Merge pull request #208 from embassy-rs/deconfigure-pins

nRF lowpower improvements

9 files changed, 310 insertions, 62 deletions

diff --git a/embassy-nrf-examples/src/bin/qspi.rs b/embassy-nrf-examples/src/bin/qspi.rs
index 14f215187..1f33192e9 100644
--- a/embassy-nrf-examples/src/bin/qspi.rs
+++ b/embassy-nrf-examples/src/bin/qspi.rs
@@ -33,7 +33,7 @@ async fn main(_spawner: Spawner, p: Peripherals) {
 
     let config = qspi::Config::default();
     let irq = interrupt::take!(QSPI);
-    let mut q = qspi::Qspi::new(p.QSPI, irq, sck, csn, io0, io1, io2, io3, config);
+    let mut q = qspi::Qspi::new(p.QSPI, irq, sck, csn, io0, io1, io2, io3, config).await;
 
     let mut id = [1; 3];
     q.custom_instruction(0x9F, &[], &mut id).await.unwrap();
diff --git a/embassy-nrf-examples/src/bin/qspi_lowpower.rs b/embassy-nrf-examples/src/bin/qspi_lowpower.rs
new file mode 100644
index 000000000..9bbc87caa
--- /dev/null
+++ b/embassy-nrf-examples/src/bin/qspi_lowpower.rs
@@ -0,0 +1,81 @@
+#![no_std]
+#![no_main]
+#![feature(min_type_alias_impl_trait)]
+#![feature(impl_trait_in_bindings)]
+#![feature(type_alias_impl_trait)]
+#![allow(incomplete_features)]
+
+#[path = "../example_common.rs"]
+mod example_common;
+
+use core::mem;
+use defmt::panic;
+use embassy::executor::Spawner;
+use embassy::time::{Duration, Timer};
+use embassy::traits::flash::Flash;
+use embassy_nrf::Peripherals;
+use embassy_nrf::{interrupt, qspi};
+use example_common::*;
+
+// Workaround for alignment requirements.
+// Nicer API will probably come in the future.
+#[repr(C, align(4))]
+struct AlignedBuf([u8; 64]);
+
+#[embassy::main]
+async fn main(_spawner: Spawner, mut p: Peripherals) {
+    let mut irq = interrupt::take!(QSPI);
+
+    loop {
+        let mut config = qspi::Config::default();
+        config.deep_power_down = Some(qspi::DeepPowerDownConfig {
+            enter_time: 3, // tDP = 30uS
+            exit_time: 3,  // tRDP = 35uS
+        });
+
+        let mut q = qspi::Qspi::new(
+            &mut p.QSPI,
+            &mut irq,
+            &mut p.P0_19,
+            &mut p.P0_17,
+            &mut p.P0_20,
+            &mut p.P0_21,
+            &mut p.P0_22,
+            &mut p.P0_23,
+            config,
+        )
+        .await;
+
+        let mut id = [1; 3];
+        q.custom_instruction(0x9F, &[], &mut id).await.unwrap();
+        info!("id: {}", id);
+
+        // Read status register
+        let mut status = [4; 1];
+        q.custom_instruction(0x05, &[], &mut status).await.unwrap();
+
+        info!("status: {:?}", status[0]);
+
+        if status[0] & 0x40 == 0 {
+            status[0] |= 0x40;
+
+            q.custom_instruction(0x01, &status, &mut []).await.unwrap();
+
+            info!("enabled quad in status");
+        }
+
+        let mut buf = AlignedBuf([0u8; 64]);
+
+        info!("reading...");
+        q.read(0, &mut buf.0).await.unwrap();
+        info!("read: {=[u8]:x}", buf.0);
+
+        // Drop the QSPI instance. This disables the peripehral and deconfigures the pins.
+        // This clears the borrow on the singletons, so they can now be used again.
+        mem::drop(q);
+
+        // Sleep for 1 second. The executor ensures the core sleeps with a WFE when it has nothing to do.
+        // During this sleep, the nRF chip should only use ~3uA
+        Timer::after(Duration::from_secs(1)).await;
+    }
+}
