zephyr: device: Add led-strip wrapper

Add a simple wrapper for the led strip driver.

Signed-off-by: David Brown <[email protected]>

Author: d3zd3z

dt-rust.yaml

@@ -97,6 +97,28 @@
       device: "crate::device::uart::Uart"
       kconfig: CONFIG_SERIAL
 
+- name: led-strip
+  rules:
+  - type: or
+    value:
+    - type: compatible
+      value:
+        names:
+        - "worldsemi,wd2812-spi"
+        level: 0
+    - type: compatible
+      value:
+        names:
+        - "worldsemi,ws2812-rpi_pico-pio"
+        level: 1
+  actions:
+  - type: instance
+    value:
+      raw:
+        type: myself
+      device: "crate::device::led_strip::LedStrip"
+      kconfig: CONFIG_LED_STRIP
+
 # Generate a pseudo node that matches all of the labels across the tree with their nodes.
 - name: labels
   rules:

zephyr-sys/build.rs

@@ -67,7 +67,7 @@ fn main() -> Result<()> {
         // one from the minimal libc.
         .clang_arg("-DRUST_BINDGEN")
         .clang_arg(format!("-I{}/lib/libc/minimal/include", zephyr_base))
-        .derive_copy(false)
+        .derive_copy(true)
         .allowlist_function("k_.*")
         .allowlist_function("gpio_.*")
         .allowlist_function("flash_.*")
@@ -82,6 +82,7 @@ fn main() -> Result<()> {
         // Each DT node has a device entry that is a static.
         .allowlist_item("__device_dts_ord.*")
         .allowlist_function("device_.*")
+        .allowlist_function("led_strip.*")
         .allowlist_function("sys_.*")
         .allowlist_function("uart_.*")
         .allowlist_item("E.*")

zephyr-sys/wrapper.h

@@ -41,6 +41,7 @@ extern int errno;
 #include <zephyr/drivers/gpio.h>
 #include <zephyr/drivers/flash.h>
 #include <zephyr/drivers/uart.h>
+#include <zephyr/drivers/led_strip.h>
 
 /*
  * bindgen will only output #defined constants that resolve to simple numbers.  These are some

zephyr/src/device.rs

@@ -10,6 +10,7 @@ use crate::sync::atomic::{AtomicUsize, Ordering};
 pub mod gpio;
 pub mod flash;
 pub mod uart;
+pub mod led_strip;
 
 // Allow dead code, because it isn't required for a given build to have any devices.
 /// Device uniqueness.

zephyr/src/device/led_strip.rs

@@ -0,0 +1,45 @@
+//! Simple led strip driver
+
+use crate::raw;
+use crate::error::{Result, to_result_void};
+
+use super::Unique;
+
+/// A simple led strip wrapper.
+pub struct LedStrip {
+    /// The underlying device itself.
+    #[allow(dead_code)]
+    pub(crate) device: *const raw::device,
+}
+
+// This is send, safe with Zephyr.
+unsafe impl Send for LedStrip { }
+
+impl LedStrip {
+    /// Constructor, used by the devicetree generated code.
+    #[allow(dead_code)]
+    pub(crate) unsafe fn new(unique: &Unique, device: *const raw::device) -> Option<LedStrip> {
+        if !unique.once() {
+            return None;
+        }
+
+        Some(LedStrip { device })
+    }
+
+    /// Return the number of LEDS in the chain.
+    pub fn chain_len(&self) -> usize {
+        unsafe { raw::led_strip_length(self.device) as usize}
+    }
+
+    /// Update the state of the LEDs.
+    ///
+    /// It is unclear from the API docs whether this is supposed to be an array of rgb_led
+    /// (which is what the samples assume), or packed rgb data.
+    pub unsafe fn update(&mut self, channels: &[raw::led_rgb]) -> Result<()> {
+        to_result_void(unsafe {
+            raw::led_strip_update_rgb(self.device,
+                channels.as_ptr() as *mut _,
+                channels.len())
+        })
+    }
+}

zephyr/src/sys.rs

@@ -41,6 +41,13 @@ pub fn uptime_get() -> i64 {
     }
 }
 
+/// Busy wait.
+///
+/// Busy wait for a give number of microseconds.  This directly calls `zephyr_sys::k_busy_wait`.
+///
+/// Zephyr has numerous caveats on configurations where this function doesn't work.
+pub use zephyr_sys::k_busy_wait as busy_wait;
+
 pub mod critical {
     //! Zephyr implementation of critical sections.
     //!