Unverified Commit 8b9f9d4d authored Apr 02, 2019 by Han Nandor Committed by Mark Brown Apr 03, 2019

regmap: verify if register is writeable before writing operations



regmap provides a couple of ways to validate the register range used.
a) maxim allowed register, b) writable/readable register tables,
c) callback function that can be provided by the driver to validate
a register. regmap framework should verify if registers
are writeable before every write operation. However this doesn't
seems to happen in every situation.

The method `_regmap_raw_write_impl` is only using the `writeable_reg`
callback to verify if register is writeable, ignoring the other two.
This can lead to undefined behaviour since this allows to write to
registers that could be declared un-writeable by using any other
option.

Change `_regmap_raw_write_impl` to use the `regmap_writeable` method
to verify if registers are writable before the write operation.

Signed-off-by: Nandor Han <nandor.han@vaisala.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

parent cc6a8d69

drivers/base/regmap/regmap.c

+4 −5

Original line number	Diff line number	Diff line
		@@ -1493,9 +1493,8 @@ static int _regmap_raw_write_impl(struct regmap *map, unsigned int reg,
		WARN_ON(!map->bus);

		/* Check for unwritable registers before we start */
		if (map->writeable_reg)
		for (i = 0; i < val_len / map->format.val_bytes; i++)
		if (!map->writeable_reg(map->dev,
		if (!regmap_writeable(map,
		reg + regmap_get_offset(map, i)))
		return -EINVAL;