USBC PD: update usb-c doc
change new state machine file references to be up to date with
the current code.
BRANCH=none
TEST=none
@@ -83,8 +83,11 @@ Right now platform/ec has two different implementations of USB-C PD stack.
[`usb_pd_protocol.c`](../common/usb_pd_protocol.c)
2. The newer implementation is broken up into multiple different files and
state machines
- * Policy engine state machine files, such as `usb_pe_*_sm.c`.
- * Type-C physical layer state machine: `usb_tc_sm.c`
+ * 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`.
+ * Type-C physical layer state machine files, `usb_tc_*_sm.c`.
+ * USB-C PD Task file, `usbc_task.c`.
The older implementation supports firmware for device types other than
Chromebooks. For example, the older stack supports the Zinger, which is the
@@ -106,7 +109,7 @@ In both older and newer implementations, the following details apply:
* The `PD_C#` task runs the state machine (old or new) for the port and
communicates with the TCPC, MUX, and PPC. This task needs a large task
stack.
- * The `PD_INT_C#` tasks runs at a higher priority than the state machine
+ * The `PD_INT_C#` tasks run at a higher priority than the state machine
task, and its sole job is to receive interrupts from the TCPC as quickly
as possible then send appropriate messages to other tasks (including
`PD_C#`). This task shouldn't need much stack space, but the i2c
