power: supply: macsmc_power: Add CHLS charge thresholds

Since macOS Sequoia firmware, CHLS replaced CHWA and now allows an
arbitrary end charge threshold to be configured.

Prefer CHWA over CHLS since the SMC firmware from iBoot-10151.1.1
(macOS 14.0) is not compatible with our CHGLS usage. It was working
with the SMC firmware from iBoot-10151.121.1 (macOS 14.5).

Signed-off-by: Hector Martin <marcan@marcan.st>
Signed-off-by: Janne Grunau <j@jannau.net>

Author: marcan

drivers/power/supply/macsmc_power.c

@@ -38,6 +38,7 @@ struct macsmc_power {
 	char serial_number[MAX_STRING_LENGTH];
 	char mfg_date[MAX_STRING_LENGTH];
 	bool has_chwa;
+	bool has_chls;
 	u8 num_cells;
 	int nominal_voltage_mv;
 
@@ -72,6 +73,7 @@ static struct macsmc_power *g_power;
 #define CHNC_NOCHG_CH0B_CH0K	BIT(15)
 #define CHNC_BATTERY_FULL_2	BIT(18)
 #define CHNC_BMS_BUSY		BIT(23)
+#define CHNC_CHLS_LIMIT		BIT(24)
 #define CHNC_NOAC_CH0J		BIT(53)
 #define CHNC_NOAC_CH0I		BIT(54)
 
@@ -89,7 +91,9 @@ static struct macsmc_power *g_power;
 #define ACSt_CAN_BOOT_AP	BIT(2)
 #define ACSt_CAN_BOOT_IBOOT	BIT(1)
 
-#define CHWA_FIXED_START_THRESHOLD	75
+#define CHWA_CHLS_FIXED_START_OFFSET	5
+#define CHLS_MIN_END_THRESHOLD		10
+#define CHLS_FORCE_DISCHARGE		0x100
 #define CHWA_FIXED_END_THRESHOLD	80
 #define CHWA_PROP_WRITE_THRESHOLD	95
 
@@ -183,7 +187,7 @@ static int macsmc_battery_get_status(struct macsmc_power *power)
 		u8 buic = 0;
 
 		if (apple_smc_read_u8(power->smc, SMC_KEY(BUIC), &buic) >= 0 &&
-			buic >= CHWA_FIXED_START_THRESHOLD)
+			buic >= (CHWA_FIXED_END_THRESHOLD - CHWA_CHLS_FIXED_START_OFFSET))
 			chwa_limit = true;
 	}
 
@@ -465,14 +469,23 @@ static int macsmc_battery_get_property(struct power_supply *psy,
 		ret = macsmc_battery_get_date(&power->mfg_date[4], &val->intval);
 		break;
 	case POWER_SUPPLY_PROP_CHARGE_CONTROL_START_THRESHOLD:
-		ret = apple_smc_read_flag(power->smc, SMC_KEY(CHWA));
-		val->intval = ret == 1 ? CHWA_FIXED_START_THRESHOLD : 100;
-		ret = ret < 0 ? ret : 0;
-		break;
 	case POWER_SUPPLY_PROP_CHARGE_CONTROL_END_THRESHOLD:
-		ret = apple_smc_read_flag(power->smc, SMC_KEY(CHWA));
-		val->intval = ret == 1 ? CHWA_FIXED_END_THRESHOLD : 100;
-		ret = ret < 0 ? ret : 0;
+		if (power->has_chls) {
+			ret = apple_smc_read_u16(power->smc, SMC_KEY(CHLS), &vu16);
+			val->intval = vu16 & 0xff;
+			if (val->intval < CHLS_MIN_END_THRESHOLD || val->intval >= 100)
+				val->intval = 100;
+		}
+		else if (power->has_chwa) {
+			ret = apple_smc_read_flag(power->smc, SMC_KEY(CHWA));
+			val->intval = ret == 1 ? CHWA_FIXED_END_THRESHOLD : 100;
+			ret = ret < 0 ? ret : 0;
+		} else {
+			return -EINVAL;
+		}
+		if (psp == POWER_SUPPLY_PROP_CHARGE_CONTROL_START_THRESHOLD &&
+		    ret >= 0 && val->intval < 100 && val->intval >= CHLS_MIN_END_THRESHOLD)
+			val->intval -= CHWA_CHLS_FIXED_START_OFFSET;
 		break;
 	default:
 		return -EINVAL;
@@ -493,13 +506,25 @@ static int macsmc_battery_set_property(struct power_supply *psy,
 	case POWER_SUPPLY_PROP_CHARGE_CONTROL_START_THRESHOLD:
 		/*
 		 * Ignore, we allow writes so userspace isn't confused but this is
-		 * not configurable independently, it always is 75 or 100 depending
-		 * on the end_threshold boolean setting.
+		 * not configurable independently, it always is end - 5 or 100 depending
+		 * on the end_threshold setting.
 		 */
 		return 0;
 	case POWER_SUPPLY_PROP_CHARGE_CONTROL_END_THRESHOLD:
-		return apple_smc_write_flag(power->smc, SMC_KEY(CHWA),
-					    val->intval <= CHWA_PROP_WRITE_THRESHOLD);
+		if (power->has_chls) {
+			u16 kval = 0;
+			/* TODO: Make CHLS_FORCE_DISCHARGE configurable */
+			if (val->intval < CHLS_MIN_END_THRESHOLD)
+				kval = CHLS_FORCE_DISCHARGE | CHLS_MIN_END_THRESHOLD;
+			else if (val->intval < 100)
+				kval = CHLS_FORCE_DISCHARGE | (val->intval & 0xff);
+			return apple_smc_write_u16(power->smc, SMC_KEY(CHLS), kval);
+		} else if (power->has_chwa) {
+			return apple_smc_write_flag(power->smc, SMC_KEY(CHWA),
+						    val->intval <= CHWA_PROP_WRITE_THRESHOLD);
+		} else {
+			return -EINVAL;
+		}
 	default:
 		return -EINVAL;
 	}
@@ -515,7 +540,7 @@ static int macsmc_battery_property_is_writeable(struct power_supply *psy,
 		return true;
 	case POWER_SUPPLY_PROP_CHARGE_CONTROL_START_THRESHOLD:
 	case POWER_SUPPLY_PROP_CHARGE_CONTROL_END_THRESHOLD:
-		return power->has_chwa;
+		return power->has_chwa || power->has_chls;
 	default:
 		return false;
 	}
@@ -750,6 +775,7 @@ static int macsmc_power_probe(struct platform_device *pdev)
 	struct power_supply_config psy_cfg = {};
 	struct macsmc_power *power;
 	u32 val;
+	u16 vu16;
 	int ret;
 
 	power = devm_kzalloc(&pdev->dev, sizeof(*power), GFP_KERNEL);
@@ -774,8 +800,14 @@ static int macsmc_power_probe(struct platform_device *pdev)
 	apple_smc_write_u8(power->smc, SMC_KEY(CH0K), 0);
 	apple_smc_write_u8(power->smc, SMC_KEY(CH0B), 0);
 
+	/*
+	 * Prefer CHWA as the SMC firmware from iBoot-10151.1.1 is not compatible with
+	 * this CHLS usage.
+	 */
 	if (apple_smc_read_flag(power->smc, SMC_KEY(CHWA)) >= 0) {
 		power->has_chwa = true;
+	} else if (apple_smc_read_u16(power->smc, SMC_KEY(CHLS), &vu16) >= 0) {
+		power->has_chls = true;
 	} else {
 		/* Remove the last 2 properties that control the charge threshold */
 		power->batt_desc.num_properties -= 2;