[问答]

请问RK3288如何利用GPIO解析模拟脉冲信号？

问答对人有帮助，内容完整，我也想知道答案 0 请问RK3288如何利用GPIO解析模拟脉冲信号？ 0
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答案对人有帮助，有参考价值 0 需求：外部有个脉冲发生器，输出<500HZ的方波给RK3288，CPU这边需要计算每秒内的脉冲数分析： 1.大佬建议参考Linux RC框架实现：参考kernel/driver/media/rc（研究了下，没看明白） 2.个人想用用中断实现： A.设置中断为上升沿触发，两个触摸为一个周期，计算两次中断的时间差，即使周期T，脉冲数f=1/T。时间差计算使用kset_set()实现ns级别的时间差计算。（do_gettimeofday()只能实现ms级的的时间差计算） B.在中断函数中，累计中断个数，然后用精准定时器没1S中读取中断数差值。 A: 代码段： /获取当前时间/ if(flag == 0) calltime = ktime_get(); flag++; { /获取当前时间/ rettime = ktime_get(); /计算时间差 ktime_sub(B,A) 计算A-B的时间差这时候获取的时间是纳秒/ delta = ktime_sub(rettime,calltime); calltime = rettime; /转换成微秒/ duration = (unsigned long long) ktime_to_ns(delta) >> 10;//微秒 printk("%s after %lld usecs,ns=%lldn",FUNCTION, duration,ktime_to_us(delta)); } 实际测试发现，用固定500HZ外部输入情况下，每个上升沿触发中断的时间差不固定，从1.72到2.2MS不等，理论值是T = 1/500 = 2ms 效果不太满意； AT5:/ # cat /proc/kmsg cat /proc/kmsg <4>[ 577.658551] hw_gpio_switch_3tobserve_work after 360954181 usecs,ns=369617081 <4>[ 577.658627] start_time = hw_gpio_switch_3tobserve_work <4>[ 577.660506] hw_gpio_switch_3tobserve_work after 1915 usecs,ns=1961 <4>[ 577.660575] start_time = hw_gpio_switch_3tobserve_work <4>[ 577.662525] hw_gpio_switch_3tobserve_work after 1969 usecs,ns=2016 <4>[ 577.662601] start_time = hw_gpio_switch_3tobserve_work <4>[ 577.664535] hw_gpio_switch_3tobserve_work after 1964 usecs,ns=2011 <4>[ 577.664612] start_time = hw_gpio_switch_3tobserve_work <4>[ 577.666805] hw_gpio_switch_3tobserve_work after 2218 usecs,ns=2271 <4>[ 577.666878] start_time = hw_gpio_switch_3tobserve_work <4>[ 577.670876] hw_gpio_switch_3tobserve_work after 2280 usecs,ns=2335 <4>[ 577.672503] hw_gpio_switch_3tobserve_work after 1589 usecs,ns=1627 <4>[ 577.672578] start_time = hw_gpio_switch_3tobserve_work <4>[ 577.677201] hw_gpio_switch_3tobserve_work after 2566 usecs,ns=2627 <4>[ 577.677281] start_time = hw_gpio_switch_3tobserve_work <4>[ 577.680491] hw_gpio_switch_3tobserve_work after 1935 usecs,ns=1982 <4>[ 577.680562] start_time = hw_gpio_switch_3tobserve_work <4>[ 577.682461] hw_gpio_switch_3tobserve_work after 1927 usecs,ns=1974 <4>[ 577.682526] start_time = hw_gpio_switch_3tobserve_work <4>[ 577.684515] hw_gpio_switch_3tobserve_work after 2005 usecs,ns=2053 <4>[ 577.684583] start_time = hw_gpio_switch_3tobserve_work <4>[ 577.686636] hw_gpio_switch_3tobserve_work after 2070 usecs,ns=2119 <4>[ 577.686708] start_time = hw_gpio_switch_3tobserve_work <4>[ 577.688605] hw_gpio_switch_3tobserve_work after 1920 usecs,ns=1966 <4>[ 577.688677] start_time = hw_gpio_switch_3tobserve_work <4>[ 577.690577] hw_gpio_switch_3tobserve_work after 1927 usecs,ns=1974 <4>[ 577.690647] start_time = hw_gpio_switch_3tobserve_work <4>[ 577.692534] hw_gpio_switch_3tobserve_work after 1912 usecs,ns=1958 <4>[ 577.692604] start_time = hw_gpio_switch_3tobserve_work <4>[ 