There's several things here that will really help my CI.

Thanks to Dan and Guenter's very prompt updates of the rbtree and maple
caches to support GPF_ATOMIC allocations and since the update shook out
a bunch of users at least some of whom have been suitably careful about
ensuring that the cache is prepoulated so there are no dynamic
allocations after init let's revert the warnings.

Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20230721-regmap-enable-kmalloc-v1-1-f78287e794d3@kernel.org

REGCACHE_RBTREE and REGCACHE_MAPLE dynamically allocate memory for regmap
operations. This is incompatible with spinlock based locking which is used
for fast_io operations. Reject affected configurations.

Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20230720032848.1306349-2-linux@roeck-us.net
Signed-off-by: Mark Brown <broonie@kernel.org>

When problems were noticed with the register address not being taken
into account when limiting raw transfers with I2C devices we fixed this
in the core.  Unfortunately it has subsequently been realised that a lot
of buses were relying on the prior behaviour, partly due to unclear
documentation not making it obvious what was intended in the core.  This
is all more involved to fix than is sensible for a fix commit so let's
just drop the original fixes, a separate commit will fix the originally
observed problem in an I2C specific way

Fixes: 3981514180c9 ("regmap: Account for register length when chunking")
Fixes: c8e796895e23 ("regmap: spi-avmm: Fix regmap_bus max_raw_write")
Signed-off-by: Mark Brown <broonie@kernel.org>
Reviewed-by: Xu Yilun <yilun.xu@intel.com>
Cc: stable@kernel.org
Link: https://lore.kernel.org/r/20230712-regmap-max-transfer-v1-1-80e2aed22e83@kernel.org
Signed-off-by: Mark Brown <broonie@kernel.org>

With unsigned int type we never ever can pass 64-bit value.
Remove never properly worked code.

Note, there are no users in kernel for this size of register
offsets or data.

This reverts commit afcc00b91f1865f6d0bbdb687dd642ce8a3c3c9e.

Also revert other 64-bit code excerpts in the regmap implementation
that had been induced by the false impression made by the above
mentioned change that there is a support of that data size.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20230622183613.58762-2-andriy.shevchenko@linux.intel.com
Signed-off-by: Mark Brown <broonie@kernel.org>

We have some drivers that have a use case for cached write only
registers, doing read/modify/writes on read only registers in order to
work more easily with bitfields.  Go back to trying the cache before we
check if we can read from the device.

Fixes: eab5abdeb79f0 ("regmap: Check for register readability before checking cache during read")
Reported-by: Konrad Dybcio <konradybcio@kernel.org>
Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20230615-regmap-drop-early-readability-v1-1-8135094362de@kernel.org
Signed-off-by: Mark Brown <broonie@kernel.org>

Ensure that we don't return a spurious cache hit for unreadable registers
(eg, with the flat cache which doesn't understand sparseness) by checking
for readability before we do a cache lookup.

Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20230613-b4-regmap-check-readability-before-cache-v1-1-b144c0b01ed9@kernel.org
Signed-off-by: Mark Brown <broonie@kernel.org>

`_regmap_update_bits()` checks if the current register value differs
from the new value, and only writes to the register if they differ. When
testing hardware drivers, it might be desirable to always force a
register write, for example when writing to a `regmap_field`. This
enables and simplifies testing and verification of the hardware
interaction. For example, when using a hardware mock/simulation model,
one can then more easily verify that the driver makes the correct
expected register writes during certain events.

Add a bool variable `force_write_field` and a corresponding debugfs
entry to enable this. Since this feature could interfere with driver
operation, guard it with a macro.

Signed-off-by: Waqar Hameed <waqar.hameed@axis.com>
Link: https://lore.kernel.org/r/pnd1qifa7sj.fsf@axis.com
Signed-off-by: Mark Brown <broonie@kernel.org>

The fix for maple tree RCU locking on sync is a dependency for the
block sync code for the maple tree.

The current behaviour around cache_only is slightly inconsistent,
most paths will only check cache_only if cache_bypass is false,
and will return -EBUSY if a read attempts to go to the hardware
whilst cache_only is true. However, a couple of paths will not check
cache_only at all.  The most notable of these being regmap_raw_read
which will check cache_only in the case it processes the transaction
one register at a time, but not in the case it handles them as a
block. In the typical case a device has been put into cache_only
whilst powered down this can cause physical reads to happen whilst the
device is unavailable.

Add a check in regmap_raw_read and move the check in regmap_noinc_read,
adding a check for cache_bypass, such that all paths are covered and
consistent.

Signed-off-by: Charles Keepax <ckeepax@opensource.cirrus.com>
Link: https://lore.kernel.org/r/20230601101036.1499612-2-ckeepax@opensource.cirrus.com
Signed-off-by: Mark Brown <broonie@kernel.org>