[PATCH v4 0/2] iio: proximity: add driver for ST VL53L1X ToF sensor

[Siratul Islam <email@sirat.me>]

This series adds support for the STMicroelectronics VL53L1X
Time-of-Flight ranging sensor.

The VL53L1X is a ToF laser-ranging sensor with I2C interface,
capable of measuring distances up to 4 meters. The driver
supports both interrupt-driven and polled operation.

Why a separate driver is needed (instead of extending vl53l0x-i2c.c):
The VL53L1X is fundamentally different from the VL53L0X despite the
similar naming. Extending the existing driver would require rewriting
the majority of it.

Key differences include:
- A different register map (16-bit addresses vs. 8-bit addresses).
- Requires a 91-byte firmware configuration blob to be loaded at boot.
- Requires a VHV calibration cycle.
- Has distance mode and timing budget configurations.
- Uses the regmap API rather than raw i2c_smbus calls.

I also reviewed other drivers in drivers/iio/proximity/ and can
confirm this IP block does not appear to be shared by any other
existing driver.

Tested on Raspberry Pi 5 with a VL53L1X breakout board.

Note on vdd-supply:
In v2, I added vdd-supply as required. Since I'm using the
shared st,vl53l0x.yaml binding now, I had to drop that requirement
to avoid breaking backward compatibility for existing st,vl53l0x
devicetrees. The driver itself still uses non-optional
devm_regulator_get() so no change there.

---
Changes in v4:
- Move i2c_check_functionality() to the top of probe before allocations.
- Use struct u32_fract for oscillator correction math.
- Explicitly set .cache_type = REGCACHE_NONE.
- Document intentional predisable drain
- Use dev_err_probe() for firmware boot timeout and remove duplicate IRQ request error message.
- Use sizeof() in regmap bulk read/writes instead of hardcoded lengths.
- Add missing headers (<linux/math.h>, <linux/time.h>, <asm/byteorder.h>).
- Various formatting cleanups per Andy's review.


Changes in v3:
- Merge DT binding into existing st,vl53l0x.yaml (per Krzysztof).
- Use "reset-gpios" in the binding but xshut_gpio in the driver since that's the actual pin name.
- Replace manual polling loops in chip_init and read_proximity with regmap_read_poll_timeout().
- Remove irq_get_trigger_type() and pass IRQF_NO_THREAD directly (per Andy).
- Drop struct i2c_client from private data and store irq as int instead. Derive struct device from regmap where needed.
- Add dev_err_probe() to first devm_request_irq() error path.
- Replace linux/device.h with linux/dev_printk.h, add linux/array_size.h, linux/err.h, linux/types.h (per Andy).
- Use USEC_PER_MSEC for poll timeouts.
- Remove unnecessary casts.
- Divide long config blob to 8 values per line.
- Rename goto label to notify_and_clear_irq and drop unused dev_dbg.
- Add datasheet section reference for boot delay comment.
- vdd-supply no longer required in shared binding to avoid breaking existing st,vl53l0x devicetrees.


Changes in v2:
- Skip software reset in chip_init when xshut GPIO is available, since the device was already hardware-reset during power-on.
- Rename "reset" GPIO to "xshut" to match the datasheet pin name and updated DT binding accordingly.
- Make vdd-supply required in DT binding.
- Use reg_sequence arrays and regmap_multi_reg_write() for distance mode configuration.
- Switch to a hardirq handler with iio_trigger_poll() and IRQF_NO_THREAD instead of a threaded handler.
- Drop IRQF_TRIGGER_FALLING fallback. Leave trigger type to firmware/DT.
- Use iio_validate_own_trigger() instead of a custom validate_trigger, drop trig pointer from driver data.
- Switch usleep_range() to fsleep() throughout and add comments for sleep values.
- Don't fail probe on unknown model ID, just log with dev_info().
- Split stop_ranging cleanup into its own devm action, separate from power_off.
- Add missing includes: device.h, bitfield.h, completion.h, mod_devicetable.h.
- Use FIELD_GET() for range status checks.
- Move configure_irq() closer to probe(), use dev_err_probe() for its error paths.
- Fix buffer ops symmetry: postdisable -> predisable.
- Drop reg_format_endian from regmap config.
- Various alignment and formatting fixes.

Link to v3: https://lore.kernel.org/linux-iio/20260311224044.21480-1-email@sirat.me
Link to v2: https://lore.kernel.org/linux-iio/20260308113728.40860-1-email@sirat.me
Link to v1: https://lore.kernel.org/linux-iio/20260303090253.42076-1-email@sirat.me

Siratul Islam (2):
  dt-bindings: iio: proximity: add ST VL53L1X ToF sensor
  iio: proximity: add driver for ST VL53L1X ToF sensor

 .../bindings/iio/proximity/st,vl53l0x.yaml    |   7 +-
 MAINTAINERS                                   |   7 +
 drivers/iio/proximity/Kconfig                 |  14 +
 drivers/iio/proximity/Makefile                |   1 +
 drivers/iio/proximity/vl53l1x-i2c.c           | 774 ++++++++++++++++++
 5 files changed, 801 insertions(+), 2 deletions(-)
 create mode 100644 drivers/iio/proximity/vl53l1x-i2c.c

--
2.53.0