leds: add new LED driver for TI LP5812

This patch series adds initial support for the TI LP5812, a 4x3 matrix RGB LED driver with autonomous engine control. This version provides a minimal, clean implementation focused on core functionality only. The goal is to upstream a solid foundation, with the expectation that additional features can be added incrementally in future patches.

The driver integrates with the LED multicolor framework and supports a set of basic sysfs interfaces for LED control and chip management.

This version contains only the remaining driver and documentation patches. The DT binding patch included in earlier versions has already been applied to for-leds-next.

The series is rebased onto:
https://git.kernel.org/pub/scm/linux/kernel/git/lee/leds.git (for-leds-next)

---
Changes in v22:
- Rebased onto for-leds-next. No functional changes.
- Dropped the DT binding patch (already applied)
- Link to v21: https://lore.kernel.org/linux-leds/[email protected]/

Changes in v21:
- Rebased onto Linux Next. No functional changes.
- Link to v20: https://lore.kernel.org/linux-leds/[email protected]/

Changes in v20:
- Rebase on v6.19-rc1
- Link to v19: https://lore.kernel.org/linux-leds/[email protected]/

Changes in v19:
- DT bindings: Reverted to v17, as making label required in v18 was incorrect.
- Driver: Drop validation code enforcing parsing of the optional label property.
- Driver: Renamed unions for clarity: replaced u_scan_order { s_scan_order, scan_order_val} with lp5812_scan_order { bits, val }. Applied the same pattern to the drive-mode union.
- Driver: Updated all code to use the new bits and val fields.
- Documentation: Fix links (remove backticks, add .rst) and make attribute formatting consistent.
- Link to v18: https://lore.kernel.org/linux-leds/[email protected]/

Changes in v18:
- Mark label as required for all LED nodes for proper sysfs naming, including single-color (led@[0-3]) and multi-color parent nodes (multi-led@[4-7]); remove previous Reviewed-by tag.
- Simplified parse_drive_mode() logic: replaced nested if checks with continue to reduce indentation.
- Use leds[i] instead of each in lp5812_register_leds() for clarity.
- Remove wrapper function lp5812_auto_dc()
- Define all magic numbers.
- Handle parsing properties safely and removed unnecessary pre-initialization.
- Rename lp5812_of_populate_pdata() to lp5812_of_probe().
- Save chip in i2c_set_clientdata(), not led; use leds instead of led for the array in lp5812_probe().
- Remove chip register map structure; use register addresses directly.
- Minor formatting, blank line, comment clean-ups, and add email to MODULE_AUTHOR().
- Link to v17: https://lore.kernel.org/linux-leds/[email protected]/

Changes in v17:
- Dropped direct_mode from ti,scan-mode property.
- Updated logic so that omitting ti,scan-mode now implies direct-drive mode by default.
- Refactor lp5812_parse_led_channel() to simplify function arguments.
- Mark lp5812_cfg as const since it contains only static configuration data.
- Link to v16: https://lore.kernel.org/linux-leds/[email protected]/

Changes in v16:
- Renamed property 'ti,operation-mode' to 'ti,scan-mode'.
- Simplified allowed values using regex pattern instead of long enum list.
- Updated description accordingly and noted 'direct_mode' as default.
- Updated core driver to match the binding change.
- Link to v15: https://lore.kernel.org/linux-leds/[email protected]/

Changes in v15:
- Removed all custom sysfs attributes; driver now fully relies on standard LED multicolor class interfaces.
- Added new device tree property ti,operation-mode to configure direct, TCM, and mix scan modes.
- Dropped previous Reviewed-by tag from the binding patch due to property addition.
- Removed ABI documentation since no new sysfs entries are created.
- Updated lp5812.rst documentation accordingly.
- Link to v14: https://lore.kernel.org/linux-leds/[email protected]/

Changes in v14:
- Replaced inline constants with proper macros for readability and maintainability.
- Refactored lp5812_read() and lp5812_write() to simplify logic and improve clarity.
- Updated lp5812_fault_clear() to use switch() instead of if/else chain.
- Refactored parse_drive_mode() for cleaner logic, removed string parsing of concatenated data.
- Updated activate_store() and led_current_store() to replace strsep()/kstrtoint() parsing with sscanf().
- Removed redundant comments and renamed variables for better clarity.
- Link to v13: https://lore.kernel.org/lkml/[email protected]/

Changes in v13:
- Fixes build warnings reported by kernel test robot:
- Inconsistent indent in lp5812_probe()
- Uninitialized variable 'ret' in lp5812_multicolor_brightness()
- Drop of_match_ptr() and directly assign of_match_table, as the driver is DT-only.
- Link to v12: https://lore.kernel.org/lkml/[email protected]/

