From:   Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
To:     gregkh@linuxfoundation.org
Cc:     linux-kernel@vger.kernel.org, Michael Walle <michael@walle.cc>,
        Alexander Stein <alexander.stein@ew.tq-group.com>,
        Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Subject: [PATCH] nvmem: core: return -ENOENT if nvmem cell is not found
Date:   Fri, 10 Mar 2023 09:48:45 +0000
Message-Id: <20230310094845.139400-1-srinivas.kandagatla@linaro.org>
MIME-Version: 1.0
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From: Michael Walle <michael@walle.cc>

Prior to commit 5d8e6e6c10a3 ("nvmem: core: add an index parameter to
the cell") of_nvmem_cell_get() would return -ENOENT if the cell wasn't
found. Particularly, if of_property_match_string() returned -EINVAL,
that return code was passed as the index to of_parse_phandle(), which
then detected it as invalid and returned NULL. That led to an return
code of -ENOENT.

With the new code, the negative index will lead to an -EINVAL of
of_parse_phandle_with_optional_args() which pass straight to the
caller and break those who expect an -ENOENT.

Fix it by always returning -ENOENT.

Fixes: 5d8e6e6c10a3 ("nvmem: core: add an index parameter to the cell")
Reported-by: Alexander Stein <alexander.stein@ew.tq-group.com>
Link: https://lore.kernel.org/r/2143916.GUh0CODmnK@steina-w/
Signed-off-by: Michael Walle <michael@walle.cc>
Tested-by: Alexander Stein <alexander.stein@ew.tq-group.com>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
---
Hi Greg, 

Could you please pick this nvmem fix for next possible rc.
thanks for your help.

--Srini

 drivers/nvmem/core.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/nvmem/core.c b/drivers/nvmem/core.c
index 174ef3574e07..22024b830788 100644
--- a/drivers/nvmem/core.c
+++ b/drivers/nvmem/core.c
@@ -1231,7 +1231,7 @@ struct nvmem_cell *of_nvmem_cell_get(struct device_node *np, const char *id)
 						  "#nvmem-cell-cells",
 						  index, &cell_spec);
 	if (ret)
-		return ERR_PTR(ret);
+		return ERR_PTR(-ENOENT);
 
 	if (cell_spec.args_count > 1)
 		return ERR_PTR(-EINVAL);
-- 
2.25.1