[PATCH] compal-laptop: add charge control limit

[Roald Frederickx <roald.frederickx@gmail.com>]

Add charge control limit to the power supply subsystem of the Compal
platform driver.
This apparently was present in the original driver by Cezary Jackiewicz
at http://eko.one.pl/index.php?page=compal-laptop but it seems to have been
overlooked.

The Kconfig description is updated to reflect this addition. It now also
mentions the hwmon interface that was already present.

Signed-off-by: Roald Frederickx <roald.frederickx@gmail.com>
---
 drivers/platform/x86/Kconfig         |  4 ++--
 drivers/platform/x86/compal-laptop.c | 43 +++++++++++++++++++++++++++++++++++-
 2 files changed, 44 insertions(+), 3 deletions(-)

diff --git a/drivers/platform/x86/Kconfig b/drivers/platform/x86/Kconfig
index c69bb70..2f9026d 100644
--- a/drivers/platform/x86/Kconfig
+++ b/drivers/platform/x86/Kconfig
@@ -309,8 +309,8 @@ config COMPAL_LAPTOP
 	  This is a driver for laptops built by Compal, and some models by
 	  other brands (e.g. Dell, Toshiba).
 
-	  It adds support for rfkill, Bluetooth, WLAN and LCD brightness
-	  control.
+	  It adds support for rfkill, Bluetooth, WLAN, LCD brightness, hwmon
+	  and battery charging level control.
 
 	  For a (possibly incomplete) list of supported laptops, please refer
 	  to: Documentation/platform/x86-laptop-drivers.txt
diff --git a/drivers/platform/x86/compal-laptop.c b/drivers/platform/x86/compal-laptop.c
index f2706d2..e1c2b6d 100644
--- a/drivers/platform/x86/compal-laptop.c
+++ b/drivers/platform/x86/compal-laptop.c
@@ -151,6 +151,8 @@
 #define BAT_STATUS2			0xF1
 #define BAT_STOP_CHARGE1		0xF2
 #define BAT_STOP_CHARGE2		0xF3
+#define BAT_CHARGE_LIMIT		0x03
+#define BAT_CHARGE_LIMIT_MAX		100
 
 #define BAT_S0_DISCHARGE		(1 << 0)
 #define BAT_S0_DISCHRG_CRITICAL		(1 << 2)
@@ -601,6 +603,12 @@ static int bat_get_property(struct power_supply *psy,
 	case POWER_SUPPLY_PROP_CHARGE_NOW:
 		val->intval = ec_read_u16(BAT_CHARGE_NOW) * 1000;
 		break;
+	case POWER_SUPPLY_PROP_CHARGE_CONTROL_LIMIT:
+		val->intval = ec_read_u8(BAT_CHARGE_LIMIT);
+		break;
+	case POWER_SUPPLY_PROP_CHARGE_CONTROL_LIMIT_MAX:
+		val->intval = BAT_CHARGE_LIMIT_MAX;
+		break;
 	case POWER_SUPPLY_PROP_CAPACITY:
 		val->intval = ec_read_u8(BAT_CAPACITY);
 		break;
@@ -634,6 +642,36 @@ static int bat_get_property(struct power_supply *psy,
 	return 0;
 }
 
+static int bat_set_property(struct power_supply *psy,
+				enum power_supply_property psp,
+				const union power_supply_propval *val)
+{
+	int level;
+
+	switch (psp) {
+	case POWER_SUPPLY_PROP_CHARGE_CONTROL_LIMIT:
+		level = val->intval;
+		if (level < 0 || level > BAT_CHARGE_LIMIT_MAX)
+			return -EINVAL;
+		if (ec_write(BAT_CHARGE_LIMIT, level) < 0)
+			return -EIO;
+		break;
+	default:
+		break;
+	}
+	return 0;
+}
+
+static int bat_writeable_property(struct power_supply *psy,
+				enum power_supply_property psp)
+{
+	switch (psp) {
+	case POWER_SUPPLY_PROP_CHARGE_CONTROL_LIMIT:
+		return 1;
+	default:
+		return 0;
+	}
+}
 
 
 
@@ -726,6 +764,8 @@ static enum power_supply_property compal_bat_properties[] = {
 	POWER_SUPPLY_PROP_POWER_NOW,
 	POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN,
 	POWER_SUPPLY_PROP_CHARGE_NOW,
+	POWER_SUPPLY_PROP_CHARGE_CONTROL_LIMIT,
+	POWER_SUPPLY_PROP_CHARGE_CONTROL_LIMIT_MAX,
 	POWER_SUPPLY_PROP_CAPACITY,
 	POWER_SUPPLY_PROP_CAPACITY_LEVEL,
 	POWER_SUPPLY_PROP_TEMP,
@@ -880,11 +920,12 @@ static const struct power_supply_desc psy_bat_desc = {
 	.properties	= compal_bat_properties,
 	.num_properties	= ARRAY_SIZE(compal_bat_properties),
 	.get_property	= bat_get_property,
+	.set_property	= bat_set_property,
+	.property_is_writeable = bat_writeable_property,
 };
 
 static void initialize_power_supply_data(struct compal_data *data)
 {
-
 	ec_read_sequence(BAT_MANUFACTURER_NAME_ADDR,
 					data->bat_manufacturer_name,
 					BAT_MANUFACTURER_NAME_LEN);
-- 
1.9.2