linux RTC 驱动

这个是2.6.24内核自带的驱动，只要在平台上添加好相应的配置即可。

platform驱动+RTC_device驱动

 

/* drivers/rtc/rtc-s3c.c * * Copyright (c) 2004,2006 Simtec Electronics *Ben Dooks, <[e-mail]> *http://armlinux.simtec.co.uk/ * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 as * published by the Free Software Foundation. * * S3C2410/S3C2440/S3C24XX Internal RTC Driver*/#include <linux/module.h>#include <linux/fs.h>#include <linux/string.h>#include <linux/init.h>#include <linux/platform_device.h>#include <linux/interrupt.h>#include <linux/rtc.h>#include <linux/bcd.h>#include <linux/clk.h>#include <asm/hardware.h>#include <asm/uaccess.h>#include <asm/io.h>#include <asm/irq.h>#include <asm/rtc.h>#include <asm/mach/time.h>#include <asm/plat-s3c/regs-rtc.h>/* I have yet to find an S3C implementation with more than one * of these rtc blocks in */static struct resource *s3c_rtc_mem;static void __iomem *s3c_rtc_base;static int s3c_rtc_alarmno = NO_IRQ;static int s3c_rtc_tickno  = NO_IRQ;static int s3c_rtc_freq    = 1;static DEFINE_SPINLOCK(s3c_rtc_pie_lock);static unsigned int tick_count;/* IRQ Handlers */static irqreturn_t s3c_rtc_alarmirq(int irq, void *id){struct rtc_device *rdev = id;rtc_update_irq(rdev, 1, RTC_AF | RTC_IRQF);return IRQ_HANDLED;}static irqreturn_t s3c_rtc_tickirq(int irq, void *id){struct rtc_device *rdev = id;rtc_update_irq(rdev, tick_count++, 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", __FUNCTION__, 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 void s3c_rtc_setpie(int to){unsigned int tmp;pr_debug("%s: pie=%d\n", __FUNCTION__, to);spin_lock_irq(&s3c_rtc_pie_lock);tmp = readb(s3c_rtc_base + S3C2410_TICNT) & ~S3C2410_TICNT_ENABLE;if (to)tmp |= S3C2410_TICNT_ENABLE;writeb(tmp, s3c_rtc_base + S3C2410_TICNT);spin_unlock_irq(&s3c_rtc_pie_lock);}static void s3c_rtc_setfreq(int freq){unsigned int tmp;spin_lock_irq(&s3c_rtc_pie_lock);tmp = readb(s3c_rtc_base + S3C2410_TICNT) & S3C2410_TICNT_ENABLE;s3c_rtc_freq = freq;tmp |= (128 / freq)-1;writeb(tmp, s3c_rtc_base + S3C2410_TICNT);spin_unlock_irq(&s3c_rtc_pie_lock);}/* 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);BCD_TO_BIN(rtc_tm->tm_sec);BCD_TO_BIN(rtc_tm->tm_min);BCD_TO_BIN(rtc_tm->tm_hour);BCD_TO_BIN(rtc_tm->tm_mday);BCD_TO_BIN(rtc_tm->tm_mon);BCD_TO_BIN(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_getalarm(struct device *dev, struct rtc_wkalrm *alrm){struct rtc_time *alm_tm = &alrm->time;void __iomem *base = s3c_rtc_base;unsigned int alm_en;alm_tm->tm_sec  = readb(base + S3C2410_ALMSEC);alm_tm->tm_min  = readb(base + S3C2410_ALMMIN);alm_tm->tm_hour = readb(base + S3C2410_ALMHOUR);alm_tm->tm_mon  = readb(base + S3C2410_ALMMON);alm_tm->tm_mday = readb(base + S3C2410_ALMDATE);alm_tm->tm_year = readb(base + S3C2410_ALMYEAR);alm_en = readb(base + S3C2410_RTCALM);alrm->enabled = (alm_en & S3C2410_RTCALM_ALMEN) ? 1 : 0;pr_debug("read alarm %02x %02x.%02x.