Revert "i2c: core: support bus regulator controlling in adapter"

This largely reverts commit 5a7b95f. It
breaks suspend with AMD GPUs, and we couldn't incrementally fix it. So,
let's remove the code and go back to the drawing board. We keep the
header extension to not break drivers already populating the regulator.
We expect to re-add the code handling it soon.

Fixes: 5a7b95f ("i2c: core: support bus regulator controlling in adapter")
Reported-by: "Tareque Md.Hanif" <tarequemd.hanif@yahoo.com>
Link: https://lore.kernel.org/r/1295184560.182511.1639075777725@mail.yahoo.com
Reported-by: Konstantin Kharlamov <hi-angel@yandex.ru>
Link: https://lore.kernel.org/r/7143a7147978f4104171072d9f5225d2ce355ec1.camel@yandex.ru
BugLink: https://gitlab.freedesktop.org/drm/amd/-/issues/1850
Tested-by: "Tareque Md.Hanif" <tarequemd.hanif@yahoo.com>
Tested-by: Konstantin Kharlamov <hi-angel@yandex.ru>
Signed-off-by: Wolfram Sang <wsa@kernel.org>
Cc: <stable@vger.kernel.org> # 5.14+

drivers/i2c/i2c-core-base.c

@@ -466,14 +466,12 @@ 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;
 	struct i2c_driver	*driver;
 	int status;
 
 	if (!client)
 		return 0;
 
-	adap = client->adapter;
 	client->irq = client->init_irq;
 
 	if (!client->irq) {
@@ -539,14 +537,6 @@ static int i2c_device_probe(struct device *dev)
 
 	dev_dbg(dev, "probe\n");
 
-	if (adap->bus_regulator) {
-		status = regulator_enable(adap->bus_regulator);
-		if (status < 0) {
-			dev_err(&adap->dev, "Failed to enable bus regulator\n");
-			goto err_clear_wakeup_irq;
-		}
-	}
-
 	status = of_clk_set_defaults(dev->of_node, false);
 	if (status < 0)
 		goto err_clear_wakeup_irq;
@@ -605,10 +595,8 @@ static int i2c_device_probe(struct device *dev)
 static void i2c_device_remove(struct device *dev)
 {
 	struct i2c_client	*client = to_i2c_client(dev);
-	struct i2c_adapter      *adap;
 	struct i2c_driver	*driver;
 
-	adap = client->adapter;
 	driver = to_i2c_driver(dev->driver);
 	if (driver->remove) {
 		int status;
@@ -623,8 +611,6 @@ static void i2c_device_remove(struct device *dev)
 	devres_release_group(&client->dev, client->devres_group_id);
 
 	dev_pm_domain_detach(&client->dev, !i2c_acpi_waive_d0_probe(dev));
-	if (!pm_runtime_status_suspended(&client->dev) && adap->bus_regulator)
-		regulator_disable(adap->bus_regulator);
 
 	dev_pm_clear_wake_irq(&client->dev);
 	device_init_wakeup(&client->dev, false);
@@ -634,86 +620,6 @@ static void i2c_device_remove(struct device *dev)
 		pm_runtime_put(&client->adapter->dev);
 }
 
-#ifdef CONFIG_PM_SLEEP
-static int i2c_resume_early(struct device *dev)
-{
-	struct i2c_client *client = i2c_verify_client(dev);
-	int err;
-
-	if (!client)
-		return 0;
-
-	if (pm_runtime_status_suspended(&client->dev) &&
-		client->adapter->bus_regulator) {
-		err = regulator_enable(client->adapter->bus_regulator);
-		if (err)
-			return err;
-	}
-
-	return pm_generic_resume_early(&client->dev);
-}
-
-static int i2c_suspend_late(struct device *dev)
-{
-	struct i2c_client *client = i2c_verify_client(dev);
-	int err;
-
-	if (!client)
-		return 0;
-
-	err = pm_generic_suspend_late(&client->dev);
-	if (err)
-		return err;
-
-	if (!pm_runtime_status_suspended(&client->dev) &&
-		client->adapter->bus_regulator)
-		return regulator_disable(client->adapter->bus_regulator);
-
-	return 0;
-}
-#endif
-
-#ifdef CONFIG_PM
-static int i2c_runtime_resume(struct device *dev)
-{
-	struct i2c_client *client = i2c_verify_client(dev);
-	int err;
-
-	if (!client)
-		return 0;
-
-	if (client->adapter->bus_regulator) {
-		err = regulator_enable(client->adapter->bus_regulator);
-		if (err)
-			return err;
-	}
-
-	return pm_generic_runtime_resume(&client->dev);
-}
-
-static int i2c_runtime_suspend(struct device *dev)
-{
-	struct i2c_client *client = i2c_verify_client(dev);
-	int err;
-
-	if (!client)
-		return 0;
-
-	err = pm_generic_runtime_suspend(&client->dev);
-	if (err)
-		return err;
-
-	if (client->adapter->bus_regulator)
-		return regulator_disable(client->adapter->bus_regulator);
-	return 0;
-}
-#endif
-
-static const struct dev_pm_ops i2c_device_pm = {
-	SET_LATE_SYSTEM_SLEEP_PM_OPS(i2c_suspend_late, i2c_resume_early)
-	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);
@@ -773,7 +679,6 @@ 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);