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From:   Maxime Chevallier <maxime.chevallier@bootlin.com>
To:     Mark Brown <broonie@kernel.org>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        "Rafael J . Wysocki" <rafael@kernel.org>,
        Colin Foster <colin.foster@in-advantage.com>,
        Lee Jones <lee@kernel.org>
Cc:     Maxime Chevallier <maxime.chevallier@bootlin.com>,
        linux-kernel@vger.kernel.org, thomas.petazzoni@bootlin.com,
        alexis.lothore@bootlin.com
Subject: [PATCH] regmap: don't check for alignment when using reg_shift
Date:   Thu, 20 Apr 2023 17:06:17 +0200
Message-Id: <20230420150617.381922-1-maxime.chevallier@bootlin.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

On regmap consumers that require address translation through
up/downshifting, the alignment check in the regmap core doesn't take the
translation into account. This doesn't matter when downshifting the
register address, as any address that fits a given alignment requirement
will still meet it when downshifted (a 4-byte aligned address will
always also be 2-bytes aligned for example).

However, when upshifting, this check causes spurious errors, as it
occurs before the upshifting.

Therefore, we can just skip the alignment check when using
up/downshifting, as it's not relevant.

Signed-off-by: Maxime Chevallier <maxime.chevallier@bootlin.com>
---
 drivers/base/regmap/regmap.c | 20 ++++++++++----------
 1 file changed, 10 insertions(+), 10 deletions(-)

diff --git a/drivers/base/regmap/regmap.c b/drivers/base/regmap/regmap.c
index 167b3c73c13f..8eb26ac24356 100644
--- a/drivers/base/regmap/regmap.c
+++ b/drivers/base/regmap/regmap.c
@@ -2022,7 +2022,7 @@ int regmap_write(struct regmap *map, unsigned int reg, unsigned int val)
 {
 	int ret;
 
-	if (!IS_ALIGNED(reg, map->reg_stride))
+	if (!map->format.reg_shift && !IS_ALIGNED(reg, map->reg_stride))
 		return -EINVAL;
 
 	map->lock(map->lock_arg);
@@ -2049,7 +2049,7 @@ int regmap_write_async(struct regmap *map, unsigned int reg, unsigned int val)
 {
 	int ret;
 
-	if (!IS_ALIGNED(reg, map->reg_stride))
+	if (!map->format.reg_shift && !IS_ALIGNED(reg, map->reg_stride))
 		return -EINVAL;
 
 	map->lock(map->lock_arg);
@@ -2264,7 +2264,7 @@ int regmap_noinc_write(struct regmap *map, unsigned int reg,
 		return -EINVAL;
 	if (val_len % map->format.val_bytes)
 		return -EINVAL;
-	if (!IS_ALIGNED(reg, map->reg_stride))
+	if (!map->format.reg_shift && !IS_ALIGNED(reg, map->reg_stride))
 		return -EINVAL;
 	if (val_len == 0)
 		return -EINVAL;
@@ -2405,7 +2405,7 @@ int regmap_bulk_write(struct regmap *map, unsigned int reg, const void *val,
 	int ret = 0, i;
 	size_t val_bytes = map->format.val_bytes;
 
-	if (!IS_ALIGNED(reg, map->reg_stride))
+	if (!map->format.reg_shift && !IS_ALIGNED(reg, map->reg_stride))
 		return -EINVAL;
 
 	/*
@@ -2644,7 +2644,7 @@ static int _regmap_multi_reg_write(struct regmap *map,
 			int reg = regs[i].reg;
 			if (!map->writeable_reg(map->dev, reg))
 				return -EINVAL;
-			if (!IS_ALIGNED(reg, map->reg_stride))
+			if (!map->format.reg_shift && !IS_ALIGNED(reg, map->reg_stride))
 				return -EINVAL;
 		}
 
@@ -2795,7 +2795,7 @@ int regmap_raw_write_async(struct regmap *map, unsigned int reg,
 
 	if (val_len % map->format.val_bytes)
 		return -EINVAL;
-	if (!IS_ALIGNED(reg, map->reg_stride))
+	if (!map->format.reg_shift && !IS_ALIGNED(reg, map->reg_stride))
 		return -EINVAL;
 
 	map->lock(map->lock_arg);
@@ -2917,7 +2917,7 @@ int regmap_read(struct regmap *map, unsigned int reg, unsigned int *val)
 {
 	int ret;
 
-	if (!IS_ALIGNED(reg, map->reg_stride))
+	if (!map->format.reg_shift && !IS_ALIGNED(reg, map->reg_stride))
 		return -EINVAL;
 
 	map->lock(map->lock_arg);
@@ -2951,7 +2951,7 @@ int regmap_raw_read(struct regmap *map, unsigned int reg, void *val,
 
 	if (val_len % map->format.val_bytes)
 		return -EINVAL;
-	if (!IS_ALIGNED(reg, map->reg_stride))
+	if (!map->format.reg_shift && !IS_ALIGNED(reg, map->reg_stride))
 		return -EINVAL;
 	if (val_count == 0)
 		return -EINVAL;
@@ -3046,7 +3046,7 @@ int regmap_noinc_read(struct regmap *map, unsigned int reg,
 
 	if (val_len % map->format.val_bytes)
 		return -EINVAL;
-	if (!IS_ALIGNED(reg, map->reg_stride))
+	if (!map->format.reg_shift && !IS_ALIGNED(reg, map->reg_stride))
 		return -EINVAL;
 	if (val_len == 0)
 		return -EINVAL;
@@ -3168,7 +3168,7 @@ int regmap_bulk_read(struct regmap *map, unsigned int reg, void *val,
 	size_t val_bytes = map->format.val_bytes;
 	bool vol = regmap_volatile_range(map, reg, val_count);
 
-	if (!IS_ALIGNED(reg, map->reg_stride))
+	if (!map->format.reg_shift && !IS_ALIGNED(reg, map->reg_stride))
 		return -EINVAL;
 	if (val_count == 0)
 		return -EINVAL;
-- 
2.39.2