ssd1963 and ft5205 device tree overlay

[tiibro]

Hi Folks,

I am adding a 3.5" screen with a capacitive touch panel to a Compute Module 3. You can read about my project here: https://www.raspberrypi.org/forums/viewtopic.php?t=185948.

I can get my screen working with the following commands:

sudo modprobe --first-time flexfb width=320 height=240 regwidth=16 buswidth=16 init=-1,0x01,-2,10,-1,0xE2,0x1D,0x02,0x04,-1,0xE0,0x01,-2,5,-1,0xE0,0x03,-2,5,-1,0X01,-2,10,-1,0XB0,0X00,0X00,0X01,0X3F,0X00,0XEF,0X00,-1,0XF0,0X03,-1,0XE6,0X01,0X06,0X24,-1,0XB4,0X01,0X97,0X00,0X46,0X00,0X00,0X00,0X00,-1,0XB6,0X01,0X6,0X00,0X0D,0X00,0X00,0X00,-1,0X2A,0X00,0X00,0X01,0X3F,-1,0X2B,0X00,0X00,0X00,0XEF,0X00,0XEF,-1,0XB8,0X0F,0X01,0XBA,0X01,-1,0X29,-3

and

sudo modprobe --first-time fbtft_device name=flexpfb gpios=reset:23,dc:5,wr:6,db00:7,db01:8,db02:9,db03:10,db04:11,db05:12,db06:13,db07:14,db08:15,db09:16,db10:17,db11:18,db12:19,db13:20,db14:21,db15:22 rotate=0

then setting fbcp running using

/usr/local/bin/fbcp

I'd like to use a device tree overlay to set these parameters on boot. Here is the dts file I've started:

/dts-v1/;
/plugin/;

/ {
    compatible = "brcm,bcm2810"; /* CM3 */

    fragment@0 {
        target = <&i2c1>;
        __overlay__ {
            status = "okay";
        };
    };

    fragment@1 {
        target = <&gpio>;
        __overlay__ {
            ssd1963_gpio_pins: ssd1963_gpio_pins {
                brcm,pins = <5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23>;
                brcm,function = <1>; /* out */
            };

            ft5206_gpio_pins: ft5206_gpio_pins {
                brcm,pins = <>;
                brcm,function = <1>; /* out */
            };
        };
    };

    fragment@2 {
        target-path = "/soc";
        __overlay__ {
            ssd1963_gpio: ssd1963_gpio {
                compatible = "ssd1963-gpio";
                pinctrl-names = "default";
                pinctrl-0 = <&i80_gpio_pins>;
                #address-cells = <1>;
                #size-cells = <1>;

                width = <320>;
                height = <240>;
                rotate = <0>;
                fps = <20>;
                regwidth = <16>;
                buswidth = <16>;

                reset-gpios = = <&gpio 23 0>;
                dc-gpios = <&gpio 5 0>;
                wr-gpios = <&gpio 6 0>;
                data-gpios = <&gpio 7 0>, /* db0 */
                <&gpio 8 0>, /* db1 */
                <&gpio 9 0>, /* db2 */
                <&gpio 10 0>, /* db3 */
                <&gpio 11 0>, /* db4 */
                <&gpio 12 0>, /* db5 */
                <&gpio 13 0>, /* db6 */
                <&gpio 14 0>, /* db7 */
                <&gpio 15 0>, /* db8 */
                <&gpio 16 0>, /* db9 */
                <&gpio 17 0>, /* db10 */
                <&gpio 18 0>, /* db11 */
                <&gpio 19 0>, /* db12 */
                <&gpio 20 0>, /* db13 */
                <&gpio 21 0>, /* db14 */
                <&gpio 22 0>; /* db15 */

                init = <0x1000001 /* soft_reset */
                0x10000e2 0x1d 0x02 0x04 /* set_pll_mn */
                0x10000e0 0x01       /* set_pll */
                0x10000e0 0x03       /* set_pll */
                0x1000001        /* soft_reset */
                0x10000b0 0x00 0x00 0x01 0x3f 0x00 0xef 0x00 /* set_lcd_mode */
                0x10000f0 0x03 /* set_pixel_data_interface */
                0x10000e6 0x01 0x06 0x24 /* set_lshift_freq */
                0x10000b4 0x01 0x97 0x00 0x46 0x00 0x00 0x00 0x00 /* set_hori_period */
                0x10000b6 0x01 0x06 0x00 0x0D 0x00 0x00 0x00 /* set_vert_period */
                0x100002a 0x00 0x00 0x01 0x3f /* set_column_address */
                0x100002b 0x00 0x00 0x00 0xef 0x00 0xef /* set_page_address */
                0x10000b8 0x0f 0x01 0xba 0x01 /* set_gpio_conf */
                0x1000029>; /* set_display_on */
            };
        };
    };

    fragment@3 {
                target = <&i2c1>;
                __overlay__ {
                        /* needed to avoid dtc warning */
                        #address-cells = <1>;
                        #size-cells = <0>;

                        ft5206: ft5206@38 {
                                compatible = "focaltech,ft5x06";
                                reg = <0x38>;

                /* options need to match driver */
                                /* interrupt-parent = <&gpio>; */
                                /* interrupts = <24 2>; */
                                /* touchscreen-size-x = <320>; */
                                /* touchscreen-size-y = <240>; */
                        };
                };
        };
};

I haven't tried to compile and load because I know there are issues. My questions are:

1. For the TFT I am using the flexfb and fbtft_device drivers, how do I reference these from the dts? I have looked at other examples, but I don't think I've found any parallel (flexpfb) examples. I know that compatible properly links the software (driver?) to the hardware, but I am struggling (sorry).
2. I wonder if I've properly moved the arguements from the modprobe statements and added these to the dts file.
3. I've left space in the dts for the touchscreen control (via FT5206); currently I am struggling to compile a driver (or find a suitable pre-compiled driver). Any advice would be most welcome. I have asked here: https://github.com/notro/rpi-source/issues/29 for help, but maybe that's not the most appropriate place.

Again, any help with my questions/problems listed above would be most welcome. Thanks in advance for the help!

[notro]

1. flexfb doesn't have DT support. You can use any of the fbtft drivers that are MIPI compatible: set_addr_win() uses MIPI_DCSSET*, or 0x2a,2b,2c. However the problem is that you get set_var() as well, which flexfb doesn't set. This means that register MIPI_DCS_SET_ADDRESS_MODE,0x36 is set as well, and the value might not suit your need. It controls flip/mirror/bgr.

2. Turn on debug output and you'll see if the driver has picked up the right values.

[tiibro]

flexfb doesn't have DT support.

I am sorry. I missed this in my research so I apologise for asking.

As dt support isn't available for the flexfb, is the next best option to add the terminal commands into the /etc/rc.local files? Additionally, I use crontab to start other scripts and could add a shell script for the screen, but timing-wise this seems to execute about the same as the rc.local file. Any advice on which is the "better" option?

Thanks.

[notro]

If you use systemd (Raspian): https://github.com/notro/fbtft/wiki#make-it-permanent-debian-jessie-arch-linux-systemd

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