mmc: use new-types for the card type

Adds the `CardType` enum to represent the device type for a SD/MMC
perpipheral.

Author: rmsyn

embedded-hal/src/mmc.rs

@@ -1,6 +1,7 @@
 //! Types and traits for SD/MMC peripherals.
 
 mod bus_width;
+mod card_type;
 mod fifo_status;
 mod reset;
 
@@ -9,6 +10,7 @@ pub mod response;
 pub mod tuning;
 
 pub use bus_width::BusWidth;
+pub use card_type::CardType;
 pub use fifo_status::FifoStatus;
 pub use reset::Reset;
 
@@ -21,13 +23,8 @@ pub trait MmcOps {
     /// Associated error type for the SD/MMC trait.
     type Error;
 
-    /// Gets whether the device is a MMC card.
-    fn is_mmc(&self) -> bool;
-
-    /// Gets whether the device is a SD card.
-    fn is_sd(&self) -> bool {
-        !self.is_mmc()
-    }
+    /// Gets whether the device [CardType].
+    fn card_type(&self) -> CardType;
 
     /// Gets whether the device is configured for SPI mode.
     fn is_spi(&self) -> bool;

embedded-hal/src/mmc/card_type.rs

@@ -0,0 +1,32 @@
+/// Represents the card type of the peripheral.
+#[repr(u8)]
+#[derive(Clone, Copy, Debug, Eq, PartialEq)]
+pub enum CardType {
+    /// Represents a SD device.
+    Sd,
+    /// Represents a MMC device.
+    Mmc,
+}
+
+impl CardType {
+    /// Creates a new [CardType].
+    pub const fn new() -> Self {
+        Self::Sd
+    }
+
+    /// Convenience function to get if the [CardType] is a SD.
+    pub const fn is_sd(&self) -> bool {
+        matches!(self, Self::Sd)
+    }
+
+    /// Convenience function to get if the [CardType] is a MMC.
+    pub const fn is_mmc(&self) -> bool {
+        matches!(self, Self::Mmc)
+    }
+}
+
+impl Default for CardType {
+    fn default() -> Self {
+        Self::new()
+    }
+}