[PATCH 7.1 335/438] power: supply: macsmc: Support macOS 27 SMC firmware

7.1-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Sasha Finkelstein <[email protected]>

commit f7b253a6e217f71d754d70c525e9b4c1dcbd4414 upstream.

The SMC firmware included in macOS 27 changed the size of BCF0 key from
4 to 1 bytes. This key is used for indicating that battery state is
critically low. In addition, B0RM key has changed endianness.

Reviewed-by: Sven Peter <[email protected]>
Reviewed-by: Joshua Peisach <[email protected]>
Reviewed-by: Janne Grunau <[email protected]>
Cc: [email protected]
Fixes: 0ebf821cf6c7 ("power: supply: Add macsmc-power driver for Apple Silicon")
Signed-off-by: Sasha Finkelstein <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Sebastian Reichel <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
 drivers/power/supply/macsmc-power.c |   52 +++++++++++++++++++++++++++++++-----
 1 file changed, 45 insertions(+), 7 deletions(-)

--- a/drivers/power/supply/macsmc-power.c
+++ b/drivers/power/supply/macsmc-power.c
@@ -86,6 +86,11 @@ struct macsmc_power {
 	bool has_ch0i; /* Force discharge (Older firmware) */
 	bool has_ch0c; /* Inhibit charge (Older firmware) */
 	bool has_chte; /* Inhibit charge (Modern firmware) */
+	/*
+	 * Battery critical key is 1 byte and charge key is little endian
+	 * (Modern firmware)
+	 */
+	bool fw_ge_27;
 
 	u8 num_cells;
 	int nominal_voltage_mv;
@@ -273,6 +278,20 @@ static int macsmc_battery_get_date(const
 	return 0;
 }
 
+static int macsmc_battery_read_bcf0(struct macsmc_power *power, u32 *val)
+{
+	u8 tval = 0;
+	int ret;
+
+	if (power->fw_ge_27) {
+		ret = apple_smc_read_u8(power->smc, SMC_KEY(BCF0), &tval);
+		*val = tval;
+		return ret;
+	}
+
+	return apple_smc_read_u32(power->smc, SMC_KEY(BCF0), val);
+}
+
 static int macsmc_battery_get_capacity_level(struct macsmc_power *power)
 {
 	bool flag;
@@ -280,7 +299,7 @@ static int macsmc_battery_get_capacity_l
 	int ret;
 
 	/* Check for emergency shutdown condition */
-	if (apple_smc_read_u32(power->smc, SMC_KEY(BCF0), &val) >= 0 && val)
+	if (macsmc_battery_read_bcf0(power, &val) >= 0 && val)
 		return POWER_SUPPLY_CAPACITY_LEVEL_CRITICAL;
 
 	/* Check AC status for whether we could boot in this state */
@@ -303,6 +322,12 @@ static int macsmc_battery_get_capacity_l
 		return POWER_SUPPLY_CAPACITY_LEVEL_NORMAL;
 }
 
+static s16 macsmc_swap_b0rm(struct macsmc_power *power, s16 b0rm)
+{
+	/* B0RM was Big Endian, likely pass through from TI gas gauge */
+	return power->fw_ge_27 ? b0rm : (s16)swab16(b0rm);
+}
+
 static int macsmc_battery_get_property(struct power_supply *psy,
 				       enum power_supply_property psp,
 				       union power_supply_propval *val)
@@ -397,8 +422,7 @@ static int macsmc_battery_get_property(s
 		break;
 	case POWER_SUPPLY_PROP_CHARGE_NOW:
 		ret = apple_smc_read_u16(power->smc, SMC_KEY(B0RM), &vu16);
-		/* B0RM is Big Endian, likely pass through from TI gas gauge */
-		val->intval = (s16)swab16(vu16) * 1000;
+		val->intval = macsmc_swap_b0rm(power, vu16) * 1000;
 		break;
 	case POWER_SUPPLY_PROP_ENERGY_FULL_DESIGN:
 		ret = apple_smc_read_u16(power->smc, SMC_KEY(B0DC), &vu16);
@@ -410,8 +434,7 @@ static int macsmc_battery_get_property(s
 		break;
 	case POWER_SUPPLY_PROP_ENERGY_NOW:
 		ret = apple_smc_read_u16(power->smc, SMC_KEY(B0RM), &vu16);
-		/* B0RM is Big Endian, likely pass through from TI gas gauge */
-		val->intval = (s16)swab16(vu16) * power->nominal_voltage_mv;
+		val->intval = macsmc_swap_b0rm(power, vu16) * power->nominal_voltage_mv;
 		break;
 	case POWER_SUPPLY_PROP_TEMP:
 		ret = apple_smc_read_u16(power->smc, SMC_KEY(B0AT), &vu16);
@@ -577,7 +600,7 @@ static void macsmc_power_critical_work(s
 	 * Check if SMC flagged the battery as empty.
 	 * We trigger a graceful shutdown to let the OS save data.
 	 */
-	if (apple_smc_read_u32(power->smc, SMC_KEY(BCF0), &bcf0) == 0 && bcf0 != 0) {
+	if (macsmc_battery_read_bcf0(power, &bcf0) == 0 && bcf0 != 0) {
 		power->orderly_shutdown_triggered = true;
 		dev_crit(power->dev, "Battery critical (empty flag set). Triggering orderly shutdown.\n");
 		orderly_poweroff(true);
@@ -616,6 +639,7 @@ static int macsmc_power_probe(struct pla
 	struct device *dev = &pdev->dev;
 	struct apple_smc *smc = dev_get_drvdata(pdev->dev.parent);
 	struct power_supply_config psy_cfg = {};
+	struct apple_smc_key_info info;
 	struct macsmc_power *power;
 	bool has_battery = false;
 	bool has_ac_adapter = false;
@@ -714,6 +738,20 @@ static int macsmc_power_probe(struct pla
 		if (apple_smc_key_exists(smc, SMC_KEY(CH0I)))
 			power->has_ch0i = true;
 
+		ret = apple_smc_get_key_info(power->smc, SMC_KEY(BCF0), &info);
+		if (ret) {
+			dev_err(&pdev->dev, "Failed to determine BCF0 key size\n");
+			return ret;
+		}
+		if (info.size == 1)
+			power->fw_ge_27 = true;
+		else if (info.size == 4)
+			power->fw_ge_27 = false;
+		else {
+			dev_err(&pdev->dev, "Unexpected BCF0 key size %d\n", info.size);
+			return -EIO;
+		}
+
 		/* Reset "Optimised Battery Charging" flags to default state */
 		if (power->has_chte)
 			apple_smc_write_u32(smc, SMC_KEY(CHTE), 0);
@@ -766,7 +804,7 @@ static int macsmc_power_probe(struct pla
 		power->nominal_voltage_mv = MACSMC_NOMINAL_CELL_VOLTAGE_MV * power->num_cells;
 
 		/* Enable critical shutdown notifications by reading status once */
-		apple_smc_read_u32(power->smc, SMC_KEY(BCF0), &val32);
+		macsmc_battery_read_bcf0(power, &val32);
 
 		psy_cfg.drv_data = power;
 		power->batt = devm_power_supply_register(dev, &power->batt_desc, &psy_cfg);