If val_count is zero we return -EINVAL with map->lock_arg locked, which
will deadlock the kernel next time we try to acquire this lock.

In 3.12, this was introduced by a0b8d8d906d267987d507138003048c5fdf774
("regmap: fix possible ZERO_SIZE_PTR pointer dereferencing error.")
which improperly back-ported d6b41cb06044a7d895db82bdd54f6e4219970510.

This issue was found during review of Ubuntu Trusty 3.13.0-40.68 kernel to
prepare Ksplice rebootless updates.

Fixes: f5942dd ("regmap: fix possible ZERO_SIZE_PTR pointer dereferencing error.")
Signed-off-by: Quentin Casasnovas <quentin.casasnovas@oracle.com>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>

commit d6b41cb06044a7d895db82bdd54f6e4219970510 upstream.

Since we cannot make sure the 'val_count' will always be none zero
here, and then if it equals to zero, the kmemdup() will return
ZERO_SIZE_PTR, which equals to ((void *)16).

So this patch fix this with just doing the zero check before calling
kmemdup().

Signed-off-by: Xiubo Li <Li.Xiubo@freescale.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>

commit 5336be8416a71b5568d2cf54a2f2066abe9f2a53 upstream.

If LOG_DEVICE is defined and map->dev is NULL it will lead to NULL
pointer dereference. This patch fixes this issue by adding check for
dev->NULL in all such places in regmap.c

Signed-off-by: Pankaj Dubey <pankaj.dubey@samsung.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>

commit 5844a8b9d98ec11ce1d77610daacf3f0a0e14715 upstream.

A previous over-zealous factorisation of code means that we only treat
registers as volatile if they are readable. For most devices this is fine
since normally most registers can be read and volatility implies
readability but for format_write() devices where there is no readback from
the hardware and we use volatility to mean simply uncacheability this means
that we end up treating all registers as cacheble.

A bigger refactoring of the code to clarify this is in order but as a fix
make a minimal change and only check readability when checking volatility
if there is no format_write() operation defined for the device.

Signed-off-by: Mark Brown <broonie@linaro.org>
Tested-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>

It may be useful to register multiple patches with regmap, for example
one that depends on the device revision and one that depends on the system
configuration. Add support for doing this, appending any new patches to
the existing patches.

Signed-off-by: Mark Brown <broonie@linaro.org>

The regmap_writeable() check should not be done in
regcache_write() because this prevents read-only
registers to be cached. After a read on a read-only
register its value will not be stored in the cache
and the next time someone will try to read it the
value will be read from the bus instead of the
cache.

Instead the regmap_writeable() check should be done
in _regmap_write() to prevent callers from writing
to read-only registers.

Signed-off-by: Ionut Nicu <ioan.nicu.ext@nsn.com>
Signed-off-by: Mark Brown <broonie@linaro.org>

I see no reason why a virtual range shouldn't be allowed to cover its
own data window if the page selection register is in the same place
on every page.
For chips which use paged access for all of their registers, but only
when connected via I2C, and which can access the whole register space
directly when connected via SPI, this allows to avoid acrobatics with
the register ranges by simply mapping the I2C ranges over the data
window beginning at 0x0, and then using linear access for the SPI
variant.

Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
Signed-off-by: Mark Brown <broonie@linaro.org>