docs: Updates to USB-PD
Minor updates to the USB-PD description.
BRANCH=none
TEST=make buildall
@@ -80,12 +80,13 @@ Modes in the EC codebase.
Right now platform/ec has two different implementations of USB-C PD stack.
1. The older implementation is mainly contained within
- [`usb_pd_protocol.c`](../common/usb_pd_protocol.c)
-2. The newer implementation is broken up into multiple different files and
- state machines
+ [`usb_pd_protocol.c`](../common/usb_pd_protocol.c) and
+ [`usb_pd_policy.c`](../common/usb_pd_policy.c)
+2. The newer implementation is found under [`common/usbc`](../common/usbc) and
+ is broken up into multiple different files and state machines
* Policy engine state machine files, `usb_pe_*_sm.c`.
- * Protocol engine state machine file, `usb_prl_sm.c`.
- * State machine manager file, `usb_sm.c`.
+ * Protocol engine state machine file, `usb_prl_*_sm.c`.
+ * State machine framework file, `usb_sm.c`.
* Type-C physical layer state machine files, `usb_tc_*_sm.c`.
* USB-C PD Task file, `usbc_task.c`.
@@ -94,6 +95,9 @@ Chromebooks. For example, the older stack supports the Zinger, which is the
USB-C charging device that shipped with Samus, the Google Chromebook Pixel 2.
The Zinger implements the charger only side of the USB PD protocol.
+To use the newer USB-C PD stack implementation, see `CONFIG_USB_SM_FRAMEWORK`
+description in [config.h][config header link].
+
The newer implementation only supports Chromebooks at the moment. There are
multiple policy engine definitions to choose from depending on the different
USB-C features the Chromebook should support. As of now, you must choose one and
@@ -189,9 +193,6 @@ PPC IC.
Many USB-C policies and features are gated by various `CONFIG_*` options that
should be defined in `board.h` (or baseboard equivalent).
-To use the newer USB-C PD stack implementation, see `CONFIG_USB_SM_FRAMEWORK`
-description in [config.h][config header link].
-
Most USB-C options will start with `CONFIG_USB_PD_` or `CONFIG_USBC_`. For their
full descriptions see [config.h][config header link]
