[RFC,5/6] power: supply: test-power: implement a power supply extension

diff --git a/drivers/power/supply/test_power.c b/drivers/power/supply/test_power.c
index 442ceb7795e1..5730cbff6159 100644
--- a/drivers/power/supply/test_power.c
+++ b/drivers/power/supply/test_power.c
@@ -37,6 +37,7 @@  static int battery_charge_counter	= -1000;
 static int battery_current		= -1600;
 static enum power_supply_charge_behaviour battery_charge_behaviour =
 	POWER_SUPPLY_CHARGE_BEHAVIOUR_AUTO;
+static bool battery_hook;
 
 static bool module_initialized;
 
@@ -238,6 +239,80 @@  static const struct power_supply_config test_power_configs[] = {
 	},
 };
 
+static int power_supply_ext_manufacture_year = 1234;
+static enum power_supply_property power_supply_ext_props[] = {
+	POWER_SUPPLY_PROP_CHARGE_COUNTER, /* overridden from base supply */
+	POWER_SUPPLY_PROP_MANUFACTURE_YEAR,
+};
+
+static int power_supply_ext_get_property(struct power_supply *psy,
+					 enum power_supply_property psp,
+					 union power_supply_propval *val)
+{
+	switch (psp) {
+	case POWER_SUPPLY_PROP_MANUFACTURE_YEAR:
+		val->intval = power_supply_ext_manufacture_year;
+		break;
+	case POWER_SUPPLY_PROP_CHARGE_COUNTER:
+		val->intval = 1234;
+		break;
+	default:
+		pr_info("%s: some properties deliberately report errors.\n",
+			__func__);
+		return -EINVAL;
+	}
+	return 0;
+}
+
+static int power_supply_ext_set_property(struct power_supply *psy,
+					 enum power_supply_property psp,
+					 const union power_supply_propval *val)
+{
+	switch (psp) {
+	case POWER_SUPPLY_PROP_MANUFACTURE_YEAR:
+		power_supply_ext_manufacture_year = val->intval;
+		break;
+	default:
+		return -EINVAL;
+	}
+	return 0;
+}
+
+static int power_supply_ext_property_is_writeable(struct power_supply *psy,
+						  enum power_supply_property psp)
+{
+	return psp == POWER_SUPPLY_PROP_MANUFACTURE_YEAR;
+}
+
+static const struct power_supply_ext power_supply_ext = {
+	.properties = power_supply_ext_props,
+	.num_properties = ARRAY_SIZE(power_supply_ext_props),
+	.get_property = power_supply_ext_get_property,
+	.set_property = power_supply_ext_set_property,
+	.property_is_writeable = power_supply_ext_property_is_writeable,
+};
+
+static void test_battery_configure_battery_hook(bool enable)
+{
+	struct power_supply *psy;
+
+	if (battery_hook == enable)
+		return;
+
+	psy = test_power_supplies[TEST_BATTERY];
+
+	if (enable) {
+		if (power_supply_register_extension(psy, &power_supply_ext)) {
+			pr_err("registering battery extension failed\n");
+			return;
+		}
+	} else {
+		power_supply_unregister_extension(psy, &power_supply_ext);
+	}
+
+	battery_hook = enable;
+}
+
 static int __init test_power_init(void)
 {
 	int i;
@@ -258,6 +333,8 @@  static int __init test_power_init(void)
 		}
 	}
 
+	test_battery_configure_battery_hook(true);
+
 	module_initialized = true;
 	return 0;
 failed:
@@ -524,6 +601,22 @@  static int param_set_battery_current(const char *key,
 
 #define param_get_battery_current param_get_int
 
+static int param_set_battery_hook(const char *key,
+				  const struct kernel_param *kp)
+{
+	int tmp;
+
+	if (1 != sscanf(key, "%d", &tmp))
+		return -EINVAL;
+	if (tmp != 1 && tmp != 0)
+		return -EINVAL;
+
+	test_battery_configure_battery_hook(tmp);
+	return 0;
+}
+
+#define param_get_battery_hook param_get_int
+
 static const struct kernel_param_ops param_ops_ac_online = {
 	.set = param_set_ac_online,
 	.get = param_get_ac_online,
@@ -574,6 +667,11 @@  static const struct kernel_param_ops param_ops_battery_current = {
 	.get = param_get_battery_current,
 };
 
+static const struct kernel_param_ops param_ops_battery_hook = {
+	.set = param_set_battery_hook,
+	.get = param_get_battery_hook,
+};
+
 #define param_check_ac_online(name, p) __param_check(name, p, void);
 #define param_check_usb_online(name, p) __param_check(name, p, void);
 #define param_check_battery_status(name, p) __param_check(name, p, void);
@@ -584,6 +682,7 @@  static const struct kernel_param_ops param_ops_battery_current = {
 #define param_check_battery_voltage(name, p) __param_check(name, p, void);
 #define param_check_battery_charge_counter(name, p) __param_check(name, p, void);
 #define param_check_battery_current(name, p) __param_check(name, p, void);
+#define param_check_battery_hook(name, p) __param_check(name, p, void);
 
 
 module_param(ac_online, ac_online, 0644);
@@ -621,6 +720,9 @@  MODULE_PARM_DESC(battery_charge_counter,
 module_param(battery_current, battery_current, 0644);
 MODULE_PARM_DESC(battery_current, "battery current (milliampere)");
 
+module_param(battery_hook, battery_hook, 0644);
+MODULE_PARM_DESC(battery_hook, "battery hook");
+
 MODULE_DESCRIPTION("Power supply driver for testing");
 MODULE_AUTHOR("Anton Vorontsov <cbouatmailru@gmail.com>");
 MODULE_LICENSE("GPL");