spi: orion: support armada extended baud rates

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The Armada SoC family implementation of this SPI hardware module has
extended the configuration register to allow for a wider range of SPI
clock rates. Specifically the Serial Baud Rate Pre-selection bits in the
SPI Interface Configuration Register now also use bits 6 and 7 as well.

Modify the baud rate calculation to handle these differences for the
Armada case. Potentially a baud rate can be setup using a number of
different pre-scalar and scalar combinations. This code tries all
possible pre-scalar divisors (8 in total) to try and find the most
accurate set.

This change introduces (and documents) a new device tree compatible
device name "armada-370-spi" to support this.

Signed-off-by: Greg Ungerer <gerg@uclinux.org>
Tested-by: Ezequiel Garcia <ezequiel.garcia@free-electrons.com>
Reviewed-by: Ezequiel Garcia <ezequiel.garcia@free-electrons.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

...

This commit is contained in:

Greg Ungerer 2014-09-28 23:24:04 +10:00 • committed by Mark Brown

parent 7d1311b93e

commit df59fa7f4b

2 changed files with 95 additions and 23 deletions

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2

Documentation/devicetree/bindings/spi/spi-orion.txt

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90

drivers/spi/spi-orion.c

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