xref: /linux/samples/rust/rust_driver_platform.rs (revision c79cbde9b7bc7a650af96269588518950e3c2441)
1 // SPDX-License-Identifier: GPL-2.0
2 
3 //! Rust Platform driver sample.
4 
5 use kernel::{
6     c_str,
7     device::{
8         self,
9         property::{FwNodeReferenceArgs, NArgs},
10         Core,
11     },
12     of, platform,
13     prelude::*,
14     str::CString,
15     types::ARef,
16 };
17 
18 struct SampleDriver {
19     pdev: ARef<platform::Device>,
20 }
21 
22 struct Info(u32);
23 
24 kernel::of_device_table!(
25     OF_TABLE,
26     MODULE_OF_TABLE,
27     <SampleDriver as platform::Driver>::IdInfo,
28     [(of::DeviceId::new(c_str!("test,rust-device")), Info(42))]
29 );
30 
31 impl platform::Driver for SampleDriver {
32     type IdInfo = Info;
33     const OF_ID_TABLE: Option<of::IdTable<Self::IdInfo>> = Some(&OF_TABLE);
34 
35     fn probe(
36         pdev: &platform::Device<Core>,
37         info: Option<&Self::IdInfo>,
38     ) -> Result<Pin<KBox<Self>>> {
39         dev_dbg!(pdev.as_ref(), "Probe Rust Platform driver sample.\n");
40 
41         if let Some(info) = info {
42             dev_info!(pdev.as_ref(), "Probed with info: '{}'.\n", info.0);
43         }
44 
45         Self::properties_parse(pdev.as_ref())?;
46 
47         let drvdata = KBox::new(Self { pdev: pdev.into() }, GFP_KERNEL)?;
48 
49         Ok(drvdata.into())
50     }
51 }
52 
53 impl SampleDriver {
54     fn properties_parse(dev: &device::Device) -> Result {
55         let fwnode = dev.fwnode().ok_or(ENOENT)?;
56 
57         if let Ok(idx) =
58             fwnode.property_match_string(c_str!("compatible"), c_str!("test,rust-device"))
59         {
60             dev_info!(dev, "matched compatible string idx = {}\n", idx);
61         }
62 
63         let name = c_str!("compatible");
64         let prop = fwnode.property_read::<CString>(name).required_by(dev)?;
65         dev_info!(dev, "'{name}'='{prop:?}'\n");
66 
67         let name = c_str!("test,bool-prop");
68         let prop = fwnode.property_read_bool(c_str!("test,bool-prop"));
69         dev_info!(dev, "'{name}'='{prop}'\n");
70 
71         if fwnode.property_present(c_str!("test,u32-prop")) {
72             dev_info!(dev, "'test,u32-prop' is present\n");
73         }
74 
75         let name = c_str!("test,u32-optional-prop");
76         let prop = fwnode.property_read::<u32>(name).or(0x12);
77         dev_info!(dev, "'{name}'='{prop:#x}' (default = 0x12)\n",);
78 
79         // A missing required property will print an error. Discard the error to
80         // prevent properties_parse from failing in that case.
81         let name = c_str!("test,u32-required-prop");
82         let _ = fwnode.property_read::<u32>(name).required_by(dev);
83 
84         let name = c_str!("test,u32-prop");
85         let prop: u32 = fwnode.property_read(name).required_by(dev)?;
86         dev_info!(dev, "'{name}'='{prop:#x}'\n");
87 
88         let name = c_str!("test,i16-array");
89         let prop: [i16; 4] = fwnode.property_read(name).required_by(dev)?;
90         dev_info!(dev, "'{name}'='{prop:?}'\n");
91         let len = fwnode.property_count_elem::<u16>(name)?;
92         dev_info!(dev, "'{name}' length is {len}\n",);
93 
94         let name = c_str!("test,i16-array");
95         let prop: KVec<i16> = fwnode.property_read_array_vec(name, 4)?.required_by(dev)?;
96         dev_info!(dev, "'{name}'='{prop:?}' (KVec)\n");
97 
98         for child in fwnode.children() {
99             let name = c_str!("test,ref-arg");
100             let nargs = NArgs::N(2);
101             let prop: FwNodeReferenceArgs = child.property_get_reference_args(name, nargs, 0)?;
102             dev_info!(dev, "'{name}'='{prop:?}'\n");
103         }
104 
105         Ok(())
106     }
107 }
108 
109 impl Drop for SampleDriver {
110     fn drop(&mut self) {
111         dev_dbg!(self.pdev.as_ref(), "Remove Rust Platform driver sample.\n");
112     }
113 }
114 
115 kernel::module_platform_driver! {
116     type: SampleDriver,
117     name: "rust_driver_platform",
118     authors: ["Danilo Krummrich"],
119     description: "Rust Platform driver",
120     license: "GPL v2",
121 }
122