PCHG: Handle WLC_CHG_CTRL_DEVICE_STATE_DEVICE_DOCKED

We'll extend the period for a stylus to be statically charged so that
EEPROM corruption can be avoided by not entering negotiated mode with
a depleted battery.

During this static charge period, the user currently doesn't see any
charging indication. To prevent users from removing a stylus, we'll
add a new state 'device docked' to ctn730.

The EC firmware is updated to handle this new state as follows:

- PCHG_STATE_DETECTED will be reused to indicate a device is in
proximity but not ready for communication.
- PCHG_STATE_CONNECTED will be added to indicate a device is ready
for digital communication. This is formerly called DETECTED.
- CTN730 driver produces PCHG_EVENT_DETECTED on 'docked' event and
PCHG_EVENT_CONNECTED on 'detected' event.
- When DEVICE_UNDOCKED is received in PCHG_STATE_DETECTED,
transition to PCHG_STATE_ENABLED.

BUG=b:189323070, b:173235954
BRANCH=trogdor
TEST=Verify unpowered listener board can be detected.

Signed-off-by: Daisuke Nojiri <dnojiri@chromium.org>
Change-Id: I7fa83f6dd31cf74eab7c158e557ddc09f8976798
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/2920628
Reviewed-by: Vincent Palatin <vpalatin@chromium.org>

2 files changed, 24 insertions, 14 deletions

diff --git a/include/ec_commands.h b/include/ec_commands.h
index c0bea49322..09592c8b96 100644
--- a/include/ec_commands.h
+++ b/include/ec_commands.h
@@ -6820,16 +6820,18 @@ enum pchg_state {
 	PCHG_STATE_INITIALIZED,
 	/* Charger is enabled and ready to detect a device. */
 	PCHG_STATE_ENABLED,
-	/* Device is detected in proximity. */
+	/* Device is in proximity. */
 	PCHG_STATE_DETECTED,
 	/* Device is being charged. */
 	PCHG_STATE_CHARGING,
 	/* Device is fully charged. It implies DETECTED (& not charging). */
 	PCHG_STATE_FULL,
-	/* In download (or firmware update) mode. Update session is closed. */
+	/* In download (a.k.a. firmware update) mode */
 	PCHG_STATE_DOWNLOAD,
-	/* In download mode. Session is opened. Ready for receiving data. */
+	/* In download mode. Ready for receiving data. */
 	PCHG_STATE_DOWNLOADING,
+	/* Device is ready for data communication. */
+	PCHG_STATE_CONNECTED,
 	/* Put no more entry below */
 	PCHG_STATE_COUNT,
 };
@@ -6843,6 +6845,7 @@ enum pchg_state {
 	[PCHG_STATE_FULL] = "FULL", \
 	[PCHG_STATE_DOWNLOAD] = "DOWNLOAD", \
 	[PCHG_STATE_DOWNLOADING] = "DOWNLOADING", \
+	[PCHG_STATE_CONNECTED] = "CONNECTED", \
 	}
 
 /**
diff --git a/include/peripheral_charger.h b/include/peripheral_charger.h
index 93d6427814..702d3c9835 100644
--- a/include/peripheral_charger.h
+++ b/include/peripheral_charger.h
@@ -37,26 +37,32 @@
  *                          |
  *                          | INITIALIZED
  *                          v
- *                  +-------+-------+
+ *                  +---------------+
  *                  |  INITIALIZED  |<--------------+
- *                  +------+-+------+               |
+ *                  +------+--------+               |
  *                         | ^                      |
  *                 ENABLED | | DISABLED             |
  *                         v |                      |
- *                  +------+--------+               |
- *   +------------->+    ENABLED    |               |
- *   |              +-------+-------+               |
- *   |                      |                       |
- *   |                      | DEVICE_DETECTED       |
- *   |                      v                       |
+ *                  +--------+------+               |
+ *   +------------->|    ENABLED    |               |
+ *   |              +-----+-+-------+               |
+ *   |                    | |                       |
+ *   |   DEVICE_CONNECTED | | DEVICE_DOCKED         |
+ *   |                    | v                       |
+ *   | DEVICE_LOST  +---------------+               |
+ *   +--------------+     DOCKED    +---------------+
  *   |              +-------+-------+               |
- *   +--------------+   DETECTED    +---------------+
- *   | DEVICE_LOST  +------+-+------+  ERROR        |
+ *   |                    | |                       |
+ *   |                    | | DEVICE_CONNECTED      |
+ *   |                    v v                       |
+ *   |              +---------------+               |
+ *   +--------------+   CONNECTED   +---------------+
+ *   | DEVICE_LOST  +------+--------+  ERROR        |
  *   |                     | ^                      |
  *   |      CHARGE_STARTED | | CHARGE_ENDED         |
  *   |                     | | CHARGE_STOPPED       |
  *   |                     v |                      |
- *   |              +------+-+------+               |
+ *   |              +--------+------+               |
  *   +--------------+   CHARGING    +---------------+
  *     DEVICE_LOST  +---------------+  ERROR
  *
@@ -94,6 +100,7 @@ enum pchg_event {
 	PCHG_EVENT_ENABLED,
 	PCHG_EVENT_DISABLED,
 	PCHG_EVENT_DEVICE_DETECTED,
+	PCHG_EVENT_DEVICE_CONNECTED,
 	PCHG_EVENT_DEVICE_LOST,
 	PCHG_EVENT_CHARGE_STARTED,
 	PCHG_EVENT_CHARGE_UPDATE,