ARMLinux驱动RTC(实时时钟)驱动分析

时间：11-09 来源：互联网点击：

interrupt.h>#include #include #include #include #include #include #include #include #include static struct resource *s3c_rtc_mem;static void __iomem *s3c_rtc_base;static int s3c_rtc_tickno = NO_IRQ;static DEFINE_SPINLOCK(s3c_rtc_pie_lock);static irqreturn_t s3c_rtc_tickirq(int irq, void *id){struct rtc_device *rdev = id;rtc_update_irq(rdev, 1, RTC_PF | RTC_IRQF);return IRQ_HANDLED;}/* Update control registers */static void s3c_rtc_setaie(int to){unsigned int tmp;pr_debug("%s: aie=%d\n", __func__, to);tmp = readb(s3c_rtc_base + S3C2410_RTCALM) & ~S3C2410_RTCALM_ALMEN;if (to)tmp |= S3C2410_RTCALM_ALMEN;writeb(tmp, s3c_rtc_base + S3C2410_RTCALM);}static int s3c_rtc_setpie(struct device *dev, int enabled){unsigned int tmp;pr_debug("%s: pie=%d\n", __func__, enabled);spin_lock_irq(&s3c_rtc_pie_lock);tmp = readb(s3c_rtc_base + S3C2410_TICNT) & ~S3C2410_TICNT_ENABLE;if (enabled)tmp |= S3C2410_TICNT_ENABLE;writeb(tmp, s3c_rtc_base + S3C2410_TICNT);spin_unlock_irq(&s3c_rtc_pie_lock);return 0;}static int s3c_rtc_setfreq(struct device *dev, int freq){unsigned int tmp;spin_lock_irq(&s3c_rtc_pie_lock);tmp = readb(s3c_rtc_base + S3C2410_TICNT) & S3C2410_TICNT_ENABLE;tmp |= (128 / freq)-1;writeb(tmp, s3c_rtc_base + S3C2410_TICNT);spin_unlock_irq(&s3c_rtc_pie_lock);return 0;}/* Time read/write */static int s3c_rtc_gettime(struct device *dev, struct rtc_time *rtc_tm){unsigned int have_retried = 0;void __iomem *base = s3c_rtc_base;retry_get_time:rtc_tm->tm_min = readb(base + S3C2410_RTCMIN);rtc_tm->tm_hour = readb(base + S3C2410_RTCHOUR);rtc_tm->tm_mday = readb(base + S3C2410_RTCDATE);rtc_tm->tm_mon = readb(base + S3C2410_RTCMON);rtc_tm->tm_year = readb(base + S3C2410_RTCYEAR);rtc_tm->tm_sec = readb(base + S3C2410_RTCSEC);/* the only way to work out wether the system was mid-update* when we read it is to check the second counter, and if it* is zero, then we re-try the entire read*/if (rtc_tm->tm_sec == 0 && !have_retried) {have_retried = 1;goto retry_get_time;}pr_debug("read time %02x.%02x.%02x %02x/%02x/%02x\n",rtc_tm->tm_year, rtc_tm->tm_mon, rtc_tm->tm_mday,rtc_tm->tm_hour, rtc_tm->tm_min, rtc_tm->tm_sec);rtc_tm->tm_sec = bcd2bin(rtc_tm->tm_sec);rtc_tm->tm_min = bcd2bin(rtc_tm->tm_min);rtc_tm->tm_hour = bcd2bin(rtc_tm->tm_hour);rtc_tm->tm_mday = bcd2bin(rtc_tm->tm_mday);rtc_tm->tm_mon = bcd2bin(rtc_tm->tm_mon);rtc_tm->tm_year = bcd2bin(rtc_tm->tm_year);rtc_tm->tm_year += 100;rtc_tm->tm_mon -= 1;return 0;}static int s3c_rtc_settime(struct device *dev, struct rtc_time *tm){void __iomem *base = s3c_rtc_base;int year = tm->tm_year - 100;pr_debug("set time %02d.%02d.%02d %02d/%02d/%02d\n",tm->tm_year, tm->tm_mon, tm->tm_mday,tm->tm_hour, tm->tm_min, tm->tm_sec);/* we get around y2k by simply not supporting it */if (year < 0 || year >= 100) {dev_err(dev, "rtc only supports 100 years\n");return -EINVAL;}writeb(bin2bcd(tm->tm_sec), base + S3C2410_RTCSEC);writeb(bin2bcd(tm->tm_min), base + S3C2410_RTCMIN);writeb(bin2bcd(tm->tm_hour), base + S3C2410_RTCHOUR);writeb(bin2bcd(tm->tm_mday), base + S3C2410_RTCDATE);writeb(bin2bcd(tm->tm_mon + 1), base + S3C2410_RTCMON);writeb(bin2bcd(year), base + S3C2410_RTCYEAR);return 0;}static int s3c_rtc_open(struct device *dev){struct platform_device *pdev = to_platform_device(dev);struct rtc_device *rtc_dev = platform_get_drvdata(pdev);int ret;ret = request_irq(s3c_rtc_tickno, s3c_rtc_tickirq,IRQF_DISABLED, "s3c2410-rtc tick", rtc_dev);if (ret) {dev_err(dev, "IRQ%d error %d\n", s3c_rtc_tickno, ret);goto tick_err;}tick_err:return ret;}static void s3c_rtc_release(struct device *dev){struct platform_device *pdev = to_platform_device(dev);struct