* Capella CM3218/CM32180/CM32181 ambient light sensor

nvs_ drivers use the NVidia Sensor (NVS) framework.
See the nvs.txt documentation for NVS DT capabilities.
The nvs_cm3218 ALS sensor driver supports the CM3218, CM32180, and CM32181
devices.

Required properties:
- compatible: Device or generic name.
	      Supported device names:
	      - capella,cm3218x
	      - capella,cm3218
	      - capella,cm32180
	      - capella,cm32181
  Note: If the part is known and is populated, then it can be specified:
	Example: compatible = "capella,cm32181";
	When specifying a device this way, the driver will assume this specific
	device is populated during system boot and will not verify its
	existence.  If, however, the device is unknown or may not be populated,
	then the label, cm3218x, (Example: compatible = "capella,cm3218x";),
	must be used.  This tells the driver to find which device is used.  If
	the device is not found, the driver will unload itself.  This requires
	regulators to be setup correctly for the probe function.
- reg: i2c address of the device. It should be 0x10 or 0x48.
- gpio_irq: GPIO to be used for the interrupt.
  Note: This is required for the CM3218 & CM32180 since these devices require
        an ACK of the interrupt (regardless of whether the interrupt is used or
	not) using the I2C ARA (Alert Response Address).  Defining the GPIO
	allows the driver the device's INT pin visibility for the action
	required.

Optional properties:
- status: set to "ok" or "okay" for normal operation.  Set to anything else
	  to unload the driver without ever communicating with the device.
  Note: The "anything else" above is typically "disabled".
	Since the driver will unload without communicating with the device, the
	device will be left in its POR state.
	This device's POR comes up in an operational mode and will draw power.
	If it is desired to unload the driver leaving the device in a low power
	sleep state, then use the individual sensor disable mechanism below.
- light_disable: Setting this property to <1> will disable the device and
                 unload the driver.
- vdd-supply: regulator supply for the chip
  Note: This is required if the driver is to control the regulator.
- interrupt-parent:  GPIO number
- interrupts:  GPIO macro
  Note: The driver will operate in poll mode if an interrupt is not specified.
	The interrupt-parent/interrupts properties can only be specified with
	the CM32181 device.  If the cm3218x is used for the compatibility
	(defined above) then the gpio_irq (defined above) can be used instead.
- als_cfg: User selection of the configuration register (register 0).
  Note: This allows selection of the ALS_SM and ALS_PERS fields.
- als_psm: User selection of the PSM register.
  Note: This only applies to the CM32181 device.

Example:
	cm3218x@48 {
		compatible = "capella,cm32180";
		reg = <0x48>;
		vdd-supply = <&vdd_3v3>;
		gpio_irq = <&gpio TEGRA_GPIO(X, 3) GPIO_ACTIVE_LOW>;
	};