参考:
linux内核device-tree基础 在设备树里描述platform_device

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在设备树里描述一个mydt的设备，此设备有多种属性及两个子节点，每个子节点也有多种属性. 修改设备树的文本文件: arch/arm/boot/dts/sun8i-h3-orangepi-lite.dts 51 / { 52 model = "Xunlong Orange Pi Lite"; 53 compatible = "xunlong,orangepi-lite", "allwinner,sun8i-h3"; 54 55 mydt@11223344{ 56 compatible = "mydt,test"; 57 hello = "hello", "world"; 58 what = "shift"; 59 hehe = <88>, <99>; 60 haha = <33>; 61 mymac = [11 22 33 44 55 66]; 62 63 dt1 { 64 hello = "hello", "dt1"; 65 what = "what dt1"; 66 hehe = <22>, <88>; 67 haha = <99>; 68 mymac = [11 22 33 44 55 66]; 69 }; 70 dt2 { 71 hello = "hello", "dt2"; 72 what = "what dt2"; 73 hehe = <11>, <44>; 74 haha = <55>; 75 mymac = [11 22 33 44 55 66]; 76 }; 77 }; 修改完成后，重编译并更新使用设备树文件: make dtbs ARCH=arm CROSS_COMPILE=arm-linux-gnueabihf- 编译完成后: arch/arm/boot/dts/sun8i-h3-orangepi-lite.dtb就是所需的设备树文件。 使用新的设备树文件启动系统后，可查看到: / # ls /sys/bus/platform/devices/mydt@11223344/ driver/ modalias power/ uevent driver_override of_node/ subsystem/ / # ls /sys/bus/platform/devices/mydt@11223344/of_node/ compatible dt2/ hehe mymac what dt1/ haha hello name / # ls /sys/bus/platform/devices/mydt@11223344/of_node/dt1/ haha hehe hello mymac name what / # ls /sys/bus/platform/devices/mydt@11223344/of_node/dt1/

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编写一个与mydt平台设备匹配的平台驱动对象，并获取设备的属性及它的子节点属性值. #include #include #include #include int myprobe(struct platform_device *pdev) { struct fwnode_handle *child; const char *p, *p2[2]; int n, n2[2]; char mymac[6]; //取属性what的值 if (device_property_read_string(&pdev->dev, "what", &p) < 0) return -ENODEV; //取属性hello的字符串数组值 if (device_property_read_string_array(&pdev->dev, "hello", p2, 2) < 0) return -ENODEV; //取属性haha的整型值 if (device_property_read_u32_array(&pdev->dev, "haha", &n, 1) < 0) return -ENODEV; //取属性hehe的整型数组 if (device_property_read_u32_array(&pdev->dev, "hehe", n2, 2) < 0) return -ENODEV; //取属性mymac的字节数组 if (device_property_read_u8_array(&pdev->dev, "mymac", mymac, 6) < 0) return -ENODEV; printk(KERN_ERR"in myprobe ...%s ", p); printk(KERN_ERR"%s,%s ", p2[0], p2[1]); printk(KERN_ERR"n = %d ", n); printk(KERN_ERR"n2: %d, %d ", n2[0], n2[1]); printk(KERN_ERR"mymac=%x,%x,%x,%x,%x,%x ", mymac[0], mymac[1], mymac[2], mymac[3], mymac[4], mymac[5]); printk(KERN_ERR"###################################### "); /////////////////////////////////////////////////////////////////// //获取设备子节点的属性值 //循环获取每个子节点的属性值 device_for_each_child_node(&pdev->dev, child) { //取子节点的属性what的值 if (0 <= fwnode_property_read_string(child, "what", &p)) printk(KERN_ERR"child what=%s ", p); //取子节点的属性hello的字符串数组值 if (0 <= fwnode_property_read_string_array(child, "hello", p2, 2)) printk(KERN_ERR"child hello=%s, %s ", p2[0], p2[1]); //取子节点的属性haha的整型值 if (0 <= fwnode_property_read_u32_array(child, "haha", &n, 1)) printk(KERN_ERR"child haha=%d ", n); //取子节点的属性hehe的整型数组 if (0 <= fwnode_property_read_u32_array(child, "hehe", n2, 2)) printk(KERN_ERR"child hehe=%d,%d ", n2[0], n2[1]); //取子节点属性mymac的字节数组 if (0 <= fwnode_property_read_u8_array(child, "mymac", mymac, 6)) printk(KERN_ERR"child mymac=%x,%x,%x,%x,%x,%x ", mymac[0], mymac[1], mymac[2], mymac[3], mymac[4], mymac[5]); printk(KERN_ERR"--------------------- "); } return 0; } int myremove(struct platform_device *pdev) { printk(KERN_ERR"in myremove ... "); return 0; } struct of_device_id ids[] = { {.compatible = "mydt,test"}, {}, }; struct platform_driver pdrv = { .driver = { .name = "mydrv", .owner = THIS_MODULE, .of_match_table = ids, }, .probe = myprobe, .remove = myremove, }; module_platform_driver(pdrv); MODULE_LICENSE("GPL");

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执行结果: /mnt/kernel_coding/30device_tree/01mydrv # insmod test.ko [ 1930.702739] in myprobe ...shift [ 1930.705891] hello,world [ 1930.708362] n = 33 [ 1930.710372] n2: 88, 99 [ 1930.712728] mymac=11,22,33,44,55,66 [ 1930.716210] ###################################### [ 1930.721005] child what=what dt1 [ 1930.724142] child hello=hello, dt1 [ 1930.727553] child haha=99 [ 1930.730170] child hehe=22,88 [ 1930.733048] child mymac=11,22,33,44,55,66 [ 1930.737057] --------------------- [ 1930.740367] child what=what dt2 [ 1930.743503] child hello=hello, dt2 [ 1930.746898] child haha=55 [ 1930.749521] child hehe=11,44 [ 1930.752398] child mymac=11,22,33,44,55,66 [ 1930.756399] ---------------------