hwrng: iproc-rng200 - Implement suspend and resume calls

Chips such as BCM7278 support system wide suspend/resume which will
cause the HWRNG block to lose its state and reset to its power on reset
register values. We need to cleanup and re-initialize the HWRNG for it
to be functional coming out of a system suspend cycle.

Fixes: c3577f61 ("hwrng: iproc-rng200 - Add support for BCM7278")
Signed-off-by: Florian Fainelli <florian.fainelli@broadcom.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

drivers/char/hw_random/iproc-rng200.c

@@ -181,6 +181,8 @@ static int iproc_rng200_probe(struct platform_device *pdev)
 		return PTR_ERR(priv->base);
 	}
 
+	dev_set_drvdata(dev, priv);
+
 	priv->rng.name = "iproc-rng200";
 	priv->rng.read = iproc_rng200_read;
 	priv->rng.init = iproc_rng200_init;
@@ -198,6 +200,28 @@ static int iproc_rng200_probe(struct platform_device *pdev)
 	return 0;
 }
 
+static int __maybe_unused iproc_rng200_suspend(struct device *dev)
+{
+	struct iproc_rng200_dev *priv = dev_get_drvdata(dev);
+
+	iproc_rng200_cleanup(&priv->rng);
+
+	return 0;
+}
+
+static int __maybe_unused iproc_rng200_resume(struct device *dev)
+{
+	struct iproc_rng200_dev *priv =  dev_get_drvdata(dev);
+
+	iproc_rng200_init(&priv->rng);
+
+	return 0;
+}
+
+static const struct dev_pm_ops iproc_rng200_pm_ops = {
+	SET_SYSTEM_SLEEP_PM_OPS(iproc_rng200_suspend, iproc_rng200_resume)
+};
+
 static const struct of_device_id iproc_rng200_of_match[] = {
 	{ .compatible = "brcm,bcm2711-rng200", },
 	{ .compatible = "brcm,bcm7211-rng200", },
@@ -211,6 +235,7 @@ static struct platform_driver iproc_rng200_driver = {
 	.driver = {
 		.name		= "iproc-rng200",
 		.of_match_table = iproc_rng200_of_match,
+		.pm		= &iproc_rng200_pm_ops,
 	},
 	.probe		= iproc_rng200_probe,
 };