diff --git a/embassy-nrf-examples/src/bin/twim.rs b/embassy-nrf-examples/src/bin/twim.rs
new file mode 100644
index 000000000..537cea160
--- /dev/null
+++ b/embassy-nrf-examples/src/bin/twim.rs
@@ -0,0 +1,35 @@
+//! Example on how to read a 24C/24LC i2c eeprom.
+//!
+//! Connect SDA to P0.03, SCL to P0.04
+
+#![no_std]
+#![no_main]
+#![feature(min_type_alias_impl_trait)]
+#![feature(impl_trait_in_bindings)]
+#![feature(type_alias_impl_trait)]
+#![allow(incomplete_features)]
+
+#[path = "../example_common.rs"]
+mod example_common;
+
+use defmt::{panic, *};
+use embassy::executor::Spawner;
+use embassy_nrf::twim::{self, Twim};
+use embassy_nrf::{interrupt, Peripherals};
+
+const ADDRESS: u8 = 0x50;
+
+#[embassy::main]
+async fn main(_spawner: Spawner, p: Peripherals) {
+    info!("Initializing TWI...");
+    let config = twim::Config::default();
+    let irq = interrupt::take!(SPIM0_SPIS0_TWIM0_TWIS0_SPI0_TWI0);
+    let mut twi = Twim::new(p.TWISPI0, irq, p.P0_03, p.P0_04, config);
+
+    info!("Reading...");
+
+    let mut buf = [0u8; 16];
+    twi.write_then_read(ADDRESS, &mut [0x00], &mut buf).unwrap();
+
+    info!("Read: {=[u8]:x}", buf);
+}
diff --git a/embassy-nrf-examples/src/bin/twim_lowpower.rs b/embassy-nrf-examples/src/bin/twim_lowpower.rs
new file mode 100644
index 000000000..1cd66a18e
--- /dev/null
+++ b/embassy-nrf-examples/src/bin/twim_lowpower.rs
@@ -0,0 +1,54 @@
+//! Example on how to read a 24C/24LC i2c eeprom with low power consumption.
+//! The eeprom is read every 1 second, while ensuring lowest possible power while
+//! sleeping between reads.
+//!
+//! Connect SDA to P0.03, SCL to P0.04
+
+#![no_std]
+#![no_main]
+#![feature(min_type_alias_impl_trait)]
+#![feature(impl_trait_in_bindings)]
+#![feature(type_alias_impl_trait)]
+#![allow(incomplete_features)]
+
+#[path = "../example_common.rs"]
+mod example_common;
+
+use core::mem;
+
+use defmt::{panic, *};
+use embassy::executor::Spawner;
+use embassy::time::{Duration, Timer};
+use embassy_nrf::twim::{self, Twim};
+use embassy_nrf::{interrupt, Peripherals};
+
+const ADDRESS: u8 = 0x50;
+
+#[embassy::main]
+async fn main(_spawner: Spawner, mut p: Peripherals) {
+    info!("Started!");
+    let mut irq = interrupt::take!(SPIM0_SPIS0_TWIM0_TWIS0_SPI0_TWI0);
+
+    loop {
+        info!("Initializing TWI...");
+        let config = twim::Config::default();
+
+        // Create the TWIM instance with borrowed singletons, so they're not consumed.
+        let mut twi = Twim::new(&mut p.TWISPI0, &mut irq, &mut p.P0_03, &mut p.P0_04, config);
+
+        info!("Reading...");
+
+        let mut buf = [0u8; 16];
+        twi.write_then_read(ADDRESS, &mut [0x00], &mut buf).unwrap();
+
+        info!("Read: {=[u8]:x}", buf);
+
+        // Drop the TWIM instance. This disables the peripehral and deconfigures the pins.
+        // This clears the borrow on the singletons, so they can now be used again.
+        mem::drop(twi);
+
+        // Sleep for 1 second. The executor ensures the core sleeps with a WFE when it has nothing to do.
+        // During this sleep, the nRF chip should only use ~3uA
+        Timer::after(Duration::from_secs(1)).await;
+    }
+}
diff --git a/embassy-nrf/src/gpio.rs b/embassy-nrf/src/gpio.rs
index 3ae160ca8..b02e77874 100644
--- a/embassy-nrf/src/gpio.rs
+++ b/embassy-nrf/src/gpio.rs
@@ -12,6 +12,8 @@ use gpio::pin_cnf::DRIVE_A;
 use crate::pac;
 use crate::pac::p0 as gpio;
 
