[yocto] FrameBuffer support

[Martin Townsend]

Hi Jonathan,

On Mon, Sep 19, 2016 at 11:01 AM, Jonathan Vervaeke
<jonathan.vervaeke at basalte.be> wrote:
> Hi,
>
>
>
> I'm trying to make framebuffers work on imx6(ul) using yocto.
>
>
>
> I suppose I need to make changes in the following:
>
> 1) Kernel modules
>
> 2) Device tree
>
> 3) U-Boot bootargs
>
>
>
> I've build my kernel with the following modules
>
>
> ********************************************
>
> FB_TFT=y
>
> CONFIG_FB_TFT_ILI9325=m
>
> ********************************************
>
>
> I added the following to the device tree
>
>
>
> ********************************************
>
> / {
>      itdb28 {
>         compatible = "ilitek,ili9325";
>         status = "okay";
>
>         rotate = <0>;
>         bgr;
>         buswidth = <8>;
>         reset-gpios = <&gpio3 23 0>;
>         dc-gpios = <&gpio3  5 0>;
>         cs-gpios = <&gpio3  1 0>;
>         wr-gpios = <&gpio3  0 0>;
>         db-gpios = <&gpio3  7 0>,
>                <&gpio3  8 0>,
>                <&gpio3  9 0>,
>                <&gpio3 10 0>,
>                <&gpio3 11 0>,
>                <&gpio3 15 0>,
>                <&gpio3 16 0>,
>                <&gpio3 17 0>;
>         /* LED pin drives backlight directly. Use transistor (50mA) */
>         /* led-gpios = <&gpio 4 1>; */
>         debug = <7>;
>     };
>
>
>     framebuffer {
>         compatible = "simple-framebuffer";
>         reg = <0x1d385000 (240 * 320 * 2)>;
>         width = <240>;
>         height = <320>;
>         stride = <(240 * 2)>;
>         format = "r5g6b5";
>     };
> };
>
> ********************************************
>
>
> When I boot, I get the following error:
>
>
>
> ********************************************
>
> Error opening /dev/fb0: No such file or directory
>
> ********************************************
>
>
> Did I forget something or is there a decent manual available?
>
> Thanks!
>
> Jonathan.
>
>
> --
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>

Looks to me like the driver hasn't loaded due to error or maybe
compatible string mismatch.  Have you included the simple framebuffer
in the kernel configuration?  Is there anything in dmesg?

Cheers, Martin.