Pull regmap fix from Mark Brown:
 "Fix regmap crash for async operation on busless maps

  This fixes a crash if something tries to do an asynchronous operation
  on busless maps which was introduced during the merge window"

* tag 'regmap-v3.11-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/regmap:
  regmap: cache: bail in regmap_async_complete() for bus-less maps

Commit f8bd822cb ("regmap: cache: Factor out block sync") made
regcache_rbtree_sync() call regmap_async_complete(), which in turn does
not check for map->bus before dereferencing it.

This causes a NULL pointer dereference on bus-less maps.

Signed-off-by: Daniel Mack <zonque@gmail.com>
Cc: stable@vger.kernel.org [v3.10 only]
Signed-off-by: Mark Brown <broonie@linaro.org>

The cache is based on the full register map so confuses things if used
for a partial map.

Reported-by: Bard Liao <bardliao@realtek.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

It is common to access regmap registers at bit level, using
regmap_update_bits or regmap_read functions, however the end user has to
take care of a mask or shifting. This becomes overhead when such use
cases are high. Having a common function to do this is much convenient
and less error prone.

The idea of regmap_field is simple, regmap_field gives a logical
structure to bits of the regmap register, and the driver can use this
logical entity without the knowledge of the bit positions and masks all
over the code. This way code looks much neat and it need not handle the
masks, shifts every time it access the those entities.

With this new regmap_field_read/write apis the end user can setup a
regmap field using regmap_field_init and use the return regmap_field to
read write the register field without worrying about the masks or
shifts.

Also this apis will be useful for drivers which are based on regmaps,
like some clocks or pinctrls which can work on the regmap_fields
directly without having to worry about bit positions.

Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@st.com>
Signed-off-by: Mark Brown <broonie@linaro.org>

Currently all register maps with a cache need to provide a volatile
callback since the default is to assume all registers are volatile.
This is not sensible if we have a cache so change the default to be
fully cached if a cache is provided.

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