+use self::sealed::Pin as _;
+
 /// A GPIO port with up to 32 pins.
 #[derive(Debug, Eq, PartialEq)]
 pub enum Port {
@@ -487,6 +489,17 @@ impl OptionalPin for NoPin {
 
 // ====================
 
+pub(crate) fn deconfigure_pin(psel_bits: u32) {
+    if psel_bits & 0x8000_0000 != 0 {
+        return;
+    }
+    unsafe {
+        AnyPin::steal(psel_bits as _).conf().reset();
+    }
+}
+
+// ====================
+
 macro_rules! impl_pin {
     ($type:ident, $port_num:expr, $pin_num:expr) => {
         impl crate::gpio::Pin for peripherals::$type {}
diff --git a/embassy-nrf/src/qspi.rs b/embassy-nrf/src/qspi.rs
index e5d21ceaf..6cabe1168 100644
--- a/embassy-nrf/src/qspi.rs
+++ b/embassy-nrf/src/qspi.rs
@@ -2,6 +2,7 @@
 
 use core::future::Future;
 use core::marker::PhantomData;
+use core::ptr;
 use core::task::Poll;
 use embassy::interrupt::{Interrupt, InterruptExt};
 use embassy::traits::flash::{Error, Flash};
@@ -10,7 +11,8 @@ use embassy_extras::unborrow;
 use futures::future::poll_fn;
 
 use crate::fmt::{assert, assert_eq, *};
-use crate::gpio::Pin as GpioPin;
+use crate::gpio::sealed::Pin as _;
+use crate::gpio::{self, Pin as GpioPin};
 use crate::pac;
 
 pub use crate::pac::qspi::ifconfig0::ADDRMODE_A as AddressMode;
@@ -29,7 +31,9 @@ pub use crate::pac::qspi::ifconfig0::WRITEOC_A as WriteOpcode;
 // - set gpio in high drive
 
 pub struct DeepPowerDownConfig {
+    /// Time required for entering DPM, in units of 16us
     pub enter_time: u16,
+    /// Time required for exiting DPM, in units of 16us
     pub exit_time: u16,
 }
 
@@ -55,11 +59,12 @@ impl Default for Config {
 }
 
 pub struct Qspi<'d, T: Instance> {
+    dpm_enabled: bool,
     phantom: PhantomData<&'d mut T>,
 }
 
 impl<'d, T: Instance> Qspi<'d, T> {
-    pub fn new(
+    pub async fn new(
         _qspi: impl Unborrow<Target = T> + 'd,
         irq: impl Unborrow<Target = T::Interrupt> + 'd,
         sck: impl Unborrow<Target = impl GpioPin> + 'd,
@@ -69,20 +74,21 @@ impl<'d, T: Instance> Qspi<'d, T> {
         io2: impl Unborrow<Target = impl GpioPin> + 'd,
         io3: impl Unborrow<Target = impl GpioPin> + 'd,
         config: Config,
-    ) -> Self {
+    ) -> Qspi<'d, T> {
         unborrow!(irq, sck, csn, io0, io1, io2, io3);
 
         let r = T::regs();
 
