[PATCH 10/10] samples: rust: platform: Add property read examples

Remo Senekowitsch
2025-03-26T17:15:21Z

Add some example usage of the device property read methods for
DT/ACPI/swnode properties.

Co-developed-by: Rob Herring (Arm) <robh@kernel.org>
Signed-off-by: Rob Herring (Arm) <robh@kernel.org>
Signed-off-by: Remo Senekowitsch <remo@buenzli.dev>
---
drivers/of/unittest-data/tests-platform.dtsi | 3 ++
samples/rust/rust_driver_platform.rs | 56 +++++++++++++++++++-
2 files changed, 58 insertions(+), 1 deletion(-)

diff --git a/drivers/of/unittest-data/tests-platform.dtsi b/drivers/of/unittest-data/tests-platform.dtsi
index 4171f43cf..50a51f38a 100644
--- a/drivers/of/unittest-data/tests-platform.dtsi
+++ b/drivers/of/unittest-data/tests-platform.dtsi
@@ -37,6 +37,9 @@ dev@100 {
test-device@2 {
compatible = "test,rust-device";
reg = <0x2>;
+
+ test,u32-prop = <0xdeadbeef>;
+ test,i16-array = /bits/ 16 <1 2 (-3) (-4)>;
};
};

diff --git a/samples/rust/rust_driver_platform.rs b/samples/rust/rust_driver_platform.rs
index 8120609e2..ed25a3781 100644
--- a/samples/rust/rust_driver_platform.rs
+++ b/samples/rust/rust_driver_platform.rs
@@ -2,7 +2,7 @@

//! Rust Platform driver sample.

-use kernel::{c_str, of, platform, prelude::*};
+use kernel::{c_str, of, platform, prelude::*, str::CString};

struct SampleDriver {
pdev: platform::Device,
@@ -28,6 +28,60 @@ fn probe(pdev: &mut platform::Device, info: Option<&Self::IdInfo>) -> Result<Pin
dev_info!(pdev.as_ref(), "Probed with info: '{}'.\n", info.0);
}

+ let dev = pdev.as_ref();
+ if let Ok(idx) = dev.property_match_string(c_str!("compatible"), c_str!("test,rust-device"))
+ {
+ dev_info!(pdev.as_ref(), "matched compatible string idx = {}\n", idx);
+ }
+
+ if let Ok(str) = dev
+ .property_read::<CString>(c_str!("compatible"))
+ .required()
+ {
+ dev_info!(pdev.as_ref(), "compatible string = {:?}\n", str);
+ }
+
+ let prop = dev
+ .property_read::<bool>(c_str!("test,bool-prop"))
+ .required()?;
+ dev_info!(dev, "bool prop is {}\n", prop);
+
+ if dev.property_present(c_str!("test,u32-prop")) {
+ dev_info!(dev, "'test,u32-prop' is present\n");
+ }
+
+ let prop = dev
+ .property_read::<u32>(c_str!("test,u32-optional-prop"))
+ .or(0x12);
+ dev_info!(
+ dev,
+ "'test,u32-optional-prop' is {:#x} (default = {:#x})\n",
+ prop,
+ 0x12
+ );
+
+ // Missing property without a default will print an error
+ let _ = dev
+ .property_read::<u32>(c_str!("test,u32-required-prop"))
+ .required()?;
+
+ let prop: u32 = dev.property_read(c_str!("test,u32-prop")).required()?;
+ dev_info!(dev, "'test,u32-prop' is {:#x}\n", prop);
+
+ let prop: [i16; 4] = dev.property_read(c_str!("test,i16-array")).required()?;
+ dev_info!(dev, "'test,i16-array' is {:?}\n", prop);
+ dev_info!(
+ dev,
+ "'test,i16-array' length is {}\n",
+ dev.property_count_elem::<u16>(c_str!("test,i16-array"))
+ .unwrap()
+ );
+
+ let prop: KVec<i16> = dev
+ .property_read_array_vec(c_str!("test,i16-array"), 4)?
+ .required()?;
+ dev_info!(dev, "'test,i16-array' is KVec {:?}\n", prop);
+
let drvdata = KBox::new(Self { pdev: pdev.clone() }, GFP_KERNEL)?;

Ok(drvdata.into())
--
2.49.0