WhyCan Forum(哇酷开发者社区)

/* 
 * This RTC count flow on sun8iw8 platform. 
 * 32.768KHz---   --- [32768 count] --- 
 *              \/                     \___[seconds reg] 
 *              /\                     / 
 * 32KHz    ---   --- [32000 count] --- 
 * 
 * We can calculate how much seconds missing, call sunxi_rtc_fixup. 
 */ 
void sunxi_rtc_fixup(unsigned long long*org_time, unsigned long long *time) 
{ 
    unsigned long long delta; 
    unsigned long long t1, t2; 
    bool out; 

    if (!time) 
        return; 

    if (!org_time) 
    { 
        t1 = (unsigned long long)(V3S_RTC->GP_DATA[6]&(~0x80000000)) << 32; /*readl( base + SUNXI_GPDATA_REG(6))*/ 
        t1 |= (unsigned long)V3S_RTC->GP_DATA[7]; /*readl( base + SUNXI_GPDATA_REG(7))*/ 
    } 
    else 
    { 
        t1 = *org_time; 
    } 
    t2 = *time; 

    out = V3S_RTC->LOSC_CTRL & SUN6I_LOSC_CTRL_EXT_OSC; //if used external 32768Hz oscillator 

    delta = (t2 > t1) ? (t2 - t1) : (t1 - t2); 
    delta = (delta * (OSC_ORG - OSC_32K)) / OSC_ORG; 

    if (out) 
        *time -= delta; 
    else 
        *time += delta; 
}