net: dsa: initial support for MaxLinear MxL862xx switches

This series adds very basic DSA support for the MaxLinear MxL86252
(5 PHY ports) and MxL86282 (8 PHY ports) switches.

MxL862xx integrates a firmware running on an embedded processor (Zephyr
RTOS). Host interaction uses a simple API transported over MDIO/MMD.
This series includes only what's needed to pass traffic between user
ports and the CPU port: relayed MDIO to internal PHYs, basic port
enable/disable, and CPU-port special tagging.

At this point the driver does NOT configure any bridges and bridge
ports, so isolation of the userports depends on the pre-configuration
stored on the flash chip attached to the switch IC.

This is going to be addressed in follow-up series adding support for
configuring bridges and bridge-ports, and also use the added API for
that to make sure the switch is always in a well-defined condition (ie.
all ports isolated in individual bridges, learning disabled, and not
depending on attached pre-configuration) after reset.


Changes since RFC v4
1/4 dt-bindings: net: dsa: add MaxLinear MxL862xx
 * no changes

2/4 net: dsa: add tag format for MxL862xx switches
 * drop unused precompiler macros

3/4 net: mdio: add unlocked mdiodev C45 bus accessors
 * fix indentation

4/4 net: dsa: add basic initial driver for MxL862xx switches
 * output warning in .setup regarding unknown pre-configuration
 * add comment explaining why CFGGET is used in reset function


Changes since RFC v3
1/4 dt-bindings: net: dsa: add MaxLinear MxL862xx
 * remove labels from example
 * remove 'bindings for' from commit title

2/4 net: dsa: add tag format for MxL862xx switches
 * describe fields and variables with comments
 * sub-interface is only 5 bits
 * harmonize Kconfig symbol name
 * maintain alphabetic order in Kconfig
 * fix typo s/beginnig/beginning/
 * fix typo s/swtiches/switches/
 * arrange local variables in reverse xmas tree order

3/4 net: mdio: add unlocked mdiodev C45 bus accessors
 * unchanged

4/4 net: dsa: add basic initial driver for MxL862xx switches
 * poll switch readiness after reset
 * implement driver shutdown
 * added port_fast_aging API call and driver op
 * unified port setup in new .port_setup op
 * improve comment explaining special handlign for unaligned API read
 * various typos and formatting improvements


Changes since RFC v2
1/4, 2/4, 3/4: unchanged

4/4 net: dsa: add basic initial driver for MxL862xx switches
 * fix return value being uninitialized on error in mxl862xx_api_wrap()
 * add missing description in kerneldoc comment of
   struct mxl862xx_ss_sp_tag


Changes since initial RFC

1/4 dt-bindings: net: dsa: add bindings for MaxLinear MxL862xx
 * better description in dt-bindings doc

2/4 net: dsa: add tag formats for MxL862xx switches
 * make sure all tag fields are initialized

3/4 net: mdio: add unlocked mdiodev C45 bus accessors
 * new patch

4/4 net: dsa: add basic initial driver for MxL862xx switches
 * make use of struct mdio_device
 * add phylink_mac_ops stubs
 * drop leftover nonsense from mxl862xx_phylink_get_caps()
 * fix endian conversions
 * use __le32 instead of enum types in over-the-wire structs
 * use existing MDIO_* macros whenever possible
 * simplify API constants to be more readable
 * use readx_poll_timeout instead of open-coding poll timeout loop
 * add mxl862xx_reg_read() and mxl862xx_reg_write() helpers
 * demystify error codes returned by the firmware
 * add #defines for mxl862xx_ss_sp_tag member values
 * move reset to dedicated function, clarify magic number being the
   reset command ID


Daniel Golle (4):
  dt-bindings: net: dsa: add MaxLinear MxL862xx
  net: dsa: add tag format for MxL862xx switches
  net: mdio: add unlocked mdiodev C45 bus accessors
  net: dsa: add basic initial driver for MxL862xx switches

 .../bindings/net/dsa/maxlinear,mxl862xx.yaml  | 154 +++++++
 MAINTAINERS                                   |   8 +
 drivers/net/dsa/Kconfig                       |   2 +
 drivers/net/dsa/Makefile                      |   1 +
 drivers/net/dsa/mxl862xx/Kconfig              |  12 +
 drivers/net/dsa/mxl862xx/Makefile             |   3 +
 drivers/net/dsa/mxl862xx/mxl862xx-api.h       | 177 +++++++
 drivers/net/dsa/mxl862xx/mxl862xx-cmd.h       |  32 ++
 drivers/net/dsa/mxl862xx/mxl862xx-host.c      | 230 ++++++++++
 drivers/net/dsa/mxl862xx/mxl862xx-host.h      |   5 +
 drivers/net/dsa/mxl862xx/mxl862xx.c           | 433 ++++++++++++++++++
 drivers/net/dsa/mxl862xx/mxl862xx.h           |  24 +
 include/linux/mdio.h                          |  13 +
 include/net/dsa.h                             |   2 +
 net/dsa/Kconfig                               |   7 +
 net/dsa/Makefile                              |   1 +
 net/dsa/tag_mxl862xx.c                        | 116 +++++
 17 files changed, 1220 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/net/dsa/maxlinear,mxl862xx.yaml
 create mode 100644 drivers/net/dsa/mxl862xx/Kconfig
 create mode 100644 drivers/net/dsa/mxl862xx/Makefile
 create mode 100644 drivers/net/dsa/mxl862xx/mxl862xx-api.h
 create mode 100644 drivers/net/dsa/mxl862xx/mxl862xx-cmd.h
 create mode 100644 drivers/net/dsa/mxl862xx/mxl862xx-host.c
 create mode 100644 drivers/net/dsa/mxl862xx/mxl862xx-host.h
 create mode 100644 drivers/net/dsa/mxl862xx/mxl862xx.c
 create mode 100644 drivers/net/dsa/mxl862xx/mxl862xx.h
 create mode 100644 net/dsa/tag_mxl862xx.c

-- 
2.52.0