linux-kernel - [PATCH] regmap: fix bogus error on regcache

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Date:   Sun,  3 Dec 2023 23:22:16 +0100
From:   Matthias Reichl <hias@...us.com>
To:     Mark Brown <broonie@...nel.org>
Cc:     linux-kernel@...r.kernel.org, Matthias Reichl <hias@...us.com>
Subject: [PATCH] regmap: fix bogus error on regcache_sync success

Since commit 0ec7731655de ("regmap: Ensure range selector registers
are updated after cache sync") opening pcm512x based soundcards fail
with EINVAL and dmesg shows sync cache and pm_runtime_get errors:

[  228.794676] pcm512x 1-004c: Failed to sync cache: -22
[  228.794740] pcm512x 1-004c: ASoC: error at snd_soc_pcm_component_pm_runtime_get on pcm512x.1-004c: -22

This is caused by the cache check result leaking out into the
regcache_sync return value.

Fix this by making the check local-only, as the comment above the
regcache_read call states a non-zero return value means there's
nothing to do so the return value should not be altered.

Fixes: 0ec7731655de ("regmap: Ensure range selector registers are updated after cache sync")
Cc: stable@...r.kernel.org
Signed-off-by: Matthias Reichl <hias@...us.com>
---
 drivers/base/regmap/regcache.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/base/regmap/regcache.c b/drivers/base/regmap/regcache.c
index 92592f944a3d..ac63a73ccdaa 100644
--- a/drivers/base/regmap/regcache.c
+++ b/drivers/base/regmap/regcache.c
@@ -410,8 +410,7 @@ int regcache_sync(struct regmap *map)
 			rb_entry(node, struct regmap_range_node, node);
 
 		/* If there's nothing in the cache there's nothing to sync */
-		ret = regcache_read(map, this->selector_reg, &i);
-		if (ret != 0)
+		if (regcache_read(map, this->selector_reg, &i) != 0)
 			continue;
 
 		ret = _regmap_write(map, this->selector_reg, i);
-- 
2.39.2