dmaengine: dma-jz4780: Return error if not probed from DT

BugLink: https://bugs.launchpad.net/bugs/1810947

[ Upstream commit 54f919a0 ]

The driver calls clk_get() with the clock name set to NULL, which means
that the driver could only work when probed from devicetree. From now
on, we explicitly require the driver to be probed from devicetree.
Signed-off-by: Paul Cercueil <paul@crapouillou.net>
Tested-by: Mathieu Malaterre <malat@debian.org>
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Juerg Haefliger <juergh@canonical.com>
Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>

drivers/dma/dma-jz4780.c

@@ -750,6 +750,11 @@ static int jz4780_dma_probe(struct platform_device *pdev)
 	struct resource *res;
 	int i, ret;
 
+	if (!dev->of_node) {
+		dev_err(dev, "This driver must be probed from devicetree\n");
+		return -EINVAL;
+	}
+
 	jzdma = devm_kzalloc(dev, sizeof(*jzdma), GFP_KERNEL);
 	if (!jzdma)
 		return -ENOMEM;