Driving the ili9488 LCD (4.0 inch cheap chinese clone)

[forumtrekker]

Good to know. I'm interested in getting the red LCD's to work as they are cheaper and more available, I purchased the waveshare only to test my SPI, SBC, and DTS formatting were functional. Now that I confirmed how to translate DTS to work with my SBC, I can work on the red ili9486/8 without worrying about it being a formatting issue.

[forumtrekker]

I think I have a partial success but I'm struggling to get anything but white on the red display! Will update when I have more results. panel-mipi is loading, and Card-1-SPI appears under /sys/class/drm/ which is very promising. Verified that /lib/firmware/panel-mipi-dbi-spi is still present, still patched with Kungfupancake's init, and is loaded according to lsmod (as well as dmesg)

 

Spoiler

 

sudo dmesg | grep drm
[    4.002790] rockchip-drm display-subsystem: bound ff900000.vop (ops vop_component_ops [rockchipdrm])
[    4.004049] rockchip-drm display-subsystem: bound ff8f0000.vop (ops vop_component_ops [rockchipdrm])
[    4.028685] rockchip-drm display-subsystem: bound ff940000.hdmi (ops dw_hdmi_rockchip_ops [rockchipdrm])
[    4.030113] [drm] Initialized rockchip 1.0.0 for display-subsystem on minor 0
[    4.030278] rockchip-drm display-subsystem: [drm] Cannot find any crtc or sizes
[    4.030440] rockchip-drm display-subsystem: [drm] Cannot find any crtc or sizes
[    6.796700] systemd[1]: Starting modprobe@drm.service - Load Kernel Module drm...
[    6.863822] systemd[1]: modprobe@drm.service: Deactivated successfully.
[    6.864868] systemd[1]: Finished modprobe@drm.service - Load Kernel Module drm.
[    8.238975] [drm] Initialized panel-mipi-dbi 1.0.0 for spi1.0 on minor 1
[    8.345046] [drm] Initialized panfrost 1.4.0 for ff9a0000.gpu on minor 2
[    9.048179] panel-mipi-dbi-spi spi1.0: [drm] fb0: panel-mipi-dbid frame buffer device

sudo dmesg | grep mipi
[    8.230250] panel-mipi-dbi-spi spi1.0: supply power not found, using dummy regulator
[    8.230448] panel-mipi-dbi-spi spi1.0: supply io not found, using dummy regulator
[    8.238975] [drm] Initialized panel-mipi-dbi 1.0.0 for spi1.0 on minor 1
[    9.048179] panel-mipi-dbi-spi spi1.0: [drm] fb0: panel-mipi-dbid frame buffer device

sudo dmesg | grep spi
[    8.074489] OF: /spi@ff1d0000/ads7846@1: Read of boolean property 'ti,swap-xy' with a value.
[    8.076419] ads7846 spi1.1: touchscreen, irq 77
[    8.078736] input: ADS7846 Touchscreen as /devices/platform/ff1d0000.spi/spi_master/spi1/spi1.1/input/input0
[    8.230250] panel-mipi-dbi-spi spi1.0: supply power not found, using dummy regulator
[    8.230448] panel-mipi-dbi-spi spi1.0: supply io not found, using dummy regulator
[    8.238975] [drm] Initialized panel-mipi-dbi 1.0.0 for spi1.0 on minor 1
[    9.048179] panel-mipi-dbi-spi spi1.0: [drm] fb0: panel-mipi-dbid frame buffer device

sudo ls -al /sys/class/drm/
total 0
drwxr-xr-x  2 root root    0 Dec 31  1969 .
drwxr-xr-x 73 root root    0 Dec 31  1969 ..
lrwxrwxrwx  1 root root    0 Dec  5 01:28 card0 -> ../../devices/platform/display-subsystem/drm/card0
lrwxrwxrwx  1 root root    0 Dec  5 01:28 card0-HDMI-A-1 -> ../../devices/platform/display-subsystem/drm/card0/card0-HDMI-A-1
lrwxrwxrwx  1 root root    0 Dec  5 01:29 card1 -> ../../devices/platform/ff1d0000.spi/spi_master/spi1/spi1.0/drm/card1
lrwxrwxrwx  1 root root    0 Dec  5 01:28 card1-SPI-1 -> ../../devices/platform/ff1d0000.spi/spi_master/spi1/spi1.0/drm/card1/card1-SPI-1
lrwxrwxrwx  1 root root    0 Dec  5 01:29 card2 -> ../../devices/platform/ff9a0000.gpu/drm/card2
lrwxrwxrwx  1 root root    0 Dec  5 01:29 renderD128 -> ../../devices/platform/ff9a0000.gpu/drm/renderD128

