[v8,4/4] i2c: core: support bus regulator controlling in adapter

diff --git a/drivers/i2c/i2c-core-base.c b/drivers/i2c/i2c-core-base.c
index 9333c865d4a9..75f609d37ef3 100644
--- a/drivers/i2c/i2c-core-base.c
+++ b/drivers/i2c/i2c-core-base.c
@@ -306,6 +306,7 @@  static int i2c_smbus_host_notify_to_irq(const struct i2c_client *client)
 static int i2c_device_probe(struct device *dev)
 {
 	struct i2c_client	*client = i2c_verify_client(dev);
+	struct i2c_adapter	*adap = client->adapter;
 	struct i2c_driver	*driver;
 	int status;
 
@@ -371,6 +372,12 @@  static int i2c_device_probe(struct device *dev)
 
 	dev_dbg(dev, "probe\n");
 
+	status = regulator_enable(adap->bus_reg);
+	if (status != 0) {
+		dev_err(&adap->dev, "Failed to enable power regulator\n");
+		goto err_clear_wakeup_irq;
+	}
+
 	status = of_clk_set_defaults(dev->of_node, false);
 	if (status < 0)
 		goto err_clear_wakeup_irq;
@@ -407,6 +414,7 @@  static int i2c_device_probe(struct device *dev)
 static int i2c_device_remove(struct device *dev)
 {
 	struct i2c_client	*client = i2c_verify_client(dev);
+	struct i2c_adapter      *adap = client->adapter;
 	struct i2c_driver	*driver;
 	int status = 0;
 
@@ -420,6 +428,8 @@  static int i2c_device_remove(struct device *dev)
 	}
 
 	dev_pm_domain_detach(&client->dev, true);
+	if (pm_runtime_status_suspended(&adap->dev))
+		regulator_disable(adap->bus_reg);
 
 	dev_pm_clear_wake_irq(&client->dev);
 	device_init_wakeup(&client->dev, false);
@@ -431,6 +441,54 @@  static int i2c_device_remove(struct device *dev)
 	return status;
 }
 
+#ifdef CONFIG_PM_SLEEP
+static int i2c_resume(struct device *dev)
+{
+	struct i2c_client *client = i2c_verify_client(dev);
+	struct i2c_adapter *adap = client->adapter;
+
+	return pm_generic_resume(&adap->dev);
+}
+
+static int i2c_suspend(struct device *dev)
+{
+	struct i2c_client *client = i2c_verify_client(dev);
+	struct i2c_adapter *adap = client->adapter;
+
+	return pm_generic_suspend(&adap->dev);
+}
+#endif
+
+#ifdef CONFIG_PM
+static int i2c_runtime_resume(struct device *dev)
+{
+	struct i2c_client *client = i2c_verify_client(dev);
+	struct i2c_adapter *adap = client->adapter;
+
+	pm_generic_runtime_resume(&adap->dev);
+
+	return regulator_enable(adap->bus_reg);
+}
+
+static int i2c_runtime_suspend(struct device *dev)
+{
+	struct i2c_client *client = i2c_verify_client(dev);
+	struct i2c_adapter *adap = client->adapter;
+
+	pm_generic_runtime_suspend(&adap->dev);
+
+	if (pm_runtime_status_suspended(&adap->dev))
+		return regulator_disable(client->adapter->bus_reg);
+
+	return 0;
+}
+#endif
+
+static const struct dev_pm_ops i2c_device_pm = {
+	SET_SYSTEM_SLEEP_PM_OPS(i2c_suspend, i2c_resume)
+	SET_RUNTIME_PM_OPS(i2c_runtime_suspend, i2c_runtime_resume, NULL)
+};
+
 static void i2c_device_shutdown(struct device *dev)
 {
 	struct i2c_client *client = i2c_verify_client(dev);
@@ -488,6 +546,7 @@  struct bus_type i2c_bus_type = {
 	.probe		= i2c_device_probe,
 	.remove		= i2c_device_remove,
 	.shutdown	= i2c_device_shutdown,
+	.pm		= &i2c_device_pm,
 };
 EXPORT_SYMBOL_GPL(i2c_bus_type);
 
@@ -1351,6 +1410,12 @@  static int i2c_register_adapter(struct i2c_adapter *adap)
 		goto out_reg;
 
 	dev_dbg(&adap->dev, "adapter [%s] registered\n", adap->name);
+	adap->bus_reg = devm_regulator_get(&adap->dev, "bus");
+	if (IS_ERR(adap->bus_reg)) {
+		dev_err(&adap->dev, "failed to get adapter bus regulator\n");
+		res = PTR_ERR(adap->bus_reg);
+		goto out_reg;
+	}
 
 	pm_runtime_no_callbacks(&adap->dev);
 	pm_suspend_ignore_children(&adap->dev, true);
@@ -1580,6 +1645,7 @@  void i2c_del_adapter(struct i2c_adapter *adap)
 	dev_dbg(&adap->dev, "adapter [%s] unregistered\n", adap->name);
 
 	pm_runtime_disable(&adap->dev);
+	devm_regulator_put(adap->bus_reg);
 
 	i2c_host_notify_irq_teardown(adap);
 
diff --git a/include/linux/i2c.h b/include/linux/i2c.h
index d2f786706657..833b81a680da 100644
--- a/include/linux/i2c.h
+++ b/include/linux/i2c.h
@@ -15,6 +15,7 @@ 
 #include <linux/device.h>	/* for struct device */
 #include <linux/sched.h>	/* for completion */
 #include <linux/mutex.h>
+#include <linux/regulator/consumer.h>
 #include <linux/rtmutex.h>
 #include <linux/irqdomain.h>		/* for Host Notify IRQ */
 #include <linux/of.h>		/* for struct device_node */
@@ -330,6 +331,7 @@  struct i2c_client {
 	int init_irq;			/* irq set at initialization	*/
 	int irq;			/* irq issued by device		*/
 	struct list_head detected;
+
 #if IS_ENABLED(CONFIG_I2C_SLAVE)
 	i2c_slave_cb_t slave_cb;	/* callback for slave mode	*/
 #endif
@@ -723,6 +725,7 @@  struct i2c_adapter {
 	const struct i2c_adapter_quirks *quirks;
 
 	struct irq_domain *host_notify_domain;
+	struct regulator *bus_reg;
 };
 #define to_i2c_adapter(d) container_of(d, struct i2c_adapter, dev)