Device manufacturers frequently provide register sequences, usually not
fully documented, to be run at startup in order to provide better defaults
for devices (for example, improving performance in the light of silicon
evaluation). Support such updates by allowing drivers to register update
sets with the core. These updates will be written to the device immediately
and will also be rewritten when the cache is synced.
The assumption is that the reason for resyncing the cache will always be
that the device has been powered off. If this turns out to not be the case
then a separate operation can be provided.
Currently the implementation only allows a single set of updates to be
specified for a device, this could be extended in future.
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
When we reinitialise the cache make sure that we reset the cache access
flags, ensuring that the reinitialised cache is in the default state
which is what callers would and do expect given the function name.
This is particularly likely to cause issues in systems where there was no
cache previously as those systems have cache bypass enabled, as for the
wm8994 driver where this was noticed.
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Some devices, especially those with high speed control interfaces, require
padding between the register and the data. Support this in the regmap API
by providing a pad_bits configuration parameter.
Only devices with integer byte counts are supported.
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Allows devices to discover their own interrupt without having to remember
it themselves.
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Sometimes the register map information may change in ways that drivers can
discover at runtime. For example, new revisions of a device may add new
registers. Support runtime discovery by drivers by allowing the register
cache to be reinitialised with a new function regmap_reinit_cache() which
discards the existing cache and creates a new one.
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Currently we only trace physical reads, there's no instrumentation if
the read is satisfied from cache.
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Some users of regmap_update_bits() would like to be able to tell their
users if they actually did an update so provide a variant which also
returns a flag indicating if an update took place. We could return a
tristate in the return value of regmap_update_bits() but this makes the
API more cumbersome to use and doesn't fit with the general zero for
success idiom we have.
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
While the IRQ core doesn't currently support shared threaded interrupts
that's no reason for drivers not to do their bit and report IRQ_NONE when
they don't get an interrupt. This allows the core spurious/wedget interrupt
detection support to do its thing.
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
The debugfs functions don't stub themselves out quite so well as might
be desirable so provide functions which do do this stubbing.
Reported-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Show the register ranges we have in each rbtree node in debugfs, plus
some statistics on how big each node is and the total number of nodes.
It may also be worth collecting data on the ranges of dirty registers
to see if there's much mileage in trying to coalesce writes on sync.
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
If the new register value is identical to the original one then suppress
the write to the hardware in regmap_update_bits(), saving some I/O cost.
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
There should be no situation where it offers any advantage over rbtree
and there are no current users so remove the code for simplicity.
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
One of the reasons for using a cache is to have a software shadow of a register
which is writable but not readable. This allows us to do a read-modify-write
operation on such a register.
Currently regcache checks whether a register is readable when performing a
cached read and returns an error if it is not. Drop this check, since it will
prevent us from using the cache for registers where read-back is not possible.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
regcache currently only properly works with val bit sizes of 8 or 16, since
it will, when calculating the cache word size, round down. This causes the
cache storage to be too small to hold the full register value. Fix this by
rounding up instead.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
This patch adds support for 10 bits register, 14 bits value type register
formating. This is for example used by the Analog Devices AD5380.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
For some register format types we do not provide a parse_val so we can not do a
hardware read. But a cached read is still possible, so try to read from the
cache first, before checking whether a hardware read is possible. Otherwise the
cache becomes pretty useless for these register types.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
The reg_defaults field usually points to a static per driver array, which should
not be modified. Make requirement this explicit by making reg_defaults const.
To allow this the regcache_init code needs some minor changes. Previoulsy the
reg_config was not available in regcache_init and regmap->reg_defaults was used
to pass the default register set to regcache_init. Now that the reg_config is
available we can work on it directly.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Move the initialization regcache related fields of the regmap struct to
regcache_init. This allows us to keep regmap and regcache code better
separated.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Calling regcache_exit from regcache_lzo_init is first of all a layering
violation and secondly will cause double frees. regcache_exit will free buffers
allocated by the core, but the core will also free the same buffers when the
cacheops init callback returns an error. Thus we end up with a double free.
