zephyr: Add Leds driver

Add support for Leds, and a simple augment for the pwm drivers.

Author: d3zd3z

dt-rust.yaml

@@ -14,6 +14,8 @@
     value:
       raw:
         type: myself
+        value:
+          args: []
       device: crate::device::gpio::Gpio
 
 # The gpio-leds node will have #children nodes describing each led.  We'll match on the parent
@@ -49,6 +51,8 @@
     value:
       raw:
         type: myself
+        value:
+          args: []
       device: crate::device::flash::FlashController
 
 # Flash partitions exist as children of a node compatible with "soc-nv-flash" that itself is a child
@@ -94,6 +98,8 @@
     value:
       raw:
         type: myself
+        value:
+          args: []
       device: "crate::device::uart::Uart"
       kconfig: CONFIG_SERIAL
 
@@ -116,9 +122,28 @@
     value:
       raw:
         type: myself
+        value:
+          args: []
       device: "crate::device::led_strip::LedStrip"
       kconfig: CONFIG_LED_STRIP
 
+- name: pwm-leds
+  rules:
+  - type: compatible
+    value:
+      names:
+      - "pwm-leds"
+      level: 0
+  actions:
+  - type: instance
+    value:
+      raw:
+        type: myself
+        value:
+          args:
+          - type: child_count
+      device: "crate::device::led::Leds"
+
 # This doesn't really belong here, and can be moved once we support modules having their own augment
 # files.
 - name: bbq-kbd-matrix

zephyr-build/src/devicetree/augment.rs

@@ -247,7 +247,9 @@ fn decode_gpios_gpio(unique: &Ident, entry: &Value) -> TokenStream {
 #[serde(tag = "type", rename_all = "snake_case", content = "value")]
 pub enum RawInfo {
     /// Get the raw device directly from this node.
-    Myself,
+    Myself {
+        args: Vec<ArgInfo>,
+    },
     /// Get the reference from a parent of this node, at a given level.
     Parent {
         /// How many levels to look up.  0 would refer to this node (but would also be an error).
@@ -272,7 +274,9 @@ impl RawInfo {
         };
 
         match self {
-            RawInfo::Myself => {
+            RawInfo::Myself { args } => {
+                let get_args = args.iter().map(|arg| arg.args(node));
+
                 let ord = node.ord;
                 let rawdev = format_ident!("__device_dts_ord_{}", ord);
                 quote! {
@@ -288,7 +292,7 @@ impl RawInfo {
                     pub fn get_instance() -> Option<#device_id> {
                         unsafe {
                             let device = get_instance_raw();
-                            #device_id::new(&UNIQUE, device)
+                            #device_id::new(&UNIQUE, device, #(#get_args),*)
                         }
                     }
                 }
@@ -354,6 +358,8 @@ impl RawInfo {
 pub enum ArgInfo {
     /// The arguments come from a 'reg' property.
     Reg,
+    /// A count of the number of child nodes.
+    ChildCount,
 }
 
 impl ArgInfo {
@@ -366,6 +372,12 @@ impl ArgInfo {
                     #(#reg),*
                 }
             }
+            ArgInfo::ChildCount => {
+                let count = node.children.len();
+                quote! {
+                    #count
+                }
+            }
         }
     }
 }

zephyr-sys/build.rs

@@ -82,7 +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("led_.*")
         .allowlist_function("sys_.*")
         .allowlist_function("uart_.*")
         .allowlist_item("E.*")

zephyr-sys/wrapper.h

@@ -42,6 +42,7 @@ extern int errno;
 #include <zephyr/drivers/flash.h>
 #include <zephyr/drivers/uart.h>
 #include <zephyr/drivers/led_strip.h>
+#include <zephyr/drivers/led.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;
 pub mod led_strip;
 
 // Allow dead code, because it isn't required for a given build to have any devices.

zephyr/src/device/led.rs

@@ -0,0 +1,44 @@
+//! LED driver, with support for PWMLED driver, with support for PWM.
+
+use crate::raw;
+use crate::error::{Result, to_result_void};
+
+use super::Unique;
+
+/// A simple led strip wrapper.
+pub struct Leds {
+    /// The underlying device itself.
+    #[allow(dead_code)]
+    pub(crate) device: *const raw::device,
+    /// How many are configured in the DT.
+    pub(crate) count: usize,
+}
+
+// This is send, safe with Zephyr.
+unsafe impl Send for Leds { }
+
+impl Leds {
+    /// Constructor, used by the devicetree generated code.
+    #[allow(dead_code)]
+    pub(crate) unsafe fn new(unique: &Unique, device: *const raw::device, count: usize) -> Option<Leds> {
+        if !unique.once() {
+            return None;
+        }
+
+        Some(Leds { device, count })
+    }
+
+    /// Return the number of LEDS.
+    pub fn len(&self) -> usize {
+        self.count
+    }
+
+    /// Set the brightness of one of the described LEDs
+    pub unsafe fn set_brightness(&mut self, index: usize, value: u8) -> Result<()> {
+        to_result_void(unsafe {
+            raw::led_set_brightness(self.device,
+                                    index as u32,
+                                    value)
+        })
+    }
+}