NVIDIA tegra isc mgr driver

This file documents the properties used by the isc-mgr driver in tegra platform

Required properties:
- compatible : Should be "nvidia,isc-mgr"
- i2c-bus : Should contain the i2c bus number that the device is attached to tegra for controlling the isc
- csi-port : Should contain the csi port number that the device is attached to tegra for image streaming

Optional properties:
- pwdn-gpios : Should contain the list for gpios to control power in order of aggregator and camera instances
- pwr-items : Map power items to the GPIO item specified in the pwdn-gpios list, starting from 0. For example,
              pwr-item 0 is for the deserializer, while pwr-item 1, 2, 3, 4 are for links 0, 1, 2, 3
- default-power-on : If this property is used, while probing the device, pwdn-gpios are powered on
- interrupt-parent : Should contain interrupt parent for gpio interrupt
- interrupts : Should contain the gpio number that is connected to status pin in isc device
- pwms : PWM property to point to the PWM chip, chip-relative PWM number and period in nano seconds

Example:
isc-mgr.0 {
    compatible = "nvidia,isc-mgr";
    i2c-bus = <2>;
    csi-port = <0>;
    pwdn-gpios = < &gpio TEGRA_GPIO(X, 1) GPIO_ACTIVE_HIGH  /* GMSL_IN1_PDN */
        &gpio TEGRA_GPIO(H, 2) GPIO_ACTIVE_HIGH     /* TA_TV1_TV2_ENA */
        &gpio TEGRA_GPIO(H, 5) GPIO_ACTIVE_HIGH>;   /* TA_TV3_TV4_ENA */
    pwr-items =  <0 1 1 2 2>; /* map pwr-items to pwdn-gpios */
    /* default-power-on; */ /* Deactivate pwdn-gpios */
    interrupt-parent = <&gpio>;
    interrupts = <TEGRA_GPIO(V, 2) 2>; /* gpio PS3 : falling edge sensitive */
    pwms = <&isc_pwm 0 33333333>; /* PWM name, chip-relative PWM number, period in nano seconds */
    status = "okay";
};