蜗窝科技
蜗窝科技

为什么这个DTS不好用呢

蜗窝讨论区存档 · Linux kernel技术问答 · 楼主 Kerry · 2016-07-28 · 6 帖

本文是原「蜗窝讨论区」的历史存档（2016-07-28），来自版块「Linux kernel技术问答」，共 6 帖。讨论区已停止服务，此处仅供查阅。

Kerry · 2016-07-28 13:51

这个定义是好用的，

** 写道：**

/ { model = "××××××××××××"; compatible = "××××××××××××××××"; #address-cells = <1>; #size-cells = <1>;

pll2: pll2 {
    #clock-cells = &lt;0&gt;;
    compatible = "fixed-clock";
    clock-frequency = &lt;800000000&gt;;
};

sdclk0: sdclk1 {
compatible = “fixed-factor-clock”;
#clock-cells = &lt;0&gt;;
clock-div = &lt;1&gt;;
clock-mult = &lt;1&gt;;
clocks = &lt;&amp;pll2&gt;;
clock-output-names = “ahbs”;
};


gate_sd1: gate_sd1 {
compatible = “xacti,ev9x-gates-sd-clk”;
#clock-cells = &lt;0&gt;;
reg = &lt;0x300A3010 0x4&gt;;
div_reg = &lt;0x30000A34&gt;;
clocks = &lt;&amp;pll2&gt;;
};


gate_sd0: gate_sd0 {
compatible = “xacti,ev9x-gates-sd-clk”;
#clock-cells = &lt;0&gt;;
reg = &lt;0x300A3000 0x4&gt;;
div_reg = &lt;0x30000A30&gt;;
clocks = &lt;&amp;pll2&gt;;
};

gate_sd2: gate_sd2 { compatible = "xacti,ev9x-gates-sd-clk"; #clock-cells = <0>; reg = <0x300A3040 0x4>; div_reg = <0x30000A38>; clocks = <&pll2>; };

sdhci: sdhci@21A10000 {
    compatible = "inrevium,te4395-sdhci";
    reg = &lt;0x21A10000 0x1000&gt;;
    int_mod = &lt;0x300A30F0 0x0020&gt;;
    int_stt = &lt;0x300A30F4 0x0020&gt;;
    clocks = &lt;&amp;gate_sd1&gt;;
    interrupt-parent = &lt;&amp;vic0&gt;;
    interrupts = &lt;21&gt;;
};

这个定义是不好用的，

** 写道：**

/ { model = "××××××××××××"; compatible = "××××××××××××××××"; #address-cells = <1>; #size-cells = <1>;

pll2: pll2 {
    #clock-cells = &lt;0&gt;;
    compatible = "fixed-clock";
    clock-frequency = &lt;800000000&gt;;
};

sdclk0: sdclk1 {
compatible = “fixed-factor-clock”;
#clock-cells = &lt;0&gt;;
clock-div = &lt;1&gt;;
clock-mult = &lt;1&gt;;
clocks = &lt;&amp;pll2&gt;;
clock-output-names = “ahbs”;
};


gate_sd0: gate_sd0 {
compatible = “xacti,ev9x-gates-sd-clk”;
#clock-cells = &lt;0&gt;;
reg = &lt;0x300A3000 0x4&gt;;
div_reg = &lt;0x30000A30&gt;;
clocks = &lt;&amp;pll2&gt;;
};


gate_sd1: gate_sd1 {
compatible = “xacti,ev9x-gates-sd-clk”;
#clock-cells = &lt;0&gt;;
reg = &lt;0x300A3010 0x4&gt;;
div_reg = &lt;0x30000A34&gt;;
clocks = &lt;&amp;pll2&gt;;
};

gate_sd2: gate_sd2 { compatible = "xacti,ev9x-gates-sd-clk"; #clock-cells = <0>; reg = <0x300A3040 0x4>; div_reg = <0x30000A38>; clocks = <&pll2>; };

sdhci: sdhci@21A10000 {
    compatible = "inrevium,te4395-sdhci";
    reg = &lt;0x21A10000 0x1000&gt;;
    int_mod = &lt;0x300A30F0 0x0020&gt;;
    int_stt = &lt;0x300A30F4 0x0020&gt;;
    clocks = &lt;&amp;gate_sd1&gt;;
    interrupt-parent = &lt;&amp;vic0&gt;;
    interrupts = &lt;21&gt;;
};

我的sdhci用的是gate_sd1时钟， 在这里把gate_sd1写在前面就好用，是为什么呢， 在代码里会调用devm_clk_get获取时钟

** 写道：**

pltfm_host-&gt;clk = devm_clk_get(&amp;pdev-&gt;dev, NULL);
if (IS_ERR(pltfm_host-&gt;clk)) {
    ret = PTR_ERR(pltfm_host-&gt;clk);
    pr_info("devm_clk_get( failed, return %d, got clk:%p\n", ret, pltfm_host-&gt;clk);
    goto err;
}

