1 files changed, 150 insertions, 121 deletions

diff --git a/drivers/power/bq27x00_battery.c b/drivers/power/bq27x00_battery.c
index 44bc76be0780..dbe3fcb3b0ba 100644
--- a/drivers/power/bq27x00_battery.c
+++ b/drivers/power/bq27x00_battery.c
@@ -51,17 +51,30 @@
 
 struct bq27x00_device_info;
 struct bq27x00_access_methods {
-	int (*read)(struct bq27x00_device_info *, u8 reg, int *rt_value,
-			bool single);
+	int (*read)(struct bq27x00_device_info *di, u8 reg, bool single);
 };
 
 enum bq27x00_chip { BQ27000, BQ27500 };
 
+struct bq27x00_reg_cache {
+	int temperature;
+	int time_to_empty;
+	int time_to_empty_avg;
+	int time_to_full;
+	int capacity;
+	int flags;
+
+	int current_now;
+};
+
 struct bq27x00_device_info {
 	struct device 		*dev;
 	int			id;
 	enum bq27x00_chip	chip;
 
+	struct bq27x00_reg_cache cache;
+	unsigned long last_update;
+
 	struct power_supply	bat;
 
 	struct bq27x00_access_methods bus;
@@ -85,48 +98,93 @@ static enum power_supply_property bq27x00_battery_props[] = {
  */
 
 static inline int bq27x00_read(struct bq27x00_device_info *di, u8 reg,
-		int *rt_value, bool single)
+		bool single)
 {
-	return di->bus.read(di, reg, rt_value, single);
+	return di->bus.read(di, reg, single);
 }
 
 /*
- * Return the battery temperature in tenths of degree Celsius
+ * Return the battery Relative State-of-Charge
  * Or < 0 if something fails.
  */
-static int bq27x00_battery_temperature(struct bq27x00_device_info *di)
+static int bq27x00_battery_read_rsoc(struct bq27x00_device_info *di)
 {
-	int ret;
-	int temp = 0;
-
-	ret = bq27x00_read(di, BQ27x00_REG_TEMP, &temp, false);
-	if (ret) {
-		dev_err(di->dev, "error reading temperature\n");
-		return ret;
-	}
+	int rsoc;
 
 	if (di->chip == BQ27500)
-		return temp - 2731;
+		rsoc = bq27x00_read(di, BQ27500_REG_SOC, false);
 	else
-		return ((temp * 5) - 5463) / 2;
+		rsoc = bq27x00_read(di, BQ27000_REG_RSOC, true);
+
+	if (rsoc < 0)
+		dev_err(di->dev, "error reading relative State-of-Charge\n");
+
+	return rsoc;
 }
 
 /*
- * Return the battery Voltage in milivolts
- * Or < 0 if something fails.
+ * Read a time register.
+ * Return < 0 if something fails.
  */
-static int bq27x00_battery_voltage(struct bq27x00_device_info *di)
+static int bq27x00_battery_read_time(struct bq27x00_device_info *di, u8 reg)
 {
-	int ret;
-	int volt = 0;
+	int tval;
 
-	ret = bq27x00_read(di, BQ27x00_REG_VOLT, &volt, false);
-	if (ret) {
-		dev_err(di->dev, "error reading voltage\n");
-		return ret;
+	tval = bq27x00_read(di, reg, false);
+	if (tval < 0) {
+		dev_err(di->dev, "error reading register %02x: %d\n", reg, tval);
+		return tval;
 	}
 
