2025-3-6_V2.5.1_WalnutPi-1B_6.1.31_debian12_server系统CPU频率被定在了480MHZ，而且好像没用留下更改的接口。

产品（Products） WalnutPi 1（1B / ZeroW / CM1 / BOX）
1

pi@WalnutPi:~/Documents/Pydemo$ cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_available_frequencies
cat: /sys/devices/system/cpu/cpu0/cpufreq/scaling_available_frequencies: No such file or directory
pi@WalnutPi:~/Documents/Pydemo$ cat /proc/cpuinfo
processor : 0
BogoMIPS : 48.00
Features : fp asimd evtstrm aes pmull sha1 sha2 crc32 cpuid
CPU implementer : 0x41
CPU architecture: 8
CPU variant : 0x0
CPU part : 0xd03
CPU revision : 4

processor : 1
BogoMIPS : 48.00
Features : fp asimd evtstrm aes pmull sha1 sha2 crc32 cpuid
CPU implementer : 0x41
CPU architecture: 8
CPU variant : 0x0
CPU part : 0xd03
CPU revision : 4

processor : 2
BogoMIPS : 48.00
Features : fp asimd evtstrm aes pmull sha1 sha2 crc32 cpuid
CPU implementer : 0x41
CPU architecture: 8
CPU variant : 0x0
CPU part : 0xd03
CPU revision : 4

processor : 3
BogoMIPS : 48.00
Features : fp asimd evtstrm aes pmull sha1 sha2 crc32 cpuid
CPU implementer : 0x41
CPU architecture: 8
CPU variant : 0x0
CPU part : 0xd03
CPU revision : 4

pi@WalnutPi:~/Documents/Pydemo$ lscpu
Architecture: aarch64
CPU op-mode(s): 32-bit, 64-bit
Byte Order: Little Endian
CPU(s): 4
On-line CPU(s) list: 0-3
Vendor ID: ARM
Model name: Cortex-A53
Model: 4
Thread(s) per core: 1
Core(s) per cluster: 4
Socket(s): -
Cluster(s): 1
Stepping: r0p4
BogoMIPS: 48.00
Flags: fp asimd evtstrm aes pmull sha1 sha2 crc32 cpuid
NUMA:
NUMA node(s): 1
NUMA node0 CPU(s): 0-3
Vulnerabilities:
Itlb multihit: Not affected
L1tf: Not affected
Mds: Not affected
Meltdown: Not affected
Mmio stale data: Not affected
Retbleed: Not affected
Spec store bypass: Not affected
Spectre v1: Mitigation; __user pointer sanitization
Spectre v2: Not affected
Srbds: Not affected
Tsx async abort: Not affected
pi@WalnutPi:~/Documents/Pydemo$

好像是内核 / DTS 双重锁死了频率，没法更改。不知道有没有什么能人重新编译了 uboot dts 以及镜像。

2

内核驱动 (drivers/mfd/axp20x.c) 找匹配时：
axp305 → 驱动里没有这个型号，跳过
axp805 → 驱动里也没有，跳过
axp806 → 在驱动里！匹配上了！

于是内核用 AXP806 的寄存器去读写实际是 AXP313A 的芯片——寄存器地址完全不同，读回来的电压值全是错的。cpufreq 驱动找不到正确的调压器，就放弃注册了。CPU 锁在默认频率（480MHz），不管你怎么设置 governor 都上不去。

改法很简单：把 compatible 改成 “x-powers,axp313a”，AXP313A 驱动在内核 6.1.31 里已经有了，只是一直没被匹配到。

3 
&r_i2c {
status = “okay”;


    axp313: pmic@36 {
            compatible = "x-powers,axp313a";
            reg = <0x36>;
            #interrupt-cells = <1>;
            interrupt-controller;

            vin1-supply = <&reg_vcc5v>;
            vin2-supply = <&reg_vcc5v>;
            vin3-supply = <&reg_vcc5v>;

            regulators {
                    reg_dcdc1: dcdc1 {
                            regulator-always-on;
                            regulator-min-microvolt = <810000>;
                            regulator-max-microvolt = <1160000>;
                            regulator-name = "vdd-gpu-sys";
                    };

                    reg_dcdc2: dcdc2 {
                            regulator-always-on;
                            regulator-min-microvolt = <810000>;
                            regulator-max-microvolt = <1120000>;
                            regulator-name = "vdd-cpu";
                    };

                    reg_dcdc3: dcdc3 {
                            regulator-always-on;
                            regulator-min-microvolt = <1500000>;
                            regulator-max-microvolt = <1500000>;
                            regulator-name = "vdd-dram";
                    };

                    reg_aldo1: aldo1 {
                            regulator-always-on;
                            regulator-min-microvolt = <1800000>;
                            regulator-max-microvolt = <1800000>;
                            regulator-name = "vcc-1v8";
                    };

                    reg_dldo1: dldo1 {
                            regulator-always-on;
                            regulator-min-microvolt = <3300000>;
                            regulator-max-microvolt = <3300000>;
                            regulator-name = "vcc-3v3";
                    };
            };
    };