Fix this by not calling regcache_exit but only free those buffers which, have
been allocated in this function.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Acked-by: Dimitris Papastamos <dp@opensource.wolfsonmicro.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Calling regcache_exit from regcache_rbtree_init is first of all a layering
violation and secondly will cause double frees. regcache_exit will free buffers
allocated by the core, but the core will also free the same buffers when the
cacheops init callback returns an error. Thus we end up with a double free.
Fix this by not calling regcache_exit but only free those buffers which, have
been allocated in this function.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Acked-by: Dimitris Papastamos <dp@opensource.wolfsonmicro.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Make sure all allocated memory gets freed again in case initializing the cache
failed.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Acked-by: Dimitris Papastamos <dp@opensource.wolfsonmicro.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Make sure reg_defaults_raw gets freed in case of an error.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Acked-by: Dimitris Papastamos <dp@opensource.wolfsonmicro.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
The regmap_init documentation states that it will either return a pointer to a
valid regmap structure or a ERR_PTR in case of an error. Currently it returns a
NULL pointer in case no bus or no config was given. Since NULL is not a
ERR_PTR a caller might assume that it is a pointer to a valid regmap structure,
so return a ERR_PTR(-EINVAL) instead.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
If regcache initialization fails regmap_init will currently exit without
freeing work_buf.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Commit 10a08d9f ("regmap: Support some block operations on cached devices")
allowed raw read operations without throwing a warning when using caches if
all registers are volatile. This patch does the same for raw write operations.
This is for example useful when loading a firmware in a predefined volatile
region on a chip where we otherwise want registers to be cached.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
We already have the same code for checking whether a register range is volatile
in two different places. Instead of duplicating it once more add a small helper
function for checking whether a register range is voltaile.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Users probably don't care about the specific compression algorithm and
we might want to use a different algorithm (snappy being the one I'm
thinking of right now) so update the public interface to have a more
generic name.
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Allow drivers to optimise out the register cache sync if they didn't need
to do one. If the hardware is desynced from the register cache (by power
loss for example) then the driver should call regcache_mark_dirty() to
let the core know about this.
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Give regcache_lzo_block_count() a copy of the map so that when we decide
we want to make the LZO cache more controllable we can more easily do so.
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Acked-by: Dimitris Papastamos <dp@opensource.wolfsonmicro.com>
There seem to be lots of regmap-using devices with very similar interrupt
controllers with a small bank of interrupt registers and mask registers
with an interrupt per bit. This won't cover everything but it's a good
start.
Each chip supplies a base for the status registers, a base for the mask
registers, an optional base for writing acknowledgements (which may be the
same as the status registers) and an array of bits within each of these
register banks which indicate the interrupt.
There is an assumption that the bit for each interrupt will be the same
in each of the register bank.
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Most of these files were implicitly getting EXPORT_SYMBOL via
device.h which was including module.h, but that path will be broken
soon.
[ with input from Stephen Rothwell <sfr@canb.auug.org.au> ]
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
* 'for-linus' of git://opensource.wolfsonmicro.com/regmap: (62 commits)
mfd: Enable rbtree cache for wm831x devices
regmap: Support some block operations on cached devices
regmap: Allow caches for devices with no defaults
regmap: Ensure rbtree syncs registers set to zero properly
regmap: Allow rbtree to cache zero default values
regmap: Warn on raw I/O as well as bulk reads that bypass cache
regmap: Return a sensible error code if we fail to read the cache
regmap: Use bsearch() to search the register defaults
regmap: Fix doc comment
regmap: Optimize the lookup path to use binary search
regmap: Ensure we scream if we enable cache bypass/only at the same time
regmap: Implement regcache_cache_bypass helper function
regmap: Save/restore the bypass state upon syncing
regmap: Lock the sync path, ensure we use the lockless _regmap_write()
regmap: Fix apostrophe usage
regmap: Make _regmap_write() global
regmap: Fix lock used for regcache_cache_only()
regmap: Grab the lock in regcache_cache_only()
regmap: Modify map->cache_bypass directly
regmap: Fix regcache_sync generic implementation
...
