Fizz: Monitor input current (version 2.0)

Fizz has three FETs connected to three registers: PR257, PR258,
PR7824. These control the thresholds of the current monitoring
system.
                              PR257  PR7824 PR258
  For BJ (65W or 90W)           off     off   off
  For 4.35A (87W)                on     off   off
  For 3.25A (65W)               off     off    on
  For 3.00A (60W)               off      on   off

The system power consumption is capped by PR259, which is stuffed
differently depending on the SKU (65W v.s. 90W or U42 v.s. U22).
So, we only need to monitor type-c adapters. For example:

  a 90W system powered by 65W type-c charger
  b 65W system powered by 60W type-c charger
  c 65W system powered by 87W type-c charger

In a case such as (c), we actually do not need to monitor the current
because the max is capped by PR259.

AP is expected to read type-c adapter wattage from EC and control
power consumption to avoid over-current or system browns out.

The current monitoring system doesn't support less than 3A
(e.g. 2.25A, 2.00A). These currents most likely won't be enough to
power the system. However, if they're needed, EC can monitor
PMON_PSYS and trigger H_PROCHOT by itself.

BUG=b:72883633,b:64442692,b:72710630
BRANCH=none
TEST=Boot Fizz on 60W/87W/BJ charger. Verify GPIOs are set as expected.

Change-Id: Ic4c0e599f94b24b5e6c02bbf1998b0b89ecad7bf
Signed-off-by: Daisuke Nojiri <dnojiri@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/900491
Commit-Ready: ChromeOS CL Exonerator Bot <chromiumos-cl-exonerator@appspot.gserviceaccount.com>
Reviewed-by: Vincent Palatin <vpalatin@chromium.org>

1 files changed, 7 insertions, 57 deletions

diff --git a/board/fizz/usb_pd_policy.c b/board/fizz/usb_pd_policy.c
index 1d87c7eb75..3a607c50d1 100644
--- a/board/fizz/usb_pd_policy.c
+++ b/board/fizz/usb_pd_policy.c
@@ -218,29 +218,6 @@ int pd_custom_vdm(int port, int cnt, uint32_t *payload,
 	return 0;
 }
 
-#define CHARGE_PORT_SYSJUMP_TAG 0x4350 /* "CP" - Charge Port */
-#define CHARGE_PORT_HOOK_VERSION 1
-
-static int restore_active_charge_port(struct charge_port_info *cpi)
-{
-	int version, size;
-	const struct charge_port_info *prev;
-
-	if (!(system_get_reset_flags() & RESET_FLAG_SYSJUMP))
-		return EC_ERROR_UNCHANGED;
-
-	prev = (const struct charge_port_info *)system_get_jump_tag(
-				CHARGE_PORT_SYSJUMP_TAG, &version, &size);
-	if (!prev || version != CHARGE_PORT_HOOK_VERSION ||
-			size != sizeof(*prev))
-		return EC_ERROR_INVAL;
-
-	cpi->current = prev->current;
-	cpi->voltage = prev->voltage;
-
-	return EC_SUCCESS;
-}
-
 /*
  * Since fizz has no battery, it must source all of its power from either
  * USB-C or the barrel jack (preferred). Fizz operates in continuous safe
@@ -274,14 +251,8 @@ static void board_charge_manager_init(void)
 		typec_set_input_current_limit(port, 3000, 5000);
 		break;
 	case CHARGE_PORT_BARRELJACK:
-		/* TODO: Once transition from GPIO to CBI completes, get BJ
-		 * adapter info locally. No need to save & restore it. */
-		if (restore_active_charge_port(&cpi)) {
-			/* Set it to the default. Will be updated by AP. */
-			CPRINTS("Previous charge info not found. Use default.");
-			cpi.voltage = 19000;
-			cpi.current = 3330;
-		}
+		cpi.voltage = 19500;
+		cpi.current = 3330;
 		charge_manager_update_charge(CHARGE_SUPPLIER_DEDICATED,
 					     DEDICATED_CHARGE_PORT, &cpi);
 		break;
@@ -290,24 +261,6 @@ static void board_charge_manager_init(void)
 DECLARE_HOOK(HOOK_INIT, board_charge_manager_init,
 	     HOOK_PRIO_CHARGE_MANAGER_INIT + 1);
 
-static void preserve_active_charge_port(void)
-{
-	struct charge_port_info cpi;
-
-	/* If it's not a dedicated charge port, we don't bother. Saving &
-	 * restoring PD charger info is a much bigger problem. */
-	if (charge_manager_get_active_charge_port() != DEDICATED_CHARGE_PORT)
-		return;
-	cpi.current = charge_manager_get_charger_current();
-	cpi.voltage = charge_manager_get_charger_voltage();
-	CPRINTS("Saving charge port info: %dmA %dmV", cpi.current, cpi.voltage);
-	cflush();
-
-	system_add_jump_tag(CHARGE_PORT_SYSJUMP_TAG, CHARGE_PORT_HOOK_VERSION,
-			    sizeof(cpi), &cpi);
-}
-DECLARE_HOOK(HOOK_SYSJUMP, preserve_active_charge_port, HOOK_PRIO_DEFAULT);
-
 int board_set_active_charge_port(int port)
 {
 	const int active_port = charge_manager_get_active_charge_port();
@@ -326,6 +279,7 @@ int board_set_active_charge_port(int port)
 
 	switch (port) {
 	case CHARGE_PORT_TYPEC0:
+		/* This is connected to TP on board version 2.2+ thus no-op */
 		gpio_set_level(GPIO_USB_C0_CHARGE_L, 0);
 		gpio_set_level(GPIO_AC_JACK_CHARGE_L, 1);
 		gpio_enable_interrupt(GPIO_ADP_IN_L);
@@ -334,15 +288,11 @@ int board_set_active_charge_port(int port)
 		/* Make sure BJ adapter is sourcing power */
 		if (gpio_get_level(GPIO_ADP_IN_L))
 			return EC_ERROR_INVAL;
+		/* This will cause brown out when switching from type-c on
+		 * board version 2.2+ thus the rest of the code is no-op. */
 		gpio_set_level(GPIO_AC_JACK_CHARGE_L, 0);
-		/* If this is switching from type-c to BJ, we have to wait until
-		 * PU3 comes up to keep the system continuously powered.
-		 * NX20P5090 datasheet says turn-on time for 20V is 29 msec. */
-		if (active_port == CHARGE_PORT_TYPEC0)
-			msleep(30);
-		/* We don't check type-c voltage here. If it's higher than
-		 * BJ voltage, we'll brown out due to the reverse current
-		 * protection of PU3. */
+		/* If type-c voltage > BJ voltage, we'll brown out due to the
+		 * reverse current protection of PU3 but it's intended. */
 		gpio_set_level(GPIO_USB_C0_CHARGE_L, 1);
 		gpio_disable_interrupt(GPIO_ADP_IN_L);
 		break;