// V4L2 clocks // subdevices: 子设备 camera sensors,TV decoders and encoders // need a clocksignal to be supplied by the system. Often this clock is supplied by the // respective bridge device // clock object // Common Clock Framework 并不适用所有架构 v4l2_clk_register() v4l2_clk_unregister() v4l2_clk_get() v4l2_clk_put() v4l2_clk_enable() v4l2_clk_disable() v4l2_clk_get_rate() v4l2_clk_set_rate()