pchg: Notify host of only device detection in suspend

Currently, pchg sends a host event for any event including charging
update. This will prevent the host from staying in S3 while charging
a peripheral device.

This patch makes pchg notify the host only a device attach or detach
event when the system is in S3/S0ix.

Tested resume on detach as follows:
1. Verify system can suspend with a stylus attached.
2. Detach a stylus.
3. Verify system resumes.

Tested resume on attach as follows:
1. Suspend with a stylus detached.
2. Attach a stylus.
3. Verify system resumes.

BUG=b:177664326,b:173235954
BRANCH=trogdor
TEST=CoachZ. See above.

Signed-off-by: Daisuke Nojiri <dnojiri@chromium.org>
Change-Id: Icf7c6c46f94f27f1f24eb2ac9634d317bc14f4d9
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/2665407
Reviewed-by: Vincent Palatin <vpalatin@chromium.org>

1 files changed, 18 insertions, 11 deletions

diff --git a/common/peripheral_charger.c b/common/peripheral_charger.c
index 326b0bb495..131d660d40 100644
--- a/common/peripheral_charger.c
+++ b/common/peripheral_charger.c
@@ -268,7 +268,6 @@ static int pchg_run(struct pchg *ctx)
 		rv = ctx->cfg->drv->get_event(ctx);
 		if (rv) {
 			CPRINTS("ERR: get_event (%d)", rv);
-			ctx->event = PCHG_EVENT_NONE;
 			return 0;
 		}
 		CPRINTS("IRQ:EVENT_%s", _text_event(ctx->event));
@@ -298,9 +297,19 @@ static int pchg_run(struct pchg *ctx)
 	if (previous_state != ctx->state)
 		CPRINTS("->STATE_%s", _text_state(ctx->state));
 
-	ctx->event = PCHG_EVENT_NONE;
+	/*
+	 * Notify the host of
+	 * - [S0] any event
+	 * - [S3/S0IX] device attach or detach (for wake-up)
+	 * - [S5/G3] no events.
+	 */
+	if (chipset_in_state(CHIPSET_STATE_ON))
+		return ctx->event != PCHG_EVENT_NONE;
+	else if (chipset_in_state(CHIPSET_STATE_ANY_SUSPEND))
+		return (ctx->event == PCHG_EVENT_DEVICE_DETECTED)
+			|| (ctx->event == PCHG_EVENT_DEVICE_LOST);
 
-	return 1;
+	return 0;
 }
 
 void pchg_irq(enum gpio_signal signal)
@@ -356,7 +365,6 @@ void pchg_task(void *u)
 {
 	struct pchg *ctx;
 	int p;
-	int rv;
 
 	/* In case we arrive here after power-on (for late sysjump) */
 	if (chipset_in_state(CHIPSET_STATE_ON))
@@ -364,7 +372,8 @@ void pchg_task(void *u)
 
 	while (true) {
 		/* Process pending events for all ports. */
-		rv = 0;
+		int rv = 0;
+
 		for (p = 0; p < pchg_count; p++) {
 			ctx = &pchgs[p];
 			do {
@@ -373,13 +382,11 @@ void pchg_task(void *u)
 				rv |= pchg_run(ctx);
 			} while (queue_count(&ctx->events));
 		}
-		/*
-		 * Send one host event for all ports. Currently PCHG supports
-		 * only WLC but in the future other types (e.g. WPC Qi) should
-		 * send different device events.
-		 */
+
+		/* Send one host event for all ports. */
 		if (rv)
 			device_set_single_event(EC_DEVICE_EVENT_WLC);
+
 		task_wait_event(-1);
 	}
 }
@@ -432,7 +439,7 @@ static int cc_pchg(int argc, char **argv)
 	ctx = &pchgs[port];
 
 	if (argc == 2) {
-		ccprintf("P%d %s %s\n", port,
+		ccprintf("P%d STATE_%s EVENT_%s\n", port,
 			 _text_state(ctx->state), _text_event(ctx->event));
 		return EC_SUCCESS;
 	}