regmap: Add support for discarding parts of the register cache

Allow drivers to discard parts of the register cache, for example if part
of the hardware has been reset.

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
regmap: fix regcache_reg_present() for empty cache

In the initial case when no reg_defaults values are
provided and no register value was added to the cache
yet, the cache_present bitmap is NULL. If this function
is invoked for any register it should return false
(i.e. the register is not cached) instead of true.

Signed-off-by: Ionut Nicu <ioan.nicu.ext@nsn.com>
Signed-off-by: Mark Brown <broonie@linaro.org>
regcache-rbtree: Fix reg_stride != 1

There are a couple of calculations, which convert between register addresses and
block indices, in regcache_rbtree_sync() and regcache_rbtree_node_alloc() which
assume that reg_stride is 1. This will break the rb cache for configurations
which do not use a reg_stride of 1.

Also rename 'base' in regcache_rbtree_sync() to 'start' to avoid confusion with
'base_reg'.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Mark Brown <broonie@linaro.org>
regmap: rbtree: Simplify adjacent node look-up

A register which is adjacent to a node will either be left to the first
register or right to the last register. It will not be within the node's range,
so there is no point in checking for each register cached by the node whether
the new register is next to it. It is sufficient to check whether the register
comes before the first register or after the last register of the node.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Mark Brown <broonie@linaro.org>
regmap: rbtree: Reduce number of nodes, take 2

Support for reducing the number of nodes and memory consumption of the rbtree
cache by allowing for small unused holes in the node's register cache block was
initially added in commit 0c7ed856 ("regmap: Cut down on the average # of nodes
in the rbtree cache"). But the commit had problems and so its effect was
reverted again in commit 4e67fb5 ("regmap: rbtree: Fix overlapping rbnodes.").
This patch brings the feature back of reducing the average number of nodes,
which will speedup node look-up, while at the same time also reducing the memory
usage of the rbtree cache. This patch takes a slightly different approach than
the original patch though. It modifies the adjacent node look-up to not only
consider nodes that are just one to the left or the right of the register but
any node that falls in a certain range around the register. The range is
calculated based on how much memory it would take to allocate a new node
compared to how much memory it takes adding a set of unused registers to an
existing node. E.g. if a node takes up 24 bytes and each register in a block
uses 1 byte the range will be from the register address - 24 to the register
address + 24. If we find a node that falls within this range it is cheaper or as
expensive to add the register to the existing node and have a couple of unused
registers in the node's cache compared to allocating a new node.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Mark Brown <broonie@linaro.org>
regmap: rbtree: Make cache_present bitmap per node

With devices which have a dense and small register map but placed at a large
offset the global cache_present bitmap imposes a huge memory overhead. Making
the cache_present per rbtree node avoids the issue and easily reduces the memory
footprint by a factor of ten. For devices with a more sparse map or without a
large base register offset the memory usage might increase slightly by a few
bytes, but not significantly. E.g. for a device which has ~50 registers at
offset 0x4000 the memory footprint of the register cache goes down form 2496
bytes to 175 bytes.

Moving the bitmap to a per node basis means that the handling of the bitmap is
now cache implementation specific and can no longer be managed by the core. The
regcache_sync_block() function is extended by a additional parameter so that the
cache implementation can tell the core which registers in the block are set and
which are not. The parameter is optional and if NULL the core assumes that all
registers are set. The rbtree cache also needs to implement its own drop
callback instead of relying on the core to handle this.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Mark Brown <broonie@linaro.org>
ASoC: adau1761: Fix register default values

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Revert "ASoC: Add support for virtual switch controls"

This reverts commit 376a50a17fdabe4530f703a9d7bebd963f383e05.
ASoC: Remove unused dapm_get_snd_card() and dapm_get_soc_card()

These two functions were added two years ago in commit 4805608 ("ASoC: dapm -
Add methods to retrieve snd_card and soc_card from dapm context.") but have
remained unused so far. Considering that the dapm context actually has a direct
pointer to the card the functions also seem to be unnecessary. E.g. the
expressions 'dapm_get_soc_card(dapm)' and 'dapm->card' yield the same result.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Mark Brown <broonie@linaro.org>
ASoC: dapm: Fix return value of snd_soc_dapm_put_{volsw,enum_virt}()

The ALSA core expect the put callback of a control to return 1 if the value of
the control changed and 0 if it did not. Both snd_soc_dapm_put_volsw() and
snd_soc_dapm_put_enum_virt() currently always returns 0. For both functions we
already have a 'change' variable which either contains 1 or 0 depending on
whether the value has changed or not, so just return that.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Mark Brown <broonie@linaro.org>
ASoC: dapm: Use generic power check for everything except DAIs

As noticed by Lars-Peter Clausen since the move to using widgets to hook
into the DAIs we no longer directly manage the power of AIF or DAC/ADC
widgets from the stream integration so they can just use the generic power
checks instead of the custom stream integration ones they currently do.