577.694504] hw_gpio_switch_3tobserve_work after 1922 usecs,ns=1968 <4>[ 577.694575] start_time = hw_gpio_switch_3tobserve_work <4>[ 577.696632] hw_gpio_switch_3tobserve_work after 2079 usecs,ns=2129 <4>[ 577.696706] start_time = hw_gpio_switch_3tobserve_work <4>[ 577.698465] hw_gpio_switch_3tobserve_work after 1791 usecs,ns=1834 <4>[ 577.698534] start_time = hw_gpio_switch_3tobserve_work <4>[ 577.700562] hw_gpio_switch_3tobserve_work after 2045 usecs,ns=2095 <4>[ 577.700633] start_time = hw_gpio_switch_3tobserve_work <4>[ 577.702977] hw_gpio_switch_3tobserve_work after 2358 usecs,ns=2415 <4>[ 577.703052] start_time = hw_gpio_switch_3tobserve_work <4>[ 577.708538] hw_gpio_switch_3tobserve_work after 1925 usecs,ns=1971 <4>[ 577.708608] start_time = hw_gpio_switch_3tobserve_work <4>[ 577.710541] hw_gpio_switch_3tobserve_work after 1954 usecs,ns=2001 <4>[ 577.710613] start_time = hw_gpio_switch_3tobserve_work <4>[ 577.712484] hw_gpio_switch_3tobserve_work after 1895 usecs,ns=1941 <4>[ 577.712557] start_time = hw_gpio_switch_3tobserve_work <4>[ 577.714487] hw_gpio_switch_3tobserve_work after 1956 usecs,ns=2003 <4>[ 577.714667] start_time = hw_gpio_switch_3tobserve_work <4>[ 577.716512] hw_gpio_switch_3tobserve_work after 1977 usecs,ns=2025 <4>[ 577.716581] start_time = hw_gpio_switch_3tobserve_work <4>[ 577.718564] hw_gpio_switch_3tobserve_work after 2000 usecs,ns=2048 <4>[ 577.718642] start_time = hw_gpio_switch_3tobserve_work <4>[ 577.720520] hw_gpio_switch_3tobserve_work after 1915 usecs,ns=1961 <4>[ 577.720698] start_time = hw_gpio_switch_3tobserve_work <4>[ 577.722620] hw_gpio_switch_3tobserve_work after 2049 usecs,ns=2098 <4>[ 577.722691] start_time = hw_gpio_switch_3tobserve_work <4>[ 577.724520] hw_gpio_switch_3tobserve_work after 1856 usecs,ns=1900 <4>[ 577.724591] start_time = hw_gpio_switch_3tobserve_work <4>[ 577.726471] hw_gpio_switch_3tobserve_work after 1905 usecs,ns=1951 <4>[ 577.726652] start_time = hw_gpio_switch_3tobserve_work <4>[ 577.728539] hw_gpio_switch_3tobserve_work after 2018 usecs,ns=2067 <4>[ 577.728734] start_time = hw_gpio_switch_3tobserve_work <4>[ 577.730548] hw_gpio_switch_3tobserve_work after 1960 usecs,ns=2007 <4>[ 577.730625] start_time = hw_gpio_switch_3tobserve_work <4>[ 577.732556] hw_gpio_switch_3tobserve_work after 1961 usecs,ns=2008 <4>[ 577.732627] start_time = hw_gpio_switch_3tobserve_work <4>[ 577.734757] hw_gpio_switch_3tobserve_work after 2149 usecs,ns=2200 <4>[ 577.734830] start_time = hw_gpio_switch_3tobserve_work <4>[ 577.736483] hw_gpio_switch_3tobserve_work after 1687 usecs,ns=1728 <4>[ 577.736553] start_time = hw_gpio_switch_3tobserve_work <4>[ 577.738763] hw_gpio_switch_3tobserve_work after 2224 usecs,ns=2277 <4>[ 577.738840] start_time = hw_gpio_switch_3tobserve_work <4>[ 577.740488] hw_gpio_switch_3tobserve_work after 1686 usecs,ns=1726 <4>[ 577.740557] start_time = hw_gpio_switch_3tobserve_work <4>[ 577.742475] hw_gpio_switch_3tobserve_work after 1937 usecs,ns=1983 <4>[ 577.742549] start_time = hw_gpio_switch_3tobserve_work <4>[ 577.744522] hw_gpio_switch_3tobserve_work after 2001 usecs,ns=2049 <4>[ 577.744595] start_time = hw_gpio_switch_3tobserve_work <4>[ 577.746469] hw_gpio_switch_3tobserve_work after 1900 usecs,ns=1946 <4>[ 577.746650] start_time = hw_gpio_switch_3tobserve_work <4>[ 577.748504] hw_gpio_switch_3tobserve_work after 1987 usecs,ns=2034 <4>[ 577.748576] start_time = hw_gpio_switch_3tobserve_work <4>[ 577.750504] hw_gpio_switch_3tobserve_work after 1953 usecs,ns=2000 <4>[ 577.750572] start_time = hw_gpio_switch_3tobserve_work <4>[ 577.752550] hw_gpio_switch_3tobserve_work after 1996 usecs,ns=2044 <4>[ 577.752624] start_time = hw_gpio_switch_3tobserve_work <4>[ 577.754563] hw_gpio_switch_3tobserve_work after 1966 usecs,ns=2013 <4>[ 577.754635] start_time = hw_gpio_switch_3tobserve_work <4>[ 577.756622] hw_gpio_switch_3tobserve_work after 2011 usecs,ns=2060 <4>[ 577.756695] start_time = hw_gpio_switch_3tobserve_work <4>[ 577.758530] hw_gpio_switch_3tobserve_work after 1863 usecs,ns=1908 <4>[ 577.760699] hw_gpio_switch_3tobserve_work after 2118 usecs,ns=2169 <4>[ 577.762490] hw_gpio_switch_3tobserve_work after 1751 usecs,ns=1793 <4>[ 577.762558] start_time = hw_gpio_switch_3tobserve_work <4>[ 577.764462] hw_gpio_switch_3tobserve_work after 1922 usecs,ns=1968 <4>[ 577.764535] start_time = hw_gpio_switch_3tobserve_work <4>[ 577.766576] hw_gpio_switch_3tobserve_work after 2067 usecs,ns=2117 <4>[ 577.766644] start_time = hw_gpio_switch_3tobserve_work <4>[ 577.768514] hw_gpio_switch_3tobserve_work after 1892 usecs,ns=1938 <4>[ 577.768583] start_time = hw_gpio_switch_3tobserve_work <4>[ 577.770500] hw_gpio_switch_3tobserve_work after 1936 usecs,ns=1983 <4>[ 577.770573] start_time = hw_gpio_switch_3tobserve_work <4>[ 577.772541] hw_gpio_switch_3tobserve_work after 1992 usecs,ns=2040 <4>[ 577.772612] start_time = hw_gpio_switch_3tobserve_work <4>[ 577.774604] hw_gpio_switch_3tobserve_work after 2017 usecs,ns=2065 <4>[ 577.774760] start_time = hw_gpio_switch_3tobserve_work <4>[ 577.780518] hw_gpio_switch_3tobserve_work after 1902 usecs,ns=1947 <4>[ 577.780582] start_time = hw_gpio_switch_3tobserve_work <4>[ 577.782522] hw_gpio_switch_3tobserve_work after 1953 usecs,ns=2000 <4>[ 577.782597] start_time = hw_gpio_switch_3tobserve_work <4>[ 577.788530] hw_gpio_switch_3tobserve_work after 1904 usecs,ns=1950 <4>[ 577.788597] start_time = hw_gpio_switch_3tobserve_work AT5:/ # 听大佬说参考RK 红外遥控的实现，绑定CPU core处理中断 cpumask_clear(&cpumask); cpumask_set_cpu(cpu_id, &cpumask); irq_set_affinity(hw_gpio_switch_1->irq[3], &cpumask); 依旧没有改善换一种思路，由于脉冲脉宽是和车速有关系的，并不是唯一的，只计算脉冲跳转，然后用定时器（高精度定时器hrtime）每个1秒读取脉冲个数, 核心代码如下： static struct hrtimer