-	return volt * 1000;
+	if (tval == 65535)
+		return -ENODATA;
+
+	return tval * 60;
+}
+
+static void bq27x00_update(struct bq27x00_device_info *di)
+{
+	struct bq27x00_reg_cache cache = {0, };
+	bool is_bq27500 = di->chip == BQ27500;
+
+	cache.flags = bq27x00_read(di, BQ27x00_REG_FLAGS, is_bq27500);
+	if (cache.flags >= 0) {
+		cache.capacity = bq27x00_battery_read_rsoc(di);
+		cache.temperature = bq27x00_read(di, BQ27x00_REG_TEMP, false);
+		cache.time_to_empty = bq27x00_battery_read_time(di, BQ27x00_REG_TTE);
+		cache.time_to_empty_avg = bq27x00_battery_read_time(di, BQ27x00_REG_TTECP);
+		cache.time_to_full = bq27x00_battery_read_time(di, BQ27x00_REG_TTF);
+
+		if (!is_bq27500)
+			cache.current_now = bq27x00_read(di, BQ27x00_REG_AI, false);
+	}
+
+	/* Ignore current_now which is a snapshot of the current battery state
+	 * and is likely to be different even between two consecutive reads */
+	if (memcmp(&di->cache, &cache, sizeof(cache) - sizeof(int)) != 0) {
+		di->cache = cache;
+		power_supply_changed(&di->bat);
+	}
+
+	di->last_update = jiffies;
+}
+
+/*
+ * Return the battery temperature in tenths of degree Celsius
+ * Or < 0 if something fails.
+ */
+static int bq27x00_battery_temperature(struct bq27x00_device_info *di,
+	union power_supply_propval *val)
+{
+	if (di->cache.temperature < 0)
+		return di->cache.temperature;
+
+	if (di->chip == BQ27500)
+		val->intval = di->cache.temperature - 2731;
+	else
+		val->intval = ((di->cache.temperature * 5) - 5463) / 2;
+
+	return 0;
 }
 
 /*
@@ -134,109 +192,84 @@ static int bq27x00_battery_voltage(struct bq27x00_device_info *di)
  * Note that current can be negative signed as well
  * Or 0 if something fails.
  */
-static int bq27x00_battery_current(struct bq27x00_device_info *di)
+static int bq27x00_battery_current(struct bq27x00_device_info *di,
+	union power_supply_propval *val)
 {
-	int ret;
-	int curr = 0;
-	int flags = 0;
+	int curr;
 
-	ret = bq27x00_read(di, BQ27x00_REG_AI, &curr, false);
-	if (ret) {
-		dev_err(di->dev, "error reading current\n");
-		return 0;
-	}
+	if (di->chip == BQ27500)
+	    curr = bq27x00_read(di, BQ27x00_REG_AI, false);
+	else
+	    curr = di->cache.current_now;
+
+	if (curr < 0)
+		return curr;
 
 	if (di->chip == BQ27500) {
 		/* bq27500 returns signed value */
-		curr = (int)((s16)curr) * 1000;
+		val->intval = (int)((s16)curr) * 1000;
 	} else {
-		ret = bq27x00_read(di, BQ27x00_REG_FLAGS, &flags, false);
-		if (ret < 0) {
-			dev_err(di->dev, "error reading flags\n");
-			return 0;
-		}
-		if (flags & BQ27000_FLAG_CHGS) {
+		if (di->cache.flags & BQ27000_FLAG_CHGS) {
 			dev_dbg(di->dev, "negative current!\n");
 			curr = -curr;
 		}
-		curr = curr * 3570 / BQ27000_RS;
-	}
-
-	return curr;
-}
-
-/*
- * Return the battery Relative State-of-Charge
- * Or < 0 if something fails.
- */
-static int bq27x00_battery_rsoc(struct bq27x00_device_info *di)
-{
-	int ret;
-	int rsoc = 0;
 
-	if (di->chip == BQ27500)
-		ret = bq27x00_read(di, BQ27500_REG_SOC, &rsoc, false);
-	else
-		ret = bq27x00_read(di, BQ27000_REG_RSOC, &rsoc, true);
-	if (ret) {
-		dev_err(di->dev, "error reading relative State-of-Charge\n");
-		return ret;
+		val->intval = curr * 3570 / BQ27000_RS;
 	}
 
