add support for pf1550 PMIC MFD-based drivers

This series adds support for pf1550 PMIC. It provides the core driver and
sub-drivers for the regulator, power supply and input subsystems.

Patch 1 adds the DT binding document for the PMIC. Patches 2-5 adds the
pertinent drivers. Last patch adds a MAINTAINERS entry for the drivers.

The patches 3-5 depend on the core driver provided in patch 2.

Changes since v1:
   - DT bindings for all devices included
   - Add onkey driver
   - Add driver for the regulators
   - Ensure charger is activated as some variants have it off by default
   - Update mfd and charger driver per feedback from eballetbo@gmail.com
   - Add myself as maintainer for these drivers
   - Link to v1: https://lore.kernel.org/1523974819-8711-1-git-send-email-...

Changes since v2:
   - Rebase on recent mainline kernel v6.15
   - Single yaml file containing dt bindings for all pf1550 devices
   - irq mapping done in MFD driver as suggested by Dmitry Torokhov
   - Drop unnecessary includes in drivers
   - Replace dev_err with dev_err_probe in probe method of drivers
   - Drop compatible string from drivers of the sub-devices
   - Remove dependency on OF from drivers of the sub-devices
   - onkey: move driver from input/keyboard into input/misc
   - onkey: remove dependency on OF
   - onkey: use onkey virqs instead of central irq
   - onkey: fix integer overflow for regmap_write when unmasking
     interrupts during pf1550_onkey_resume
   - charger: add support for monitored-battery which is used in setting
     a constant voltage for the charger.
   - Address other feedback from Dmitry Torokhov and Krzysztof Kozlowski
   - Link to v2: https://lore.kernel.org/cover.1747409892.git.samuel.kayod...

Changes since v3:
   - Update manufacturer from Freescale to NXP in compatible,
     dt-binding and Kconfigs
   - Use C++ style comments for SPDX license in .c code
   - Add portions copyright to source code
   - irqs are defined as struct resource in mfd cell such that
     platform_get_irq is used in the sub-devices
   - Make struct pf1550_dev of type const in sub-device driver
   - irq variable dropped from sub-device driver struct
   - EXPORT_SYMBOL of global pf1550_read_otp function for use in
     regulator driver
   - Drop unneeded info in driver_data when defining device table id
   - regulator: validate ramp_delay
   - regulator: report overcurrent and over temperature events
   - onkey: drop unnecessary keycode variable
   - onkey: change wakeup variable to type bool
   - onkey: replace (error < 0) with error in if statement when possible
   - onkey: use pm_sleep_ptr when defining driver.pm
   - charger: finish handling of some interrupts in threaded irq handler
   - Link to v3: https://lore.kernel.org/20250527-pf1550-v3-0-45f69453cd51...

Changes since v4:
   - Use top level interrupt to minimize number of registers checked on
     each interrupt
   - Fix bad offset for temperature interrupts of regulator irq chip
   - Address Krzysztof's comments for dt-binding
   - regulator: add comments to clarify difference in its interrupts
   - regulator: issue warn event for _LS interrupt and error event for
     _HS interrupt
   - regulator: validate maximum and minimum ramp_delay
   - charger: drop lock in battery and charger delayed_work
   - charger: more conservative locking for vbus delayed_work
   - charger: apply lock when setting power_supply type during register
     intialization
   - Link to v4: https://lore.kernel.org/r/20250603-pf1550-v4-0-bfdf51ee59...

Changes since v5:
   - Ensure lowercase when assigning hex values
   - Add imx@lists.linux.dev to relevant mailing list in MAINTAINERS file
   - Use GENMASK macro
   - Drop unused chips variable
   - Read the OTP in the mfd driver probe for new dvs_enb variable
   - Hardcode IRQ flags in pf1550_add_child function
   - charger: drop the mutex entirely
   - charger: reverse christmas tree style local variable definition in
     probe
   - Link to v5: https://lore.kernel.org/r/20250610-pf1550-v5-0-ed0d9e3aaa...

Changes since v6:
   - Use reverse christmas tree order
   - Drop 0 in table id's driver data
   - charger: store virq to avoid reinvoking platform_get_irq in ISR
   - Link to v6: https://lore.kernel.org/r/20250611-pf1550-v6-0-34f2ddfe04...

Changes since v7:
  - Thanks everyone for the reviews
  - Use C++ comment only for SPDX license header in core, charger and
    onkey drivers
  - Drop filenames from comments
  - Rename pf1550_dev to pf1550_ddata
  - Define OTP register for accessing status of DVS
  - core: rename from `mfd driver` to `core driver`
  - core: add child devices in a cleaner manner
  - charger: define two power supplies: battery and external power
  - charger: use devm_delayed_work_autocancel
  - Link to v7: https://lore.kernel.org/r/20250612-pf1550-v7-0-0e393b0f45...

Changes since v8:
  - Collect Frank's `Reviewed-by` tags
  - core: use consistent whitespace
  - regulator: add standby support for regulators requested by Sean Nyekjaer
  - regulator: add support for SW1 DVS enable/disable
  - regulator: fix improper DVS activation
  - regulator: add map_voltage for regulators
  - regulator: add enable/disable for regulators
  - charger: use datasheet thermal regulation temperature ranges
  - charger: select charger operation mode based on the application
  - onkey: add support for disabling system power down via onkey
  - dt-bindings: changed temperature ranges
  - dt-bindings: added `disable-key-power`
  - Link to v8: https://lore.kernel.org/r/20250707-pf1550-v8-0-6b6eb67c03...

Changes since v9:
  - add Sean's Tested-by tag
  - core: style changes
  - dt-bindings: add regulator-state-mem to examples
  - onkey: use regmap_clear_bits to avoid overwriting all bits of the
    PWRCTRL register
  - Link to v9: https://lore.kernel.org/r/20250716-pf1550-v9-0-502a647f04...

Signed-off-by: Samuel Kayode <samuel.kayode@savoirfairelinux.com>
---
Samuel Kayode (6):
      dt-bindings: mfd: add pf1550
      mfd: pf1550: add core driver
      regulator: pf1550: add support for regulator
      input: pf1550: add onkey support
      power: supply: pf1550: add battery charger support
      MAINTAINERS: add an entry for pf1550 mfd driver

 .../devicetree/bindings/mfd/nxp,pf1550.yaml        | 161 ++++++
 MAINTAINERS                                        |  11 +
 drivers/input/misc/Kconfig                         |  11 +
 drivers/input/misc/Makefile                        |   1 +
 drivers/input/misc/pf1550-onkey.c                  | 197 +++++++
 drivers/mfd/Kconfig                                |  16 +
 drivers/mfd/Makefile                               |   2 +
 drivers/mfd/pf1550.c                               | 367 ++++++++++++
 drivers/power/supply/Kconfig                       |  11 +
 drivers/power/supply/Makefile                      |   1 +
 drivers/power/supply/pf1550-charger.c              | 636 +++++++++++++++++++++
 drivers/regulator/Kconfig                          |   9 +
 drivers/regulator/Makefile                         |   1 +
 drivers/regulator/pf1550-regulator.c               | 429 ++++++++++++++
 include/linux/mfd/pf1550.h                         | 273 +++++++++
 15 files changed, 2126 insertions(+)
---
base-commit: 0a4b866d08c6adaea2f4592d31edac6deeb4dcbd
change-id: 20250527-pf1550-d401f0d07b80

Best regards,
-- 
Samuel Kayode <samuel.kayode@savoirfairelinux.com>