From efc0041ca08e73f97e68cbab5e7eff8d30fef7b9 Mon Sep 17 00:00:00 2001
From: Stephen Just <stephenjust@gmail.com>
Date: Tue, 28 Jun 2016 23:37:11 -0600
Subject: [PATCH 2/2] power: surface3_power: Improve battery capacity reporting

Read additional registers from the battery device to get more
accurate status reading. Also properly report battery (dis)charge
state and current.
---
 drivers/power/supply/surface3_power.c | 55 ++++++++++++++++++++++++++++++-----
 1 file changed, 48 insertions(+), 7 deletions(-)

diff --git a/drivers/power/supply/surface3_power.c b/drivers/power/supply/surface3_power.c
index eee21d3..ac8155b 100644
--- a/drivers/power/supply/surface3_power.c
+++ b/drivers/power/supply/surface3_power.c
@@ -61,6 +61,7 @@ struct mshw0011_data {
 	bool			charging;
 	bool			bat_charging;
 	u8			trip_point;
+	s32			full_capacity;
 };
 
 struct mshw0011_lookup {
@@ -122,6 +123,10 @@ struct gsb_buffer {
 	} __packed;
 } __packed;
 
+#define ACPI_BATTERY_STATE_DISCHARGING	0x1
+#define ACPI_BATTERY_STATE_CHARGING	0x2
+#define ACPI_BATTERY_STATE_CRITICAL	0x4
+
 #define MSHW0011_CMD_DEST_BAT0		0x01
 #define MSHW0011_CMD_DEST_ADP1		0x03
 
@@ -140,11 +145,14 @@ struct gsb_buffer {
 
 #define MSHW0011_NOTIFY_GET_VERSION	0x00
 #define MSHW0011_NOTIFY_ADP1		0x01
-#define MSHW0011_NOTIFY_BAT0		0x02
+#define MSHW0011_NOTIFY_BAT0_BST	0x02
+#define MSHW0011_NOTIFY_BAT0_BIX	0x05
 
 #define MSHW0011_ADP1_REG_PSR		0x03
 
-#define MSHW0011_BAT0_REG_CAPACITY	0x0c
+#define MSHW0011_BAT0_REG_CAPACITY		0x0c
+#define MSHW0011_BAT0_REG_FULL_CHG_CAPACITY	0x0e
+#define MSHW0011_BAT0_REG_DESIGN_CAPACITY	0x40
 #define MSHW0011_BAT0_REG_VOLTAGE	0x08
 #define MSHW0011_BAT0_REG_RATE		0x14
 #define MSHW0011_BAT0_REG_OEM		0x45
@@ -235,6 +243,22 @@ static int mshw0011_bix(struct mshw0011_data *cdata, struct bix *bix)
 
 	*bix = default_bix;
 
+	/* get design capacity */
+	ret = i2c_smbus_read_word_data(client, MSHW0011_BAT0_REG_DESIGN_CAPACITY);
+	if (ret < 0) {
+		dev_err(&client->dev, "Error reading design capacity: %d\n", ret);
+		return ret;
+	}
+	bix->design_capacity = le16_to_cpu(ret);
+
+	/* get last full charge capacity */
+	ret = i2c_smbus_read_word_data(client, MSHW0011_BAT0_REG_FULL_CHG_CAPACITY);
+	if (ret < 0) {
+		dev_err(&client->dev, "Error reading last full charge capacity: %d\n", ret);
+		return ret;
+	}
+	bix->last_full_charg_capacity = le16_to_cpu(ret);
+
 	/* get serial number */
 	ret = mshw0011_i2c_read_block(client, MSHW0011_BAT0_REG_SERIAL_NO,
 				      buf, 10);
@@ -269,7 +293,7 @@ static int mshw0011_bix(struct mshw0011_data *cdata, struct bix *bix)
 static int mshw0011_bst(struct mshw0011_data *cdata, struct bst *bst)
 {
 	struct i2c_client *client = cdata->bat0;
-	int rate, capacity, voltage;
+	int rate, capacity, voltage, state;
 	s16 tmp;
 
 	rate = i2c_smbus_read_word_data(client, MSHW0011_BAT0_REG_RATE);
@@ -285,8 +309,15 @@ static int mshw0011_bst(struct mshw0011_data *cdata, struct bst *bst)
 		return voltage;
 
 	tmp = le16_to_cpu(rate);
-	bst->battery_present_rate = (s32)tmp;
-	bst->battery_state = bst->battery_present_rate < 0 ? 0x01 : 0x02;
+	bst->battery_present_rate = abs((s32)tmp);
+
+	state = 0;
+	if ((s32) tmp > 0)
+		state |= ACPI_BATTERY_STATE_CHARGING;
+	else if ((s32) tmp < 0)
+		state |= ACPI_BATTERY_STATE_DISCHARGING;
+	bst->battery_state = state;
+
 	bst->battery_remaining_capacity = le16_to_cpu(capacity);
 	bst->battery_present_voltage = le16_to_cpu(voltage);
 
@@ -308,6 +339,7 @@ static int mshw0011_adp_psr(struct mshw0011_data *cdata)
 static int mshw0011_isr(struct mshw0011_data *cdata)
 {
 	struct bst bst;
+	struct bix bix;
 	int ret;
 	bool status, bat_status;
 
@@ -327,14 +359,23 @@ static int mshw0011_isr(struct mshw0011_data *cdata)
 	if (ret < 0)
 		return ret;
 
-	bat_status = bst.battery_present_rate >= 0;
+	bat_status = bst.battery_state;
 
 	if (bat_status != cdata->bat_charging)
 		mshw0011_notify(cdata, cdata->notify_version,
-				MSHW0011_NOTIFY_BAT0, &ret);
+				MSHW0011_NOTIFY_BAT0_BST, &ret);
 
 	cdata->bat_charging = bat_status;
 
+	ret = mshw0011_bix(cdata, &bix);
+	if (ret < 0)
+		return ret;
+	if (bix.last_full_charg_capacity != cdata->full_capacity)
+		mshw0011_notify(cdata, cdata->notify_version,
+				MSHW0011_NOTIFY_BAT0_BIX, &ret);
+
+	cdata->full_capacity = bix.last_full_charg_capacity;
+
 	return 0;
 }
 
-- 
2.9.3