8 files changed, 141 insertions, 27 deletions
diff --git a/lib/pbdrv/drv/arduino/include.cmake b/lib/pbdrv/drv/arduino/include.cmake
index 1e2ff08..5ec1124 100644
--- a/lib/pbdrv/drv/arduino/include.cmake
+++ b/lib/pbdrv/drv/arduino/include.cmake
@@ -3,7 +3,7 @@ if(NOT DEFINED ARDUINO)
 endif()
 
 target_sources(pbdrv-mod PRIVATE "${CMAKE_CURRENT_LIST_DIR}/mod.cpp")
-target_link_arduino_libraries(pbdrv-mod core Wire)
+target_link_arduino_libraries(pbdrv-mod PRIVATE core Wire)
 
 # freertos is used to defer the handling of i2c messages outside the receive
 # interrupt service routine
diff --git a/lib/pbdrv/drv/arduino/index.dox b/lib/pbdrv/drv/arduino/index.dox
index 4c74222..03510dd 100644
--- a/lib/pbdrv/drv/arduino/index.dox
+++ b/lib/pbdrv/drv/arduino/index.dox
@@ -2,18 +2,24 @@
 /**
 \ingroup pb_drv
 \defgroup pb_drv_arduino Arduino
-\brief Arduino (Arduino-CMake-Toolchain) driver
-
-This driver is automatically enabled if the variable \c ARDUINO is defined in
-your CMakeLists.txt (it is by default when using Arduino-CMake-Toolchain).
-
-\note This driver automatically includes the
-\ref pb_ext_freertos "FreeRTOS extension" for deferring calls to \c
-pb_i2c_recv() from the I2C ISR.
+\brief Arduino ATmega (w/ Arduino-CMake-Toolchain) driver
 
 This driver is known to work with the following MCUs:
 - ATmega328P (Arduino Uno)
 - ATmega2560 (Arduino Mega)
 
+\par Usage
+- Link the \c pbdrv-mod library with your main executable
+
+\note This driver is automatically enabled if the variable \c ARDUINO is
+defined in your CMakeLists.txt (it is by default when using
+Arduino-CMake-Toolchain).
+
+\note This driver automatically includes the \ref pb_ext_freertos
+"FreeRTOS extension" for deferring calls to \c pb_i2c_recv() from the I2C ISR.
+
+A complete example for this driver is available in the \ref puzzle/dummy
+folder.
+
 */
 
diff --git a/lib/pbdrv/drv/arduino/mod.cpp b/lib/pbdrv/drv/arduino/mod.cpp
index 2eef8d5..c381077 100644
--- a/lib/pbdrv/drv/arduino/mod.cpp
+++ b/lib/pbdrv/drv/arduino/mod.cpp
@@ -1,7 +1,3 @@
-#ifndef ARDUINO
-#error This driver only works on the Arduino platform!
-#endif
-
 #include <Arduino.h>
 #include <Wire.h>
 #include <avr/delay.h>
@@ -42,8 +38,17 @@ static void pb_setup() {
 	Wire.onReceive(recv_event);
 }
 
-/// \ingroup pb_drv_arduino
+/**
+ * \ingroup pb_drv_arduino
+ * \warning This function includes a hard-coded 10ms delay before sending. This
+ * is to work around a weird issue where the Arduino pulls both SDA and SCL low
+ * while attempting to initiate an I2C transmission. We were able to verify
+ * that the Arduino correctly handles bus arbitration under a test scenario
+ * with 2 Uno's, but ran into issues while integrating the Arduino's with the
+ * RP2040.
+ */
 __weak void pb_i2c_send(i2c_addr_t addr, const uint8_t * buf, size_t sz) {
+	vTaskDelay(10 / portTICK_PERIOD_MS); // prevent bus collisions
 	Wire.beginTransmission((int) addr);
 	Wire.write(buf, sz);
 	Wire.endTransmission(true);
@@ -69,6 +74,10 @@ void loop_task() {
  * \ingroup pb_drv_arduino
  * \brief Application entrypoint
  *
+ * This function overrides the default (weak) implementation of the \c main()
+ * function in the Arduino framework. No additional setup is required to use
+ * this driver.
+ *
  * \note I should really be able to use Arduino's initVariant function for
  * this, but I can't seem to get it to link properly using the CMake setup in
  * this repository. Overriding the main() function seems to work, and the
diff --git a/lib/pbdrv/drv/index.dox b/lib/pbdrv/drv/index.dox
index 1fe09e2..89b9247 100644
--- a/lib/pbdrv/drv/index.dox
+++ b/lib/pbdrv/drv/index.dox
@@ -7,19 +7,6 @@
 Like \ref pb_ext "extensions", drivers provide platform-specific
 implementations for various functions used in \ref pbdrv-mod.
 
