drivers: Add driver for SC18IS604 I2C controller

This driver relies on the asynchronous transfer functions provided by the
MFD driver to handle interrupts through non-blocking system work queue
items.

The asynchronous API function is implemented via fully non-blocking work
items running on the system work queue. Tracking each in-flight transfer
requires ~100 bytes of heap allocation, so the driver requests some heap
space by default.

Signed-off-by: Sarah Renkhoff <[email protected]>

drivers/CMakeLists.txt

@@ -4,6 +4,7 @@
 
 add_subdirectory_ifdef(CONFIG_DISPLAY display)
 add_subdirectory_ifdef(CONFIG_GPIO gpio)
+add_subdirectory_ifdef(CONFIG_I2C i2c)
 add_subdirectory_ifdef(CONFIG_MFD mfd)
 add_subdirectory_ifdef(CONFIG_RTC rtc)
 add_subdirectory_ifdef(CONFIG_SENSOR sensor)

drivers/Kconfig

@@ -6,6 +6,7 @@ menu "Device Drivers"
 
 rsource "display/Kconfig"
 rsource "gpio/Kconfig"
+rsource "i2c/Kconfig"
 rsource "mfd/Kconfig"
 rsource "rtc/Kconfig"
 rsource "sensor/Kconfig"

drivers/i2c/CMakeLists.txt

@@ -0,0 +1,10 @@
+# Copyright (c) 2024 TiaC Systems
+# SPDX-License-Identifier: Apache-2.0
+
+# Add to the existing i2c library from zephyr instead of defining our own.
+# It is actually required to add I2C drivers to that library, otherwise
+# build errors can occur!
+zephyr_library_amend()
+
+zephyr_library_sources_ifdef(CONFIG_I2C_SC18IS604 i2c_sc18is604.c)
+zephyr_library_sources_ifdef(CONFIG_I2C_CALLBACK i2c_sc18is604_callback.c)

drivers/i2c/Kconfig

@@ -0,0 +1,8 @@
+# Copyright (c) 2024 TiaC Systems
+# SPDX-License-Identifier: Apache-2.0
+
+if I2C
+
+rsource "Kconfig.sc18is604"
+
+endif # I2C

drivers/i2c/Kconfig.sc18is604

@@ -0,0 +1,29 @@
+# Copyright (c) 2024 TiaC Systems
+# SPDX-License-Identifier: Apache-2.0
+
+menuconfig I2C_SC18IS604
+	bool "I2C controller part of an SC18IM604 bridge"
+	default y
+	depends on DT_HAS_NXP_SC18IS604_I2C_ENABLED
+	depends on MFD_SC18IS604
+	select MFD_SC18IS604_ASYNC
+	select POLL              # dependency of MFD_SC18IS604_ASYNC
+	select DYNAMIC_THREAD    # dependency of MFD_SC18IS604_ASYNC
+	select THREAD_STACK_INFO # dependency of DYNAMIC_THREAD
+	help
+	  Enable driver for I2C controller part of an SC18IM604 bridge.
+
+config I2C_SC18IS604_INIT_PRIORITY
+	int "Init priority"
+	default 60
+	depends on I2C_SC18IS604
+	help
+	  Device driver initialization priority.
+
+if I2C_CALLBACK
+
+	config HEAP_MEM_POOL_ADD_SIZE_I2C_SC18IS604
+		int
+		default 512 # Enough for 5 in-flight async transfers
+
+endif