 

 

My current DTS:

Spoiler

/dts-v1/;

/ {

    fragment@0 {
        target = <0xffffffff>;

        __overlay__ {
            status = "okay";
            #address-cells = <0x01>;
            #size-cells = <0x00>;

            ili9486@0 {
                compatible = "panel-mipi-dbi-spi";
                reg = <0>;
                spi-max-frequency = <40000000>;
                reset-gpios = <0xffffffff 0x1d 0x00>;
                dc-gpios = <0xffffffff 0x1c 0x00>;
                                write-only;
                                format = "b6x2g6x2r6x2";
                                width-mm= <84>;
                                height-mm=<56>;
                                panel-timing {
                                        hactive = <480>;
                                        vactive = <320>;
                                        hback-porch = <0>;
                                        vback-porch = <0>;
                                        clock-frequency = <0>;
                                        hfront-porch = <0>;
                                        hsync-len = <0>;
                                        vfront-porch = <0>;
                                        vsync-len = <0>;
                                };
            };

            ads7846@1 {
                compatible = "ti,ads7846";
                status = "okay";
                reg = <1>;
                id = <1>;
                spi-max-frequency = <2000000>;
                ti,x-plate-ohms = [00 3c];
                ti,pressure-max = [00 ff];
                ti,swap-xy = <0>;
                ti,invert-y = <1>;
                vcc-supply = <0xffffffff>;
                interrupts = <0x12 0x02>;
                interrupt-parent = <0xffffffff>;
                pendown-gpio = <0xffffffff 0x12 0x00>;
                phandle = <0x02>;
            };
        };
    };

    metadata {
        title = "Enable ili9486/8 Red LCD 3.5inch on SPI1";
        compatible = "rockchip,rk3399";
        category = "misc";
        exclusive = "GPIO1_B0\0GPIO1_A7\0GPIO1_B1\0GPIO1_B2\0GPIO4_D2\0GPIO4_D4\0GPIO4_D5";
        description = "Enable Waveshare 3.5inch RPi LCD (C) on SPI1.";
    };

    fragment@1 {
        target = <0xffffffff>;

        __overlay__ {
            num-cs = <0x02>;
            cs-gpios = <0xffffffff 0x0a 0x00 0xffffffff 0x1a 0x00>;
            pinctrl-names = "default\0high_speed";
            pinctrl-0 = <0xffffffff 0xffffffff 0xffffffff>;
        };
    };

    __symbols__ {
        ili9486 = "/fragment@0/__overlay__/ili9486@0";
        ads7846 = "/fragment@0/__overlay__/ads7846@1";
    };

    __fixups__ {
        spi1 = "/fragment@0:target:0\0/fragment@1:target:0";
        gpio4 = "/fragment@0/__overlay__/ili9486@0:reset-gpios:0\0/fragment@0/__overlay__/ili9486@0:dc-gpios:0\0/fragment@0/__overlay__/ads7846@1:interrupt-parent:0\0/fragment@0/__overlay__/ads7846@1:pendown-gpio:0\0/fragment@1/__overlay__:cs-gpios:12";
        vcc5v0_sys = "/fragment@0/__overlay__/ads7846@1:vcc-supply:0";
        gpio1 = "/fragment@1/__overlay__:cs-gpios:0";
        spi1_clk = "/fragment@1/__overlay__:pinctrl-0:0";
        spi1_rx = "/fragment@1/__overlay__:pinctrl-0:4";
        spi1_tx = "/fragment@1/__overlay__:pinctrl-0:8";
    };
};

 

 

Edit: I installed XFCE to test, and strangely this has caused dmesg to throw errors related to panel-mipi. I had these same errors when panel-mipi was missing from /lib/firmware but it is still present there.

Spoiler

sudo dmesg | grep mipi

[ 4.601157] panel-mipi-dbi-spi spi1.0: supply power not found, using dummy regulator

[ 4.601515] panel-mipi-dbi-spi spi1.0: supply io not found, using dummy regulator

[ 4.601904] panel-mipi-dbi-spi spi1.0: Direct firmware load for panel-mipi-dbi-spi.bin failed wit

h error -2

[ 4.601941] panel-mipi-dbi-spi spi1.0: No config file found for compatible 'panel-mipi-dbi-spi' (

error=-2)

[ 4.601960] panel-mipi-dbi-spi spi1.0: probe with driver panel-mipi-dbi-spi failed with error -2

 

Edited 52 minutes ago by forumtrekker