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>

4 files changed, 79 insertions, 21 deletions

diff --git a/common/peripheral_charger.c b/common/peripheral_charger.c
index 0b467afc6e..0a597ad6bd 100644
--- a/common/peripheral_charger.c
+++ b/common/peripheral_charger.c
@@ -65,6 +65,7 @@ static const char *_text_event(enum pchg_event event)
 		[PCHG_EVENT_ENABLED] = "ENABLED",
 		[PCHG_EVENT_DISABLED] = "DISABLED",
 		[PCHG_EVENT_DEVICE_DETECTED] = "DEVICE_DETECTED",
+		[PCHG_EVENT_DEVICE_CONNECTED] = "DEVICE_CONNECTED",
 		[PCHG_EVENT_DEVICE_LOST] = "DEVICE_LOST",
 		[PCHG_EVENT_CHARGE_STARTED] = "CHARGE_STARTED",
 		[PCHG_EVENT_CHARGE_UPDATE] = "CHARGE_UPDATE",
@@ -194,15 +195,15 @@ static void pchg_state_enabled(struct pchg *ctx)
 		ctx->state = PCHG_STATE_INITIALIZED;
 		break;
 	case PCHG_EVENT_DEVICE_DETECTED:
+		ctx->state = PCHG_STATE_DETECTED;
+		break;
+	case PCHG_EVENT_DEVICE_CONNECTED:
 		/*
 		 * Proactively query SOC in case charging info won't be sent
 		 * because device is already charged.
 		 */
 		ctx->cfg->drv->get_soc(ctx);
-		ctx->state = PCHG_STATE_DETECTED;
-		break;
-	case PCHG_EVENT_CHARGE_STARTED:
-		ctx->state = PCHG_STATE_CHARGING;
+		ctx->state = PCHG_STATE_CONNECTED;
 		break;
 	default:
 		break;
@@ -228,6 +229,42 @@ static void pchg_state_detected(struct pchg *ctx)
 	case PCHG_EVENT_DISABLED:
 		ctx->state = PCHG_STATE_INITIALIZED;
 		break;
+	case PCHG_EVENT_DEVICE_CONNECTED:
+		/*
+		 * Proactively query SOC in case charging info won't be sent
+		 * because device is already charged.
+		 */
+		ctx->cfg->drv->get_soc(ctx);
+		ctx->state = PCHG_STATE_CONNECTED;
+		break;
+	case PCHG_EVENT_DEVICE_LOST:
+		ctx->battery_percent = 0;
+		ctx->state = PCHG_STATE_ENABLED;
+		break;
+	default:
+		break;
+	}
+}
+
+static void pchg_state_connected(struct pchg *ctx)
+{
+	int rv;
+
+	switch (ctx->event) {
+	case PCHG_EVENT_RESET:
+		ctx->state = pchg_reset(ctx);
+		break;
+	case PCHG_EVENT_DISABLE:
+		ctx->error |= PCHG_ERROR_HOST;
+		rv = ctx->cfg->drv->enable(ctx, false);
+		if (rv == EC_SUCCESS)
+			ctx->state = PCHG_STATE_INITIALIZED;
+		else if (rv != EC_SUCCESS_IN_PROGRESS)
+			CPRINTS("ERR: Failed to disable");
+		break;
+	case PCHG_EVENT_DISABLED:
+		ctx->state = PCHG_STATE_INITIALIZED;
+		break;
 	case PCHG_EVENT_CHARGE_STARTED:
 		ctx->state = PCHG_STATE_CHARGING;
 		break;
@@ -273,7 +310,7 @@ static void pchg_state_charging(struct pchg *ctx)
 		break;
 	case PCHG_EVENT_CHARGE_ENDED:
 	case PCHG_EVENT_CHARGE_STOPPED:
-		ctx->state = PCHG_STATE_DETECTED;
+		ctx->state = PCHG_STATE_CONNECTED;
 		break;
 	default:
 		break;
@@ -395,6 +432,9 @@ static int pchg_run(struct pchg *ctx)
 	case PCHG_STATE_DETECTED:
 		pchg_state_detected(ctx);
 		break;
+	case PCHG_STATE_CONNECTED:
+		pchg_state_connected(ctx);
+		break;
 	case PCHG_STATE_CHARGING:
 		pchg_state_charging(ctx);
 		break;
@@ -546,7 +586,7 @@ static enum ec_status hc_pchg(struct host_cmd_handler_args *args)
 
 	ctx = &pchgs[port];
 
-	if (ctx->state == PCHG_STATE_DETECTED
+	if (ctx->state == PCHG_STATE_CONNECTED
 			&& ctx->battery_percent >= ctx->cfg->full_percent)
 		r->state = PCHG_STATE_FULL;
 	else
diff --git a/driver/nfc/ctn730.c b/driver/nfc/ctn730.c
index b3da1bbb79..1fe5a48b1b 100644
--- a/driver/nfc/ctn730.c
+++ b/driver/nfc/ctn730.c
@@ -98,6 +98,8 @@ static const int _detection_interval_ms = 500;
 #define WLC_CHG_CTRL_DEVICE_STATE_DEVICE_DEACTIVATED		0x01
 #define WLC_CHG_CTRL_DEVICE_STATE_DEVICE_DEVICE_LOST		0x02
 #define WLC_CHG_CTRL_DEVICE_STATE_DEVICE_DEVICE_BAD_VERSION	0x03
+#define WLC_CHG_CTRL_DEVICE_STATE_DEVICE_DOCKED			0x04
+#define WLC_CHG_CTRL_DEVICE_STATE_DEVICE_UNDOCKED		0x05
 #define WLC_CHG_CTRL_DEVICE_STATE_EVT_SIZE_DETECTED		8
 #define WLC_CHG_CTRL_DEVICE_STATE_EVT_SIZE			1
 
@@ -502,12 +504,18 @@ static int _process_payload_event(struct pchg *ctx, struct ctn730_msg *res)
 		break;
 	case WLC_CHG_CTRL_DEVICE_STATE:
 		switch (buf[0]) {
+		case WLC_CHG_CTRL_DEVICE_STATE_DEVICE_DOCKED:
+			if (len != WLC_CHG_CTRL_DEVICE_STATE_EVT_SIZE)
+				return EC_ERROR_INVAL;
+			ctx->event = PCHG_EVENT_DEVICE_DETECTED;
+			break;
 		case WLC_CHG_CTRL_DEVICE_STATE_DEVICE_DETECTED:
 			if (len != WLC_CHG_CTRL_DEVICE_STATE_EVT_SIZE_DETECTED)
 				return EC_ERROR_INVAL;
-			ctx->event = PCHG_EVENT_DEVICE_DETECTED;
+			ctx->event = PCHG_EVENT_DEVICE_CONNECTED;
 			break;
 		case WLC_CHG_CTRL_DEVICE_STATE_DEVICE_DEVICE_LOST:
+		case WLC_CHG_CTRL_DEVICE_STATE_DEVICE_UNDOCKED:
 			if (len != WLC_CHG_CTRL_DEVICE_STATE_EVT_SIZE)
 				return EC_ERROR_INVAL;
 			ctx->event = PCHG_EVENT_DEVICE_LOST;
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,