1 files changed, 57 insertions, 0 deletions

diff --git a/embassy-rp/src/qmi_cs1.rs b/embassy-rp/src/qmi_cs1.rs
new file mode 100644
index 000000000..b8ae41e35
--- /dev/null
+++ b/embassy-rp/src/qmi_cs1.rs
@@ -0,0 +1,57 @@
+//! QMI CS1 peripheral for RP235x
+//!
+//! This module provides access to the QMI CS1 functionality for use with external memory devices
+//! such as PSRAM. The QMI (Quad SPI) controller supports CS1 as a second chip select signal.
+//!
+//! This peripheral is only available on RP235x chips.
+
+#![cfg(feature = "_rp235x")]
+
+use embassy_hal_internal::{Peri, PeripheralType};
+
+use crate::gpio::Pin as GpioPin;
+use crate::{pac, peripherals};
+
+/// QMI CS1 driver.
+pub struct QmiCs1<'d> {
+    _inner: Peri<'d, peripherals::QMI_CS1>,
+}
+
+impl<'d> QmiCs1<'d> {
+    /// Create a new QMI CS1 instance.
+    pub fn new(qmi_cs1: Peri<'d, peripherals::QMI_CS1>, cs1: Peri<'d, impl QmiCs1Pin>) -> Self {
+        // Configure CS1 pin for QMI function (funcsel = 9)
+        cs1.gpio().ctrl().write(|w| w.set_funcsel(9));
+
+        // Configure pad settings for high-speed operation
+        cs1.pad_ctrl().write(|w| {
+            #[cfg(feature = "_rp235x")]
+            w.set_iso(false);
+            w.set_ie(true);
+            w.set_drive(pac::pads::vals::Drive::_12M_A);
+            w.set_slewfast(true);
+        });
+
+        Self { _inner: qmi_cs1 }
+    }
+}
+
+trait SealedInstance {}
+
+/// QMI CS1 instance trait.
+#[allow(private_bounds)]
+pub trait Instance: SealedInstance + PeripheralType {}
+
+impl SealedInstance for peripherals::QMI_CS1 {}
+
+impl Instance for peripherals::QMI_CS1 {}
+
+/// CS1 pin trait for QMI.
+pub trait QmiCs1Pin: GpioPin {}
+
+// Implement pin traits for CS1-capable GPIO pins
+impl QmiCs1Pin for peripherals::PIN_0 {}
+impl QmiCs1Pin for peripherals::PIN_8 {}
+impl QmiCs1Pin for peripherals::PIN_19 {}
+#[cfg(feature = "rp235xb")]
+impl QmiCs1Pin for peripherals::PIN_47 {}