1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
#![allow(clippy::missing_safety_doc)]
const BCM2711_GPIO_REGISTER_COUNT: usize = 58;
const GPIO_MMAP_LEN: usize = BCM2711_GPIO_REGISTER_COUNT * std::mem::size_of::<u32>();
const GPFSEL0: usize = 0x00;
const GPSET0: usize = 0x1c / std::mem::size_of::<u32>();
const GPCLR0: usize = 0x28 / std::mem::size_of::<u32>();
const GPLEV0: usize = 0x34 / std::mem::size_of::<u32>();
#[repr(u32)]
pub enum SaksPins {
Buzzer = 12,
Ds = 6,
Stcp = 13,
Shcp = 19,
Di = 25,
Clk = 5,
}
impl From<SaksPins> for u32 {
fn from(pin_num: SaksPins) -> Self {
pin_num as Self
}
}
#[repr(u32)]
pub enum PinMode {
Input = 0b000,
Output = 0b001,
}
impl From<PinMode> for u32 {
fn from(pin_mode: PinMode) -> Self {
pin_mode as Self
}
}
#[derive(Clone, Copy, PartialEq, Eq, Debug)]
#[repr(u8)]
pub enum VoltageLevel {
Low = 0,
High = 1,
}
impl From<VoltageLevel> for bool {
#[inline]
fn from(level: VoltageLevel) -> Self {
match level {
VoltageLevel::Low => false,
VoltageLevel::High => true,
}
}
}
impl std::ops::Not for VoltageLevel {
type Output = Self;
#[inline]
fn not(self) -> Self {
match self {
Self::Low => Self::High,
Self::High => Self::Low,
}
}
}
pub struct Saks {
mapped_addr: *mut u32,
}
impl Default for Saks {
fn default() -> Self {
Self::new()
}
}
impl Saks {
#[must_use]
pub fn new() -> Self {
let model = std::fs::read_to_string("/sys/firmware/devicetree/base/model").unwrap();
if !model.starts_with("Raspberry Pi 4 Model") {
panic!("only support Raspberry Pi 4");
}
let fd = unsafe { libc::open("/dev/gpiomem\0".as_ptr().cast(), libc::O_RDWR) };
if fd == -1 {
panic!("{}", std::io::Error::last_os_error());
}
let mapped_addr = unsafe {
libc::mmap(
std::ptr::null_mut(),
GPIO_MMAP_LEN,
libc::PROT_READ | libc::PROT_WRITE,
libc::MAP_SHARED,
fd,
0,
)
};
if mapped_addr == libc::MAP_FAILED {
panic!("{}", std::io::Error::last_os_error());
}
unsafe {
libc::close(fd);
}
let saks = Self {
mapped_addr: mapped_addr.cast(),
};
saks.init_pins();
saks
}
fn set_mode(&self, pin: SaksPins, pin_mode: PinMode) {
let bcm_pin_num = u32::from(pin);
let gpfsel_index = bcm_pin_num / 10;
let pin_mode_shift = (bcm_pin_num % 10) * 3;
let reg_ptr = unsafe {
self.mapped_addr
.offset(GPFSEL0 as isize + gpfsel_index as isize)
};
let mut reg_val = unsafe { *reg_ptr };
let bit_mask_to_clear_bcm_pin_num_pin_mode = !(0b111 << pin_mode_shift);
reg_val &= bit_mask_to_clear_bcm_pin_num_pin_mode;
reg_val |= (u32::from(pin_mode)) << pin_mode_shift;
unsafe {
*reg_ptr = reg_val;
}
}
pub fn set_level(&self, pin: SaksPins, level: VoltageLevel) {
self.set_is_high_level(pin, bool::from(level));
}
pub fn set_is_high_level(&self, pin: SaksPins, is_high_level: bool) {
let bcm_pin_num = u32::from(pin);
let addr_offset = if is_high_level { GPSET0 } else { GPCLR0 } + bcm_pin_num as usize / 32;
unsafe {
*self.mapped_addr.add(addr_offset) = 1 << (bcm_pin_num % 32);
}
}
pub fn get_level(&self, pin: SaksPins) -> VoltageLevel {
let bcm_pin_num = u32::from(pin);
let addr_offset = GPLEV0 + bcm_pin_num as usize / 32;
let reg_val = unsafe { *self.mapped_addr.add(addr_offset) };
if reg_val & (1 << (bcm_pin_num % 32)) == 0 {
VoltageLevel::Low
} else {
VoltageLevel::High
}
}
pub fn led_row_write_a_byte(&self, byte: u8) {
for bit_mask in 0..8 {
self.set_is_high_level(SaksPins::Ds, (byte >> bit_mask) & 1 == 1);
self.set_level(SaksPins::Shcp, VoltageLevel::Low);
self.set_level(SaksPins::Shcp, VoltageLevel::High);
}
self.set_level(SaksPins::Stcp, VoltageLevel::Low);
self.set_level(SaksPins::Stcp, VoltageLevel::High);
}
fn init_pins(&self) {
self.set_mode(SaksPins::Buzzer, PinMode::Output);
self.set_mode(SaksPins::Ds, PinMode::Output);
self.set_mode(SaksPins::Stcp, PinMode::Output);
self.set_mode(SaksPins::Shcp, PinMode::Output);
self.set_mode(SaksPins::Di, PinMode::Output);
self.set_mode(SaksPins::Clk, PinMode::Output);
}
unsafe fn clear_all(&self) {
*self.mapped_addr.add(GPCLR0) = 0b1111_1111;
*self.mapped_addr.add(GPCLR0 + 1) = 0b1111_1111;
}
pub fn i2c_bus_start(&self) {
self.set_level(SaksPins::Clk, VoltageLevel::High);
self.set_level(SaksPins::Di, VoltageLevel::High);
self.i2c_bus_delay();
self.set_level(SaksPins::Di, VoltageLevel::Low);
self.i2c_bus_delay();
self.set_level(SaksPins::Clk, VoltageLevel::Low);
self.i2c_bus_delay();
}
pub fn i2c_bus_delay(&self) {
std::thread::sleep(std::time::Duration::from_millis(1));
}
pub fn i2c_bus_write_byte(&self, byte: u8) {
for bit_mask in 0..8 {
let di_level = (byte >> bit_mask) & 1 == 1;
self.set_level(SaksPins::Clk, VoltageLevel::Low);
self.i2c_bus_delay();
if di_level {
self.set_level(SaksPins::Di, VoltageLevel::High);
} else {
self.set_level(SaksPins::Di, VoltageLevel::Low);
}
self.i2c_bus_delay();
self.set_level(SaksPins::Clk, VoltageLevel::High);
self.i2c_bus_delay();
}
self.set_level(SaksPins::Clk, VoltageLevel::Low);
self.i2c_bus_delay();
self.set_level(SaksPins::Di, VoltageLevel::High);
self.i2c_bus_delay();
self.set_level(SaksPins::Clk, VoltageLevel::High);
self.i2c_bus_delay();
}
pub fn i2c_bus_write_command(&self, command: u8) {
self.i2c_bus_start();
self.i2c_bus_write_byte(command);
self.i2c_bus_start();
}
}
impl Drop for Saks {
fn drop(&mut self) {
unsafe {
self.clear_all();
self.set_level(SaksPins::Buzzer, VoltageLevel::High);
let ret = libc::munmap(self.mapped_addr.cast(), GPIO_MMAP_LEN);
if ret == -1 {
panic!("{}", std::io::Error::last_os_error());
}
}
}
}