linux-kernel - [PATCH] mfd: core: Fix handle of OF disabled MFD cells

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Date:   Sat,  1 Aug 2020 15:01:30 +0800
From:   Icenowy Zheng <icenowy@...c.io>
To:     Lee Jones <lee.jones@...aro.org>
Cc:     linux-kernel@...r.kernel.org, Icenowy Zheng <icenowy@...c.io>
Subject: [PATCH] mfd: core: Fix handle of OF disabled MFD cells

When rewriting the OF match code of MFD core, addition of cells disabled
in OF will result in a failure with error -ENODEV. This is an unexpected
behavior, as the previous behavior is silently ignore the cell. On
SBCs with AXP20x PMICs, this leads to boot failure if AXP20x PMIC
support is built-in and some cells (especially power supply ones) are
disabled.

Silently ignore the cell when -ENODEV occurs.

Fixes: e49aa9a9bd22 ("mfd: core: Make a best effort attempt to match devices with the correct of_nodes")
Signed-off-by: Icenowy Zheng <icenowy@...c.io>
---
 drivers/mfd/mfd-core.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/mfd/mfd-core.c b/drivers/mfd/mfd-core.c
index c3ef58a802bee..31b363c64f4b4 100644
--- a/drivers/mfd/mfd-core.c
+++ b/drivers/mfd/mfd-core.c
@@ -215,8 +215,13 @@ static int mfd_add_device(struct device *parent, int id,
 				ret = mfd_match_of_node_to_dev(pdev, np, cell);
 				if (ret == -EAGAIN)
 					continue;
-				if (ret)
+				if (ret) {
+					if (ret == -ENODEV) {
+						/* Ignore disabled devices error free */
+						ret = 0;
+					}
 					goto fail_alias;
+				}
 
 				break;
 			}
-- 
2.27.0