mb/google/bluey: Implement off-mode charging applet

Add launch_charger_applet() to handle the system state when booting
in off-mode charging or low-power modes with a charger present.

Key features:
1. Monitoring: Periodically checks battery current (I-current) via
   SPMI/PMIC registers.
2. Event Handling: Detects and clears EC power button and lid events.
   If a manual power-on event is detected, the system triggers a
   full board reset to ensure a clean boot to the OS (preventing
   firmware state conflicts like ADSP-lite vs ADSP).
3. Shutdown: If the charger is removed, it signals the EC via
   off-mode heartbeat and initiates an AP power-off.

BUG=b:439819922
BRANCH=None
TEST=Verified that the device enters the charging loop when plugged
in while off, and transitions to a full boot when the power button
is pressed.

Change-Id: I152f71eac89f5b522ea7b286517724e213c31e9a
Signed-off-by: Subrata Banik <subratabanik@google.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/91485
Reviewed-by: Kapil Porwal <kapilporwal@google.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/mainboard/google/bluey/board.h

@@ -35,6 +35,9 @@
 #define GPIO_PANEL_POWER_ON	GPIO(70)
 #define GPIO_PANEL_HPD		GPIO(119)
 
+/* Charging GPIOs */
+#define GPIO_PARALLEL_CHARGING_CFG GPIO(71)
+
 /* SD card specific GPIOs. Only for SD-enabled devices. */
 #if CONFIG(MAINBOARD_HAS_SD_CONTROLLER)
 #define GPIO_SD_CD_L		GPIO(71)
@@ -56,5 +59,6 @@ void configure_parallel_charging(void);
 void configure_parallel_charging_late(void);
 void enable_slow_battery_charging(void);
 void disable_slow_battery_charging(void);
+void launch_charger_applet(void);
 
 #endif /* MAINBOARD_GOOGLE_BLUEY_BOARD_H */

src/mainboard/google/bluey/charging.c

@@ -1,6 +1,10 @@
 /* SPDX-License-Identifier: GPL-2.0-only */
 
 #include "board.h"
+
+#include <delay.h>
+#include <ec/google/chromeec/ec.h>
+#include <reset.h>
 #include <soc/pmic.h>
 #include <soc/qcom_spmi.h>
 #include <types.h>
@@ -16,16 +20,14 @@
 #define SMB2_CHGR_CHRG_EN_CMD ((SMB2_SLAVE_ID << 16) | SCHG_CHGR_CHARGING_ENABLE_CMD)
 #define SMB1_SCHG_TYPE_C_TYPE_C_DEBUG_ACCESS_SNK_CFG \
 ((SMB1_SLAVE_ID << 16) | SCHG_TYPE_C_TYPE_C_DEBUG_ACCESS_SNK_CFG)
+#define SCHG_CHGR_CHARGING_FCC 0x260A
+#define SMB1_CHGR_CHARGING_FCC ((SMB1_SLAVE_ID << 16) | SCHG_CHGR_CHARGING_FCC)
+#define SMB2_CHGR_CHARGING_FCC ((SMB2_SLAVE_ID << 16) | SCHG_CHGR_CHARGING_FCC)
 
 #define FCC_1A_STEP_50MA 0x14
 #define FCC_DISABLE 0x8c
 #define EN_DEBUG_ACCESS_SNK 0x1B
 
-enum charging_status {
-	CHRG_DISABLE,
-	CHRG_ENABLE,
-};
-
 #define PMC8380F_SLAVE_ID	0x05
 #define GPIO07_MODE_CTL			0x8E40
 #define GPIO07_DIG_OUT_SOURCE_CTL	0x8E44
@@ -38,7 +40,87 @@ enum charging_status {
 #define OUTPUT_INVERT		0x80
 #define PERPH_EN		0x80
 
