On Fri, 28 Jul 2017, Richard Fitzgerald wrote:

This patch adds a header file of register definitions for Cirrus
Logic "Madera" class codecs. These codecs are all based off a common
set of hardware IP so have a common register map (with a few minor
device-to-device variations).

The registers.h file is tool-generated directly from the hardware design
but has been manually stripped down to reduce size (full register
map is >44000 lines). All names are kept the same as datasheet names
so that they can be cross-referenced between source and datasheet without
confusion.

The register map layout is kept fully-defined rather than factored into
macros and/or block-indexing code. The major reasons for this are:

 - #1 is that it makes the source highly greppable, which is important.
   "What does the driver do with register bits XYZ" or "Where does it use
   register bits XYZ" are commonly types of questions. These can be quickly
   answered by a grep. Squashing definitions into generator macros or block-
   indexing code is a way of defeating grep.

 - most of the register definitions are used in tables, so a constant value
   is required. Using generator macros make the table definition clunky and
   obscure.

 - the code is clearer when it's there in the source exactly what register
   and field it is using

 - it is easier to diff the register map of a new (unsupported) codec against
   what is already supported and merge in differences

 - it makes the register map available in source for maintenance/debugging
   instead of having to refer back to the datasheet for a register map

Signed-off-by: Richard Fitzgerald <redacted>
---
Changes since V3:
- Manually stripped out a lot more stuff, defines we're not using right now
- Added the explanation above to the commit message of why we define the
  map effectively verbatim

 MAINTAINERS                          |   10 +
 include/linux/mfd/madera/registers.h | 3987 ++++++++++++++++++++++++++++++++++
 2 files changed, 3997 insertions(+)
 create mode 100644 include/linux/mfd/madera/registers.h

For my own reference:
  Acked-for-MFD-by: Lee Jones [off-list ref]

-- 
Lee Jones
Linaro STMicroelectronics Landing Team Lead
Linaro.org │ Open source software for ARM SoCs
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