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stm32/rtc: autocompute wakeup psc.

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This commit is contained in:
xoviat 2023-08-10 18:59:18 -05:00
parent 0705152105
commit a0c69ffe02
1 changed files with 80 additions and 16 deletions
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96
embassy-stm32/src/rtc/v2.rs
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@ -5,6 +5,69 @@ use crate::pac::rtc::Rtc;
use crate::peripherals::RTC;
use crate::rtc::sealed::Instance;
#[derive(Clone, Copy)]
pub(crate) enum WakeupPrescaler {
Div2,
Div4,
Div8,
Div16,
}
#[cfg(stm32wb)]
impl From<WakeupPrescaler> for crate::pac::rtc::vals::Wucksel {
fn from(val: WakeupPrescaler) -> Self {
use crate::pac::rtc::vals::Wucksel;
match val {
WakeupPrescaler::Div2 => Wucksel::DIV2,
WakeupPrescaler::Div4 => Wucksel::DIV4,
WakeupPrescaler::Div8 => Wucksel::DIV8,
WakeupPrescaler::Div16 => Wucksel::DIV16,
}
}
}
#[cfg(stm32wb)]
impl From<crate::pac::rtc::vals::Wucksel> for WakeupPrescaler {
fn from(val: crate::pac::rtc::vals::Wucksel) -> Self {
use crate::pac::rtc::vals::Wucksel;
match val {
Wucksel::DIV2 => WakeupPrescaler::Div2,
Wucksel::DIV4 => WakeupPrescaler::Div4,
Wucksel::DIV8 => WakeupPrescaler::Div8,
Wucksel::DIV16 => WakeupPrescaler::Div16,
_ => unreachable!(),
}
}
}
impl From<WakeupPrescaler> for u32 {
fn from(val: WakeupPrescaler) -> Self {
match val {
WakeupPrescaler::Div2 => 2,
WakeupPrescaler::Div4 => 4,
WakeupPrescaler::Div8 => 8,
WakeupPrescaler::Div16 => 16,
}
}
}
impl WakeupPrescaler {
pub fn compute_min(val: u32) -> Self {
*[
WakeupPrescaler::Div2,
WakeupPrescaler::Div4,
WakeupPrescaler::Div8,
WakeupPrescaler::Div16,
]
.iter()
.skip_while(|psc| <WakeupPrescaler as Into<u32>>::into(**psc) <= val)
.next()
.unwrap_or(&WakeupPrescaler::Div16)
}
}
impl super::Rtc {
fn unlock_registers() {
#[cfg(any(rtc_v2f2, rtc_v2f3, rtc_v2l1))]
@ -24,44 +87,45 @@ impl super::Rtc {
#[allow(dead_code)]
#[cfg(all(feature = "time", stm32wb))]
// start the wakeup alarm with the given duration
pub(crate) fn start_wakeup_alarm(duration: embassy_time::Duration) {
use embassy_time::TICK_HZ;
use stm32_metapac::rtc::vals::Wucksel;
/// start the wakeup alarm and return the actual duration of the alarm
/// the actual duration will be the closest value possible that is less
/// than the requested duration.
pub(crate) fn start_wakeup_alarm(requested_duration: embassy_time::Duration) -> embassy_time::Duration {
use embassy_time::{Duration, TICK_HZ};
use crate::interrupt::typelevel::Interrupt;
use crate::rcc::get_freqs;
let rtc_hz = unsafe { get_freqs() }.rtc.unwrap().0 as u64;
// Choose the lowest prescaler available
#[cfg(stm32wb)]
let rtc_hz = rtc_hz / 2;
let rtc_ticks = requested_duration.as_ticks() * rtc_hz / TICK_HZ;
let prescaler = WakeupPrescaler::compute_min((rtc_ticks / u16::MAX as u64) as u32);
let rtc_ticks = duration.as_ticks() * rtc_hz / TICK_HZ;
// adjust the rtc ticks to the prescaler
let rtc_ticks = rtc_ticks / (<WakeupPrescaler as Into<u32>>::into(prescaler) as u64);
let rtc_ticks = if rtc_ticks > u16::MAX as u64 {
u16::MAX
} else {
rtc_ticks as u16
};
while !RTC::regs().isr().read().wutf() {}
RTC::regs().isr().modify(|w| w.set_wutf(false));
RTC::regs().wutr().modify(|w| w.set_wut(rtc_ticks));
let duration = Duration::from_ticks(
rtc_ticks as u64 * TICK_HZ * (<WakeupPrescaler as Into<u32>>::into(prescaler) as u64) / rtc_hz,
);
crate::interrupt::typelevel::RTC_WKUP::unpend();
unsafe { crate::interrupt::typelevel::RTC_WKUP::enable() };
RTC::regs().wutr().modify(|w| w.set_wut(rtc_ticks));
RTC::regs().cr().modify(|w| {
// Choose the lowest prescaler available
#[cfg(stm32wb)]
w.set_wucksel(Wucksel::DIV2);
w.set_wucksel(prescaler.into());
w.set_wutie(true);
w.set_wute(true);
});
duration
}
#[allow(dead_code)]