hrtimer_pluse_timer; static int pluse_time_out_ms = 1000 ;//每隔1秒，定时器函数调用一次 static int pluse_count = 0; //static ktime_t calltime; //static int flag; static enum hrtimer_restart hrtimer_pluse_timer_poll(struct hrtimer timer) { #if 0 static ktime_t rettime; static ktime_t delta; unsigned long long duration; /获取当前时间/ if(flag == 0) calltime = ktime_get(); flag++; //if(flag%10 == 0) { /获取当前时间/ rettime = ktime_get(); /计算时间差 ktime_sub(B,A) 计算A-B的时间差这时候获取的时间是纳秒/ delta = ktime_sub(rettime,calltime); calltime = rettime; /转换成微秒/ //duration = (unsigned long long) ktime_to_ns(delta) >> 10;//微秒 duration = (unsigned long long )ktime_to_ns(delta); printk("%s after %lld usecs,ns=%lldn",FUNCTION, duration,ktime_to_us(delta)); } #endif printk("simon%s:%d,pluse_count = %dn",FUNCTION,LINE,pluse_count); // hrtimer_forward(timer, timer->base->get_time(), m_kt);//hrtimer_forward(timer, now, tick_period); hw_gpio_switch_1->status[4] = pluse_count; switch_set_state(&hw_gpio_switch_1->sdev[4], hw_gpio_switch_1->status[4]); pluse_count = 0; hrtimer_start(&hrtimer_pluse_timer, ktime_set(pluse_time_out_ms / 1000, (pluse_time_out_ms % 1000) * 1000000),HRTIMER_MODE_REL); return HRTIMER_RESTART; } hrtimer_init(&hrtimer_pluse_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); hrtimer_pluse_timer.function = hrtimer_pluse_timer_poll; hrtimer_start(&hrtimer_pluse_timer, ktime_set(pluse_time_out_ms / 1000, (pluse_time_out_ms % 1000) * 1000000),HRTIMER_MODE_REL); 实现效果还可以： <4>[ 119.949466] *simonhrtimer_pluse_timer_poll:456,pluse_count = 500 <4>[ 121.950783] *simonhrtimer_pluse_timer_poll:456,pluse_count = 500 <4>[ 123.951533] *simonhrtimer_pluse_timer_poll:456,pluse_count = 501 <4>[ 125.952791] *simonhrtimer_pluse_timer_poll:456,pluse_count = 500 <4>[ 126.952911] *simonhrtimer_pluse_timer_poll:456,pluse_count = 500 <4>[ 127.953029] *simonhrtimer_pluse_timer_poll:456,pluse_count = 500 <4>[ 128.953149] *simonhrtimer_pluse_timer_poll:456,pluse_count = 500 <4>[ 129.953268] *simonhrtimer_pluse_timer_poll:456,pluse_count = 500 <4>[ 132.954622] *simonhrtimer_pluse_timer_poll:456,pluse_count = 500 <4>[ 140.958945] *simonhrtimer_pluse_timer_poll:456,pluse_count = 499 <4>[ 146.962185] *simonhrtimer_pluse_timer_poll:456,pluse_count = 500 <4>[ 147.962321] *simonhrtimer_pluse_timer_poll:456,pluse_count = 500 <4>[ 148.962462] *simonhrtimer_pluse_timer_poll:456,pluse_count = 500 <4>[ 149.962595] *simonhrtimer_pluse_timer_poll:456,pluse_count = 500 <4>[ 152.963971] *simonhrtimer_pluse_timer_poll:456,pluse_count = 500 <4>[ 156.965962] *simonhrtimer_pluse_timer_poll:456,pluse_count = 500 <4>[ 157.966079] *simonhrtimer_pluse_timer_poll:456,pluse_count = 500 <4>[ 158.966194] *simonhrtimer_pluse_timer_poll:456,pluse_count = 500 <4>[ 160.966950] *simonhrtimer_pluse_timer_poll:456,pluse_count = 499 提交代码，发布版本测试。

2022-3-3 09:30:05 评论举报康大争