AXI HDMI HDL

AXI HDMI HDL Linux Driver.

Supported Devices

This driver supports the ADV7511 HDL project

Description

The AXI HDMI HDL driver is the driver for the HDL graphics core which is used on various FPGA designs interfacing to the ADV7511. The driver is implemented as a DRM KMS driver.

Source Code

Status

Source

Mainlined?

drivers/gpu/drm/analog/analog_drm_drv.c

WIP

Files

Function

File

driver

drivers/gpu/drm/adi/axi_hdmi_drv.c

driver

drivers/gpu/drm/adi/axi_hdmi_drv.h

driver

drivers/gpu/drm/adi/axi_hdmi_crtc.c

driver

drivers/gpu/drm/adi/axi_hdmi_encoder.c

Example platform device initialization

The AXI HDMI driver is a platform driver and can currently only be instantiated via device tree.

Required devicetree properties:

  • compatible: Should always be adi,cf-adv7x11-core-1.00.a

  • reg: Base address and register area size. This parameter expects two register ranges. The first for the axi-hdmi core’s registers and the second for the axi-clockgen core’s registers.

  • slave_adapter: Phandle to the I2C device on which the ADV7511 can be found

  • dma-request: Phandle to the Xilinx VDMA device

Example:

axi_iic_0: i2c@41600000 {
    compatible = "xlnx,axi-iic-1.01.b", "xlnx,xps-iic-2.00.a";
    interrupt-parent = <&gic>;
    interrupts = <0 56 0x4>;
    reg = <0x41600000 0x10000>;

    #size-cells = <0>;
    #address-cells = <1>;
};

axi_vdma_0: axivdma@43000000 {
    #address-cells = <1>;
    #size-cells = <1>;
    #dma-cells = <1>;
    compatible = "xlnx,axi-vdma";
    reg = <0x43000000 0x1000>;
    xlnx,include-sg = <0x0>;
    xlnx,num-fstores = <0x3>;
    dma-channel@7e200000 {
        compatible = "xlnx,axi-vdma-mm2s-channel";
        interrupts = <0 59 0x4>;
        xlnx,datawidth = <0x40>;
        xlnx,genlock-mode = <0x0>;
        xlnx,include-dre = <0x0>;
    };
};

axi-hdmi@6c000000 {
    compatible = "adi,cf-axi-hdmi-1.00.a";
    reg = <0x6c000000 0x10000
           0x66000000 0x10000>;
    slave_adapter = <&axi_iic_0>;
    dma-request = <&axi_vdma_0 0>;
};

Enabling Linux driver support

Configure kernel with make menuconfig (alternatively use make xconfig or make qconfig)

Note

The DRM AXI HDMI driver depends on CONFIG_DRM

Linux Kernel Configuration
    Device Drivers  --->
        Graphics support  --->
            <*> Direct Rendering Manager (XFree86 4.1.0 and higher DRI support)  --->
            ...
            <*> DRM Support for Analog FPGA platforms

Driver testing

Using the framebuffer console

The driver can be tested using the Linux framebuffer console.

Enable framebuffer support in the kernel config:

Linux Kernel Configuration
    Device Drivers  --->
        Graphics support  --->
            ...
                        Console display driver support  --->
                        <*> Framebuffer Console support
                        ...

Using Xorg

The Xorg graphical environment can be used with driver either using xf86-video-fbdev or the xf86-video-modesetting Xorg module.

xf86-video-fbdev

The fbdev driver will bind to the device by default, if no other driver has been bound to the device. This usually means that running a Xorg server without any additional configuration changes will come up with the fbdev driver.

xf86-video-modesetting

The xf86-video-modesetting driver is a driver which has been written to take advantage of the new Kernel Mode Setting (KMS) API of the DRM layer. This allows to switch between different screen resolutions at runtime (using the Xservers xrandr interface) and adds plug-and-play support for monitors.

To enable the modesetting driver the following section has to be added to the Xorg config (/etc/X11/xorg.org).

Section "Device"
  Identifier "ADV7511 HDMI"
  Driver "modesetting"
EndSection

Others

Since the driver registers a Linux framebuffer device it is possible to use any application or toolkit which has support for it to display graphics on the HDMI output. This for example includes DirectFB, mplayer and SDL.

More information

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