Message-Id: <20211124073419.181799-1-marcan@marcan.st>
Date:   Wed, 24 Nov 2021 16:34:10 +0900
From:   Hector Martin <marcan@...can.st>
To:     linux-arm-kernel@...ts.infradead.org
Cc:     Hector Martin <marcan@...can.st>, Marc Zyngier <maz@...nel.org>,
        Rob Herring <robh+dt@...nel.org>,
        Arnd Bergmann <arnd@...nel.org>,
        Linus Walleij <linus.walleij@...aro.org>,
        Alyssa Rosenzweig <alyssa@...enzweig.io>,
        Krzysztof Kozlowski <krzk@...nel.org>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Mark Kettenis <mark.kettenis@...all.nl>,
        Philipp Zabel <p.zabel@...gutronix.de>,
        "Rafael J. Wysocki" <rafael@...nel.org>,
        Johan Hovold <johan@...nel.org>, devicetree@...r.kernel.org,
        linux-pm@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-samsung-soc@...r.kernel.org, linux-serial@...r.kernel.org
Subject: [PATCH v3 00/11] Apple SoC PMGR device power states driver

This series adds the driver for the Apple PMGR device power state
registers. These registers can clockgate and (in some cases) powergate
specific SoC blocks. They also control the reset line, and can have
additional features such as automatic power management.

The current driver supports only the lowest/highest power states,
provided via the genpd framework, plus reset support provided via
the reset subsystem.

Apple's PMGRs (there are two in the T8103) have a uniform register
bit layout (sometimes with varying features). To be able to support
multiple SoC generations as well as express pd relationships
dynamically, this binding describes each PMGR power state control
as a single devicetree node. Future SoC generations are expected to
retain backwards compatibility, allowing this driver to work on them
with only DT changes.

#1: MAINTAINERS updates, to go via the SoC tree to avert merge hell
#2-#5: Adds power-domains properties to existing device bindings
#6-#7: Adds the new pmgr device tree bindings
#8: The driver itself.
#9: Instantiates the driver in t8103.dtsi. This adds the entire PMGR
    node tree and references the relevant nodes from existing devices.
#7: Adds runtime-pm support to the Samsung UART driver, as a first
    working consumer.
#8: Instantiates a second UART, to more easily test this.

There are currently no consumers for the reset functionality, so
it is untested, but we will be testing it soon with the NVMe driver
(as it is required to allow driver re-binding to work properly).

== Changes since v2 ==
- DT schema review comments & patch order fix
- Added the power-domains properties to devices that already mainlined
- Now adds the entire PMGR tree. This turns off all devices we do not
  currently instantiate, and adds power-domains to those we do. The
  nodes were initially generated with [1] and manually tweaked. all
  the labels match the ADT labels (lowercased), which might be used
  by the bootloader in the future to conditionally disable nodes
  based on hardware configuration.
- Dropped apple,t8103-minipmgr, since I don't expect we will ever need
  to tell apart multiple PMGR instances within a SoC, and added
  apple,t6000-pmgr{-pwrstate} for the new SoCs.
- Driver now unconditionally enables auto-PM for all devices. This
  seems to be safe and should save power (it is not implemented for
  all devices; if not implemented, the bit just doesn't exist and is
  ignored).
- If an always-on device is not powered on at boot, turn it on and
  print a warning. This avoids the PM core complaining. We still
  want to know if/when this happens, but let's not outright fail.
- Other minor fixes (use PS names instead of offsets for messages,
  do not spuriously clear flag bits).

On the way the parent node is handled: I've decided that these syscon
nodes will only ever contain pwrstates and nothing else. We now size
them based on the register range that contains pwrstate controls
(rounded up to page size). t6000 has 3 PMGRs and t6001 has 4, and
we shouldn't have to care about telling apart the multiple instances.
Anything else PMGR does that needs a driver will be handled by
entirely separate nodes in the future.

Re t6001 and t6000 (and the rumored t6002), t6000 is basically a
cut-down version of t6001 (and t6002 is rumored to be two t6001
dies), down to the die floorplan, so I'm quite certain we won't need
t6001/2-specific compatibles for anything shared. The t6000 devicetree
will just #include the t6001 one and remove the missing devices.
Hence, everything for this SoC series is going to have compatibles
named apple,t6000-* (except the extra instances of some blocks in
t6001 which look like they may have differences; PMGR isn't one of
them, but some multimedia stuff might).

[1] https://github.com/AsahiLinux/m1n1/blob/main/proxyclient/tools/pmgr_adt2dt.py

Hector Martin (11):
  MAINTAINERS: Add PMGR power state files to ARM/APPLE MACHINE
  dt-bindings: i2c: apple,i2c: Add power-domains property
  dt-bindings: iommu: apple,dart: Add power-domains property
  dt-bindings: pinctrl: apple,pinctrl: Add power-domains property
  dt-bindings: interrupt-controller: apple,aic: Add power-domains
    property
  dt-bindings: power: Add apple,pmgr-pwrstate binding
  dt-bindings: arm: apple: Add apple,pmgr binding
  soc: apple: Add driver for Apple PMGR power state controls
  arm64: dts: apple: t8103: Add PMGR nodes
  tty: serial: samsung_tty: Support runtime PM
  arm64: dts: apple: t8103: Add UART2

 .../bindings/arm/apple/apple,pmgr.yaml        |  134 ++
 .../devicetree/bindings/i2c/apple,i2c.yaml    |    3 +
 .../interrupt-controller/apple,aic.yaml       |    3 +
 .../devicetree/bindings/iommu/apple,dart.yaml |    3 +
 .../bindings/pinctrl/apple,pinctrl.yaml       |    3 +
 .../bindings/power/apple,pmgr-pwrstate.yaml   |   71 ++
 MAINTAINERS                                   |    3 +
 arch/arm64/boot/dts/apple/t8103-j274.dts      |    5 +
 arch/arm64/boot/dts/apple/t8103-pmgr.dtsi     | 1136 +++++++++++++++++
 arch/arm64/boot/dts/apple/t8103.dtsi          |   36 +
 drivers/soc/Kconfig                           |    1 +
 drivers/soc/Makefile                          |    1 +
 drivers/soc/apple/Kconfig                     |   21 +
 drivers/soc/apple/Makefile                    |    2 +
 drivers/soc/apple/apple-pmgr-pwrstate.c       |  317 +++++
 drivers/tty/serial/samsung_tty.c              |   93 +-
 16 files changed, 1798 insertions(+), 34 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/arm/apple/apple,pmgr.yaml
 create mode 100644 Documentation/devicetree/bindings/power/apple,pmgr-pwrstate.yaml
 create mode 100644 arch/arm64/boot/dts/apple/t8103-pmgr.dtsi
 create mode 100644 drivers/soc/apple/Kconfig
 create mode 100644 drivers/soc/apple/Makefile
 create mode 100644 drivers/soc/apple/apple-pmgr-pwrstate.c

-- 
2.33.0

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