-        for cnf in &[
-            sck.conf(),
-            csn.conf(),
-            io0.conf(),
-            io1.conf(),
-            io2.conf(),
-            io3.conf(),
-        ] {
-            cnf.write(|w| w.dir().output().drive().h0h1());
+        let sck = sck.degrade();
+        let csn = csn.degrade();
+        let io0 = io0.degrade();
+        let io1 = io1.degrade();
+        let io2 = io2.degrade();
+        let io3 = io3.degrade();
+
+        for pin in [&sck, &csn, &io0, &io1, &io2, &io3] {
+            pin.set_high();
+            pin.conf().write(|w| w.dir().output().drive().h0h1());
         }
 
         r.psel.sck.write(|w| unsafe { w.bits(sck.psel_bits()) });
@@ -92,53 +98,56 @@ impl<'d, T: Instance> Qspi<'d, T> {
         r.psel.io2.write(|w| unsafe { w.bits(io2.psel_bits()) });
         r.psel.io3.write(|w| unsafe { w.bits(io3.psel_bits()) });
 
-        r.ifconfig0.write(|mut w| {
-            w = w.addrmode().variant(AddressMode::_24BIT);
-            if config.deep_power_down.is_some() {
-                w = w.dpmenable().enable();
-            } else {
-                w = w.dpmenable().disable();
-            }
-            w = w.ppsize().variant(config.write_page_size);
-            w = w.readoc().variant(config.read_opcode);
-            w = w.writeoc().variant(config.write_opcode);
+        r.ifconfig0.write(|w| {
+            w.addrmode().variant(AddressMode::_24BIT);
+            w.dpmenable().bit(config.deep_power_down.is_some());
+            w.ppsize().variant(config.write_page_size);
+            w.readoc().variant(config.read_opcode);
+            w.writeoc().variant(config.write_opcode);
             w
         });
 
         if let Some(dpd) = &config.deep_power_down {
-            r.dpmdur.write(|mut w| unsafe {
-                w = w.enter().bits(dpd.enter_time);
-                w = w.exit().bits(dpd.exit_time);
+            r.dpmdur.write(|w| unsafe {
+                w.enter().bits(dpd.enter_time);
+                w.exit().bits(dpd.exit_time);
                 w
             })
         }
 
-        r.ifconfig1.write(|w| {
-            let w = unsafe { w.sckdelay().bits(80) };
-            let w = w.dpmen().exit();
-            let w = w.spimode().mode0();
-            let w = unsafe { w.sckfreq().bits(3) };
+        r.ifconfig1.write(|w| unsafe {
+            w.sckdelay().bits(80);
+            w.dpmen().exit();
+            w.spimode().mode0();
+            w.sckfreq().bits(3);
+            w
+        });
+
+        r.xipoffset.write(|w| unsafe {
+            w.xipoffset().bits(config.xip_offset);
             w
         });
 
-        r.xipoffset
-            .write(|w| unsafe { w.xipoffset().bits(config.xip_offset) });
+        irq.set_handler(Self::on_interrupt);
+        irq.unpend();
+        irq.enable();
 
         // Enable it
         r.enable.write(|w| w.enable().enabled());
 
+        let mut res = Self {
+            dpm_enabled: config.deep_power_down.is_some(),
+            phantom: PhantomData,
+        };
+
         r.events_ready.reset();
+        r.intenset.write(|w| w.ready().set());
+
         r.tasks_activate.write(|w| w.tasks_activate().bit(true));
-        while r.events_ready.read().bits() == 0 {}
-        r.events_ready.reset();
 
-        irq.set_handler(Self::on_interrupt);
-        irq.unpend();
-        irq.enable();
+        res.wait_ready().await;
 
-        Self {
-            phantom: PhantomData,
-        }
+        res
     }
 
     fn on_interrupt(_: *mut ()) {
@@ -151,19 +160,6 @@ impl<'d, T: Instance> Qspi<'d, T> {
         }
     }
 
