Add FlexCAN pin trait, FlexCAN1 and 2 1060 impls

1060 pins implementations checked against section 44.3 in the 1060
reference manual. See imxrt-rs/imxrt-hal#122 for a related FlexCAN
driver.

src/flexcan.rs

@@ -0,0 +1,50 @@
+//! FlexCAN pad configurations
+
+/// A FlexCAN signal
+pub trait Signal: private::Sealed {}
+
+/// A tag that indicates a FlexCAN TX pad
+pub enum Tx {}
+/// A tag that indicates a FlexCAN Rx pad
+pub enum Rx {}
+
+impl Signal for Tx {}
+impl Signal for Rx {}
+mod private {
+    pub trait Sealed {}
+    impl Sealed for super::Tx {}
+    impl Sealed for super::Rx {}
+}
+
+/// A FlexCAN pin
+pub trait Pin: super::Iomuxc {
+    /// Alternate value for this pin
+    const ALT: u32;
+    /// Daisy register
+    const DAISY: Option<super::Daisy>;
+    /// CAN signal
+    type Signal: Signal;
+    /// CAN module; `U1` for `CAN1`
+    type Module: super::consts::Unsigned;
+}
+
+/// Prepare a FlexCAN pin.
+pub fn prepare<P: Pin>(pin: &mut P) {
+    super::alternate(pin, P::ALT);
+    super::set_sion(pin);
+    if let Some(daisy) = P::DAISY {
+        unsafe { daisy.write() };
+    }
+}
+
+#[allow(unused)] // Used in chip-specific modules...
+macro_rules! can {
+    (module: $module:ty, alt: $alt:expr, pad: $pad:ty, signal: $signal:ty, daisy: $daisy:expr) => {
+        impl Pin for $pad {
+            const ALT: u32 = $alt;
+            const DAISY: Option<Daisy> = $daisy;
+            type Signal = $signal;
+            type Module = $module;
+        }
+    };
+}

src/imxrt1060/flexcan.rs

@@ -0,0 +1,54 @@
+//! FlexCAN pin implementation
+
+use super::pads::{
+    gpio_ad_b0::*, gpio_ad_b1::*, gpio_b0::*, gpio_b1::*, gpio_emc::*, gpio_sd_b1::*,
+};
+
+use crate::{
+    consts::*,
+    flexcan::{Pin, Rx, Tx},
+    Daisy,
+};
+
+//
+// CAN1
+//
+can!(module: U1, alt: 2, pad: GPIO_AD_B1_08, signal: Tx, daisy: None);
+can!(module: U1, alt: 2, pad: GPIO_B0_02, signal: Tx, daisy: None);
+can!(module: U1, alt: 3, pad: GPIO_EMC_17, signal: Tx, daisy: None);
+can!(module: U1, alt: 4, pad: GPIO_SD_B1_02, signal: Tx, daisy: None);
+can!(module: U1, alt: 2, pad: GPIO_AD_B1_09, signal: Rx, daisy: Some(DAISY_CAN1_RX_GPIO_AD_B1_09));
+can!(module: U1, alt: 2, pad: GPIO_B0_03, signal: Rx, daisy: Some(DAISY_CAN1_RX_GPIO_B0_03));
+can!(module: U1, alt: 3, pad: GPIO_EMC_18, signal: Rx, daisy: Some(DAISY_CAN1_RX_GPIO_EMC_18));
+can!(module: U1, alt: 4, pad: GPIO_SD_B1_03, signal: Rx, daisy: Some(DAISY_CAN1_RX_GPIO_SD_B1_03));
+
+//
+// CAN2
+//
+can!(module: U2, alt: 0, pad: GPIO_AD_B0_02, signal: Tx, daisy: None);
+can!(module: U2, alt: 3, pad: GPIO_EMC_09, signal: Tx, daisy: None);
+can!(module: U2, alt: 6, pad: GPIO_B1_08, signal: Tx, daisy: None);
+can!(module: U2, alt: 6, pad: GPIO_AD_B0_14, signal: Tx, daisy: None);
+can!(module: U2, alt: 0, pad: GPIO_AD_B0_03, signal: Rx, daisy: Some(DAISY_CAN2_RX_GPIO_AD_B0_03));
+can!(module: U2, alt: 3, pad: GPIO_EMC_10, signal: Rx, daisy: Some(DAISY_CAN2_RX_GPIO_EMC_10));
+can!(module: U2, alt: 6, pad: GPIO_AD_B0_15, signal: Rx, daisy: Some(DAISY_CAN2_RX_GPIO_AD_B0_15));
+can!(module: U2, alt: 6, pad: GPIO_B1_09, signal: Rx, daisy: Some(DAISY_CAN2_RX_GPIO_B1_09));
+
+/// Auto-generated DAISY values
+mod daisy {
+    #![allow(unused)]
+
+    use super::Daisy;
+
+    pub const DAISY_CAN1_RX_GPIO_SD_B1_03: Daisy = Daisy::new(0x401F_844C as *mut u32, 0);
+    pub const DAISY_CAN1_RX_GPIO_EMC_18: Daisy = Daisy::new(0x401F_844C as *mut u32, 1);
+    pub const DAISY_CAN1_RX_GPIO_AD_B1_09: Daisy = Daisy::new(0x401F_844C as *mut u32, 2);
+    pub const DAISY_CAN1_RX_GPIO_B0_03: Daisy = Daisy::new(0x401F_844C as *mut u32, 3);
+
+    pub const DAISY_CAN2_RX_GPIO_EMC_10: Daisy = Daisy::new(0x401F_8450 as *mut u32, 0);
+    pub const DAISY_CAN2_RX_GPIO_AD_B0_03: Daisy = Daisy::new(0x401F_8450 as *mut u32, 1);
+    pub const DAISY_CAN2_RX_GPIO_AD_B0_15: Daisy = Daisy::new(0x401F_8450 as *mut u32, 2);
+    pub const DAISY_CAN2_RX_GPIO_B1_09: Daisy = Daisy::new(0x401F_8450 as *mut u32, 3);
+}
+
+use daisy::*;

src/imxrt1060/mod.rs

@@ -4,6 +4,7 @@
 //! functions are tagged with `imxrt-iomuxc` traits.
 
 mod adc;
+mod flexcan;
 mod flexpwm;
 mod lpi2c;
 mod lpspi;

src/lib.rs

@@ -177,6 +177,8 @@
 pub mod adc;
 mod config;
 #[macro_use]
+pub mod flexcan;
+#[macro_use]
 pub mod flexpwm;
 #[macro_use]
 pub mod lpi2c;
@@ -216,7 +218,7 @@ pub mod prelude {
     };
 
     pub use crate::{
-        adc, alternate, ccm, clear_sion, consts, flexpwm, gpio, lpi2c, lpspi, lpuart, sai,
+        adc, alternate, ccm, clear_sion, consts, flexcan, flexpwm, gpio, lpi2c, lpspi, lpuart, sai,
         set_sion, usdhc, Daisy, ErasedPad, Pad, WrongPadError,
     };
 }