fwk: implement Battery Charge Limiting battery status

In the ACPI spec _BST(battery status) has a feature 3.9.6 Battery Charge Limiting
follows the spec to implement the behavior.
This way the operating system can tell that the battery is not charging
anymore because it has reached the configured charge state limit.

Windows recognizes this and calls it smart charging:
https://support.microsoft.com/en-us/windows/use-smart-charging-in-windows-2ac1b4ba-6027-410a-b80e-f6767d867002

Linux has also added support:
torvalds/linux@526294e

Previously our ACPI code would mask off this bit, so to use this EC
change, the BIOS has to be updated not to mask this bit.

BRANCH=fwk-main
BUG=https://app.clickup.com/t/86et2u0ve (Question 3)
TEST= test on azalea, setting charger limit to 80% and Limiting has reached the steady state
(CHG state = idle), check namespec 0x4c Bit7(Limit active) is 1,
bit2(discharging) and bit3(charging) is 0.
TEST= test on azalea, setting charger limit to 80% and battery has discharging(higher than 80%)
check namespec 0x4c Bit7(Limit active) and bit2(discharging is 1, and bit3(charging) is 0.
TEST= test on azalea, setting charger limit to 80% and battery has charging(lower than 80%)
check namespec 0x4c Bit7(Limit active) and bit3(charging is 1, and bit2(discharging) is 0.
TEST= test on azalea, disable charger limit and batt extender,
check namespec 0x4c Bit7(Limit active) is 0.

Signed-off-by: LeoCX_Tsai <[email protected]>
(cherry picked from commit f82e3ffef8bcb5b233f17170f348981289fffc23)

Author: LeoCX-Tsai

common/battery_v2.c

@@ -481,6 +481,23 @@ void update_dynamic_battery_info(void)
 		tmp |= curr->batt_is_charging ? EC_BATT_FLAG_CHARGING :
 						EC_BATT_FLAG_DISCHARGING;
 	}
+
+	/*
+	 * in ACPI spec _BST(battery status) have a feature
+	 * 3.9.6 Battery Charge Limiting follows the spec
+	 * to return limiting status to OS and if Limiting is engaged
+	 * and the battery has reached the steady state need to
+	 * clear CHARGING and DISCHARGING flag.
+	 */
+	if (battery_sustainer_enabled()) {
+		tmp |= EC_BATT_FLAG_LIMIT_ACTIVE;
+		if (get_chg_ctrl_mode() == CHARGE_CONTROL_IDLE) {
+			tmp &= ~EC_BATT_FLAG_CHARGING;
+			tmp &= ~EC_BATT_FLAG_DISCHARGING;
+		}
+	} else
+		tmp &= ~EC_BATT_FLAG_LIMIT_ACTIVE;
+
 #else
 	tmp |= curr->batt_is_charging ? EC_BATT_FLAG_CHARGING :
 					EC_BATT_FLAG_DISCHARGING;

common/charge_state.c

@@ -193,7 +193,7 @@ void reset_prev_disp_charge(void)
 	prev_disp_charge = -1;
 }
 
-test_export_static bool battery_sustainer_enabled(void)
+bool battery_sustainer_enabled(void)
 {
 	return sustain_soc.lower != -1 && sustain_soc.upper != -1;
 }

include/charge_state.h

@@ -399,6 +399,14 @@ int board_want_charger_change_mode(void);
  */
 int battery_sustainer_set(int8_t lower, int8_t upper);
 
+/**
+ * return the sustainer is active or not
+ * lower and upper == -1 is mean disable
+ *
+ * @return if sustain_soc.lower and sustain_soc.upper != -1 will be true
+ */
+bool battery_sustainer_enabled(void);
+
 /* Config Charger */
 #include "charge_state.h"
 

include/ec_commands.h

@@ -271,6 +271,7 @@ extern "C" {
 /* Set if some of the static/dynamic data is invalid (or outdated). */
 #define EC_BATT_FLAG_INVALID_DATA 0x20
 #define EC_BATT_FLAG_CUT_OFF 0x40
+#define EC_BATT_FLAG_LIMIT_ACTIVE 0x80
 
 /* Switch flags at EC_MEMMAP_SWITCHES */
 #define EC_SWITCH_LID_OPEN 0x01