[PATCHv3] spi: dw-spi: Convert to 32-bit register accesses

[<tthayer-yzvPICuk2ABMcg4IHK0kFoH6Mc4MB0Vx@public.gmane.org>]

From: Thor Thayer <tthayer-yzvPICuk2ABMcg4IHK0kFoH6Mc4MB0Vx@public.gmane.org>

Altera's Arria10 SoC requires all write accesses of APB peripherals
are 32-bit. The DesignWare documentation indicates this change
is acceptable.

Request for Testing:
Please test on legacy DesignWare SPI devices. If a problem is
discovered, please reply to this thread.

Additional Documentation To Support this Change:
The DesignWare documentation DW_apb_ssi databook states:
All registers in the DW_apb_ssi are addressed on 32-bit boundaries
to remain consistent with the AHB bus. Where the physical size of
any register is less than 32-bits wide, the upper unused bits of the
32-bit boundary are reserved. Writing to these bits has no effect,
reading from these bits returns 0. [1]

Tested On:
Altera CycloneV Development Kit
Altera Arria10 Development Kit

[1] Section 6.1 of dw_apb_ssi.pdf (version 3.22a)

Thor Thayer (1):
  spi: dw-spi: Convert 16bit accesses to 32bit accesses

 drivers/spi/spi-dw.c |   34 +++++++++++++++++-----------------
 drivers/spi/spi-dw.h |   10 ----------
 2 files changed, 17 insertions(+), 27 deletions(-)

-- 
1.7.9.5

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