Add ESP32- H2 soc/efuse methods (esp-rs#486)

* feat: ✨ Implement efuse methods

* feat: ✨ Add NUM_PINS

* doc: Update link to point at specific commit

Co-authored-by: Jesse Braham <jessebraham@users.noreply.github.com>

---------

Co-authored-by: Jesse Braham <jessebraham@users.noreply.github.com>

esp-hal-common/src/soc/esp32h2/efuse.rs

@@ -1,3 +1,7 @@
+//! Reading of eFuses
+
+use crate::peripherals::EFUSE;
+
 pub struct Efuse;
 
 impl Efuse {
@@ -19,16 +23,40 @@ impl Efuse {
     /// );
     /// ```
     pub fn get_mac_address() -> [u8; 6] {
-        todo!()
+        let efuse = unsafe { &*EFUSE::ptr() };
+
+        let mac_low: u32 = efuse.rd_mac_sys_0.read().mac_0().bits();
+        let mac_high: u32 = efuse.rd_mac_sys_1.read().mac_1().bits() as u32;
+
+        let mac_low_bytes = mac_low.to_be_bytes();
+        let mac_high_bytes = mac_high.to_be_bytes();
+
+        [
+            mac_high_bytes[2],
+            mac_high_bytes[3],
+            mac_low_bytes[0],
+            mac_low_bytes[1],
+            mac_low_bytes[2],
+            mac_low_bytes[3],
+        ]
     }
 
     /// Get status of SPI boot encryption.
     pub fn get_flash_encryption() -> bool {
-        todo!()
+        let efuse = unsafe { &*EFUSE::ptr() };
+        (efuse
+            .rd_repeat_data1
+            .read()
+            .spi_boot_crypt_cnt()
+            .bits()
+            .count_ones()
+            % 2)
+            != 0
     }
 
     /// Get the multiplier for the timeout value of the RWDT STAGE 0 register.
     pub fn get_rwdt_multiplier() -> u8 {
-        todo!()
+        let efuse = unsafe { &*EFUSE::ptr() };
+        efuse.rd_repeat_data1.read().wdt_delay_sel().bits()
     }
 }

esp-hal-common/src/soc/esp32h2/gpio.rs

@@ -1,6 +1,7 @@
 use paste::paste;
 
-pub const NUM_PINS: usize = 0; // FIXME
+// https://github.com/espressif/esp-idf/blob/df9310a/components/soc/esp32h2/gpio_periph.c#L42
+pub const NUM_PINS: usize = 27;
 
 pub type OutputSignalType = u8;
 pub const OUTPUT_SIGNAL_MAX: u8 = 0; // FIXME