samples: rust: add regulator consumer driver sample

Add a basic sample for using the regulator consumer API.

Signed-off-by: Fabien Parent <fabien.parent@linaro.org>

Author: Fabo

samples/rust/Kconfig

@@ -30,6 +30,16 @@ config SAMPLE_RUST_PRINT
 
 	  If unsure, say N.
 
+config SAMPLE_RUST_REGULATOR_CONSUMER
+	tristate "Regulator consumer device driver"
+	help
+	  This option builds the Rust regulator consumer driver sample.
+
+	  To compile this as a module, choose M here:
+	  the module will be called rust_regulator_consumer.
+
+	  If unsure, say N.
+
 config SAMPLE_RUST_HOSTPROGS
 	bool "Host programs"
 	help

samples/rust/Makefile

@@ -2,5 +2,6 @@
 
 obj-$(CONFIG_SAMPLE_RUST_MINIMAL)		+= rust_minimal.o
 obj-$(CONFIG_SAMPLE_RUST_PRINT)			+= rust_print.o
+obj-$(CONFIG_SAMPLE_RUST_REGULATOR_CONSUMER)	+= rust_regulator_consumer.o
 
 subdir-$(CONFIG_SAMPLE_RUST_HOSTPROGS)		+= hostprogs

samples/rust/rust_regulator_consumer.rs

@@ -0,0 +1,27 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Rust regulator consumer driver sample.
+
+use kernel::{c_str, device, module_platform_driver, of, platform, prelude::*,
+    regulator::consumer::{Mode, Regulator}};
+
+module_platform_driver! {
+    type: Driver,
+    name: "rust_regulator_consumer",
+    license: "GPL",
+}
+
+struct Driver;
+impl platform::Driver for Driver {
+    kernel::define_of_id_table! {(), [
+        (of::DeviceId::Compatible(b"rust,regulator-consumer"), None),
+    ]}
+
+    fn probe(pdev: &mut platform::Device, _id_info: Option<&Self::IdInfo>) -> Result {
+        let dev = device::Device::from_dev(pdev);
+        let vbus = Regulator::get(&dev, c_str!("vbus"))?;
+        let _ = vbus.enable()?;
+
+        Ok(())
+    }
+}