net: dsa: realtek: support reset controller

Add support for resetting the device using a reset controller,
complementing the existing GPIO reset functionality (reset-gpios).

Although the reset is optional and the driver performs a soft reset
during setup, if the initial reset pin state was asserted, the driver
will not detect the device until the reset is deasserted.

Signed-off-by: Luiz Angelo Daros de Luca <luizluca@gmail.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Alvin Šipraga <alsi@bang-olufsen.dk>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: dsa: realtek: embed dsa_switch into realtek_priv

Embed dsa_switch within realtek_priv to eliminate the need for a second
memory allocation.

Suggested-by: Alvin Šipraga <alsi@bang-olufsen.dk>
Signed-off-by: Luiz Angelo Daros de Luca <luizluca@gmail.com>
Reviewed-by: Vladimir Oltean <olteanv@gmail.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: dsa: realtek: use the same mii bus driver for both interfaces

The realtek-mdio will now use this driver instead of the generic DSA
driver ("dsa user smi"), which should not be used with OF[1].

With a single ds_ops for both interfaces, the ds_ops in realtek_priv is
no longer necessary. Now, the realtek_variant.ds_ops can be used
directly.

The realtek_priv.setup_interface() has been removed as we can directly
call the new common function.

[1] https://lkml.kernel.org/netdev/20220630200423.tieprdu5fpabflj7@bang-olufsen.dk/T/

Signed-off-by: Luiz Angelo Daros de Luca <luizluca@gmail.com>
Reviewed-by: Vladimir Oltean <olteanv@gmail.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: dsa: realtek: common rtl83xx module

Some code can be shared between both interface modules (MDIO and SMI)
and among variants. These interface functions migrated to a common
module:

- rtl83xx_lock
- rtl83xx_unlock
- rtl83xx_probe
- rtl83xx_register_switch
- rtl83xx_unregister_switch
- rtl83xx_shutdown
- rtl83xx_remove

The reset during probe was moved to the end of the common probe. This way,
we avoid a reset if anything else fails.

Signed-off-by: Luiz Angelo Daros de Luca <luizluca@gmail.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: dsa: realtek: keep variant reference in realtek_priv

Instead of copying values from the variant, we can keep a reference in
realtek_priv.

This is a preliminary change for sharing code betwen interfaces. It will
allow to move most of the probe into a common module while still allow
code specific to each interface to read variant fields.

Signed-off-by: Luiz Angelo Daros de Luca <luizluca@gmail.com>
Reviewed-by: Vladimir Oltean <olteanv@gmail.com>
Reviewed-by: Florian Fainelli <florian.fainelli@broadcom.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: dsa: realtek: drop cleanup from realtek_ops

It was never used and never referenced.

Signed-off-by: Luiz Angelo Daros de Luca <luizluca@gmail.com>
Reviewed-by: Alvin Šipraga <alsi@bang-olufsen.dk>
Reviewed-by: Florian Fainelli <florian.fainelli@broadcom.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Vladimir Oltean <olteanv@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: dsa: Use conduit and user terms

Use more inclusive terms throughout the DSA subsystem by moving away
from "master" which is replaced by "conduit" and "slave" which is
replaced by "user". No functional changes.

Acked-by: Rob Herring <robh@kernel.org>
Acked-by: Stephen Hemminger <stephen@networkplumber.org>
Reviewed-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: Florian Fainelli <florian.fainelli@broadcom.com>
Link: https://lore.kernel.org/r/20231023181729.1191071-2-florian.fainelli@broadcom.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

net: dsa: realtek: allow subdrivers to externally lock regmap

Currently there is no way for Realtek DSA subdrivers to serialize
consecutive regmap accesses. In preparation for a bugfix relating to
indirect PHY register access - which involves a series of regmap
reads and writes - add a facility for subdrivers to serialize their
regmap access.

Specifically, a mutex is added to the driver private data structure and
the standard regmap is initialized with custom lock/unlock ops which use
this mutex. Then, a "nolock" variant of the regmap is added, which is
functionally equivalent to the existing regmap except that regmap
locking is disabled. Functions that wish to serialize a sequence of
regmap accesses may then lock the newly introduced driver-owned mutex
before using the nolock regmap.

Doing things this way means that subdriver code that doesn't care about
serialized register access - i.e. the vast majority of code - needn't
worry about synchronizing register access with an external lock: it can
just continue to use the original regmap.

Another advantage of this design is that, while regmaps with locking
disabled do not expose a debugfs interface for obvious reasons, there
still exists the original regmap which does expose this interface. This
interface remains safe to use even combined with driver codepaths that
use the nolock regmap, because said codepaths will use the same mutex
to synchronize access.

With respect to disadvantages, it can be argued that having
near-duplicate regmaps is confusing. However, the naming is rather
explicit, and examples will abound.

Finally, while we are at it, rename realtek_smi_mdio_regmap_config to
realtek_smi_regmap_config. This makes it consistent with the naming
realtek_mdio_regmap_config in realtek-mdio.c.

Signed-off-by: Alvin Šipraga <alsi@bang-olufsen.dk>
Reviewed-by: Vladimir Oltean <olteanv@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: dsa: realtek: realtek-mdio: reset before setup

Some devices, like the switch in Banana Pi BPI R64 only starts to answer
after a HW reset. It is the same reset code from realtek-smi.

Reported-by: Frank Wunderlich <frank-w@public-files.de>
Signed-off-by: Luiz Angelo Daros de Luca <luizluca@gmail.com>
Tested-by: Frank Wunderlich <frank-w@public-files.de>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Alvin Šipraga <alsi@bang-olufsen.dk>
Acked-by: Arınç ÜNAL <arinc.unal@arinc9.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: dsa: realtek: rename macro to match filename

The macro was missed while renaming realtek-smi.h to realtek.h.

Fixes: f5f119077b1c (net: dsa: realtek: rename realtek_smi to)
Signed-off-by: Luiz Angelo Daros de Luca <luizluca@gmail.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Reviewed-by: Alvin Šipraga <alsi@bang-olufsen.dk>
Acked-by: Arınç ÜNAL <arinc.unal@arinc9.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: dsa: realtek: add new mdio interface for drivers

This driver is a mdio_driver instead of a platform driver (like
realtek-smi).

ds_ops was duplicated for smi and mdio usage as mdio interfaces uses
phy_{read,write} in ds_ops and the presence of phy_read is incompatible
with external slave_mii_bus allocation.

Signed-off-by: Luiz Angelo Daros de Luca <luizluca@gmail.com>
Tested-by: Arınç ÜNAL <arinc.unal@arinc9.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: dsa: realtek: remove direct calls to realtek-smi

Remove the only two direct calls from subdrivers to realtek-smi.
Now they are called from realtek_priv. Subdrivers can now be
linked independently from realtek-smi.

Signed-off-by: Luiz Angelo Daros de Luca <luizluca@gmail.com>
Reviewed-by: Alvin Šipraga <alsi@bang-olufsen.dk>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: dsa: realtek: rename realtek_smi to realtek_priv

In preparation to adding other interfaces, the private data structure
was renamed to priv. Also, realtek_smi_variant and realtek_smi_ops
were renamed to realtek_variant and realtek_ops as those structs are
not SMI specific.

Signed-off-by: Luiz Angelo Daros de Luca <luizluca@gmail.com>
Tested-by: Arınç ÜNAL <arinc.unal@arinc9.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Reviewed-by: Alvin Šipraga <alsi@bang-olufsen.dk>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Vladimir Oltean <olteanv@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>