};
改了电源节点以后HDMI的电源节点也需要修改

&hdmi {
hvcc-supply = <&reg_aldo1>;
status = “okay”;
};

只是这样修改HDMI将无法显示
因为驱动注册中

AXP_DESC(AXP313A, LDO1, “ldo1”, …)   // of_match = “ldo1”
AXP_DESC(AXP313A, LDO2, “ldo2”, …)   // of_match = “ldo2”

regulator 核心的 OF 匹配流程：

  1. desc->regulators_node = "regulators" → 找到子节点 regulators

  2. desc->of_match = "ldo1" → 在 regulators 下找名为 "ldo1" 的子节点

  3. 找不到！ 因为真实的节点名是 "aldo1" :cross_mark:

  4. → rdev->dev.of_node = NULL

  5. → HDMI 驱动通过 hvcc-supply = <&reg_aldo1> 查找时，phandle 指向的节点没有绑定任何 regulator

  6. → "Couldn't get regulator" → deferred probe
    所以需要修改驱动代码
    在 ~/linux-6.1.31/drivers/regulator/axp20x-regulator.c 中，找到 for 循环里的这段：

                    if ((regulators == axp22x_regulators && i == AXP22X_DC5LDO) ||
                (regulators == axp809_regulators && i == AXP809_DC5LDO)) {
                new_desc = devm_kzalloc(&pdev->dev, sizeof(\*desc),
                        GFP_KERNEL);
                if (!new_desc)
                        return -ENOMEM;

                \*new_desc = regulators\[i\];
                new_desc->supply_name = dcdc5_name;
                desc = new_desc;
        }

        rdev = devm_regulator_register(&pdev->dev, desc, &config);

    **在这两段之间，`rdev = devm_regulator_register` 之前**，插入下面的代码：

                               /*
                 * AXP313A maps its regulator names differently in DTS.
                 * The ALDO1/DLDO1 hardware names are used in DTS nodes,
                 * but the regulator_desc uses generic LDO1/LDO2 names.
                 * Look up the correct OF node for proper phandle matching.
                 */
                if (axp20x->variant == AXP313A_ID) {
                        struct device_node *regs_np, *reg_np;
                        const char *hw_name = NULL;

                        if (!strcmp(regulators[i].name, "ldo1"))
                                hw_name = "aldo1";
                        else if (!strcmp(regulators[i].name, "ldo2"))
                                hw_name = "dldo1";

                        if (hw_name) {
                                regs_np = of_get_child_by_name(
                                        pdev->dev.parent->of_node, "regulators");
                                if (regs_np) {
                                        reg_np = of_get_child_by_name(regs_np, hw_name);
                                        if (reg_np)
                                                config.of_node = reg_np;
                                        of_node_put(regs_np);
                                }
                        }
                }

                rdev = devm_regulator_register(&pdev->dev, desc, &config);

然后编译Image 复制过去，但是串口内核启动过程中会出现

   \[    7.492083\] FAT-fs (mmcblk0p1): IO charset iso8859-1 not found
   \[FAILED\] Failed to mount /boot.

/boot 分区是 FAT 格式，需要 nls_iso8859_1 模块。你的内核配置里：
CONFIG_NLS_ISO8859_1=m ← 是模块，不是编译进内核的
重新编译 make Image 后，新内核的版本字符串变了（因为编译时间戳变了），于是在 /lib/modules/$(uname -r)/ 下找不到旧模块，所以所有 =m 的模块（包括 nls_iso8859_1）都加载不了 → /boot 挂载失败 → 级联到所有依赖它的服务 → 进 emergency shell。
所以记得重新编译modules 一块放回去 或者 把CONFIG_NLS_ISO8859_1=y 编译进内核里（这个方法我没试过，我把modules一块放进roofts，HDMI就好了）