-	return rsoc;
+	return 0;
 }
 
 static int bq27x00_battery_status(struct bq27x00_device_info *di,
-				  union power_supply_propval *val)
+	union power_supply_propval *val)
 {
-	int flags = 0;
 	int status;
-	int ret;
-
-	ret = bq27x00_read(di, BQ27x00_REG_FLAGS, &flags, false);
-	if (ret < 0) {
-		dev_err(di->dev, "error reading flags\n");
-		return ret;
-	}
 
 	if (di->chip == BQ27500) {
-		if (flags & BQ27500_FLAG_FC)
+		if (di->cache.flags & BQ27500_FLAG_FC)
 			status = POWER_SUPPLY_STATUS_FULL;
-		else if (flags & BQ27500_FLAG_DSC)
+		else if (di->cache.flags & BQ27500_FLAG_DSC)
 			status = POWER_SUPPLY_STATUS_DISCHARGING;
 		else
 			status = POWER_SUPPLY_STATUS_CHARGING;
 	} else {
-		if (flags & BQ27000_FLAG_CHGS)
+		if (di->cache.flags & BQ27000_FLAG_CHGS)
 			status = POWER_SUPPLY_STATUS_CHARGING;
 		else
 			status = POWER_SUPPLY_STATUS_DISCHARGING;
 	}
 
 	val->intval = status;
+
 	return 0;
 }
 
 /*
- * Read a time register.
- * Return < 0 if something fails.
+ * Return the battery Voltage in milivolts
+ * Or < 0 if something fails.
  */
-static int bq27x00_battery_time(struct bq27x00_device_info *di, int reg,
-				union power_supply_propval *val)
+static int bq27x00_battery_voltage(struct bq27x00_device_info *di,
+	union power_supply_propval *val)
 {
-	int tval = 0;
-	int ret;
+	int volt;
 
-	ret = bq27x00_read(di, reg, &tval, false);
-	if (ret) {
-		dev_err(di->dev, "error reading register %02x\n", reg);
-		return ret;
-	}
+	volt = bq27x00_read(di, BQ27x00_REG_VOLT, false);
+	if (volt < 0)
+		return volt;
 
-	if (tval == 65535)
-		return -ENODATA;
+	val->intval = volt * 1000;
+
+	return 0;
+}
+
+static int bq27x00_simple_value(int value,
+	union power_supply_propval *val)
+{
+	if (value < 0)
+		return value;
+
+	val->intval = value;
 
-	val->intval = tval * 60;
 	return 0;
 }
 
@@ -249,9 +282,11 @@ static int bq27x00_battery_get_property(struct power_supply *psy,
 {
 	int ret = 0;
 	struct bq27x00_device_info *di = to_bq27x00_device_info(psy);
-	int voltage = bq27x00_battery_voltage(di);
 
-	if (psp != POWER_SUPPLY_PROP_PRESENT && voltage <= 0)
+	if (time_is_before_jiffies(di->last_update + 5 * HZ))
+		bq27x00_update(di);
+
+	if (psp != POWER_SUPPLY_PROP_PRESENT && di->cache.flags < 0)
 		return -ENODEV;
 
 	switch (psp) {
@@ -259,29 +294,28 @@ static int bq27x00_battery_get_property(struct power_supply *psy,
 		ret = bq27x00_battery_status(di, val);
 		break;
 	case POWER_SUPPLY_PROP_VOLTAGE_NOW:
-		val->intval = voltage;
+		ret = bq27x00_battery_voltage(di, val);
 		break;
 	case POWER_SUPPLY_PROP_PRESENT:
-		if (psp == POWER_SUPPLY_PROP_PRESENT)
-			val->intval = voltage <= 0 ? 0 : 1;
+		val->intval = di->cache.flags < 0 ? 0 : 1;
 		break;
 	case POWER_SUPPLY_PROP_CURRENT_NOW:
-		val->intval = bq27x00_battery_current(di);
+		ret = bq27x00_battery_current(di, val);
 		break;
 	case POWER_SUPPLY_PROP_CAPACITY:
-		val->intval = bq27x00_battery_rsoc(di);
+		ret = bq27x00_simple_value(di->cache.capacity, val);
 		break;
 	case POWER_SUPPLY_PROP_TEMP:
-		val->intval = bq27x00_battery_temperature(di);
+		ret = bq27x00_battery_temperature(di, val);
 		break;
 	case POWER_SUPPLY_PROP_TIME_TO_EMPTY_NOW:
-		ret = bq27x00_battery_time(di, BQ27x00_REG_TTE, val);
+		ret = bq27x00_simple_value(di->cache.time_to_empty, val);
 		break;
 	case POWER_SUPPLY_PROP_TIME_TO_EMPTY_AVG:
-		ret = bq27x00_battery_time(di, BQ27x00_REG_TTECP, val);
+		ret = bq27x00_simple_value(di->cache.time_to_empty_avg, val);
 		break;
 	case POWER_SUPPLY_PROP_TIME_TO_FULL_NOW:
-		ret = bq27x00_battery_time(di, BQ27x00_REG_TTF, val);
+		ret = bq27x00_simple_value(di->cache.time_to_full, val);
 		break;
 	case POWER_SUPPLY_PROP_TECHNOLOGY:
 		val->intval = POWER_SUPPLY_TECHNOLOGY_LION;
@@ -311,6 +345,8 @@ static int bq27x00_powersupply_init(struct bq27x00_device_info *di)
 
