crypto: img-hash - Add suspend resume hooks for img hash

Current img hash claims sys and periph gate clocks
and this can be gated in system suspend scenarios.

Add support for Device pm ops for img hash to gate
the clocks claimed by img hash.

Signed-off-by: Govindraj Raja <Govindraj.Raja@imgtec.com>
Reviewed-by: Will Thomas <will.thomas@imgtec.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

drivers/crypto/img-hash.c

@@ -1016,11 +1016,38 @@ static int img_hash_remove(struct platform_device *pdev)
 	return 0;
 }
 
+#ifdef CONFIG_PM_SLEEP
+static int img_hash_suspend(struct device *dev)
+{
+	struct img_hash_dev *hdev = dev_get_drvdata(dev);
+
+	clk_disable_unprepare(hdev->hash_clk);
+	clk_disable_unprepare(hdev->sys_clk);
+
+	return 0;
+}
+
+static int img_hash_resume(struct device *dev)
+{
+	struct img_hash_dev *hdev = dev_get_drvdata(dev);
+
+	clk_prepare_enable(hdev->hash_clk);
+	clk_prepare_enable(hdev->sys_clk);
+
+	return 0;
+}
+#endif /* CONFIG_PM_SLEEP */
+
+static const struct dev_pm_ops img_hash_pm_ops = {
+	SET_SYSTEM_SLEEP_PM_OPS(img_hash_suspend, img_hash_resume)
+};
+
 static struct platform_driver img_hash_driver = {
 	.probe		= img_hash_probe,
 	.remove		= img_hash_remove,
 	.driver		= {
 		.name	= "img-hash-accelerator",
+		.pm	= &img_hash_pm_ops,
 		.of_match_table	= of_match_ptr(img_hash_match),
 	}
 };