samus: ryu: set input current limit based on PD negotiation

Set input current limit based on the max current from the
PD negotiation. For samus, this information is passed to
the EC as a host command. For ryu, the max current is set
directly following a negotiation.

CONFIG_CHARGER_INPUT_CURRENT is now just the default limit,
but after a successful PD negotiation, the limit can be
raised.

Note, for now the input current limit for samus is set to
2/3 of the value negotiated for. This is due to hardware
problems measuring input current on p2b boards.

BUG=chrome-os-partner:28532, chrome-os-partner:24461
BRANCH=none
TEST=tested on a samus. Verified input current limit using
"charger" console command from EC. Input current limit
after a reboot is 512. When zinger is plugged in, it jumps
to the appropriate value (currently 1280mA), and when
the negotiation is changed using the "pd 0 dev 5" command
on the PD console, the input current limit is adjusted to
match (2000mA).

Change-Id: Iab9186a0f9814655e3240217a9baf4a38f15f84d
Signed-off-by: Alec Berg <alecaberg@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/211023
Reviewed-by: Vincent Palatin <vpalatin@chromium.org>

2 files changed, 31 insertions, 3 deletions

diff --git a/common/host_command_pd.c b/common/host_command_pd.c
index 2f27e00d3d..1216d28ae3 100644
--- a/common/host_command_pd.c
+++ b/common/host_command_pd.c
@@ -44,8 +44,23 @@ static void pd_exchange_status(void)
 		task_wait_event(500*MSEC);
 	}
 
-	if (rv < 0)
+	if (rv < 0) {
 		CPRINTS("Host command to PD MCU failed");
+		return;
+	}
+
+	/* Set input current limit */
+#ifdef BOARD_SAMUS
+	/*
+	 * TODO(crosbug.com/p/28532): Remove this workaround for Samus p2b
+	 * boards which cannot correctly limit input current.
+	 */
+	pd_status.curr_lim_ma = pd_status.curr_lim_ma * 2 / 3;
+#endif
+	rv = charger_set_input_current(MAX(pd_status.curr_lim_ma,
+					CONFIG_CHARGER_INPUT_CURRENT));
+	if (rv < 0)
+		CPRINTS("Failed to set input current limit from PD MCU");
 }
 
 void pd_command_task(void)
diff --git a/common/usb_pd_protocol.c b/common/usb_pd_protocol.c
index 202fd490ff..a591a50f94 100644
--- a/common/usb_pd_protocol.c
+++ b/common/usb_pd_protocol.c
@@ -243,6 +243,11 @@ static struct pd_protocol {
 	enum pd_states timeout_state;
 	/* Timeout for the current state. Set to 0 for no timeout. */
 	uint64_t timeout;
+
+#ifdef CONFIG_USB_PD_DUAL_ROLE
+	/* Current limit based on the last request message */
+	uint32_t curr_limit;
+#endif
 } pd[PD_PORT_COUNT];
 
 /*
@@ -606,6 +611,7 @@ static void pd_send_request_msg(int port)
 	/* we were waiting for them, let's process them */
 	res = pd_choose_voltage(pd_src_cap_cnt[port], pd_src_caps[port], &rdo);
 	if (res >= 0) {
+		pd[port].curr_limit = res;
 		res = send_request(port, rdo);
 		if (res >= 0)
 			set_state(port, PD_STATE_SNK_REQUESTED);
@@ -694,11 +700,13 @@ static void handle_ctrl_request(int port, uint16_t head,
 	case PD_CTRL_GOTO_MIN:
 		break;
 	case PD_CTRL_PS_RDY:
-		if (pd[port].task_state == PD_STATE_SNK_DISCOVERY)
+		if (pd[port].task_state == PD_STATE_SNK_DISCOVERY) {
 			/* Don't know what power source is ready. Reset. */
 			set_state(port, PD_STATE_HARD_RESET);
-		else if (pd[port].role == PD_ROLE_SINK)
+		} else if (pd[port].role == PD_ROLE_SINK) {
 			set_state(port, PD_STATE_SNK_READY);
+			pd_set_input_current_limit(pd[port].curr_limit);
+		}
 		break;
 	case PD_CTRL_REJECT:
 		set_state(port, PD_STATE_SNK_DISCOVERY);
@@ -915,6 +923,9 @@ static void execute_hard_reset(int port)
 	if (pd[port].task_state != PD_STATE_VDM_COMM)
 		set_state(port, pd[port].role == PD_ROLE_SINK ?
 			PD_STATE_SNK_DISCONNECTED : PD_STATE_SRC_DISCONNECTED);
+
+	/* Clear the input current limit */
+	pd_set_input_current_limit(0);
 #else
 	set_state(port, PD_STATE_SRC_DISCONNECTED);
 #endif
@@ -1253,6 +1264,8 @@ void pd_task(void)
 			if (pd[port].task_state != PD_STATE_VDM_COMM) {
 				/* Sink: detect disconnect by monitoring VBUS */
 				set_state(port, PD_STATE_SNK_DISCONNECTED);
+				/* Clear the input current limit */
+				pd_set_input_current_limit(0);
 				/* set timeout small to reconnect fast */
 				timeout = 5*MSEC;
 			}