Changes in v12:
- Reordered helper functions above lp5812_probe() for better structure.
- Clarified DT-only support by removing fallback paths and i2c_device_id table.
- Directly assign platform_data to the correct pointer instead of relying on string comparisons (LP5812_SC_LED, LP5812_MC_LED) and container_of() casting. This simplifies the logic and avoids unnecessary type checks.
- Removed redundant messages.
- Update ABI documentation to reflect reduced feature set.
- Link to v11: https://lore.kernel.org/lkml/[email protected]/

Changes in v11:
- Drop autonomous animation and other advanced features; reduce driver to core functionality only.
- Simplify LED parsing to use a unified path.
- Clean up and streamline code
- Use alphabetically ordered includes
- Remove redundant comments
- Fix style issues (e.g., comment capitalization, code placement)
- Update ABI documentation to reflect reduced feature set.
- Link to v10: https://lore.kernel.org/lkml/[email protected]/

Changes in v10:
- Address feedback on v9 regarding missing Reviewed-by tag
- Added explanation: binding structure changed significantly to integrate with the standard leds-class-multicolor.yaml schema and support multi-led@ nodes with nested led@ subnodes. This change introduced a new patternProperties hierarchy and removed the previous flat led@ layout used in the earlier versions. So the Reviewed-by tag was dropped out of caution.
- Address binding document feedback
- Use consistent quotes
- Replace 'max-cur' with the standard 'led-max-microamp'
- Remove 'led-cur' property
- Fix mixed indentation
- Updated core driver to align with the updated binding schema.
- Address core driver feedback
- Use for_each_available_child_of_node_scoped() to simplify the code
- Add a return checks for lp5812_write() and lp5812_read()
- Remove unneeded trailing commas
- Fix unsafe usage of stack-allocated strings
- Link to v9: https://lore.kernel.org/lkml/[email protected]/

Changes in v9:
- Move driver back to drivers/leds/rgb/
- Integrate with LED multicolor framework
- Refactor and simplify custom sysfs handling
- Extend Device Tree binding to support multi-led@ nodes using leds-class-multicolor.yaml
- Update documentation to reflect the updated sysfs.
- Link to v8: https://lore.kernel.org/lkml/[email protected]/

Changes in v8:
- Move driver to drivers/auxdisplay/ instead of drivers/leds/.
- Rename files from leds-lp5812.c/.h to lp5812.c/.h.
- Move ti,lp5812.yaml binding to auxdisplay/ directory,
and update the title and $id to match new path.
- No functional changes to the binding itself (keep Reviewed-by).
- Update commit messages and patch titles to reflect the move.
- Link to v7: https://lore.kernel.org/linux-leds/[email protected]/

Changes in v7:
- Mark chip_leds_map as const.
- Use consistent ret initialization.
- Simplify the function set_mix_sel_led().
- Refactor dev_config_show() and led_auto_animation_show() to avoid temp buffer, malloc/free.
- Simplify the code and ensure consistent use of mutex lock/unlock in show/store functions.
- Remove total_leds and total_aeu.
- Link to v6: https://lore.kernel.org/linux-leds/[email protected]/

Changes in v6:
- Add vcc-supply property to describe the LP5812 power supply.
- Remove chan-name property and entire LED subnodes, as they are not needed.
- Update LP5812 LED driver node to Raspberry Pi 4 B Device Tree, based on updated binding.
- Link to v5: https://lore.kernel.org/linux-leds/[email protected]/

Changes in v5:
- Rebase on v6.15-rc2
- Removed unused functions (lp5812_dump_regs, lp5812_update_bit).
- Address Krzysztof's review comments
- Link to v4: https://lore.kernel.org/linux-leds/[email protected]/
---

Nam Tran (2):
leds: add basic support for TI/National Semiconductor LP5812 LED
Driver
docs: leds: Document TI LP5812 LED driver

 Documentation/leds/index.rst       |   1 +
 Documentation/leds/leds-lp5812.rst |  50 +++
 MAINTAINERS                        |   5 +
 drivers/leds/rgb/Kconfig           |  13 +
 drivers/leds/rgb/Makefile          |   1 +
 drivers/leds/rgb/leds-lp5812.c     | 642 +++++++++++++++++++++++++++++
 drivers/leds/rgb/leds-lp5812.h     | 172 ++++++++
 7 files changed, 884 insertions(+)
 create mode 100644 Documentation/leds/leds-lp5812.rst
 create mode 100644 drivers/leds/rgb/leds-lp5812.c
 create mode 100644 drivers/leds/rgb/leds-lp5812.h

base-commit: 33e822f6f4eba2cfbd09ffd080af221cf8c542b2

2.25.1