-    pub fn sleep(&mut self) {
-        let r = T::regs();
-
-        info!("flash: sleeping");
-        info!("flash: state = {:?}", r.status.read().bits());
-        r.ifconfig1.modify(|_, w| w.dpmen().enter());
-        info!("flash: state = {:?}", r.status.read().bits());
-        cortex_m::asm::delay(1000000);
-        info!("flash: state = {:?}", r.status.read().bits());
-
-        r.tasks_deactivate.write(|w| w.tasks_deactivate().set_bit());
-    }
-
     pub async fn custom_instruction(
         &mut self,
         opcode: u8,
@@ -246,6 +242,44 @@ impl<'d, T: Instance> Qspi<'d, T> {
     }
 }
 
+impl<'d, T: Instance> Drop for Qspi<'d, T> {
+    fn drop(&mut self) {
+        let r = T::regs();
+
+        if self.dpm_enabled {
+            info!("qspi: doing deep powerdown...");
+
+            r.ifconfig1.modify(|_, w| w.dpmen().enter());
+
+            // Wait for DPM enter.
+            // Unfortunately we must spin. There's no way to do this interrupt-driven.
+            // The READY event does NOT fire on DPM enter (but it does fire on DPM exit :shrug:)
+            while r.status.read().dpm().is_disabled() {}
+        }
+
+        // it seems events_ready is not generated in response to deactivate. nrfx doesn't wait for it.
+        r.tasks_deactivate.write(|w| w.tasks_deactivate().set_bit());
+
+        // Workaround https://infocenter.nordicsemi.com/topic/errata_nRF52840_Rev1/ERR/nRF52840/Rev1/latest/anomaly_840_122.html?cp=4_0_1_2_1_7
+        // Note that the doc has 2 register writes, but the first one is really the write to tasks_deactivate,
+        // so we only do the second one here.
+        unsafe { ptr::write_volatile(0x40029054 as *mut u32, 1) }
+
+        r.enable.write(|w| w.enable().disabled());
+
+        // Note: we do NOT deconfigure CSN here. If DPM is in use and we disconnect CSN,
+        // leaving it floating, the flash chip might read it as zero which would cause it to
+        // spuriously exit DPM.
+        gpio::deconfigure_pin(r.psel.sck.read().bits());
+        gpio::deconfigure_pin(r.psel.io0.read().bits());
+        gpio::deconfigure_pin(r.psel.io1.read().bits());
+        gpio::deconfigure_pin(r.psel.io2.read().bits());
+        gpio::deconfigure_pin(r.psel.io3.read().bits());
+
+        info!("qspi: dropped");
+    }
+}
+
 impl<'d, T: Instance> Flash for Qspi<'d, T> {
     #[rustfmt::skip]
     type ReadFuture<'a> where Self: 'a = impl Future<Output = Result<(), Error>> + 'a;
diff --git a/embassy-nrf/src/spim.rs b/embassy-nrf/src/spim.rs
index bb43b7c7c..a29c1a3ee 100644
--- a/embassy-nrf/src/spim.rs
+++ b/embassy-nrf/src/spim.rs
@@ -14,6 +14,7 @@ use traits::spi::FullDuplex;
 use crate::gpio::sealed::Pin as _;
 use crate::gpio::{OptionalPin, Pin as GpioPin};
 use crate::interrupt::Interrupt;
+use crate::{fmt::*, gpio};
 use crate::{pac, util::slice_in_ram_or};
 
 pub use embedded_hal::spi::{Mode, Phase, Polarity, MODE_0, MODE_1, MODE_2, MODE_3};
@@ -153,6 +154,24 @@ impl<'d, T: Instance> Spim<'d, T> {
     }
 }
 
