st7735r.dts

/*
 * Device Tree overlay for st7735r
 *
 */

/dts-v1/;
/plugin/;

/ {
        compatible = "brcm,bcm2835", "brcm,bcm2708", "brcm,bcm2709";

        fragment@0 {
                target = <&spi0>;
                __overlay__ {
                        status = "okay";
                };
        };

        fragment@1 {
                target = <&spidev0>;
                __overlay__ {
                        status = "disabled";
                };
        };
/*
        fragment@2 {
                target = <&spidev1>;
                __overlay__ {
                        status = "disabled";
                };
        };
*/
        fragment@3 {
                target = <&gpio>;
                __overlay__ {
                        st7735r_display_pins: st7735r_display_pins {
                                brcm,pins = <24 25>;
                                brcm,function = <1 1>;
                                brcm,pull = <0 0>;
                        };
                };
        };
/*      fragment@4 {
                target-path = "/";
                __overlay__ {
                        backlight_gpio: backlight_gpio {
                                compatible = "gpio-backlight";
                                gpios = <&gpio 18 1>;
                        };

                        backlight_pwm: backlight_pwm {
                                pinctrl-names = "default";
                                pinctrl-0 = <&backlight_pwm_pins>;
                                status = "okay";
                                compatible = "pwm-backlight";
                                pwms = <&ehrpwm1 1 500000 0>;
                                brightness-levels = <
                                        0  1  2  3  4  5  6  7  8  9
                                        10 11 12 13 14 15 16 17 18 19
                                        20 21 22 23 24 25 26 27 28 29
                                        30 31 32 33 34 35 36 37 38 39
                                        40 41 42 43 44 45 46 47 48 49
                                        50 51 52 53 54 55 56 57 58 59
                                        60 61 62 63 64 65 66 67 68 69
                                        70 71 72 73 74 75 76 77 78 79
                                        80 81 82 83 84 85 86 87 88 89
                                        90 91 92 93 94 95 96 97 98 99
                                        100
                                >;
                                default-brightness-level = <90>;
                        };
                };
        };*/

        fragment@5 {
                target = <&spi0>;
                __overlay__ {
                        /* needed to avoid dtc warning */
                        #address-cells = <1>;
                        #size-cells = <0>;
                        
                        st7735rdisplay: st7735r-display@0{
                                compatible = "jianda,jd-t18003-t01", "sitronix,st7735r";
                                reg = <0>;
                                pinctrl-names = "default";
                                pinctrl-0 = <&st7735r_display_pins>;

                                spi-max-frequency = <32000000>;
                                rotation = <90>;
                                //bgr = <0>;
                                fps = <20>;
                                height = <160>;
                                width = <128>;
                                buswidth = <8>;
                                reset-gpios = <&gpio 25 0>;
                                dc-gpios = <&gpio 24 0>;
                                //led-gpios = <&gpio 18 0>;
                                //backlight = &backlight_gpio;
                                //debug = <0>;
                        };

                };
        };
        __overrides__ {
                speed =     <&st7735rdisplay>,"spi-max-frequency:0";
                rotate =    <&st7735rdisplay>,"rotation:0";
                fps =       <&st7735rdisplay>,"fps:0";
                debug =     <&st7735rdisplay>,"debug:0";
        };
};

In combination with gpio -g mode 18 pwm && gpio -g pwm 18 100 (assuming gpio 18 controls the displays led)

Thanks for the overlay!
Could you post the wiring you used with this overlay?

Trying to get this working with Rpi Zero W and an ST7735S breakout board. My understanding is that ST7735R and S are the same in terms of the interface.
Measuring with a scope and the signals on the SCK, MOSI, CS0 and D/C pins are there (and changing when I write to /dev/fb0).
Confused about the RST pin (GPIO 25, pin 22 on Pi Zero) - it's always 0 while it's supposed to be active low, so it's holding it in reset all the time.
Also confused about the frequency on the SCK pin, supposed to be 32MHz but is actually around 18MHz.