pd: allow new power request if the max voltage has changed

The current power request function avoids redundant requests by
checking if we have previously requested vSafe5V or the max we
can request. But, if the max voltage that we can request changes,
then sending another max request is not redundant. This CL modifies
the request function to check for redundant requests by checking
the max voltage that can be requested, so if the max voltage
changes, then a new request is allowed.

BUG=none
BRANCH=samus
TEST=on pd console:
pd 0 dev 5
pd 0 dev 12
pd 0 dev 20
all send new request immediately.

Change-Id: Ifcdcc3eac9e566714f6dc609e46bbb0b94426499
Signed-off-by: Alec Berg <alecaberg@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/236882
Reviewed-by: Shawn Nematbakhsh <shawnn@chromium.org>

1 files changed, 13 insertions, 9 deletions

diff --git a/common/usb_pd_protocol.c b/common/usb_pd_protocol.c
index 91aeb590d1..873c3473d0 100644
--- a/common/usb_pd_protocol.c
+++ b/common/usb_pd_protocol.c
@@ -254,8 +254,8 @@ static struct pd_protocol {
 	uint32_t supply_voltage;
 	/* Signal charging update that affects the port */
 	int new_power_request;
-	/* Store previously requested power type */
-	enum pd_request_type previous_pd_request;
+	/* Store previously requested voltage request */
+	int prev_request_mv;
 #endif
 
 	/* PD state for Vendor Defined Messages */
@@ -802,7 +802,7 @@ static void pd_store_src_cap(int port, int cnt, uint32_t *src_caps)
 static void pd_send_request_msg(int port, int always_send_request)
 {
 	uint32_t rdo, curr_limit, supply_voltage;
-	enum pd_request_type request;
+	int request_mv;
 	int res;
 
 #ifdef CONFIG_CHARGE_MANAGER
@@ -815,14 +815,15 @@ static void pd_send_request_msg(int port, int always_send_request)
 
 	/* Build and send request RDO */
 	/* If this port is not actively charging, select vSafe5V */
-	request = charging ? PD_REQUEST_MAX : PD_REQUEST_VSAFE5V;
+	request_mv = charging ? pd_get_max_voltage() : PD_MIN_MV;
 
-	/* Don't re-request the same state */
-	if (!always_send_request && pd[port].previous_pd_request == request)
+	/* Don't re-request the same voltage */
+	if (!always_send_request && pd[port].prev_request_mv == request_mv)
 		return;
 
 	res = pd_build_request(pd_src_cap_cnt[port], pd_src_caps[port],
-			       &rdo, &curr_limit, &supply_voltage, request);
+			       &rdo, &curr_limit, &supply_voltage,
+			       charging ? PD_REQUEST_MAX : PD_REQUEST_VSAFE5V);
 
 	if (res != EC_SUCCESS)
 		/*
@@ -833,7 +834,7 @@ static void pd_send_request_msg(int port, int always_send_request)
 
 	pd[port].curr_limit = curr_limit;
 	pd[port].supply_voltage = supply_voltage;
-	pd[port].previous_pd_request = request;
+	pd[port].prev_request_mv = request_mv;
 	res = send_request(port, rdo);
 	if (res >= 0)
 		set_state(port, PD_STATE_SNK_REQUESTED);
@@ -2606,11 +2607,14 @@ static int command_pd(int argc, char **argv)
 		set_state(port, PD_STATE_SRC_DISCONNECTED);
 		task_wake(PORT_TO_TASK_ID(port));
 	} else if (!strncasecmp(argv[2], "dev", 3)) {
-		int max_volt = -1;
+		int max_volt;
 		if (argc >= 4)
 			max_volt = strtoi(argv[3], &e, 10) * 1000;
+		else
+			max_volt = pd_get_max_voltage();
 
 		pd_request_source_voltage(port, max_volt);
+		ccprintf("max req: %dmV\n", max_volt);
 	} else if (!strcasecmp(argv[2], "clock")) {
 		int freq;