Pull spi updates from Mark Brown:
 "As well as the usual driver updates and cleanups there's a few
  improvements to the core here:

   - The start of some improvements to factor out more of the SPI
     message loop into the core.  Right now this is just simplifying the
     code a bit but hopefully next time around we'll also have managed
     to roll out some noticable performance improvements which drivers
     can take advantage of.
   - Support for loading modules for ACPI enumerated SPI devices.
   - Managed registration for SPI controllers.
   - Helper for another common I/O pattern"

* tag 'spi-v3.13' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi: (116 commits)
  spi/hspi: add device tree support
  spi: atmel: fix return value check in atmel_spi_probe()
  spi: spi-imx: only enable the clocks when we start to transfer a message
  spi/s3c64xx: Fix doubled clock disable on suspend
  spi/s3c64xx: Do not ignore return value of spi_master_resume/suspend
  spi: spi-mxs: Use u32 instead of uint32_t
  spi: spi-mxs: Don't set clock for each xfer
  spi: spi-mxs: Clean up setup_transfer function
  spi: spi-mxs: Remove check of spi mode bits
  spi: spi-mxs: Fix race in setup method
  spi: spi-mxs: Remove bogus setting of ssp clk rate field
  spi: spi-mxs: Remove full duplex check, spi core already does it
  spi: spi-mxs: Fix chip select control bits in DMA mode
  spi: spi-mxs: Fix extra CS pulses and read mode in multi-transfer messages
  spi: spi-mxs: Change flag arguments in txrx functions to bit flags
  spi: spi-mxs: Always clear INGORE_CRC, to keep CS asserted
  spi: spi-mxs: Remove mxs_spi_enable and mxs_spi_disable
  spi: spi-mxs: Always set LOCK_CS
  spi/s3c64xx: Add missing pm_runtime_put on setup fail
  spi/s3c64xx: Add missing pm_runtime_set_active() call in probe()
  ...

The equivalent of iio_sw_buffer_preenable() is now done in the IIO buffer core,
so there is no need to do this from the driver anymore.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

Since the buffer is accessed by userspace we can not just free the buffers
memory once we are done with it in kernel space. There might still be open file
descriptors and userspace still might be accessing the buffer. This patch adds
support for reference counting to the IIO buffers. When a buffer is created and
initialized its initial reference count is set to 1. Instead of freeing the
memory of the buffer the buffer's _free() function will drop that reference
again. But only after the last reference to the buffer has been dropped the
buffer the buffer's memory will be freed. The IIO device will take a reference
to its primary buffer. The patch adds a small helper function for this called
iio_device_attach_buffer() which will get a reference to the buffer and assign
the buffer to the IIO device. This function must be used instead of assigning
the buffer to the device by hand. The reference is only dropped once the IIO
device is freed and we can be sure that there are no more open file handles. A
reference to a buffer will also be taken whenever the buffer is active to avoid
the buffer being freed while data is still being send to it.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

Using spi_w8r16be() will do the conversion of the result from big endian to
native endian in the helper function. This makes the code a bit smaller and also
keeps sparse happy. Fixes the following sparse warnings:

	drivers/staging/iio/meter/ade7753.c:97:29: warning: incorrect type in argument 1 (different base types)
	drivers/staging/iio/meter/ade7753.c:97:29:    expected restricted __be16 const [usertype] *p
	drivers/staging/iio/meter/ade7753.c:97:29:    got unsigned short [usertype] *val

	drivers/staging/iio/meter/ade7754.c:97:29: warning: incorrect type in argument 1 (different base types)
	drivers/staging/iio/meter/ade7754.c:97:29:    expected restricted __be16 const [usertype] *p
	drivers/staging/iio/meter/ade7754.c:97:29:    got unsigned short [usertype] *val

	drivers/staging/iio/meter/ade7759.c:97:29: warning: incorrect type in argument 1 (different base types)
	drivers/staging/iio/meter/ade7759.c:97:29:    expected restricted __be16 const [usertype] *p
	drivers/staging/iio/meter/ade7759.c:97:29:    got unsigned short [usertype] *val

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Acked-by: Jonathan Cameron <jic23@kernel.org>
Signed-off-by: Mark Brown <broonie@linaro.org>

This resolves the merge problem with two iio drivers that Stephen
Rothwell pointed out.

Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Makes the code a bit shorter and less ugly.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

ade7854_probe can fail. Return the value obtained from it
instead of 0 (success).

Signed-off-by: Sachin Kamat <sachin.kamat@linaro.org>
Cc: Barry Song <21cnbao@gmail.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

Now that iio_push_to_buffers() takes a void pointer for the data parameter we
can remove those casts to u8*.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

devm_iio_device_alloc makes code simpler.

Signed-off-by: Sachin Kamat <sachin.kamat@linaro.org>
Cc: Barry Song <21cnbao@gmail.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

devm_iio_device_alloc makes code simpler.

Signed-off-by: Sachin Kamat <sachin.kamat@linaro.org>
Cc: Barry Song <21cnbao@gmail.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>