rtc_device *rtc_dev = platform_get_drvdata(pdev);/* do not clear AIE here, it may be needed for wake */s3c_rtc_setpie(dev, 0);free_irq(s3c_rtc_tickno, rtc_dev);}static const struct rtc_class_ops s3c_rtcops = {.open = s3c_rtc_open,.release = s3c_rtc_release,.read_time = s3c_rtc_gettime,.set_time = s3c_rtc_settime,.irq_set_freq = s3c_rtc_setfreq,.irq_set_state = s3c_rtc_setpie,};static void s3c_rtc_enable(struct platform_device *pdev, int en){void __iomem *base = s3c_rtc_base;unsigned int tmp;if (s3c_rtc_base == NULL)return;if (!en) {tmp = readb(base + S3C2410_RTCCON);writeb(tmp & ~S3C2410_RTCCON_RTCEN, base + S3C2410_RTCCON);tmp = readb(base + S3C2410_TICNT);writeb(tmp & ~S3C2410_TICNT_ENABLE, base + S3C2410_TICNT);} else {/* re-enable the device, and check it is ok */if ((readb(base+S3C2410_RTCCON) & S3C2410_RTCCON_RTCEN) == 0){dev_info(&pdev->dev, "rtc disabled, re-enabling\n");tmp = readb(base + S3C2410_RTCCON);writeb(tmp|S3C2410_RTCCON_RTCEN, base+S3C2410_RTCCON);}if ((readb(base + S3C2410_RTCCON) & S3C2410_RTCCON_CNTSEL)){dev_info(&pdev->dev, "removing RTCCON_CNTSEL\n");tmp = readb(base + S3C2410_RTCCON);writeb(tmp& ~S3C2410_RTCCON_CNTSEL, base+S3C2410_RTCCON);}if ((readb(base + S3C2410_RTCCON) & S3C2410_RTCCON_CLKRST)){dev_info(&pdev->dev, "removing RTCCON_CLKRST\n");tmp = readb(base + S3C2410_RTCCON);writeb(tmp & ~S3C2410_RTCCON_CLKRST, base+S3C2410_RTCCON);}}}static int __devexit s3c_rtc_remove(struct platform_device *dev){struct rtc_device *rtc = platform_get_drvdata(dev);platform_set_drvdata(dev, NULL);rtc_device_unregister(rtc);s3c_rtc_setpie(&dev->dev, 0);s3c_rtc_setaie(0);iounmap(s3c_rtc_base);release_resource(s3c_rtc_mem);kfree(s3c_rtc_mem);return 0;}static int __devinit s3c_rtc_probe(struct platform_device *pdev){struct rtc_device *rtc;struct resource *res;int ret;pr_debug("%s: probe=%p\n", __func__, pdev);/* find the IRQs */s3c_rtc_tickno = platform_get_irq(pdev, 1);if (s3c_rtc_tickno < 0) {dev_err(&pdev->dev, "no irq for rtc tick\n");return -ENOENT;}/* get the memory region */res = platform_get_resource(pdev, IORESOURCE_MEM, 0);if (res == NULL) {dev_err(&pdev->dev, "failed to get memory region resource\n");return -ENOENT;}s3c_rtc_mem = request_mem_region(res->start,res->end-res->start+1,pdev->name);if (s3c_rtc_mem == NULL) {dev_err(&pdev->dev, "failed to reserve memory region\n");ret = -ENOENT;goto err_nores;}s3c_rtc_base = ioremap(res->start, res->end - res->start + 1);if (s3c_rtc_base == NULL) {dev_err(&pdev->dev, "failed ioremap()\n");ret = -EINVAL;goto err_nomap;}/* check to see if everything is setup correctly */s3c_rtc_enable(pdev, 1);pr_debug("s3c2410_rtc: RTCCON=%02x\n",readb(s3c_rtc_base + S3C2410_RTCCON));s3c_rtc_setfreq(&pdev->dev, 1);/* register RTC and exit */rtc = rtc_device_register("s3c", &pdev->dev, &s3c_rtcops,THIS_MODULE);if (IS_ERR(rtc)) {dev_err(&pdev->dev, "cannot attach rtc\n");ret = PTR_ERR(rtc);goto err_nortc;}rtc->max_user_freq = 128;platform_set_drvdata(pdev, rtc);return 0;err_nortc:s3c_rtc_enable(pdev, 0);iounmap(s3c_rtc_base);err_nomap:release_resource(s3c_rtc_mem);err_nores:return ret;}static struct platform_driver s3c2410_rtc_driver = {.probe = s3c_rtc_probe,.remove = __devexit_p(s3c_rtc_remove),.driver = {.name = "s3c2410-rtc",.owner = THIS_MODULE,},};static char __initdata banner[] = "S3C24XX RTC, (c) 2004,2006 Simtec Electronics\n";static int __init s3c_rtc_init(void){printk(banner);return platform_driver_register(&s3c2410_rtc_driver);}static void __exit s3c_rtc_exit(void){platform_driver_unregister(&s3c2410_rtc_driver);}module_init(s3c_rtc_init);module_exit(s3c_rtc_exit);MODULE_DESCRIPTION("My

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