Generic set gpio state

src/gpio.rs

@@ -4,7 +4,19 @@ const GPFSEL_BASE: u32 = 0x3F20_0000;
 const GPSET_BASE: u32 = 0x3F20_001C;
 const GPCLR_BASE: u32 = 0x3F20_0028;
 
-unsafe fn set_gpio_to_output(gpio: u8) -> Result<(), &'static str> {
+#[repr(u32)]
+pub enum GPIOState {
+    input = 0b000,
+    output = 0b001,
+    alternative0 = 0b100,
+    alternative1 = 0b101,
+    alternative2 = 0b110,
+    alternative3 = 0b111,
+    alternative4 = 0b011,
+    alternative5 = 0b010,
+}
+
+pub unsafe fn set_gpio_state(gpio: u8, state: GPIOState) -> Result<(), &'static str> {
     if gpio > 53 {
         return Err("GPIO out of range");
     }
@@ -18,16 +30,15 @@ unsafe fn set_gpio_to_output(gpio: u8) -> Result<(), &'static str> {
     let mask = !(0b111 << register_offset);
     let cleared = current & mask;
 
-    let new_val = cleared | (0b001 << register_offset);
+    let new_val = cleared | ((state as u32) << register_offset);
 
     core::ptr::write_volatile(register_addr as *mut u32, new_val);
     Ok(())
 }
 
-pub fn pull_up_gpio(gpio: u8) -> Result<(), &'static str> {
+pub fn gpio_high(gpio: u8) -> Result<(), &'static str> {
     unsafe {
         uart::print("Pull Up\n");
-        set_gpio_to_output(29)?;
 
         let register_index = gpio / 32;
         let register_offset = gpio % 32;
@@ -38,7 +49,7 @@ pub fn pull_up_gpio(gpio: u8) -> Result<(), &'static str> {
     Ok(())
 }
 
-pub fn pull_down_gpio(gpio: u8) -> Result<(), &'static str> {
+pub fn gpio_low(gpio: u8) -> Result<(), &'static str> {
     unsafe {
         uart::print("Pull Down\n");
 

src/main.rs

@@ -4,7 +4,7 @@
 
 use core::{arch::asm, panic::PanicInfo};
 
-use gpio::{pull_down_gpio, pull_up_gpio};
+use gpio::{gpio_high, gpio_low, set_gpio_state};
 
 mod gpio;
 mod uart;
@@ -26,15 +26,18 @@ pub unsafe extern "C" fn _start() {
 #[no_mangle]
 extern "C" fn main() {
     uart::configure_uart();
+    unsafe {
+        let _ = set_gpio_state(29, gpio::GPIOState::output);
+    }
 
     // Delay so clock speed can stabilize
     unsafe { delay(50000) }
     uart::print("Hello World!\n");
 
     loop {
-        let _ = pull_up_gpio(29);
+        let _ = gpio_high(29);
         unsafe { delay(1_000_000) }
-        let _ = pull_down_gpio(29);
+        let _ = gpio_low(29);
         unsafe { delay(1_000_000) }
     }
 }