Support raw reads if all the registers being read are volatile, the cache
will have no impact for tem.
Support bulk reads either directly (if all the registers are volatile) or
by falling back to iterating over single register reads otherwise.
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
We only really need the defaults in order to cut down the number of
registers we sync and to satisfy reads while the device is powered off
but not all devices are going to need to do that (always on devices like
PMICs being the prime example) so don't require those devices to supply
a default. Instead only try to fall back to hardware defaults if the
driver told us to.
Devices using LZO won't be able to instantiate with this, that will require
some updates in the LZO code to handle this case.
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Acked-by: Dimitris Papastamos <dp@opensource.wolfsonmicro.com>
Simplify the check for registers set at their default value by avoiding
picking a default value in the case where we don't have one. Instead we
only compare the current value to the current value when we looked one
up. This fixes the case where we don't have a default stored but the value
was set to zero when that isn't the chip default.
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Acked-by: Dimitris Papastamos <dp@opensource.wolfsonmicro.com>
Ensure that when we start up in cache only mode we can store defaults of
zero, otherwise if the hardware is unavailable we won't be able to read.
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Acked-by: Dimitris Papastamos <dp@opensource.wolfsonmicro.com>
As with the bulk reads we really should be able to make these play
nicely with the cache but warn for now.
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Acked-by: Dimitris Papastamos <dp@opensource.wolfsonmicro.com>
If a register isn't cached then let callers know that so they can fall
back or error handle appropriately.
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Acked-by: Dimitris Papastamos <dp@opensource.wolfsonmicro.com>
Rather than open coding a binary search use the standard bsearch() using
the comparison function we're already using for sort() on insert. This
fixes a lockup I was observing due to iterating on min <= max rather
than min < max when we fail to look up.
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Acked-by: Dimitris Papastamos <dp@opensource.wolfsonmicro.com>
Since there are more lookups than insertions in a typical
scenario, optimize the linear search into a binary search. For
this to work, we need to keep reg_defaults sorted upon
insertions, for now be lazy and use sort().
Signed-off-by: Dimitris Papastamos <dp@opensource.wolfsonmicro.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Ensure we've got a function so users can enable/disable the
cache bypass option.
Signed-off-by: Dimitris Papastamos <dp@opensource.wolfsonmicro.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
In preperation for the upcoming patches, modify map->cache_bypass
directly. The helper functions will grab an exclusive lock. Because
we'll have acquired the same lock we need to avoid a deadlock.
Signed-off-by: Dimitris Papastamos <dp@opensource.wolfsonmicro.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
We want to use regmap_write() to actually write anything
to the HW.
Signed-off-by: Dimitris Papastamos <dp@opensource.wolfsonmicro.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Move the handling of the cached rbnode into regcache_rbtree_lookup. This allows
us to remove of some duplicated code sections in regcache_rbtree_read and
regcache_rbtree_write.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Acked-by: Dimitris Papastamos <dp@opensource.wolfsonmicro.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Use regcache_{set,get}_val in regcache_rbtree_{set,get}_register instead of
re-implementing its functionality.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Acked-by: Dimitris Papastamos <dp@opensource.wolfsonmicro.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
In the absence of a sync callback, do it manually. This of course
can't take advantange of the specific optimizations of each
cache type but it will do well enough in most cases.
Signed-off-by: Dimitris Papastamos <dp@opensource.wolfsonmicro.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
This patch incorporates the regcache core code into regmap. All previous
patches have been no-ops essentially up to this point.
The bulk read operation is not supported by regcache at the moment. This
will be implemented incrementally.