错误时的输出：

** 写道：**

devm_clk_get( failed, return -517, got clk:fffffdfb

是不是很奇怪

wowo · 2016-07-28 17:09

Kerry 写道： 这个定义是好用的，

** 写道：**

/ { model = "××××××××××××"; compatible = "××××××××××××××××"; #address-cells = <1>; #size-cells = <1>;

pll2: pll2 {
    #clock-cells = &lt;0&gt;;
    compatible = "fixed-clock";
    clock-frequency = &lt;800000000&gt;;
};

sdclk0: sdclk1 {
compatible = “fixed-factor-clock”;
#clock-cells = &lt;0&gt;;
clock-div = &lt;1&gt;;
clock-mult = &lt;1&gt;;
clocks = &lt;&amp;pll2&gt;;
clock-output-names = “ahbs”;
};


gate_sd1: gate_sd1 {
compatible = “xacti,ev9x-gates-sd-clk”;
#clock-cells = &lt;0&gt;;
reg = &lt;0x300A3010 0x4&gt;;
div_reg = &lt;0x30000A34&gt;;
clocks = &lt;&amp;pll2&gt;;
};


gate_sd0: gate_sd0 {
compatible = “xacti,ev9x-gates-sd-clk”;
#clock-cells = &lt;0&gt;;
reg = &lt;0x300A3000 0x4&gt;;
div_reg = &lt;0x30000A30&gt;;
clocks = &lt;&amp;pll2&gt;;
};

gate_sd2: gate_sd2 { compatible = "xacti,ev9x-gates-sd-clk"; #clock-cells = <0>; reg = <0x300A3040 0x4>; div_reg = <0x30000A38>; clocks = <&pll2>; };

sdhci: sdhci@21A10000 {
    compatible = "inrevium,te4395-sdhci";
    reg = &lt;0x21A10000 0x1000&gt;;
    int_mod = &lt;0x300A30F0 0x0020&gt;;
    int_stt = &lt;0x300A30F4 0x0020&gt;;
    clocks = &lt;&amp;gate_sd1&gt;;
    interrupt-parent = &lt;&amp;vic0&gt;;
    interrupts = &lt;21&gt;;
};

这个定义是不好用的，

** 写道：**

/ { model = "××××××××××××"; compatible = "××××××××××××××××"; #address-cells = <1>; #size-cells = <1>;

pll2: pll2 {
    #clock-cells = &lt;0&gt;;
    compatible = "fixed-clock";
    clock-frequency = &lt;800000000&gt;;
};

sdclk0: sdclk1 {
compatible = “fixed-factor-clock”;
#clock-cells = &lt;0&gt;;
clock-div = &lt;1&gt;;
clock-mult = &lt;1&gt;;
clocks = &lt;&amp;pll2&gt;;
clock-output-names = “ahbs”;
};


gate_sd0: gate_sd0 {
compatible = “xacti,ev9x-gates-sd-clk”;
#clock-cells = &lt;0&gt;;
reg = &lt;0x300A3000 0x4&gt;;
div_reg = &lt;0x30000A30&gt;;
clocks = &lt;&amp;pll2&gt;;
};


gate_sd1: gate_sd1 {
compatible = “xacti,ev9x-gates-sd-clk”;
#clock-cells = &lt;0&gt;;
reg = &lt;0x300A3010 0x4&gt;;
div_reg = &lt;0x30000A34&gt;;
clocks = &lt;&amp;pll2&gt;;
};

gate_sd2: gate_sd2 { compatible = "xacti,ev9x-gates-sd-clk"; #clock-cells = <0>; reg = <0x300A3040 0x4>; div_reg = <0x30000A38>; clocks = <&pll2>; };

sdhci: sdhci@21A10000 {
    compatible = "inrevium,te4395-sdhci";
    reg = &lt;0x21A10000 0x1000&gt;;
    int_mod = &lt;0x300A30F0 0x0020&gt;;
    int_stt = &lt;0x300A30F4 0x0020&gt;;
    clocks = &lt;&amp;gate_sd1&gt;;
    interrupt-parent = &lt;&amp;vic0&gt;;
    interrupts = &lt;21&gt;;
};

我的sdhci用的是gate_sd1时钟， 在这里把gate_sd1写在前面就好用，是为什么呢， 在代码里会调用devm_clk_get获取时钟

** 写道：**

pltfm_host-&gt;clk = devm_clk_get(&amp;pdev-&gt;dev, NULL);
if (IS_ERR(pltfm_host-&gt;clk)) {
    ret = PTR_ERR(pltfm_host-&gt;clk);
    pr_info("devm_clk_get( failed, return %d, got clk:%p\n", ret, pltfm_host-&gt;clk);
    goto err;
}

错误时的输出：

** 写道：**

devm_clk_get( failed, return -517, got clk:fffffdfb

是不是很奇怪

检查一下DTB文件在内存中，是不是有被覆盖的风险。

tigger · 2016-07-28 19:57

可以看一下wowo之前写的几篇dts的文章，会对你的问题有帮助的～

728330453 · 2016-08-26 12:36

@Kerry

可以在uboot下面，通过以下命令：
fdt addr xxxx（addr of dtb）
fdt print
将你的设备树flash上的内容打印出来，
然后对比，这两个设备树是不是一样的！！！

按照道理来说，先后顺序并不影响在内存中节点的排布以及内容吧！

希望对你有帮助~

Kerry · 2016-11-10 10:42

728330453 写道： @Kerry

可以在uboot下面，通过以下命令：
fdt addr xxxx（addr of dtb）
fdt print
将你的设备树flash上的内容打印出来，
然后对比，这两个设备树是不是一样的！！！

按照道理来说，先后顺序并不影响在内存中节点的排布以及内容吧！

希望对你有帮助~

谢谢你的回复，我没有用uboot。。。。

zhuzhiqiang · 2016-11-15 09:44

没看懂啥意思