PCHG: Handle reset event

Currently, PCHG assumes PCHG chips are reset only on POR and ignores
reset events. This can cause the state machine to be in an unexpected
state when a reset happens asynchronously.

This patch allows PCHG to handle chip reset events. It also makes the
task explicitly reset PCHG chips at start-up so that everything will
start in known & clean states.

BUG=b:181745891,b:181036152,b:173235954,b:183151376
BRANCH=trogdor
TEST=Verify PCHG behaves expectedly across cold reset, warm reset,
suspend & resume. Repeat the test with and without stylus.

Signed-off-by: Daisuke Nojiri <dnojiri@chromium.org>
Change-Id: Ia3dd1fe7ebc8dd6f4ee8149a4c25918922143fc3
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/2741282
Reviewed-by: Vincent Palatin <vpalatin@chromium.org>
(cherry picked from commit 2c703a08e866e3c3efedd8bb05d3de2323fa201c)
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/2787470

3 files changed, 52 insertions, 10 deletions

diff --git a/common/peripheral_charger.c b/common/peripheral_charger.c
index cb9a6e1f3e..05dde52a40 100644
--- a/common/peripheral_charger.c
+++ b/common/peripheral_charger.c
@@ -49,6 +49,7 @@ static const char *_text_event(enum pchg_event event)
 	static const char * const event_names[] = {
 		[PCHG_EVENT_NONE] = "NONE",
 		[PCHG_EVENT_IRQ] = "IRQ",
+		[PCHG_EVENT_RESET] = "RESET",
 		[PCHG_EVENT_INITIALIZED] = "INITIALIZED",
 		[PCHG_EVENT_ENABLED] = "ENABLED",
 		[PCHG_EVENT_DISABLED] = "DISABLED",
@@ -70,6 +71,18 @@ static const char *_text_event(enum pchg_event event)
 	return event_names[event];
 }
 
+static enum pchg_state pchg_reset(struct pchg *ctx)
+{
+	mutex_lock(&ctx->mtx);
+	queue_init(&ctx->events);
+	mutex_unlock(&ctx->mtx);
+	atomic_clear(&ctx->irq);
+
+	/* When fw update is implemented, this will be the branch point. */
+	pchg_queue_event(ctx, PCHG_EVENT_INITIALIZE);
+	return PCHG_STATE_RESET;
+}
+
 static enum pchg_state pchg_initialize(struct pchg *ctx, enum pchg_state state)
 {
 	int rv = ctx->cfg->drv->init(ctx);
@@ -94,6 +107,9 @@ static enum pchg_state pchg_state_reset(struct pchg *ctx)
 	enum pchg_state state = PCHG_STATE_RESET;
 
 	switch (ctx->event) {
+	case PCHG_EVENT_RESET:
+		state = pchg_reset(ctx);
+		break;
 	case PCHG_EVENT_INITIALIZE:
 		state = pchg_initialize(ctx, state);
 		break;
@@ -121,6 +137,9 @@ static enum pchg_state pchg_state_initialized(struct pchg *ctx)
 		return state;
 
 	switch (ctx->event) {
+	case PCHG_EVENT_RESET:
+		state = pchg_reset(ctx);
+		break;
 	case PCHG_EVENT_INITIALIZE:
 		state = pchg_initialize(ctx, state);
 		break;
@@ -147,6 +166,9 @@ static enum pchg_state pchg_state_enabled(struct pchg *ctx)
 	int rv;
 
 	switch (ctx->event) {
+	case PCHG_EVENT_RESET:
+		state = pchg_reset(ctx);
+		break;
 	case PCHG_EVENT_INITIALIZE:
 		state = pchg_initialize(ctx, state);
 		break;
@@ -185,6 +207,9 @@ static enum pchg_state pchg_state_detected(struct pchg *ctx)
 	int rv;
 
 	switch (ctx->event) {
+	case PCHG_EVENT_RESET:
+		state = pchg_reset(ctx);
+		break;
 	case PCHG_EVENT_INITIALIZE:
 		state = pchg_initialize(ctx, state);
 		break;
@@ -222,6 +247,9 @@ static enum pchg_state pchg_state_charging(struct pchg *ctx)
 	int rv;
 
 	switch (ctx->event) {
+	case PCHG_EVENT_RESET:
+		pchg_reset(ctx);
+		break;
 	case PCHG_EVENT_INITIALIZE:
 		state = pchg_initialize(ctx, state);
 		break;
@@ -346,7 +374,7 @@ static void pchg_startup(void)
 
 	for (p = 0; p < pchg_count; p++) {
 		ctx = &pchgs[p];
-		pchg_queue_event(ctx, PCHG_EVENT_INITIALIZE);
+		ctx->cfg->drv->reset(ctx);
 		gpio_enable_interrupt(ctx->cfg->irq_pin);
 	}
 