Signed-off-by: Dimitris Papastamos <dp@opensource.wolfsonmicro.com>
Tested-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
This patch adds support for LZO compression when storing the register
cache.
For a typical device whose register map would normally occupy 25kB or 50kB
by using the LZO compression technique, one can get down to ~5-7kB. There
might be a performance penalty associated with each individual read/write
due to decompressing/compressing the underlying cache, however that should not
be noticeable. These memory benefits depend on whether the target architecture
can get rid of the memory occupied by the original register defaults cache
which is marked as __devinitconst. Nevertheless there will be some memory
gain even if the target architecture can't get rid of the original register
map, this should be around ~30-32kB instead of 50kB.
Signed-off-by: Dimitris Papastamos <dp@opensource.wolfsonmicro.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
This patch adds support for the rbtree cache compression type.
Each rbnode manages a variable length block of registers. There can be no
two nodes with overlapping blocks. Each block has a base register and a
currently top register, all the other registers, if any, lie in between these
two and in ascending order.
The reasoning behind the construction of this rbtree is simple. In the
snd_soc_rbtree_cache_init() function, we iterate over the register defaults
provided by the regcache core. For each register value that is non-zero we
insert it in the rbtree. In order to determine in which rbnode we need
to add the register, we first look if there is another register already
added that is adjacent to the one we are about to add. If that is the case
we append it in that rbnode block, otherwise we create a new rbnode
with a single register in its block and add it to the tree.
There are various optimizations across the implementation to speed up lookups
by caching the most recently used rbnode.
Signed-off-by: Dimitris Papastamos <dp@opensource.wolfsonmicro.com>
Tested-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
This is the simplest form of a cache available in regcache. Any
registers whose default value is 0 are ignored. If any of those
registers are modified in the future, they will be placed in the
cache on demand. The cache layout is essentially using the provided
register defaults by the regcache core directly and does not re-map
it to another representation.
Signed-off-by: Dimitris Papastamos <dp@opensource.wolfsonmicro.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
This patch introduces caching support for regmap. The regcache API
has evolved essentially out of ASoC soc-cache so most of the actual
caching types (except LZO) have been tested in the past.
The purpose of regcache is to optimize in time and space the handling
of register caches. Time optimization is achieved by not having to go
over a slow bus like I2C to read the value of a register, instead it is
cached locally in memory and can be retrieved faster. Regarding space
optimization, some of the cache types are better at packing the caches,
for e.g. the rbtree and the LZO caches. By doing this the sacrifice in
time still wins over doing I2C transactions.
Signed-off-by: Dimitris Papastamos <dp@opensource.wolfsonmicro.com>
Tested-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Make the debugfs stubs static inline to avoid future compilation issues due to
duplicated symbols when CONFIG_DEBUG_FS=n once internal.h is included by
multiple source files.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Some buses like SPI have no standard notation of read or write operations.
The general scheme here is to set or clear specific bits in the register
address to indicate whether the operation is a read or write. We already
support having a read flag mask per bus, but as there is no standard
the bits which need to be set or cleared differ between devices and vendors,
thus we need a mechanism to specify them per device.
This patch adds two new entries to the regmap_config struct, read_flag_mask and
write_flag_mask. These will be or'ed onto the top byte when doing a read or
write operation. If both masks are empty the device will fallback to the
regmap_bus masks.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
No longer used as users link directly with the bus types so the core
module infrastructure does refcounting for us.
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
The conversion to per bus type registration functions means we don't need
to do module_get()s to hold the bus types in memory (their users will link
to them) so we removed all those calls. This left module_put() calls in
the cleanup paths which aren't needed and which cause unbalanced puts if
we ever try to unload anything.
