FAILED: patch "[PATCH] iio: adc: gyroadc: fix uninitialized return code" failed to apply to 4.19-stable tree

The patch below does not apply to the 4.19-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 90c6260c1905a68fb596844087f2223bd4657fee Mon Sep 17 00:00:00 2001
From: Arnd Bergmann <[email protected]>
Date: Thu, 18 Jul 2019 15:57:49 +0200
Subject: [PATCH] iio: adc: gyroadc: fix uninitialized return code

gcc-9 complains about a blatant uninitialized variable use that all earlier compiler versions missed:

drivers/iio/adc/rcar-gyroadc.c:510:5: warning: 'ret' may be used uninitialized in this function [-Wmaybe-uninitialized]

Return -EINVAL instead here and a few lines above it where we accidentally return 0 on failure.

index 2d685730f867..c37f201294b2 100644
@@ -382,7 +382,7 @@ static int rcar_gyroadc_parse_subdevs(struct iio_dev *indio_dev)
 				dev_err(dev,
 					"Only %i channels supported with %pOFn, but reg = <%i>.\n",
 					num_channels, child, reg);
-				return ret;
+				return -EINVAL;
 			}
 		}
 

@@ -391,7 +391,7 @@ static int rcar_gyroadc_parse_subdevs(struct iio_dev *indio_dev)
 			dev_err(dev,
 				"Channel %i uses different ADC mode than the rest.\n",
 				reg);
-			return ret;
+			return -EINVAL;
 		}
 
 		/* Channel is valid, grab the regulator. */