Linux 内核时钟架构之时钟源设备注册

/**  * __clocksource_register_scale - Used to install new clocksources  * @cs:  clocksource to be registered  * @scale: Scale factor multiplied against freq to get clocksource hz  * @freq: clocksource frequency (cycles per second) divided by scale  *  * Returns -EBUSY if registration fails, zero otherwise.  *  * This *SHOULD NOT* be called directly! Please use the  * clocksource_register_hz() or clocksource_register_khz helper functions.  */ int __clocksource_register_scale(struct clocksource *cs, u32 scale, u32 freq) {

 /* Initialize mult/shift and max_idle_ns */  __clocksource_update_freq_scale(cs, scale, freq);

 /* Add clocksource to the clocksource list */  mutex_lock(&clocksource_mutex);  clocksource_enqueue(cs);  clocksource_enqueue_watchdog(cs);  clocksource_select();  clocksource_select_watchdog(false);  mutex_unlock(&clocksource_mutex);  return 0; } EXPORT_SYMBOL_GPL(__clocksource_register_scale);