linux-kernel - [PATCH] regmap: fix writes to non incrementing registers

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Date:   Tue, 13 Aug 2019 22:22:51 +0100
From:   Ben Whitten <ben.whitten@...il.com>
To:     linux-kernel@...r.kernel.org
Cc:     afaerber@...e.de, Ben Whitten <ben.whitten@...il.com>,
        Mark Brown <broonie@...nel.org>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        "Rafael J. Wysocki" <rafael@...nel.org>
Subject: [PATCH] regmap: fix writes to non incrementing registers

When checking if a register is writable we must first check if the
register is a non incrementing writable register.
Non incrementing register are deep and do not move to the next
register when writing, for example a FIFO.

Signed-off-by: Ben Whitten <ben.whitten@...il.com>
---
 drivers/base/regmap/regmap.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/drivers/base/regmap/regmap.c b/drivers/base/regmap/regmap.c
index f1025452bb39..70645a28897c 100644
--- a/drivers/base/regmap/regmap.c
+++ b/drivers/base/regmap/regmap.c
@@ -1489,10 +1489,11 @@ static int _regmap_raw_write_impl(struct regmap *map, unsigned int reg,
 	WARN_ON(!map->bus);
 
 	/* Check for unwritable registers before we start */
-	for (i = 0; i < val_len / map->format.val_bytes; i++)
-		if (!regmap_writeable(map,
-				     reg + regmap_get_offset(map, i)))
-			return -EINVAL;
+	if (!regmap_writeable_noinc(map, reg))
+		for (i = 0; i < val_len / map->format.val_bytes; i++)
+			if (!regmap_writeable(map,
+					     reg + regmap_get_offset(map, i)))
+				return -EINVAL;
 
 	if (!map->cache_bypass && map->format.parse_val) {
 		unsigned int ival;
-- 
2.17.1