Signed-off-by: Mark Brown <broonie@linaro.org>
ASoC: dapm: Pass snd_soc_card directly to soc_dpcm_runtime_update()

soc_dpcm_runtime_update() operates on a ASoC card as a whole. Currently it takes
a snd_soc_dapm_widget as its only parameter though. The widget is then used to
look up the card and is otherwise unused. This patch changes the function to
take a pointer to the card directly. This makes it possible to to call
soc_dpcm_runtime_update() for updates which are not related to one specific
widget.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Mark Brown <broonie@linaro.org>
ASoC: dapm: Run widget updates for shared controls at the same time

Currently when updating a control that is shared between multiple widgets the
whole power-up/power-down sequence is being run once for each widget. The
control register is updated during the first run, which means the CODEC internal
routing is also updated for all widgets during this first run. The input and
output paths for each widgets are only updated though during the respective run
for that widget. This leads to a slight inconsistency between the CODEC's
internal state and ASoC's state, which causes non optimal behavior in regard to
click and pop avoidance.

E.g. consider the following setup where two MUXs share the same control.

          +------+
 A1 ------|      |
          | MUX1 |----- C1
 B1 ------|      |
          +------+
             |
  control ---+
             |
          +------+
 A2 ------|      |
          | MUX2 |----- C2
 B2 ------|      |
          +------+

If the control is updated to switch the MUXs from input A to input B with the
current code the power-up/power-down sequence will look like this:

Run soc_dapm_mux_update_power for MUX1
  Power-down A1
  Update MUXing
  Power-up B1

Run soc_dapm_mux_update_power for MUX2
  Power-down A2
  (Update MUXing)
  Power-up B2

Note that the second 'Update Muxing' is a no-op, since the register was already
updated.

While the preferred order for avoiding pops and clicks should be:

Run soc_dapm_mux_update_power for control
  Power-down A1
  Power-down A2
  Update MUXing
  Power-up B1
  Power-up B2

This patch changes the behavior to the later by running the updates for all
widgets that the control is attached to at the same time.

The new code is also a bit simpler since callers of
soc_dapm_{mux,muxer}_update_power don't have to loop over each widget anymore
and neither do we need to keep track for which of the kcontrol's widgets the
current update is.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Mark Brown <broonie@linaro.org>
ASoC: dapm: Add a update parameter to snd_soc_dapm_{mux,mixer}_update_power

In order to avoid race conditions the assignment of dapm->update should happen
while card->dapm_mutex is being held. To allow CODEC drivers to run a register
update when using snd_soc_dapm_mux_update_power() or
snd_soc_dapm_mixer_update_power() add a update parameter to these two functions.
The update parameter will be assigned to dapm->update while card->dapm_mutex is
locked.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Mark Brown <broonie@linaro.org>
ASoC: tlv320aic3x: Use snd_soc_dapm_mixer_update_power

Use snd_soc_dapm_mixer_update_power() instead of reimplementing its
functionality.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Mark Brown <broonie@linaro.org>
ASoC: dapm: Move snd_soc_dapm_update from dapm context to card

The update field of a DAPM context is only assigned while the card's dapm_mutex
is locked, the field is also cleared again while the mutex is stil locked. So
there will only ever be one DAPM context at a time with a non-NULL update field.
So it is safe to move the update field from the DAPM context struct to the card
struct. Doing so will allow further cleanups in this area.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Mark Brown <broonie@linaro.org>
ASoC: dapm: Pass card instead of dapm context to dapm_power_widgets()

DAPM operations are always performed on the card as a whole. Yet (primarily for
historic reasons) dapm_power_widgets() takes a DAPM context as its parameter.
The DAPM context is mainly used to look up a pointer to the card.  The same is
true for a couple of functions that are being called from dapm_power_widgets().
This patch changes the signature of dapm_power_widgets() and a couple of related
functions to take a snd_soc_card instead of a snd_soc_dapm_context.

Some of the functions also use the DAPM's device to print error and debug
messages. This can be a bit confusing though since this means the messages for
all widgets, also those from other contexts, will be printed with that device.
The patch updates those cases to use the device of the widget's DAPM context.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Mark Brown <broonie@linaro.org>
ASoC: dapm: Add a helper to get the CODEC for DAPM kcontrol

We use the same 3 lines to get the CODEC for a kcontrol in a quite a few places.
This patch puts them into a common helper function. Having this encapsulated in
a helper function will also make it more easier to eventually change the data
layout of the kcontrol's private data.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Mark Brown <broonie@linaro.org>
ASoC: dapm: Wrap kcontrol widget list access

In preparation for adding additional per control data wrap all access to the
widget list in helper functions.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Mark Brown <broonie@linaro.org>
ASoC: dapm: Move 'value' field from widget to control

The 'value' field is really per control and not per widget. Currently it is only
used for virtual MUXes, which only have one control per widget. So in that case
there is not so much of a difference between whether it is stored per widget or
per control. Moving the 'value' field from the widget to the control will allow
us to use it also for cases where we have more than one control per widget. E.g.
for mixers with multiple input controls.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Mark Brown <broonie@linaro.org>