 	dev_info(di->dev, "support ver. %s enabled\n", DRIVER_VERSION);
 
+	bq27x00_update(di);
+
 	return 0;
 }
 
@@ -324,13 +360,12 @@ static int bq27x00_powersupply_init(struct bq27x00_device_info *di)
 static DEFINE_IDR(battery_id);
 static DEFINE_MUTEX(battery_mutex);
 
-static int bq27x00_read_i2c(struct bq27x00_device_info *di, u8 reg,
-			int *rt_value, bool single)
+static int bq27x00_read_i2c(struct bq27x00_device_info *di, u8 reg, bool single)
 {
 	struct i2c_client *client = to_i2c_client(di->dev);
 	struct i2c_msg msg[1];
 	unsigned char data[2];
-	int err;
+	int ret;
 
 	if (!client->adapter)
 		return -ENODEV;
@@ -341,26 +376,24 @@ static int bq27x00_read_i2c(struct bq27x00_device_info *di, u8 reg,
 	msg->buf = data;
 
 	data[0] = reg;
-	err = i2c_transfer(client->adapter, msg, 1);
+	ret = i2c_transfer(client->adapter, msg, 1);
 
-	if (err >= 0) {
+	if (ret >= 0) {
 		if (!single)
 			msg->len = 2;
 		else
 			msg->len = 1;
 
 		msg->flags = I2C_M_RD;
-		err = i2c_transfer(client->adapter, msg, 1);
-		if (err >= 0) {
+		ret = i2c_transfer(client->adapter, msg, 1);
+		if (ret >= 0) {
 			if (!single)
-				*rt_value = get_unaligned_le16(data);
+				ret = get_unaligned_le16(data);
 			else
-				*rt_value = data[0];
-
-			return 0;
+				ret = data[0];
 		}
 	}
-	return err;
+	return ret;
 }
 
 static int bq27x00_battery_probe(struct i2c_client *client,
@@ -477,7 +510,7 @@ static inline void bq27x00_battery_i2c_exit(void) {};
 #ifdef CONFIG_BATTERY_BQ27X00_PLATFORM
 
 static int bq27000_read_platform(struct bq27x00_device_info *di, u8 reg,
-			int *rt_value, bool single)
+			bool single)
 {
 	struct device *dev = di->dev;
 	struct bq27000_platform_data *pdata = dev->platform_data;
@@ -504,14 +537,10 @@ static int bq27000_read_platform(struct bq27x00_device_info *di, u8 reg,
 		if (timeout == 0)
 			return -EIO;
 
-		*rt_value = (upper << 8) | lower;
-	} else {
-		lower = pdata->read(dev, reg);
-		if (lower < 0)
-			return lower;
-		*rt_value = lower;
+		return (upper << 8) | lower;
 	}
-	return 0;
+
+	return pdata->read(dev, reg);
 }
 
 static int __devinit bq27000_battery_probe(struct platform_device *pdev)