IST3602 Character LCD
-----------------------------------------------------

Required properties:
- compatible              : Specify "ist,ist3602"
- lcd-supply              : phandle of lcd regulator
- lcd_bright-supply       : phandle of backlight regulator
- dimmer-gpios            : GPIO for Dimmer
- lcd_en-gpios            : GPIO for Power to enable LCD
- lcd_rst-gpios           : GPIO for LCD reset
- display-width-chars     : Number of columns in the LCD module
- display-height-chars    : Number of lines in the LCD module
- display-font-size       : Vertical font size (1-4)
- contrast                : Contrast (0-255)
- ragulation-ratio        : Regulation Ratio (2 + 0.5 * (0-15))
- contrast-dimmer         : Contrast when dimmer on (0-255)
- ragulation-ratio-dimmer : Regulation Ratio when dimmer on (0-15)
- column-offset           : Column address offset (Optional)
- frame-rate              : Frame rate(15-300[Hz])
- bias                    : Set Voltage follow Bias(0:1/4, 1:1/5, 2:1/6, 3:1/7)
- booster                 : Set booster(0:5X, 1:6X, 2:7X, 3:8X)
- boot_on                 : Enable on boot-up
- boot_message            : Message to be displayed at startup
- dimmer_on_boot          : Whether to enable Dimmer at startup
- enable_dimmer_gpio      : Enable to control Dimmer gpio
- backlight_link          : Turn backlight on/off with turning display on/off


Example:
	spilcddev@0 {
		reg = <0>;
		compatible = "ist,ist3602";
		spi-max-frequency   = <5000000>;
		pinctrl-names = "default", "sleep";
		pinctrl-0 = <&pinctrl_ecspi2_1>;
		pinctrl-1 = <&pinctrl_ecspi2_2>;
		lcd-supply = <&pcont_lcd>;
		lcd_bright-supply = <&pcont_lcd_bright>;
		dimmer-gpios = <&ioexp 1 GPIO_ACTIVE_LOW>;
		lcd_rst-gpios = <&ioexp 19 GPIO_ACTIVE_LOW>;
		display-width-chars = <16>;
		display-height-chars = <2>;
		display-fonts-size = <1>;
		contrast = <170>;
		regulation-ratio = <8>;
		contrast-dimmer = <90>;
		regulation-ratio-dimmer = <8>;
		column-offset = <8>;
		frame-rate = <150>;
		bias = <0>;
		booster = <0>;
		boot_on;
		boot_message = "HELLO";
		dimmer_on_boot;
		backlight_link;
	};
