mfd: Implement runtime PM for WM8994 core driver

Allow the WM8994 to completely power off, including disabling the LDOs
if they are software controlled, when it goes idle. The CODEC subdevice
controls activity for the MFD as a whole.

If the GPIOs need to be used while the device is active runtime PM
should be disabled for the device by machine specific code.

Signed-off-by: Mark Brown <[e-mail]>
Signed-off-by: Samuel Ortiz <[e-mail]>

drivers/mfd/wm8994-core.c

···
 #include <linux/i2c.h>
 #include <linux/delay.h>
 #include <linux/mfd/core.h>
+#include <linux/pm_runtime.h>
 #include <linux/regulator/consumer.h>
 #include <linux/regulator/machine.h>
 
···
 EXPORT_SYMBOL_GPL(wm8994_set_bits);
 
 static struct mfd_cell wm8994_regulator_devs[] = {
-	{ .name = "wm8994-ldo", .id = 1 },
-	{ .name = "wm8994-ldo", .id = 2 },
+	{
+		.name = "wm8994-ldo",
+		.id = 1,
+		.pm_runtime_no_callbacks = true,
+	},
+	{
+		.name = "wm8994-ldo",
+		.id = 2,
+		.pm_runtime_no_callbacks = true,
+	},
 };
 
 static struct resource wm8994_codec_resources[] = {
···
 		.name = "wm8994-gpio",
 		.num_resources = ARRAY_SIZE(wm8994_gpio_resources),
 		.resources = wm8994_gpio_resources,
+		.pm_runtime_no_callbacks = true,
 	},
 };
 
···
 };
 
 #ifdef CONFIG_PM
-static int wm8994_device_suspend(struct device *dev)
+static int wm8994_suspend(struct device *dev)
 {
 	struct wm8994 *wm8994 = dev_get_drvdata(dev);
 	int ret;
···
 	return 0;
 }
 
-static int wm8994_device_resume(struct device *dev)
+static int wm8994_resume(struct device *dev)
 {
 	struct wm8994 *wm8994 = dev_get_drvdata(dev);
 	int ret;
···
 		goto err_irq;
 	}
 
+	pm_runtime_enable(wm8994->dev);
+	pm_runtime_resume(wm8994->dev);
+
 	return 0;
 
 err_irq:
···
 
 static void wm8994_device_exit(struct wm8994 *wm8994)
 {
+	pm_runtime_disable(wm8994->dev);
 	mfd_remove_devices(wm8994->dev);
 	wm8994_irq_exit(wm8994);
 	regulator_bulk_disable(wm8994->num_supplies,
···
 	return 0;
 }
 
-#ifdef CONFIG_PM
-static int wm8994_i2c_suspend(struct i2c_client *i2c, pm_message_t state)
-{
-	return wm8994_device_suspend(&i2c->dev);
-}
-
-static int wm8994_i2c_resume(struct i2c_client *i2c)
-{
-	return wm8994_device_resume(&i2c->dev);
-}
-#else
-#define wm8994_i2c_suspend NULL
-#define wm8994_i2c_resume NULL
-#endif
-
 static const struct i2c_device_id wm8994_i2c_id[] = {
 	{ "wm8994", WM8994 },
 	{ "wm8958", WM8958 },
···
 };
 MODULE_DEVICE_TABLE(i2c, wm8994_i2c_id);
 
+UNIVERSAL_DEV_PM_OPS(wm8994_pm_ops, wm8994_suspend, wm8994_resume, NULL);
+
 static struct i2c_driver wm8994_i2c_driver = {
 	.driver = {
-		   .name = "wm8994",
-		   .owner = THIS_MODULE,
+		.name = "wm8994",
+		.owner = THIS_MODULE,
+		.pm = &wm8994_pm_ops,
 	},
 	.probe = wm8994_i2c_probe,
 	.remove = wm8994_i2c_remove,
-	.suspend = wm8994_i2c_suspend,
-	.resume = wm8994_i2c_resume,
 	.id_table = wm8994_i2c_id,
 };