HID: hid-asus: Add BT keyboard dock battery monitoring support

Add battery monitoring support for Transbook T100CHI/T90CHI's Bluetooth
keyboard dock.  They report rest battery level and charging status.
Signed-off-by: NOGUCHI Hiroshi <drvlabo@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

drivers/hid/hid-asus.c

@@ -32,6 +32,7 @@
 #include <linux/platform_data/x86/asus-wmi.h>
 #include <linux/input/mt.h>
 #include <linux/usb.h> /* For to_usb_interface for T100 touchpad intf check */
+#include <linux/power_supply.h>
 
 #include "hid-ids.h"
 
@@ -61,6 +62,13 @@ MODULE_DESCRIPTION("Asus HID Keyboard and TouchPad");
 #define CONTACT_TOUCH_MAJOR_MASK 0x07
 #define CONTACT_PRESSURE_MASK 0x7f
 
+#define	BATTERY_REPORT_ID	(0x03)
+#define	BATTERY_REPORT_SIZE	(1 + 8)
+#define	BATTERY_LEVEL_MAX	((u8)255)
+#define	BATTERY_STAT_DISCONNECT	(0)
+#define	BATTERY_STAT_CHARGING	(1)
+#define	BATTERY_STAT_FULL	(2)
+
 #define QUIRK_FIX_NOTEBOOK_REPORT	BIT(0)
 #define QUIRK_NO_INIT_REPORTS		BIT(1)
 #define QUIRK_SKIP_INPUT_MAPPING	BIT(2)
@@ -101,12 +109,21 @@ struct asus_touchpad_info {
 
 struct asus_drvdata {
 	unsigned long quirks;
+	struct hid_device *hdev;
 	struct input_dev *input;
 	struct asus_kbd_leds *kbd_backlight;
 	const struct asus_touchpad_info *tp;
 	bool enable_backlight;
+	struct power_supply *battery;
+	struct power_supply_desc battery_desc;
+	int battery_capacity;
+	int battery_stat;
+	bool battery_in_query;
+	unsigned long battery_next_query;
 };
 
+static int asus_report_battery(struct asus_drvdata *, u8 *, int);
+
 static const struct asus_touchpad_info asus_i2c_tp = {
 	.max_x = 2794,
 	.max_y = 1758,
@@ -260,6 +277,9 @@ static int asus_raw_event(struct hid_device *hdev,
 {
 	struct asus_drvdata *drvdata = hid_get_drvdata(hdev);
 
+	if (drvdata->battery && data[0] == BATTERY_REPORT_ID)
+		return asus_report_battery(drvdata, data, size);
+
 	if (drvdata->tp && data[0] == INPUT_REPORT_ID)
 		return asus_report_input(drvdata, data, size);
 
@@ -429,6 +449,164 @@ static int asus_kbd_register_leds(struct hid_device *hdev)
 	return ret;
 }
 
