This version (27 Jan 2021 22:39) was approved by Robin Getz.The Previously approved version (28 Aug 2020 12:37) is available.
Table of Contents
AXI HDMI HDL Linux Driver
Supported Devices
This driver supports the
AXI HDMI HDL
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”)
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
resources/tools-software/linux-drivers/drm/hdl-axi-hdmi.txt · Last modified: 27 Jan 2021 22:35 by Robin Getz