commit f00e71091ab92eba52122332586c6ecaa9cd1a56 upstream.

We're supposed to be checking that "val_len" is not too large but
instead we check if it is smaller than the max.

The only function affected would be regmap_i2c_smbus_i2c_write() in
drivers/base/regmap/regmap-i2c.c.  Strangely that function has its own
limit check which returns an error if (count >= I2C_SMBUS_BLOCK_MAX) so
it doesn't look like it has ever been able to do anything except return
an error.

Fixes: c335931ed9d2 ("regmap: Add raw_write/read checks for max_raw_write/read sizes")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Cc: stable@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Commit 815806e39bf6 ("regmap: drop cache if the bus transfer error")
added a call to regcache_drop_region() to error path in
_regmap_raw_write(). However that path runs with regmap lock taken,
and regcache_drop_region() tries to re-take it, causing a deadlock.
Fix that by calling map->cache_ops->drop() directly.

Signed-off-by: Nikita Yushchenko <nikita.yoush@cogentembedded.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

This with the longer read and write masks allow supporting more
exotic devices. For example a little endian SPI device:

static const struct regmap_config foo_regmap_config = {
	.reg_bits = 16,
	.reg_stride = 4,
	.val_bits = 16,
	.write_flag_mask = 0x8000,
	.reg_format_endian = REGMAP_ENDIAN_LITTLE,
	.val_format_endian = REGMAP_ENDIAN_LITTLE,
	...
};

Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

We currently only support masking the top bit for read and write
flags. Let's make the mask unsigned long and mask the bytes based
on the configured register length to make things more generic.

This allows using regmap for more exotic combinations like SPI
devices that need little endian addressing.

Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

regmap_write
->_regmap_raw_write
-->regcache_write first and than use map->bus->write to wirte i2c or spi
But if the i2c or spi transfer failed, But the cache is updated, So if I use
regmap_read will get the cache data which is not the real register value.

Signed-off-by: Elaine Zhang <zhangqing@rock-chips.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

Add a function to check if a regmap register is cached. This will be used
in debugfs to dump the cached values of write only registers.

Signed-off-by: Cristian Birsan <cristian.birsan@microchip.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

When doing a bulk writes from a device which lacks raw I/O support we
fall back to doing register at a time reads but we still use the raw
formatters in order to render the data into the word size used by the
device (since bulk reads still operate on the device word size rather
than unsigned ints).  This means that devices without raw formatting
such as those that provide reg_read() are not supported.  Provide
handling for them by copying the values read into native endian values
of the appropriate size.

This complements commit d5b98eb12420 ("regmap: Support bulk reads for
devices without raw formatting").

Signed-off-by: Chen-Yu Tsai <wens@csie.org>
Signed-off-by: Mark Brown <broonie@kernel.org>