sm5803: Configure BFET alerts

The SM5803 has the capability to monitor to the power burnt across the
BFET.  There are two thresholds that can be configured: an early
threshold, and a fatal threshold in which the charger automatically
disables the BFET.

This commit configures the BFET alerts to fire at 1.5W for the early
threshold and 6.5W for the fatal threshold.

The full scale is 7.5W, the lsb is 7.5W/256 ~= 29.2mW.

BUG=b:159376384
BRANCH=None
TEST=Build and flash waddledee, charge from sub board, verify that no
alerts are seen.
TEST=Configure the thresholds significantly lower, charge from sub
board, verify that the alerts do fire and logging information is
printed on the EC console.

Signed-off-by: Aseda Aboagye <aaboagye@google.com>
Change-Id: I17b3876bc5ed4b41d2378600a8b8bf639f9757ce
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/2380404
Tested-by: Aseda Aboagye <aaboagye@chromium.org>
Auto-Submit: Aseda Aboagye <aaboagye@chromium.org>
Reviewed-by: David Schneider <dnschneid@chromium.org>
Reviewed-by: Diana Z <dzigterman@chromium.org>
Commit-Queue: Diana Z <dzigterman@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/2383914
Reviewed-by: Edward Hill <ecgh@chromium.org>
Commit-Queue: Edward Hill <ecgh@chromium.org>
Tested-by: Edward Hill <ecgh@chromium.org>

2 files changed, 54 insertions, 8 deletions

diff --git a/driver/charger/sm5803.c b/driver/charger/sm5803.c
index 63ad62ab16..17343fb3e2 100644
--- a/driver/charger/sm5803.c
+++ b/driver/charger/sm5803.c
@@ -603,6 +603,23 @@ static void sm5803_init(int chgnum)
 		reg = SM5803_CURRENT_TO_REG(batt_info->precharge_current);
 		reg = MIN(reg, SM5803_PRECHG_ICHG_PRE_SET);
 		rv |= chg_write8(chgnum, SM5803_REG_PRECHG, reg);
+
+		/*
+		 * Set up BFET alerts
+		 *
+		 * We'll set the soft limit at 1.5W and the hard limit at 6W.
+		 *
+		 * The register is 29.2 mW per bit.
+		 */
+		reg = (1500 * 10) / 292;
+		rv |= meas_write8(chgnum, SM5803_REG_BFET_PWR_MAX_TH, reg);
+		reg = (6000 * 10) / 292;
+		rv |= meas_write8(chgnum, SM5803_REG_BFET_PWR_HWSAFE_MAX_TH,
+				 reg);
+		rv |= main_read8(chgnum, SM5803_REG_INT3_EN, &reg);
+		reg |= SM5803_INT3_BFET_PWR_LIMIT |
+		       SM5803_INT3_BFET_PWR_HWSAFE_LIMIT;
+		rv |= main_write8(chgnum, SM5803_REG_INT3_EN, reg);
 	}
 
 	if (rv)
@@ -624,6 +641,8 @@ void sm5803_handle_interrupt(int chgnum)
 	enum ec_error_list rv;
 	int int_reg, meas_reg;
 	static bool throttled;
+	struct batt_params bp;
+	int act_chg, val;
 
 	/* Note: Interrupt registers are clear on read */
 	rv = main_read8(chgnum, SM5803_REG_INT1_REQ, &int_reg);
@@ -678,6 +697,30 @@ void sm5803_handle_interrupt(int chgnum)
 		 */
 	}
 
+	/* TODO(b/159376384): Take action on fatal BFET power alert. */
+	rv = main_read8(chgnum, SM5803_REG_INT3_REQ, &int_reg);
+	if (rv) {
+		CPRINTS("%s %d: Failed to read int3 register", CHARGER_NAME,
+			chgnum);
+		return;
+	}
+
+	if ((int_reg & SM5803_INT3_BFET_PWR_LIMIT) ||
+	    (int_reg & SM5803_INT3_BFET_PWR_HWSAFE_LIMIT)) {
+		battery_get_params(&bp);
+		act_chg = charge_manager_get_active_charge_port();
+		CPRINTS("%s BFET power limit reached! (%s)", CHARGER_NAME,
+			(int_reg & SM5803_INT3_BFET_PWR_LIMIT) ? "warn" :
+			"FATAL");
+		CPRINTS("\tVbat: %dmV", bp.voltage);
+		CPRINTS("\tIbat: %dmA", bp.current);
+		charger_get_voltage(act_chg, &val);
+		CPRINTS("\tVsys(aux): %dmV", val);
+		charger_get_current(act_chg, &val);
+		CPRINTS("\tIsys: %dmA", val);
+		cflush();
+	}
+
 	rv = main_read8(chgnum, SM5803_REG_INT4_REQ, &int_reg);
 	if (rv) {
 		CPRINTS("%s %d: Failed to read int4 register", CHARGER_NAME,
diff --git a/driver/charger/sm5803.h b/driver/charger/sm5803.h
index 75e4885cbc..7c0eaca78b 100644
--- a/driver/charger/sm5803.h
+++ b/driver/charger/sm5803.h
@@ -52,14 +52,14 @@
 #define SM5803_INT2_VSYS		BIT(6)
 #define SM5803_INT2_TINT		BIT(7)
 
-#define SM5803_REG_INT3_REQ		0x07
-#define SM5803_REG_INT3_EN		0x0C
-#define SM5803_INT3_GPADC0		BIT(0)
-#define SM5803_INT3_VBATC1		BIT(1)
-#define SM5803_INT3_VBATC2		BIT(2)
-#define SM5803_INT3_SPARE		BIT(3)
-#define SM5803_INT3_VBUS_PWR_LIMIT	BIT(4)
-#define SM5803_INT3_IBAT		BIT(5)
+#define SM5803_REG_INT3_REQ			0x07
+#define SM5803_REG_INT3_EN			0x0C
+#define SM5803_INT3_GPADC0			BIT(0)
+#define SM5803_INT3_BFET_PWR_LIMIT		BIT(1)
+#define SM5803_INT3_BFET_PWR_HWSAFE_LIMIT	BIT(2)
+#define SM5803_INT3_SPARE			BIT(3)
+#define SM5803_INT3_VBUS_PWR_LIMIT		BIT(4)
+#define SM5803_INT3_IBAT			BIT(5)
 
 #define SM5803_REG_INT4_REQ		0x08
 #define SM5803_REG_INT4_EN		0x0D
@@ -96,6 +96,9 @@ enum sm5803_gpio0_modes {
 	GPIO0_MODE_INPUT
 };
 
+#define SM5803_REG_BFET_PWR_MAX_TH		0x35
+#define SM5803_REG_BFET_PWR_HWSAFE_MAX_TH	0x36
+
 #define SM5803_REG_PORTS_CTRL		0x40
 #define SM5803_PORTS_VBUS_DISCH		BIT(0)
 #define SM5803_PORTS_VBUS_PULLDOWN	BIT(1)