-#define GPIO_PARALLEL_CHARGING_CFG GPIO(71)
+#define DELAY_CHARGING_APPLET_MS 2000 /* 2sec */
+
+enum charging_status {
+	CHRG_DISABLE,
+	CHRG_ENABLE,
+};
+
+static int get_battery_icurr_ma(void)
+{
+	/* Read battery i-current value */
+	int icurr = spmi_read8(SMB1_CHGR_CHARGING_FCC);
+	if (icurr <= 0)
+		icurr = spmi_read8(SMB2_CHGR_CHARGING_FCC);
+	if (icurr < 0)
+		icurr = 0;
+
+	icurr *= 50;
+	return icurr;
+}
+
+static void clear_ec_manual_poweron_event(void)
+{
+	const uint64_t manual_pwron_event_mask =
+		(EC_HOST_EVENT_MASK(EC_HOST_EVENT_POWER_BUTTON) |
+		EC_HOST_EVENT_MASK(EC_HOST_EVENT_LID_OPEN));
+	google_chromeec_clear_events_b(manual_pwron_event_mask);
+}
+
+static int detect_ec_manual_poweron_event(void)
+{
+	const uint64_t manual_pwron_event_mask =
+		(EC_HOST_EVENT_MASK(EC_HOST_EVENT_POWER_BUTTON) |
+		EC_HOST_EVENT_MASK(EC_HOST_EVENT_LID_OPEN));
+	uint64_t events = google_chromeec_get_events_b();
+
+	if (!!(events & manual_pwron_event_mask))
+		return 1;
+
+	return 0;
+}
+
+void launch_charger_applet(void)
+{
+	if (!CONFIG(EC_GOOGLE_CHROMEEC))
+		return;
+
+	printk(BIOS_INFO, "Inside %s. Initiating charging\n", __func__);
+
+	/* clear any pending power button press and lid open event */
+	clear_ec_manual_poweron_event();
+
+	do {
+		/* Add static delay before reading the charging applet pre-requisites */
+		mdelay(DELAY_CHARGING_APPLET_MS);
+
+		/*
+		 * Issue a shutdown if not charging.
+		 */
+		if (!get_battery_icurr_ma()) {
+			printk(BIOS_INFO, "Issuing power-off due to change in charging state.\n");
+			google_chromeec_offmode_heartbeat();
+			google_chromeec_ap_poweroff();
+		}
+
+		/*
+		 * Exit the charging loop in the event of lid open or power
+		 * button press.
+		 *
+		 * Reset the device to ensure a fresh boot to OS.
+		 * This is required to avoid any kind of tear-down due to ADSP-lite
+		 * being loaded and need some clean up before loading ADSP firmware by
+		 * linux kernel.
+		 */
+		if (detect_ec_manual_poweron_event()) {
+			printk(BIOS_INFO, "Exiting charging applet to boot to OS\n");
+			do_board_reset();
+		}
+
+		/* TODO: add Tsense support and issue a shutdown in the event of temperature trip */
+	} while (true);
+}
 
 /*
  * Enable PMC8380F GPIO07 & GPIO09 for parallel charging.

src/mainboard/google/bluey/mainboard.c

@@ -121,12 +121,6 @@ void lb_add_boot_mode(struct lb_header *header)
 	mode->tag = LB_TAG_BOOT_MODE;
 	mode->size = sizeof(*mode);
 	mode->boot_mode = get_boot_mode();
-
-	configure_parallel_charging_late();
-
-	/* Enable charging only during off-mode or low-battery mode with charger present */
-	if (is_low_power_boot_with_charger())
-		enable_slow_battery_charging();
 }
 
 bool mainboard_needs_pcie_init(void)
@@ -177,14 +171,22 @@ static void mainboard_init(struct device *dev)
 	if (get_boot_mode() == LB_BOOT_MODE_LOW_BATTERY)
 		trigger_critical_battery_shutdown();
 
+	configure_parallel_charging_late();
+
 	/* Skip mainboard initialization if boot mode is "low-battery" or "off-mode charging" */
 	if (is_low_power_boot_with_charger()) {
+		/* TODO: enable fast charging */
+		enable_slow_battery_charging();
+
 		/* Disable the lightbar for Low-Battery or Off-Mode charging sequences.
 		 * This maintains visual consistency between the built-in display
 		 * indicators and the external lightbar.
 		 */
 		if (CONFIG(EC_GOOGLE_CHROMEEC))
 			google_chromeec_lightbar_off();
+
+		/* Boot to charging applet */
+		launch_charger_applet();
 		return;
 	}