linux-kernel - [PATCH AUTOSEL 4.19 061/158] regmap: fix bulk writes on paged registers

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Date:   Mon, 15 Jul 2019 10:16:32 -0400
From:   Sasha Levin <sashal@...nel.org>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:     Srinivas Kandagatla <srinivas.kandagatla@...aro.org>,
        Mark Brown <broonie@...nel.org>,
        Sasha Levin <sashal@...nel.org>
Subject: [PATCH AUTOSEL 4.19 061/158] regmap: fix bulk writes on paged registers

From: Srinivas Kandagatla <srinivas.kandagatla@...aro.org>

[ Upstream commit db057679de3e9e6a03c1bcd5aee09b0d25fd9f5b ]

On buses like SlimBus and SoundWire which does not support
gather_writes yet in regmap, A bulk write on paged register
would be silently ignored after programming page.
This is because local variable 'ret' value in regmap_raw_write_impl()
gets reset to 0 once page register is written successfully and the
code below checks for 'ret' value to be -ENOTSUPP before linearising
the write buffer to send to bus->write().

Fix this by resetting the 'ret' value to -ENOTSUPP in cases where
gather_writes() is not supported or single register write is
not possible.

Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@...aro.org>
Signed-off-by: Mark Brown <broonie@...nel.org>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 drivers/base/regmap/regmap.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/base/regmap/regmap.c b/drivers/base/regmap/regmap.c
index 0360a90ad6b6..6c9f6988bc09 100644
--- a/drivers/base/regmap/regmap.c
+++ b/drivers/base/regmap/regmap.c
@@ -1618,6 +1618,8 @@ static int _regmap_raw_write_impl(struct regmap *map, unsigned int reg,
 					     map->format.reg_bytes +
 					     map->format.pad_bytes,
 					     val, val_len);
+	else
+		ret = -ENOTSUPP;

 	/* If that didn't work fall back on linearising by hand. */
 	if (ret == -ENOTSUPP) {
-- 
2.20.1