draft driver for STUSB4500

right now it is only possible to change the delivered power on the fly
by
1. selecting PDO2 slot
2. write to POO2
3. renegotiate power by sw reset command

drivers/usbmisc/Kconfig

@@ -88,4 +88,33 @@ config FUSB303_NPOLLWAITERS
 
 endif
 
+config STUSB4500
+	bool "ST standalone USB PD sink controller"
+	default n
+	select I2C
+	---help---
+		Enable device driver for ST standalone USB PD (power delivery) sink
+		controller that addresses sink up to 100 W (20 V; 5 A).
+
+if STUSB4500
+
+config STUSB4500_I2C_FREQUENCY
+	int "STUSB4500 I2C frequency"
+	default 400000
+	range 1 400000
+
+config DEBUG_STUSB4500
+	bool "Enable debug support for the STUSB4500"
+	default n
+	---help---
+		Enables debug support for the STUSB4500
+
+config STUSB4500_NPOLLWAITERS
+	int "Number of waiters to poll"
+	default 2
+	---help---
+		Maximum number of threads that can be waiting on poll()
+
+endif
+
 endif # USBMISC

drivers/usbmisc/Make.defs

@@ -36,6 +36,10 @@ ifeq ($(CONFIG_FUSB303),y)
   CSRCS += fusb303.c
 endif
 
+ifeq ($(CONFIG_STUSB4500),y)
+  CSRCS += stusb4500.c
+endif
+
 # Include USB miscellaneous build support
 
 DEPPATH += --dep-path usbmisc