@@ -376,8 +404,8 @@ void pchg_task(void *u)
 	struct pchg *ctx;
 	int p;
 
-	/* In case we arrive here after power-on (for late sysjump) */
 	if (chipset_in_state(CHIPSET_STATE_ON))
+		/* We are here after power-on (because of late sysjump). */
 		pchg_startup();
 
 	while (true) {
@@ -450,7 +478,7 @@ static int cc_pchg(int argc, char **argv)
 
 	port = strtoi(argv[1], &end, 0);
 	if (*end || port < 0 || port >= pchg_count)
-		return EC_ERROR_PARAM2;
+		return EC_ERROR_PARAM1;
 	ctx = &pchgs[port];
 
 	if (argc == 2) {
@@ -460,15 +488,16 @@ static int cc_pchg(int argc, char **argv)
 		return EC_SUCCESS;
 	}
 
-	if (!strcasecmp(argv[2], "init")) {
+	if (!strcasecmp(argv[2], "reset"))
+		pchg_queue_event(ctx, PCHG_EVENT_RESET);
+	else if (!strcasecmp(argv[2], "init"))
 		pchg_queue_event(ctx, PCHG_EVENT_INITIALIZE);
-	} else if (!strcasecmp(argv[2], "enable")) {
+	else if (!strcasecmp(argv[2], "enable"))
 		pchg_queue_event(ctx, PCHG_EVENT_ENABLE);
-	} else if (!strcasecmp(argv[2], "disable")) {
+	else if (!strcasecmp(argv[2], "disable"))
 		pchg_queue_event(ctx, PCHG_EVENT_DISABLE);
-	} else {
-		return EC_ERROR_PARAM1;
-	}
+	else
+		return EC_ERROR_PARAM2;
 
 	task_wake(TASK_ID_PCHG);
 
@@ -477,6 +506,7 @@ static int cc_pchg(int argc, char **argv)
 DECLARE_CONSOLE_COMMAND(pchg, cc_pchg,
 			"<port> [init/enable/disable]"
 			"\n\t<port>"
+			"\n\t<port> reset"
 			"\n\t<port> init"
 			"\n\t<port> enable"
 			"\n\t<port> disable",
diff --git a/driver/nfc/ctn730.c b/driver/nfc/ctn730.c
index 8e5dd2ea20..75487fa701 100644
--- a/driver/nfc/ctn730.c
+++ b/driver/nfc/ctn730.c
@@ -252,6 +252,14 @@ static int _send_command(struct pchg *ctx, const struct ctn730_msg *cmd)
 	return rv;
 }
 
+static int ctn730_reset(struct pchg *ctx)
+{
+	gpio_set_level(GPIO_WLC_NRST_CONN, 0);
+	msleep(1);
+	gpio_set_level(GPIO_WLC_NRST_CONN, 1);
+	return EC_SUCCESS_IN_PROGRESS;
+}
+
 static int ctn730_init(struct pchg *ctx)
 {
 	uint8_t buf[CTN730_MESSAGE_BUFFER_SIZE];
@@ -376,7 +384,7 @@ static int _process_payload_event(struct pchg *ctx, struct ctn730_msg *res)
 			 */
 			msleep(5);
 		} else if (buf[0] == WLC_HOST_CTRL_RESET_EVT_DOWNLOAD_MODE) {
-			ctx->event = PCHG_EVENT_NONE;
+			ctx->event = PCHG_EVENT_RESET;
 		} else {
 			return EC_ERROR_INVAL;
 		}
@@ -539,6 +547,7 @@ exit:
 }
 
 const struct pchg_drv ctn730_drv = {
+	.reset = ctn730_reset,
 	.init = ctn730_init,
 	.enable = ctn730_enable,
 	.get_event = ctn730_get_event,
diff --git a/include/peripheral_charger.h b/include/peripheral_charger.h
index 62b1b0ac01..26b7b98a2e 100644
--- a/include/peripheral_charger.h
+++ b/include/peripheral_charger.h
@@ -73,6 +73,7 @@ enum pchg_event {
 	PCHG_EVENT_IRQ,
 
 	/* External Events */
+	PCHG_EVENT_RESET,
 	PCHG_EVENT_INITIALIZED,
 	PCHG_EVENT_ENABLED,
 	PCHG_EVENT_DISABLED,
@@ -140,6 +141,8 @@ struct pchg {
  * Peripheral charger driver
  */
 struct pchg_drv {
+	/* Reset charger chip. */
+	int (*reset)(struct pchg *ctx);
 	/* Initialize the charger. */
 	int (*init)(struct pchg *ctx);
 	/* Enable/disable the charger. */