+impl<'d, T: Instance> Drop for Spim<'d, T> {
+    fn drop(&mut self) {
+        info!("spim drop");
+
+        // TODO check for abort, wait for xxxstopped
+
+        // disable!
+        let r = T::regs();
+        r.enable.write(|w| w.enable().disabled());
+
+        gpio::deconfigure_pin(r.psel.sck.read().bits());
+        gpio::deconfigure_pin(r.psel.miso.read().bits());
+        gpio::deconfigure_pin(r.psel.mosi.read().bits());
+
+        info!("spim drop: done");
+    }
+}
+
 impl<'d, T: Instance> FullDuplex<u8> for Spim<'d, T> {
     type Error = Error;
 
diff --git a/embassy-nrf/src/twim.rs b/embassy-nrf/src/twim.rs
index 05c4c260f..ea3ac7553 100644
--- a/embassy-nrf/src/twim.rs
+++ b/embassy-nrf/src/twim.rs
@@ -13,10 +13,10 @@ use embassy::util::{AtomicWaker, Unborrow};
 use embassy_extras::unborrow;
 
 use crate::chip::{EASY_DMA_SIZE, FORCE_COPY_BUFFER_SIZE};
-use crate::fmt::*;
 use crate::gpio::Pin as GpioPin;
 use crate::pac;
 use crate::util::{slice_in_ram, slice_in_ram_or};
+use crate::{fmt::*, gpio};
 
 pub enum Frequency {
     #[doc = "26738688: 100 kbps"]
@@ -30,12 +30,16 @@ pub enum Frequency {
 #[non_exhaustive]
 pub struct Config {
     pub frequency: Frequency,
+    pub sda_pullup: bool,
+    pub scl_pullup: bool,
 }
 
 impl Default for Config {
     fn default() -> Self {
         Self {
             frequency: Frequency::K100,
+            sda_pullup: false,
+            scl_pullup: false,
         }
     }
 }
@@ -61,15 +65,19 @@ impl<'d, T: Instance> Twim<'d, T> {
         sda.conf().write(|w| {
             w.dir().input();
             w.input().connect();
-            w.pull().pullup();
             w.drive().s0d1();
+            if config.sda_pullup {
+                w.pull().pullup();
+            }
             w
         });
         scl.conf().write(|w| {
             w.dir().input();
             w.input().connect();
-            w.pull().pullup();
             w.drive().s0d1();
+            if config.scl_pullup {
+                w.pull().pullup();
+            }
             w
         });
 
@@ -422,9 +430,10 @@ impl<'a, T: Instance> Drop for Twim<'a, T> {
         let r = T::regs();
         r.enable.write(|w| w.enable().disabled());
 
-        info!("uarte drop: done");
+        gpio::deconfigure_pin(r.psel.sda.read().bits());
+        gpio::deconfigure_pin(r.psel.scl.read().bits());
 
-        // TODO: disable pins
+        info!("twim drop: done");
     }
 }
 
diff --git a/embassy-nrf/src/uarte.rs b/embassy-nrf/src/uarte.rs
index 3ad7a787d..2f6d1a391 100644
--- a/embassy-nrf/src/uarte.rs
+++ b/embassy-nrf/src/uarte.rs
@@ -15,7 +15,7 @@ use futures::future::poll_fn;
 use crate::chip::EASY_DMA_SIZE;
 use crate::fmt::{assert, panic, *};
 use crate::gpio::sealed::Pin as _;
-use crate::gpio::{OptionalPin as GpioOptionalPin, Pin as GpioPin};
+use crate::gpio::{self, OptionalPin as GpioOptionalPin, Pin as GpioPin};
 use crate::interrupt::Interrupt;
 use crate::pac;
 use crate::ppi::{AnyConfigurableChannel, ConfigurableChannel, Event, Ppi, Task};
@@ -166,9 +166,12 @@ impl<'a, T: Instance> Drop for Uarte<'a, T> {
         // Finally we can disable!
         r.enable.write(|w| w.enable().disabled());
 
-        info!("uarte drop: done");
+        gpio::deconfigure_pin(r.psel.rxd.read().bits());
+        gpio::deconfigure_pin(r.psel.txd.read().bits());
+        gpio::deconfigure_pin(r.psel.rts.read().bits());
+        gpio::deconfigure_pin(r.psel.cts.read().bits());
 
-        // TODO: disable pins
+        info!("uarte drop: done");
     }
 }