction
+pub struct Rtc<'d, T: Instance> {
+    phantom: PhantomData<&'d mut T>,
+    rtc_config: RtcConfig,
+}
+
+#[derive(Copy, Clone, Debug, PartialEq)]
+#[repr(u8)]
+pub enum RtcClockSource {
+    /// 00: No clock
+    NoClock = 0b00,
+    /// 01: LSE oscillator clock used as RTC clock
+    LSE = 0b01,
+    /// 10: LSI oscillator clock used as RTC clock
+    LSI = 0b10,
+    /// 11: HSE oscillator clock divided by 32 used as RTC clock
+    HSE = 0b11,
+}
+
+#[derive(Copy, Clone, PartialEq)]
+pub struct RtcConfig {
+    /// RTC clock source
+    clock_config: RtcClockSource,
+    /// Asynchronous prescaler factor
+    /// This is the asynchronous division factor:
+    /// ck_apre frequency = RTCCLK frequency/(PREDIV_A+1)
+    /// ck_apre drives the subsecond register
+    async_prescaler: u8,
+    /// Synchronous prescaler factor
+    /// This is the synchronous division factor:
+    /// ck_spre frequency = ck_apre frequency/(PREDIV_S+1)
+    /// ck_spre must be 1Hz
+    sync_prescaler: u16,
+}
+
+impl Default for RtcConfig {
+    /// LSI with prescalers assuming 32.768 kHz.
+    /// Raw sub-seconds in 1/256.
+    fn default() -> Self {
+        RtcConfig {
+            clock_config: RtcClockSource::LSI,
+            async_prescaler: 127,
+            sync_prescaler: 255,
+        }
+    }
+}
+
+impl RtcConfig {
+    /// Sets the clock source of RTC config
+    pub fn clock_config(mut self, cfg: RtcClockSource) -> Self {
+        self.clock_config = cfg;
+        self
+    }
+
+    /// Set the asynchronous prescaler of RTC config
+    pub fn async_prescaler(mut self, prescaler: u8) -> Self {
+        self.async_prescaler = prescaler;
+        self
+    }
+
+    /// Set the synchronous prescaler of RTC config
+    pub fn sync_prescaler(mut self, prescaler: u16) -> Self {
+        self.sync_prescaler = prescaler;
+        self
+    }
+}
+
+#[derive(Copy, Clone, Debug, PartialEq)]
+#[repr(u8)]
+pub enum RtcCalibrationCyclePeriod {
+    /// 8-second calibration period
+    Seconds8,
+    /// 16-second calibration period
+    Seconds16,
+    /// 32-second calibration period
+    Seconds32,
+}
+
+impl Default for RtcCalibrationCyclePeriod {
+    fn default() -> Self {
+        RtcCalibrationCyclePeriod::Seconds32
+    }
+}
+
+impl<'d, T: Instance> Rtc<'d, T> {
+    pub fn new(_rtc: impl Peripheral<P = T> + 'd, rtc_config: RtcConfig) -> Self {
+        unsafe { enable_peripheral_clk() };
+
+        let mut rtc_struct = Self {
+            phantom: PhantomData,
+            rtc_config,
+        };
+
+        rtc_struct.apply_config(rtc_config);
+
+        rtc_struct
+    }
+
+    /// Set the datetime to a new value.
+    ///
+    /// # Errors
+    ///
+    /// Will return `RtcError::InvalidDateTime` if the datetime is not a valid range.
+    pub fn set_datetime(&mut self, t: DateTime) -> Result<(), RtcError> {
+        self::datetime::validate_datetime(&t).map_err(RtcError::InvalidDateTime)?;
+        self.write(true, |rtc| self::datetime::write_date_time(rtc, t));
+
+        Ok(())
+    }
+
+    /// Return the current datetime.
+    ///
+    /// # Errors
+    ///
+    /// Will return an `RtcError::InvalidDateTime` if the stored value in the system is not a valid [`DayOfWeek`].
+    pub fn now(&self) -> Result<DateTime, RtcError> {
+        let r = T::regs();
+        unsafe {
+            let tr = r.tr().read();
+            let second = bcd2_to_byte((tr.st(), tr.su()));
+            let minute = bcd2_to_byte((tr.mnt(), tr.mnu()));
+            let hour = bcd2_to_byte((tr.ht(), tr.hu()));
+            // Reading either RTC_SSR or RTC_TR locks the values in the higher-order
+            // calendar shadow registers until RTC_DR is read.
+            let dr = r.dr().read();
+
+            let weekday = dr.wdu();
+            let day = bcd2_to_byte((dr.dt(), dr.du()));
+            let month = bcd2_to_byte((dr.mt() as u8, dr.mu()));
+            let year = bcd2_to_byte((dr.yt(), dr.yu())) as u16 + 1970_u16;
+
+            self::datetime::datetime(year, month, day, weekday, hour, minute, second).map_err(RtcError::InvalidDateTime)
+        }
+    }
+
+    /// Check if daylight savings time is active.
+    pub fn get_daylight_savings(&self) -> bool {
+        let cr = unsafe { T::regs().cr().read() };
+        cr.bkp()
+    }
+
+    /// Enable/disable daylight savings time.
+    pub fn set_daylight_savings(&mut self, daylight_savings: bool) {
+        self.write(true, |rtc| {
+            unsafe { rtc.cr().modify(|w| w.set_bkp(daylight_savings)) };
+        })
+    }
+
+    pub fn get_config(&self) -> RtcConfig {
+        self.rtc_config
+    }
+
+    pub const BACKUP_REGISTER_COUNT: usize = BACKUP_REGISTER_COUNT;
+
+    /// Read content of the backup register.
+    ///
+    /// The registers retain their values during wakes from standby mode or system resets. They also
+    /// retain their value when Vdd is switched off as long as V_BAT is powered.
+    pub fn read_backup_register(&self, register: usize) -> Option<u32> {
+        read_backup_register(&T::regs(), register)
+    }
+
+    /// Set content of the backup register.
+    ///
+    /// The registers retain their values during wakes from standby mode or system resets. They also
+    /// retain their value when Vdd is switched off as long as V_BAT is powered.
+    pub fn write_backup_register(&self, register: usize, value: u32) {
+        write_backup_register(&T::regs(), register, value)
+    }
+}
+
+pub(crate) fn byte_to_bcd2(byte: u8) -> (u8, u8) {
+    let mut bcd_high: u8 = 0;
+    let mut value = byte;
+
+    while value >= 10 {
+        bcd_high += 1;
+        value -= 10;
+    }
+
+    (bcd_high, ((bcd_high << 4) | value) as u8)
+}
+
+pub(crate) fn bcd2_to_byte(bcd: (u8, u8)) -> u8 {
+    let value = bcd.1 | bcd.0 << 4;
+
+    let tmp = ((value & 0xF0) >> 0x4) * 10;
+
+    tmp + (value & 0x0F)
+}
+
+pub(crate) mod sealed {
+    pub trait Instance {
+        fn regs() -> crate::pac::rtc::Rtc;
+    }
+}
+
+pub trait Instance: sealed::Instance + 'static {}
+
+impl sealed::Instance for crate::peripherals::RTC {
+    fn regs() -> crate::pac::rtc::Rtc {
+        crate::pac::RTC
+    }
+}
+
+impl Instance for crate::peripherals::RTC {}