Reported-by: Jonathan Cameron <jic23@cam.ac.uk>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Commit b33f9cbd67 ("regmap: Specify a module license") added a
MODULES_LICENSE to this file without adding an include of module.h.
module.h should have been included anyway, since this file has
EXPORT_SYMBOLs as well. With the pending module.h split up, this would
probably have caused build problems.
Cc: Stephen Warren <swarren@nvidia.com>
Cc: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Let userspace know what the access map for the device is. This is helpful
for verifying that the access map is correctly configured and could also
be useful for programs that try to work with the data. File format is:
register: R W V P
where R, W, V and P are 'y' or 'n' showing readable, writable, volatile
and precious respectively.
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
We're going to be using these in quite a few places so factor out the
readable/writable/volatile/precious checks.
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
CONFIG_REGMAP_I2C/SPI are set to m when selected by a tristate config
option that's set to m. The regmap modules don't specify a license, so
fail to link to regmap_init at load time, since that is EXPORT_SYMBOL_GPL.
Fix this by specifying a license for the regmap modules.
Signed-off-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
x86_64 size_t is not an int but the printf format specifier for size_t
should be an int.
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Copy over the read parts of the ASoC debugfs implementation into regmap,
allowing users to see what the register values the device has are at
runtime. The implementation, especially the support for seeking, is
mostly due to Dimitris Papastamos' work in ASoC.
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
This is mainly intended to be used by devices which can dynamically
block register writes at runtime, for other devices there is usually
limited value.
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Trace single register reads and writes, plus start/stop tracepoints for
the actual I/O to see where we're spending time. This makes it easy to
have always on logging without overwhelming the logs and also lets us take
advantage of all the context and time information that the trace subsystem
collects for us.
We don't currently trace register values for bulk operations as this would
add complexity and overhead parsing the cooked data that's being worked
with.
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
When doing a single register write we use work_buf for both the register
and the value with the buffer formatted for sending directly to the device
so we can just do a write() directly. This saves allocating a temporary
buffer if we can't do gather writes and is likely to be faster than doing
a gather write.
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
This is currently unused but we need to know which registers exist and
their properties in order to implement diagnostics like register map
dumps and the cache features.
We use callbacks partly because properties can vary at runtime (eg, through
access locks on registers) and partly because big switch statements are a
good compromise between readable code and small data size for providing
information on big register maps.
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
We should be reading the number of bytes we were asked for, not the size
of a single register.
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Acked-by: Liam Girdwood <lrg@ti.com>
Acked-by: Wolfram Sang <w.sang@pengutronix.de>
Acked-by: Grant Likely <grant.likely@secretlab.ca>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Acked-by: Liam Girdwood <lrg@ti.com>
Acked-by: Wolfram Sang <w.sang@pengutronix.de>
Acked-by: Grant Likely <grant.likely@secretlab.ca>
There are many places in the tree where we implement register access for
devices on non-memory mapped buses, especially I2C and SPI. Since hardware
designers seem to have settled on a relatively consistent set of register
interfaces this can be effectively factored out into shared code. There
are a standard set of formats for marshalling data for exchange with the
device, with the actual I/O mechanisms generally being simple byte
streams.
We create an abstraction for marshaling data into formats which can be
sent on the control interfaces, and create a standard method for
plugging in actual transport underneath that.
This is mostly a refactoring and renaming of the bottom level of the
existing code for sharing register I/O which we have in ASoC. A
subsequent patch in this series converts ASoC to use this. The main
difference in interface is that reads return values by writing to a
location provided by a pointer rather than in the return value, ensuring
we can use the full range of the type for register data. We also use
unsigned types rather than ints for the same reason.
As some of the devices can have very large register maps the existing
ASoC code also contains infrastructure for managing register caches.
This cache work will be moved over in a future stage to allow for
separate review, the current patch only deals with the physical I/O.
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Acked-by: Liam Girdwood <lrg@ti.com>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Acked-by: Wolfram Sang <w.sang@pengutronix.de>
Acked-by: Grant Likely <grant.likely@secretlab.ca>
