I.MX6 各模块 clock 查询

/*********************************************************************
 *                   I.MX6 各模块 clock 查询
 * 说明：
 *     今天在查资料的时候无意中发现了查看内核时钟频率的方法，这东西
 * 我一直以为不能查，只能通过查看源代码来看。
 *
 *                                   2016-8-1 深圳 南山平山村 曾剑锋
 ********************************************************************/

一、参考文档：
    How to use & access iMX6 peripherals (Examples)
        http://www.imx6rex.com/software/imx6-rex-basic-hw-verification-tests/#dump_clocks

二、参考代码：
    #!/system/bin/sh

    if ! mount|grep -sq '/sys/kernel/debug'; then
        mount -t debugfs none /sys/kernel/debug
    fi

    saved_path=$PWD

    busybox printf "%-24s %-24s %3s %9s\n" "clock" "parent" "use" "rate"

    for foo in $(busybox find /sys/kernel/debug/clock -type d); do
        if [ "$foo" = '/sys/kernel/debug/clock' ]; then
            continue
        fi

        cd $foo

        use="$(cat usecount)"
        rate="$(cat rate)"

        clk="$(busybox basename $foo)"
        cd ..
        parent="$(busybox basename $PWD)"

        if [ "$parent" = 'clock' ]; then
            parent="   ---"
        fi

        busybox printf "%-24s %-24s %2d %10d\n" "$clk" "$parent" "$use" "$rate"

        cd $saved_path
    done

三、输出结果：
    root@android:/data/local # ./clock.sh
    clock                    parent                   use      rate
    ckih_clk                    ---
    ckih2_clk                   ---
    ckil_clk                    ---
    caam_mem_clk                ---
    anaclk_1                    ---
    anaclk_2                    ---
    osc_clk                     ---
    pll6_mlb150_main_clk     osc_clk
    pll7_usb_host_main_clk   osc_clk
    pll1_sys_main_clk        osc_clk
    pll1_sw_clk              pll1_sys_main_clk
    cpu_clk                  pll1_sw_clk
    twd_clk                  cpu_clk
    pll5_video_main_clk      osc_clk
    ipu1_di_clk_0            pll5_video_main_clk
    ipu1_di_clk_1            pll5_video_main_clk
    ipu2_di_clk_0            pll5_video_main_clk
    pll4_audio_main_clk      osc_clk
    asrc_clk                 pll4_audio_main_clk
    gpt_clk                  osc_clk
    pll8_enet_main_clk       osc_clk
    enet_clk                 pll8_enet_main_clk
    sata_clk                 pll8_enet_main_clk
    clko2_clk                osc_clk
    clko_clk                 clko2_clk
    pll2_528_bus_main_clk    osc_clk
    pll2_pfd_352M            pll2_528_bus_main_clk
    ldb_di0_clk              pll2_pfd_352M
    ldb_di1_clk              pll2_pfd_352M
    pll2_pfd_594M            pll2_528_bus_main_clk
    gpu3d_core_clk           pll2_pfd_594M
    gpu3d_shader_clk         pll2_pfd_594M
    gpu2d_core_clk           gpu3d_shader_clk
    pll2_pfd_400M            pll2_528_bus_main_clk
    pll2_200M                pll2_pfd_400M
    mmdc_ch1_axi_clk         pll2_pfd_400M
    usdhc1_clk               pll2_pfd_400M
    usdhc2_clk               pll2_pfd_400M
    emi_clk                  pll2_pfd_400M
    hsi_tx_clk               pll2_pfd_400M
    enfc_clk                 pll2_pfd_400M
    gpmi_io_clk              enfc_clk
    usdhc4_clk               pll2_pfd_400M
    gpmi_bch_clk             usdhc4_clk
    usdhc3_clk               pll2_pfd_400M
    apbh_dma_clk             usdhc3_clk
    gpmi_apb_clk             usdhc3_clk
    gpmi_bch_apb_clk         usdhc3_clk
    ipu2_clk                 pll2_pfd_400M
    periph_clk               pll2_pfd_400M
    ahb_clk                  periph_clk
    sdma_clk                 ahb_clk
    mx6per1_clk              ahb_clk
    pl301_mx6qperl_bch       mx6per1_clk
    ipg_clk                  ahb_clk
    spba_clk                 ipg_clk
    iim_clk                  ipg_clk
    ipg_perclk               ipg_clk
    i2c_clk_0                ipg_perclk
    i2c_clk_1                ipg_perclk
    i2c_clk_2                ipg_perclk
    pwm_clk_0                ipg_perclk
    pwm_clk_1                ipg_perclk
    pwm_clk_2                ipg_perclk
    pwm_clk_3                ipg_perclk
    usboh3_clk               ahb_clk
    hdmi_iahb_clk            ahb_clk
    aips_tz2_clk             ahb_clk
    aips_tz1_clk             ahb_clk
    mmdc_ch0_axi_clk         periph_clk
    gpu3d_axi_clk            mmdc_ch0_axi_clk
    gpu2d_axi_clk            mmdc_ch0_axi_clk
    openvg_axi_clk           gpu2d_axi_clk
    perfmon0_clk             mmdc_ch0_axi_clk
    perfmon2_clk             mmdc_ch0_axi_clk
    pll3_usb_otg_main_clk    osc_clk
    pll3_pfd_720M            pll3_usb_otg_main_clk
    pll3_pfd_508M            pll3_usb_otg_main_clk
    ssi1_clk                 pll3_pfd_508M
    ssi2_clk                 pll3_pfd_508M
    ssi3_clk                 pll3_pfd_508M
    pll3_pfd_454M            pll3_usb_otg_main_clk
    spdif0_clk_0             pll3_pfd_454M
    usb_phy1_clk             pll3_usb_otg_main_clk
    usb_phy3_clk             pll3_usb_otg_main_clk
    usb_phy4_clk             pll3_usb_otg_main_clk
    pll3_sw_clk              pll3_usb_otg_main_clk
    pll3_120M                pll3_sw_clk
    esai_clk                 pll3_sw_clk
    pll3_60M                 pll3_sw_clk
    can_clk_root             pll3_60M
    can1_module_clk          can_clk_root
    can2_module_clk          can_clk_root
    ecspi0_clk               pll3_60M
    ecspi1_clk               pll3_60M
    ecspi2_clk               pll3_60M
    ecspi3_clk               pll3_60M
    ecspi4_clk               pll3_60M
    pll3_80M                 pll3_sw_clk
    uart_clk                 pll3_80M
    asrc_serial_clk          pll3_sw_clk
    mlb150_clk               pll3_sw_clk
    pll3_pfd_540M            pll3_usb_otg_main_clk
    hdmi_isfr_clk            pll3_pfd_540M
    mipi_pllref_clk          pll3_pfd_540M
    axi_clk                  pll3_pfd_540M
    vpu_clk                  axi_clk
    emi_slow_clk             axi_clk
    pcie_axi_clk             axi_clk
    pcie_clk                 pcie_axi_clk
    vdo_axi_clk              axi_clk
    vdoa_clk                 vdo_axi_clk
    ipu2_di_clk_1            pll3_pfd_540M
    ipu1_clk                 pll3_pfd_540M
    perfmon1_clk             ipu1_clk
    ipu1_pixel_clk_0         ipu1_clk
    ipu1_pixel_clk_1         ipu1_clk
    root@android:/data/local #