power: supply: macsmc_power: Add more properties

Report more voltages from the battery, and also fudge energy numbers
from charge numbers. This way userspace doesn't try to convert on its
own (and gets it very wrong).

Signed-off-by: Hector Martin <marcan@marcan.st>

Author: marcan

drivers/power/supply/macsmc_power.c

@@ -17,6 +17,17 @@
 
 #define MAX_STRING_LENGTH 256
 
+/*
+ * This number is not reported anywhere by SMC, but seems to be a good
+ * conversion factor for charge to energy across machines. We need this
+ * to convert in the driver, since if we don't userspace will try to do
+ * the conversion with a randomly guessed voltage and get it wrong.
+ *
+ * Ideally there would be a power supply prop to inform userspace of this
+ * number, but there isn't, only min/max.
+ */
+#define MACSMC_NOMINAL_CELL_VOLTAGE_MV 3800
+
 struct macsmc_power {
 	struct device *dev;
 	struct apple_smc *smc;
@@ -27,6 +38,8 @@ struct macsmc_power {
 	char serial_number[MAX_STRING_LENGTH];
 	char mfg_date[MAX_STRING_LENGTH];
 	bool has_chwa;
+	u8 num_cells;
+	int nominal_voltage_mv;
 
 	struct power_supply *ac;
 
@@ -352,6 +365,29 @@ static int macsmc_battery_get_property(struct power_supply *psy,
 		ret = apple_smc_read_u16(power->smc, SMC_KEY(BITV), &vu16);
 		val->intval = vu16 * 1000;
 		break;
+	case POWER_SUPPLY_PROP_VOLTAGE_MAX_DESIGN:
+		/*
+		 * Battery cell max voltage? BVV* seem to return per-cell voltages,
+		 * BVV[NOP] are probably the max voltages for the 3 cells but we don't
+		 * know what will happen if they ever change the number of cells.
+		 * So go with BVVN and multiply by the cell count (BNCB).
+		 * BVVL seems to be the per-cell limit adjusted dynamically.
+		 * Guess: BVVL = Limit, BVVN = Nominal, and the other cells got filled
+		 * in around nearby letters?
+		 */
+		ret = apple_smc_read_u16(power->smc, SMC_KEY(BVVN), &vu16);
+		val->intval = vu16 * 1000 * power->num_cells;
+		break;
+	case POWER_SUPPLY_PROP_VOLTAGE_MIN:
+		/* Lifetime min */
+		ret = apple_smc_read_s16(power->smc, SMC_KEY(BLPM), &vs16);
+		val->intval = vs16 * 1000;
+		break;
+	case POWER_SUPPLY_PROP_VOLTAGE_MAX:
+		/* Lifetime max */
+		ret = apple_smc_read_s16(power->smc, SMC_KEY(BLPX), &vs16);
+		val->intval = vs16 * 1000;
+		break;
 	case POWER_SUPPLY_PROP_CHARGE_TERM_CURRENT:
 		ret = apple_smc_read_u16(power->smc, SMC_KEY(B0RC), &vu16);
 		val->intval = vu16 * 1000;
@@ -380,6 +416,18 @@ static int macsmc_battery_get_property(struct power_supply *psy,
 		ret = apple_smc_read_u16(power->smc, SMC_KEY(B0RM), &vu16);
 		val->intval = swab16(vu16) * 1000;
 		break;
+	case POWER_SUPPLY_PROP_ENERGY_FULL_DESIGN:
+		ret = apple_smc_read_u16(power->smc, SMC_KEY(B0DC), &vu16);
+		val->intval = vu16 * power->nominal_voltage_mv;
+		break;
+	case POWER_SUPPLY_PROP_ENERGY_FULL:
+		ret = apple_smc_read_u16(power->smc, SMC_KEY(B0FC), &vu16);
+		val->intval = vu16 * power->nominal_voltage_mv;
+		break;
+	case POWER_SUPPLY_PROP_ENERGY_NOW:
+		ret = apple_smc_read_u16(power->smc, SMC_KEY(B0RM), &vu16);
+		val->intval = swab16(vu16) * power->nominal_voltage_mv;
+		break;
 	case POWER_SUPPLY_PROP_TEMP:
 		ret = apple_smc_read_u16(power->smc, SMC_KEY(B0AT), &vu16);
 		val->intval = vu16 - 2732;
@@ -485,13 +533,19 @@ static const enum power_supply_property macsmc_battery_props[] = {
 	POWER_SUPPLY_PROP_CURRENT_NOW,
 	POWER_SUPPLY_PROP_POWER_NOW,
 	POWER_SUPPLY_PROP_VOLTAGE_MIN_DESIGN,
+	POWER_SUPPLY_PROP_VOLTAGE_MAX_DESIGN,
+	POWER_SUPPLY_PROP_VOLTAGE_MIN,
+	POWER_SUPPLY_PROP_VOLTAGE_MAX,
 	POWER_SUPPLY_PROP_CHARGE_TERM_CURRENT,
 	POWER_SUPPLY_PROP_CONSTANT_CHARGE_CURRENT,
 	POWER_SUPPLY_PROP_CONSTANT_CHARGE_CURRENT_MAX,
 	POWER_SUPPLY_PROP_CONSTANT_CHARGE_VOLTAGE,
 	POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN,
 	POWER_SUPPLY_PROP_CHARGE_FULL,
 	POWER_SUPPLY_PROP_CHARGE_NOW,
+	POWER_SUPPLY_PROP_ENERGY_FULL_DESIGN,
+	POWER_SUPPLY_PROP_ENERGY_FULL,
+	POWER_SUPPLY_PROP_ENERGY_NOW,
 	POWER_SUPPLY_PROP_TEMP,
 	POWER_SUPPLY_PROP_CHARGE_COUNTER,
 	POWER_SUPPLY_PROP_CYCLE_COUNT,
@@ -727,6 +781,9 @@ static int macsmc_power_probe(struct platform_device *pdev)
 		power->batt_desc.num_properties -= 2;
 	}
 
+	apple_smc_read_u8(power->smc, SMC_KEY(BNCB), &power->num_cells);
+	power->nominal_voltage_mv = MACSMC_NOMINAL_CELL_VOLTAGE_MV * power->num_cells;
+
 	/* Doing one read of this flag enables critical shutdown notifications */
 	apple_smc_read_u32(power->smc, SMC_KEY(BCF0), &val);