+/*
+ * [0]       REPORT_ID (same value defined in report descriptor)
+ * [1]	     rest battery level. range [0..255]
+ * [2]..[7]  Bluetooth hardware address (MAC address)
+ * [8]       charging status
+ *            = 0 : AC offline / discharging
+ *            = 1 : AC online  / charging
+ *            = 2 : AC online  / fully charged
+ */
+static int asus_parse_battery(struct asus_drvdata *drvdata, u8 *data, int size)
+{
+	u8 sts;
+	u8 lvl;
+	int val;
+
+	lvl = data[1];
+	sts = data[8];
+
+	drvdata->battery_capacity = ((int)lvl * 100) / (int)BATTERY_LEVEL_MAX;
+
+	switch (sts) {
+	case BATTERY_STAT_CHARGING:
+		val = POWER_SUPPLY_STATUS_CHARGING;
+		break;
+	case BATTERY_STAT_FULL:
+		val = POWER_SUPPLY_STATUS_FULL;
+		break;
+	case BATTERY_STAT_DISCONNECT:
+	default:
+		val = POWER_SUPPLY_STATUS_DISCHARGING;
+		break;
+	}
+	drvdata->battery_stat = val;
+
+	return 0;
+}
+
+static int asus_report_battery(struct asus_drvdata *drvdata, u8 *data, int size)
+{
+	/* notify only the autonomous event by device */
+	if ((drvdata->battery_in_query == false) &&
+			 (size == BATTERY_REPORT_SIZE))
+		power_supply_changed(drvdata->battery);
+
+	return 0;
+}
+
+static int asus_battery_query(struct asus_drvdata *drvdata)
+{
+	u8 *buf;
+	int ret = 0;
+
+	buf = kmalloc(BATTERY_REPORT_SIZE, GFP_KERNEL);
+	if (!buf)
+		return -ENOMEM;
+
+	drvdata->battery_in_query = true;
+	ret = hid_hw_raw_request(drvdata->hdev, BATTERY_REPORT_ID,
+				buf, BATTERY_REPORT_SIZE,
+				HID_INPUT_REPORT, HID_REQ_GET_REPORT);
+	drvdata->battery_in_query = false;
+	if (ret == BATTERY_REPORT_SIZE)
+		ret = asus_parse_battery(drvdata, buf, BATTERY_REPORT_SIZE);
+	else
+		ret = -ENODATA;
+
+	kfree(buf);
+
+	return ret;
+}
+
+static enum power_supply_property asus_battery_props[] = {
+	POWER_SUPPLY_PROP_STATUS,
+	POWER_SUPPLY_PROP_PRESENT,
+	POWER_SUPPLY_PROP_CAPACITY,
+	POWER_SUPPLY_PROP_SCOPE,
+	POWER_SUPPLY_PROP_MODEL_NAME,
+};
+
+#define	QUERY_MIN_INTERVAL	(60 * HZ)	/* 60[sec] */
+
+static int asus_battery_get_property(struct power_supply *psy,
+				enum power_supply_property psp,
+				union power_supply_propval *val)
+{
+	struct asus_drvdata *drvdata = power_supply_get_drvdata(psy);
+	int ret = 0;
+
+	switch (psp) {
+	case POWER_SUPPLY_PROP_STATUS:
+	case POWER_SUPPLY_PROP_CAPACITY:
+		if (time_before(drvdata->battery_next_query, jiffies)) {
+			drvdata->battery_next_query =
+					 jiffies + QUERY_MIN_INTERVAL;
+			ret = asus_battery_query(drvdata);
+			if (ret)
+				return ret;
+		}
+		if (psp == POWER_SUPPLY_PROP_STATUS)
+			val->intval = drvdata->battery_stat;
+		else
+			val->intval = drvdata->battery_capacity;
+		break;
+	case POWER_SUPPLY_PROP_PRESENT:
+		val->intval = 1;
+		break;
+	case POWER_SUPPLY_PROP_SCOPE:
+		val->intval = POWER_SUPPLY_SCOPE_DEVICE;
+		break;
+	case POWER_SUPPLY_PROP_MODEL_NAME:
+		val->strval = drvdata->hdev->name;
+		break;
+	default:
+		ret = -EINVAL;
+		break;
+	}
+
+	return ret;
+}
+
+static int asus_battery_probe(struct hid_device *hdev)
+{
+	struct asus_drvdata *drvdata = hid_get_drvdata(hdev);
+	struct power_supply_config pscfg = { .drv_data = drvdata };
+	int ret = 0;
+
+	drvdata->battery_capacity = 0;
+	drvdata->battery_stat = POWER_SUPPLY_STATUS_UNKNOWN;
+	drvdata->battery_in_query = false;
+
+	drvdata->battery_desc.properties = asus_battery_props;
+	drvdata->battery_desc.num_properties = ARRAY_SIZE(asus_battery_props);
+	drvdata->battery_desc.get_property = asus_battery_get_property;
+	drvdata->battery_desc.type = POWER_SUPPLY_TYPE_BATTERY;
+	drvdata->battery_desc.use_for_apm = 0;
+	drvdata->battery_desc.name = devm_kasprintf(&hdev->dev, GFP_KERNEL,
+					"asus-keyboard-%s-battery",
+					strlen(hdev->uniq) ?
+					hdev->uniq : dev_name(&hdev->dev));
+	if (!drvdata->battery_desc.name)
+		return -ENOMEM;
+
+	drvdata->battery_next_query = jiffies;
+
+	drvdata->battery = devm_power_supply_register(&hdev->dev,
+				&(drvdata->battery_desc), &pscfg);
+	if (IS_ERR(drvdata->battery)) {
+		ret = PTR_ERR(drvdata->battery);
+		drvdata->battery = NULL;
+		hid_err(hdev, "Unable to register battery device\n");
+		return ret;
+	}
+
+	power_supply_powers(drvdata->battery, &hdev->dev);
+
+	return ret;
+}
+
 static int asus_input_configured(struct hid_device *hdev, struct hid_input *hi)
 {
 	struct input_dev *input = hi->input;
@@ -661,6 +839,10 @@ static int asus_probe(struct hid_device *hdev, const struct hid_device_id *id)
 
 	drvdata->quirks = id->driver_data;
 
+	/*
+	 * T90CHI's keyboard dock returns same ID values as T100CHI's dock.
+	 * Thus, identify T90CHI dock with product name string.
+	 */
 	if (strstr(hdev->name, "T90CHI")) {
 		drvdata->quirks &= ~QUIRK_T100CHI;
 		drvdata->quirks |= QUIRK_T90CHI;
@@ -700,6 +882,17 @@ static int asus_probe(struct hid_device *hdev, const struct hid_device_id *id)
 	if (drvdata->quirks & QUIRK_NO_INIT_REPORTS)
 		hdev->quirks |= HID_QUIRK_NO_INIT_REPORTS;
 
+	drvdata->hdev = hdev;
+
+	if (drvdata->quirks & (QUIRK_T100CHI | QUIRK_T90CHI)) {
+		ret = asus_battery_probe(hdev);
+		if (ret) {
+			hid_err(hdev,
+			    "Asus hid battery_probe failed: %d\n", ret);
+			return ret;
+		}
+	}
+
 	ret = hid_parse(hdev);
 	if (ret) {
 		hid_err(hdev, "Asus hid parse failed: %d\n", ret);