i2c: kempld: Convert to use regular device PM

Provide PM callbacks through platform_driver.driver.pm instead of
platform_driver.{suspend,resume} as any good-behaved driver should do.

Use the new PM macros for the suspend and resume functions to be
automatically dropped by the compiler when CONFIG_PM or
CONFIG_PM_SLEEP are disabled, without having to use #ifdef guards.

This has the advantage of always compiling these functions in,
independently of any Kconfig option. Thanks to that, bugs and other
regressions are subsequently easier to catch.

Signed-off-by: Paul Cercueil <paul@crapouillou.net>
Acked-by: Andi Shyti <andi.shyti@kernel.org>
Link: https://lore.kernel.org/r/20230722115046.27323-11-paul@crapouillou.net
Signed-off-by: Andi Shyti <andi.shyti@kernel.org>

drivers/i2c/busses/i2c-kempld.c

@@ -350,10 +350,9 @@ static void kempld_i2c_remove(struct platform_device *pdev)
 	i2c_del_adapter(&i2c->adap);
 }
 
-#ifdef CONFIG_PM
-static int kempld_i2c_suspend(struct platform_device *pdev, pm_message_t state)
+static int kempld_i2c_suspend(struct device *dev)
 {
-	struct kempld_i2c_data *i2c = platform_get_drvdata(pdev);
+	struct kempld_i2c_data *i2c = dev_get_drvdata(dev);
 	struct kempld_device_data *pld = i2c->pld;
 	u8 ctrl;
 
@@ -366,9 +365,9 @@ static int kempld_i2c_suspend(struct platform_device *pdev, pm_message_t state)
 	return 0;
 }
 
-static int kempld_i2c_resume(struct platform_device *pdev)
+static int kempld_i2c_resume(struct device *dev)
 {
-	struct kempld_i2c_data *i2c = platform_get_drvdata(pdev);
+	struct kempld_i2c_data *i2c = dev_get_drvdata(dev);
 	struct kempld_device_data *pld = i2c->pld;
 
 	kempld_get_mutex(pld);
@@ -377,19 +376,17 @@ static int kempld_i2c_resume(struct platform_device *pdev)
 
 	return 0;
 }
-#else
-#define kempld_i2c_suspend	NULL
-#define kempld_i2c_resume	NULL
-#endif
+
+static DEFINE_SIMPLE_DEV_PM_OPS(kempld_i2c_pm_ops,
+				kempld_i2c_suspend, kempld_i2c_resume);
 
 static struct platform_driver kempld_i2c_driver = {
 	.driver = {
 		.name = "kempld-i2c",
+		.pm = pm_sleep_ptr(&kempld_i2c_pm_ops),
 	},
 	.probe		= kempld_i2c_probe,
 	.remove_new	= kempld_i2c_remove,
-	.suspend	= kempld_i2c_suspend,
-	.resume		= kempld_i2c_resume,
 };
 
 module_platform_driver(kempld_i2c_driver);