[PATCH 3/3] sample: rust: Add GPIO consumer sample driver

[Kohei Ito <koheiito.dev@gmail.com>]

Add a sample driver to demonstrate the use of the Rust GPIO APIs.

Signed-off-by: Kohei Ito <koheiito.dev@gmail.com>
---
 samples/rust/Kconfig               |  11 +++
 samples/rust/Makefile              |   1 +
 samples/rust/rust_gpio_consumer.rs | 156 +++++++++++++++++++++++++++++++++++++
 3 files changed, 168 insertions(+)

diff --git a/samples/rust/Kconfig b/samples/rust/Kconfig
index c49ab9106345..1085d90c87f3 100644
--- a/samples/rust/Kconfig
+++ b/samples/rust/Kconfig
@@ -161,6 +161,17 @@ config SAMPLE_RUST_DRIVER_AUXILIARY
 
 	  If unsure, say N.
 
+config SAMPLE_RUST_GPIO_CONSUMER
+	tristate "GPIO Consumer Driver"
+	depends on GPIOLIB
+	help
+	  This option builds the Rust GPIO consumer sample.
+
+	  To compile this as a module, choose M here:
+	  the module will be called rust_gpio_consumer.
+
+	  If unsure, say N.
+
 config SAMPLE_RUST_SOC
 	tristate "SoC Driver"
 	select SOC_BUS
diff --git a/samples/rust/Makefile b/samples/rust/Makefile
index 6c0aaa58cccc..1cf181dea6d3 100644
--- a/samples/rust/Makefile
+++ b/samples/rust/Makefile
@@ -15,6 +15,7 @@ obj-$(CONFIG_SAMPLE_RUST_DRIVER_USB)		+= rust_driver_usb.o
 obj-$(CONFIG_SAMPLE_RUST_DRIVER_FAUX)		+= rust_driver_faux.o
 obj-$(CONFIG_SAMPLE_RUST_DRIVER_AUXILIARY)	+= rust_driver_auxiliary.o
 obj-$(CONFIG_SAMPLE_RUST_CONFIGFS)		+= rust_configfs.o
+obj-$(CONFIG_SAMPLE_RUST_GPIO_CONSUMER)		+= rust_gpio_consumer.o
 obj-$(CONFIG_SAMPLE_RUST_SOC)			+= rust_soc.o
 
 rust_print-y := rust_print_main.o rust_print_events.o
diff --git a/samples/rust/rust_gpio_consumer.rs b/samples/rust/rust_gpio_consumer.rs
new file mode 100644
index 000000000000..b70b305126fc
--- /dev/null
+++ b/samples/rust/rust_gpio_consumer.rs
@@ -0,0 +1,156 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Rust GPIO consumer driver sample.
+
+use kernel::{
+    device::{
+        self,
+        Core, //
+    },
+    gpio::{
+        self,
+        consumer::{
+            GpioDesc,
+            GpiodFlags, //
+        }, //
+    },
+    of,
+    platform,
+    prelude::*,
+    time::{
+        delay::fsleep,
+        Delta, //
+    }, //
+};
+
+struct SampleDriver;
+
+impl platform::Driver for SampleDriver {
+    type IdInfo = ();
+    type Data<'bound> = Self;
+    const OF_ID_TABLE: Option<of::IdTable<Self::IdInfo>> = Some(&OF_TABLE);
+
+    fn probe<'bound>(
+        pdev: &'bound platform::Device<Core<'_>>,
+        _info: Option<&'bound Self::IdInfo>,
+    ) -> impl PinInit<Self, Error> + 'bound {
+        let dev = pdev.as_ref();
+
+        dev_dbg!(dev, "Probe Rust GPIO consumer driver sample.\n");
+
+        Self::examine_gpio(dev)?;
+
+        Ok(Self)
+    }
+}
+
+type GetValue = fn(&GpioDesc) -> Result<gpio::LogicalLineLevel>;
+type GetRawValue = fn(&GpioDesc) -> Result<gpio::PhysicalLineLevel>;
+type SetValue = fn(&GpioDesc, gpio::LogicalLineLevel) -> Result<()>;
+type SetRawValue = fn(&GpioDesc, gpio::PhysicalLineLevel) -> Result<()>;
+
+impl SampleDriver {
+    fn examine_gpio(dev: &device::Device) -> Result {
+        let gpiod = GpioDesc::get(dev, None, GpiodFlags::ASIS)?;
+
+        let cansleep = gpiod.cansleep()?;
+        let (get_value, get_raw_value, set_value, set_raw_value): (
+            GetValue,
+            GetRawValue,
+            SetValue,
+            SetRawValue,
+        ) = if cansleep {
+            (
+                |gpiod| gpiod.get_value_cansleep(),
+                |gpiod| gpiod.get_raw_value_cansleep(),
+                |gpiod, value| gpiod.set_value_cansleep(value),
+                |gpiod, value| gpiod.set_raw_value_cansleep(value),
+            )
+        } else {
+            (
+                |gpiod| gpiod.get_value(),
+                |gpiod| gpiod.get_raw_value(),
+                |gpiod, value| gpiod.set_value(value),
+                |gpiod, value| gpiod.set_raw_value(value),
+            )
+        };
+
+        let pr_status = || -> Result<()> {
+            dev_info!(
+                dev,
+                "direction: {}, value: {}, raw value: {}\n",
+                gpiod.get_direction()?,
+                get_value(&gpiod)?,
+                get_raw_value(&gpiod)?
+            );
+            Ok(())
+        };
+
+        let active_low = gpiod.is_active_low()?;
+
+        dev_info!(
+            dev,
+            "got the GPIO ({}{})\n",
+            if active_low {
+                "active low"
+            } else {
+                "active high"
+            },
+            if cansleep { ", sleepy" } else { "" }
+        );
+        pr_status()?;
+
+        gpiod.direction_output(gpio::LogicalLineLevel::Inactive)?;
+        dev_info!(dev, "line is inactivated\n");
+        pr_status()?;
+
+        fsleep(Delta::from_millis(1));
+
+        set_value(&gpiod, gpio::LogicalLineLevel::Active)?;
+        dev_info!(dev, "line is activated\n");
+        pr_status()?;
+
+        fsleep(Delta::from_millis(1));
+
+        set_value(&gpiod, gpio::LogicalLineLevel::Inactive)?;
+        dev_info!(dev, "GPIO: line is inactivated\n");
+        pr_status()?;
+
+        fsleep(Delta::from_millis(1));
+
+        let level = get_raw_value(&gpiod)?;
+
+        gpiod.direction_input()?;
+        dev_info!(dev, "line is input mode\n");
+        pr_status()?;
+
+        fsleep(Delta::from_millis(1));
+
+        gpiod.direction_output_raw(!level)?;
+        dev_info!(dev, "line is toggled\n");
+        pr_status()?;
+
+        fsleep(Delta::from_millis(1));
+
+        set_raw_value(&gpiod, !!level)?;
+        dev_info!(dev, "line is toggled\n");
+        pr_status()?;
+
+        Ok(())
+    }
+}
+
+kernel::of_device_table!(
+    OF_TABLE,
+    MODULE_OF_TABLE,
+    <SampleDriver as platform::Driver>::IdInfo,
+    [(of::DeviceId::new(c"test,rust-gpio-consumer"), ())]
+);
+
+kernel::module_platform_driver! {
+    type: SampleDriver,
+    name: "rust_gpio_consumer",
+    authors: ["Kohei Ito"],
+    description: "Rust GPIO consumer driver",
+    license: "GPL v2",
+}

-- 
2.50.1