crypto: ccree - better clock handling

Use managed clock handling, differentiate between no clock (possibly OK)
and clock init failure (never OK) and correctly handle clock detection
being deferred.
Suggested-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Gilad Ben-Yossef <gilad@benyossef.com>
Reviewed-by: Simon Horman <horms+renesas@verge.net.au>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

drivers/crypto/ccree/cc_driver.c

@@ -190,6 +190,7 @@ static int init_cc_resources(struct platform_device *plat_dev)
 	u64 dma_mask;
 	const struct cc_hw_data *hw_rev;
 	const struct of_device_id *dev_id;
+	struct clk *clk;
 	int rc = 0;
 
 	new_drvdata = devm_kzalloc(dev, sizeof(*new_drvdata), GFP_KERNEL);
@@ -219,7 +220,24 @@ static int init_cc_resources(struct platform_device *plat_dev)
 	platform_set_drvdata(plat_dev, new_drvdata);
 	new_drvdata->plat_dev = plat_dev;
 
-	new_drvdata->clk = of_clk_get(np, 0);
+	clk = devm_clk_get(dev, NULL);
+	if (IS_ERR(clk))
+		switch (PTR_ERR(clk)) {
+		/* Clock is optional so this might be fine */
+		case -ENOENT:
+			break;
+
+		/* Clock not available, let's try again soon */
+		case -EPROBE_DEFER:
+			return -EPROBE_DEFER;
+
+		default:
+			dev_err(dev, "Error getting clock: %ld\n",
+				PTR_ERR(clk));
+			return PTR_ERR(clk);
+		}
+	new_drvdata->clk = clk;
+
 	new_drvdata->coherent = of_dma_is_coherent(np);
 
 	/* Get device resources */