-Drivers are automatically included based on your build configuration, and you
-only need to ensure \c pbdrv-mod is linked with your final executable in order
-to use one of the available drivers:
-
-```cmake
-# include pbdrv
-add_subdirectory(lib/pbdrv)
-
-# link pbdrv-mod
-target_link_libraries(main pbdrv-mod)
-
-```
-
 If there is no existing driver for your target, you may implement the following
 in order to use \ref pbdrv-mod:
 
diff --git a/lib/pbdrv/drv/rp2040/include.cmake b/lib/pbdrv/drv/rp2040/include.cmake
new file mode 100644
index 0000000..6d25e96
--- /dev/null
+++ b/lib/pbdrv/drv/rp2040/include.cmake
@@ -0,0 +1,11 @@
+if(NOT PICO_PLATFORM STREQUAL "rp2040")
+	return()
+endif()
+
+target_sources(pbdrv-mod PRIVATE "${CMAKE_CURRENT_LIST_DIR}/mod.c")
+target_link_libraries(pbdrv-mod PRIVATE hardware_i2c_headers pico_i2c_slave_headers)
+target_include_directories(pbdrv-mod INTERFACE "${CMAKE_CURRENT_LIST_DIR}")
+
+# pico-stdlib is compatible with C stdlib
+include("${CMAKE_CURRENT_LIST_DIR}/../../ext/stdlib/include.cmake")
+
diff --git a/lib/pbdrv/drv/rp2040/index.dox b/lib/pbdrv/drv/rp2040/index.dox
new file mode 100644
index 0000000..eb01d15
--- /dev/null
+++ b/lib/pbdrv/drv/rp2040/index.dox
@@ -0,0 +1,31 @@
+// vim:ft=doxygen
+/**
+\ingroup pb_drv
+\defgroup pb_drv_rp2040 RP2040
+\brief Raspberry Pi Pico and Pico W driver
+
+This driver is known to work with the following MCUs:
+- Raspberry Pi Pico W
+
+\note While the RP2040's datasheet claims it supports multi-master
+configurations by implementing bus arbitration, it does not natively support
+a mode where it is configured as a (multi-)master with a slave address, such
+that it can be addressed by other multi-masters.
+
+\note This driver includes a workaround that uses both I2C peripherals on the
+RP2040. To use this driver, make sure you initialize both I2C peripherals, and
+connect their respective SDA and SCL pins to the same I2C bus.
+
+\par Usage
+- Link the \c pbdrv-mod library with your main executable
+- Call the \c pb_setup() function (from \c <pb-mod.h>) during setup
+
+\note This driver is automatically enabled if the variable \c PICO_PLATFORM is
+equal to \c "rp2040" in your CMakeLists.txt (it is by default when using the
+pico-sdk CMake library).
+
+\note This driver automatically includes the \ref pb_ext_stdlib
+"stdlib extension" as the pico-sdk implements the C standard library.
+
+*/
+
diff --git a/lib/pbdrv/drv/rp2040/mod.c b/lib/pbdrv/drv/rp2040/mod.c
new file mode 100644
index 0000000..1535da9
--- /dev/null
+++ b/lib/pbdrv/drv/rp2040/mod.c
@@ -0,0 +1,49 @@
+#include "pb.h"
+
+#include "pb.h"
+#include "pb-types.h"
+#include "pb-mod.h"
+#include "pb-send.h"
+#include "pb-buf.h"
+
+#include <hardware/i2c.h>
+#include <hardware/gpio.h>
+#include <pico/i2c_slave.h>
+
+#define PB_I2C_S i2c0
+#define PB_I2C_M i2c1
+
+#define BUF_SIZE 256
+
+uint8_t i2c_msg_buf[BUF_SIZE];
+size_t i2c_msg_buf_sz = 0;
+
+// This function is called from the I2C ISR
+static void recv_event(i2c_inst_t *i2c, i2c_slave_event_t event) {
+	switch (event) {
+		case I2C_SLAVE_RECEIVE: {
+			if (i2c_msg_buf_sz == BUF_SIZE) return;
+			i2c_msg_buf[i2c_msg_buf_sz++] = i2c_read_byte_raw(PB_I2C_S);
+			break;
+		}
+		case I2C_SLAVE_FINISH: {
+			pb_i2c_recv(i2c_msg_buf, i2c_msg_buf_sz);
+			i2c_msg_buf_sz = 0;
+			break;
+		}
+		default: break;
+	}
+}
+
+void pb_setup() {
+	i2c_init(PB_I2C_S, PB_CLOCK_SPEED_HZ);
+	i2c_init(PB_I2C_M, PB_CLOCK_SPEED_HZ);
+
+	i2c_slave_init(PB_I2C_S, PB_MOD_ADDR, &recv_event);
+}
+
+__weak void pb_i2c_send(i2c_addr_t addr, const uint8_t * buf, size_t sz) {
+	// false to write stop condition to i2c bus
+	i2c_write_timeout_us(PB_I2C_M, addr, buf, sz, false, PB_TIMEOUT_US);
+}
+
diff --git a/lib/pbdrv/drv/rp2040/pb-mod.h b/lib/pbdrv/drv/rp2040/pb-mod.h
new file mode 100644
index 0000000..96edc70
--- /dev/null
+++ b/lib/pbdrv/drv/rp2040/pb-mod.h
@@ -0,0 +1,21 @@
+#pragma once
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/**
+ * \ingroup pb_drv_rp2040
+ * \brief Puzzle bus driver setup
+ *
+ * This function must be called from a setup/init function to initialize the
+ * I2C peripherals used by this driver.
+ */
+void pb_setup();
+
+#ifdef __cplusplus
+}
+#endif
+
+#include "../../pb-mod.h"
+