怎样去配置HDMI TX地址的大小呢

HDMI TX 的地址偏移为 0xff980000，它包含 16 个地址段。Register Summary 表的偏移量在软件配置时必须是 4 的倍数。和中断寄存器一样，它的基地址是 0x0100。如果我们要配置它，它的真实地址是 0xff980000+0x0100*4。

3.2。根节点

设备树有一个根节点，所有其他设备节点都是其后代。根节点的完整路径是 /。
表 3.1 根节点属性 [tr]Property NameUsageValue TypeDefinition[/tr]

#address-cells	R		指定 单元格的数量，以表示 root 子项中 reg 属性中的地址。
#size-细胞	R		指定 单元格的数量，以表示 root 子项中 reg 属性中的大小。
模型	R	<字符串>	指定唯一标识系统板型号的字符串。推荐的格式是“制造商，型号”。
兼容的	R	<字符串列表>	指定与此平台兼容的平台架构列表。操作系统可以使用此属性来选择特定于平台的代码。推荐的属性值形式为： “manufacturer,model” 例如： compatible = “fsl,mpc8572ds”
用法图例：R=必需，O=可选，OR=可选但推荐，SD=参见定义

表 3.4 /chosen 节点属性 [tr]Property NameUsageValue TypeDefinition[/tr]

引导参数	○	<字符串>	A string that specifies the boot arguments for the client program. The value could potentially be a null string if no boot arguments are required.
stdout-path	O		A string that specifies the full path to the node representing the device to be used for boot console output. If the character “:” is present in the value it terminates the path. The value may be an alias. If the stdin-path property is not specified, stdout-path should be assumed to define the input device.
stdin-path	O		A string that specifies the full path to the node representing the device to be used for boot console input. If the character “:” is present in the value it terminates the path. The value may be an alias.
Usage legend: R=Required, O=Optional, OR=Optional but Recommended, SD=See Definition

选择的示例
{ bootargs = "root=/dev/nfs rw nfsroot=192.168.1.1 console=ttyS0,115200";}; 可能会遇到旧版本的设备树，其中包含不推荐使用的stdout-path属性形式，称为linux,stdout-path。为了兼容性，如果stdout-path属性不存在，客户端程序可能希望支持linux,stdout-path 。这两个属性的含义和用途是相同的。示例给定具有以下物理内存布局的 64 位 Power 系统：

• RAM：起始地址 0x0，长度 0x80000000 (2 GB)
  
• RAM：起始地址 0x100000000，长度 0x100000000 (4 GB)
  
  

假设#address-cells = <2> 和#size-cells = <2>，内存节点可以定义如下。
Example #1

memory@0 {
    device_type = "memory";
    reg = <0x000000000 0x00000000 0x00000000 0x80000000>;
};
memory@100000000 {
    device_type = "memory";
    reg = <0x000000001 0x00000000 0x00000001 0x00000000>;
};
示例 #2

memory@0 {
    device_type = "memory";
    reg = <0x000000000 0x00000000 0x00000000 0x80000000>;
};
memory@100000000 {
    device_type = "memory";
    reg = <0x000000001 0x00000000 0x00000001 0x00000000>;
};
The reg property is used to define the address and size of the two memory ranges. The 2 GB I/O region is skipped. Note that the #address-cells and #size-cells properties of the root node specify a value of 2, which means that two 32-bit cells are required to define the address and length for the reg property of the memory node.


hdmi_rk_fb: hdmi-rk-fb@ff940000 {
status = "disabled";
compatible = "rockchip,rk3399-hdmi";
reg = <0x0 0xff940000 0x0 0x20000>;
interrupts = ,
;
clocks = <&cru PCLK_HDMI_CTRL>,
<&cru HCLK_HDCP>,
<&cru SCLK_HDMI_CEC>,
<&cru PLL_VPLL>,
<&cru SCLK_HDMI_SFR>;
clock-names = "pclk_hdmi",
"hdcp_clk_hdmi",
"cec_clk_hdmi",
"dclk_hdmi_phy",
"sclk_hdmi_sfr";
resets = <&cru SRST_HDMI_CTRL>;
reset-names = "hdmi";
pinctrl-names = "default", "gpio";
pinctrl-0 = <&hdmi_i2c_xfer &hdmi_cec>;
pinctrl-1 = <&i2c3_gpio>;
rockchip,grf = <&grf>;
power-domains = <&power RK3399_PD_HDCP>;
};
hdmi {
hdmi_i2c_xfer: hdmi-i2c-xfer {
rockchip,pins =
<4 17 RK_FUNC_3 &pcfg_pull_none>,
<4 16 RK_FUNC_3 &pcfg_pull_none>;
};
hdmi_cec: hdmi-cec {
rockchip,pins =
<4 23 RK_FUNC_1 &pcfg_pull_none>;
};
};
i2c3_gpio: i2c3_gpio {
rockchip,pins =
<4 17 RK_FUNC_GPIO &pcfg_pull_none>,
<4 16 RK_FUNC_GPIO &pcfg_pull_none>;
};