mtd: nand: sunxi: simplify optional reset handling

As of commit bb475230 ("reset: make optional functions really
optional"), the reset framework API calls use NULL pointers to describe
optional, non-present reset controls.

This allows to return errors from devm_reset_control_get_optional and to
call reset_control_(de)assert unconditionally.
Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>

drivers/mtd/nand/sunxi_nand.c

@@ -2212,16 +2212,16 @@ static int sunxi_nfc_probe(struct platform_device *pdev)
 		goto out_ahb_clk_unprepare;
 
 	nfc->reset = devm_reset_control_get_optional(dev, "ahb");
-	if (!IS_ERR(nfc->reset)) {
+	if (IS_ERR(nfc->reset)) {
+		ret = PTR_ERR(nfc->reset);
+		goto out_mod_clk_unprepare;
+	}
+
 	ret = reset_control_deassert(nfc->reset);
 	if (ret) {
 		dev_err(dev, "reset err %d\n", ret);
 		goto out_mod_clk_unprepare;
 	}
-	} else if (PTR_ERR(nfc->reset) != -ENOENT) {
-		ret = PTR_ERR(nfc->reset);
-		goto out_mod_clk_unprepare;
-	}
 
 	ret = sunxi_nfc_rst(nfc);
 	if (ret)
@@ -2262,7 +2262,6 @@ static int sunxi_nfc_probe(struct platform_device *pdev)
 	if (nfc->dmac)
 		dma_release_channel(nfc->dmac);
 out_ahb_reset_reassert:
-	if (!IS_ERR(nfc->reset))
 	reset_control_assert(nfc->reset);
 out_mod_clk_unprepare:
 	clk_disable_unprepare(nfc->mod_clk);
@@ -2278,7 +2277,6 @@ static int sunxi_nfc_remove(struct platform_device *pdev)
 
 	sunxi_nand_chips_cleanup(nfc);
 
-	if (!IS_ERR(nfc->reset))
 	reset_control_assert(nfc->reset);
 
 	if (nfc->dmac)