%02x %02x/%02x/%02x\n", alm_en, alm_tm->tm_year, alm_tm->tm_mon, alm_tm->tm_mday, alm_tm->tm_hour, alm_tm->tm_min, alm_tm->tm_sec);/* decode the alarm enable field */if (alm_en & S3C2410_RTCALM_SECEN)BCD_TO_BIN(alm_tm->tm_sec);elsealm_tm->tm_sec = 0xff;if (alm_en & S3C2410_RTCALM_MINEN)BCD_TO_BIN(alm_tm->tm_min);elsealm_tm->tm_min = 0xff;if (alm_en & S3C2410_RTCALM_HOUREN)BCD_TO_BIN(alm_tm->tm_hour);elsealm_tm->tm_hour = 0xff;if (alm_en & S3C2410_RTCALM_DAYEN)BCD_TO_BIN(alm_tm->tm_mday);elsealm_tm->tm_mday = 0xff;if (alm_en & S3C2410_RTCALM_MONEN) {BCD_TO_BIN(alm_tm->tm_mon);alm_tm->tm_mon -= 1;} else {alm_tm->tm_mon = 0xff;}if (alm_en & S3C2410_RTCALM_YEAREN)BCD_TO_BIN(alm_tm->tm_year);elsealm_tm->tm_year = 0xffff;return 0;}static int s3c_rtc_setalarm(struct device *dev, struct rtc_wkalrm *alrm){struct rtc_time *tm = &alrm->time;void __iomem *base = s3c_rtc_base;unsigned int alrm_en;pr_debug("s3c_rtc_setalarm: %d, %02x/%02x/%02x %02x.%02x.%02x\n", alrm->enabled, tm->tm_mday & 0xff, tm->tm_mon & 0xff, tm->tm_year & 0xff, tm->tm_hour & 0xff, tm->tm_min & 0xff, tm->tm_sec);alrm_en = readb(base + S3C2410_RTCALM) & S3C2410_RTCALM_ALMEN;writeb(0x00, base + S3C2410_RTCALM);if (tm->tm_sec < 60 && tm->tm_sec >= 0) {alrm_en |= S3C2410_RTCALM_SECEN;writeb(BIN2BCD(tm->tm_sec), base + S3C2410_ALMSEC);}if (tm->tm_min < 60 && tm->tm_min >= 0) {alrm_en |= S3C2410_RTCALM_MINEN;writeb(BIN2BCD(tm->tm_min), base + S3C2410_ALMMIN);}if (tm->tm_hour < 24 && tm->tm_hour >= 0) {alrm_en |= S3C2410_RTCALM_HOUREN;writeb(BIN2BCD(tm->tm_hour), base + S3C2410_ALMHOUR);}pr_debug("setting S3C2410_RTCALM to %08x\n", alrm_en);writeb(alrm_en, base + S3C2410_RTCALM);if (0) {alrm_en = readb(base + S3C2410_RTCALM);alrm_en &= ~S3C2410_RTCALM_ALMEN;writeb(alrm_en, base + S3C2410_RTCALM);disable_irq_wake(s3c_rtc_alarmno);}if (alrm->enabled)enable_irq_wake(s3c_rtc_alarmno);elsedisable_irq_wake(s3c_rtc_alarmno);return 0;}static int s3c_rtc_ioctl(struct device *dev, unsigned int cmd, unsigned long arg){unsigned int ret = -ENOIOCTLCMD;switch (cmd) {case RTC_AIE_OFF:case RTC_AIE_ON:s3c_rtc_setaie((cmd == RTC_AIE_ON) ? 1 : 0);ret = 0;break;case RTC_PIE_OFF:case RTC_PIE_ON:tick_count = 0;s3c_rtc_setpie((cmd == RTC_PIE_ON) ? 1 : 0);ret = 0;break;case RTC_IRQP_READ:ret = put_user(s3c_rtc_freq, (unsigned long __user *)arg);break;case RTC_IRQP_SET:/* check for power of 2 */if ((arg & (arg-1)) != 0 || arg < 1) {ret = -EINVAL;goto exit;}pr_debug("s3c2410_rtc: setting frequency %ld\n", arg);s3c_rtc_setfreq(arg);ret = 0;break;case RTC_UIE_ON:case RTC_UIE_OFF:ret = -EINVAL;} exit:return ret;}static int s3c_rtc_proc(struct device *dev, struct seq_file *seq){unsigned int ticnt = readb(s3c_rtc_base + S3C2410_TICNT);seq_printf(seq, "periodic_IRQ\t: %s\n",     (ticnt & S3C2410_TICNT_ENABLE) ? "yes" : "no" );seq_printf(seq, "periodic_freq\t: %d\n", s3c_rtc_freq);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_alarmno, s3c_rtc_alarmirq,  IRQF_DISABLED,  "s3c2410-rtc alarm", rtc_dev);if (ret) {dev_err(dev, "IRQ%d error %d\n", s3c_rtc_alarmno, ret);return 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;}return ret; tick_err:free_irq(s3c_rtc_alarmno, rtc_dev);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(0);free_irq(s3c_rtc_alarmno, rtc_dev);free_irq(s3c_rtc_tickno, rtc_dev);}static const struct rtc_class_ops s3c_rtcops = {.open= s3c_rtc_open,.release= s3c_rtc_release,.ioctl= s3c_rtc_ioctl,.read_time= s3c_rtc_gettime,.set_time= s3c_rtc_settime,.read_alarm= s3c_rtc_getalarm,.set_alarm= s3c_rtc_setalarm,.proc        = s3c_rtc_proc,};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 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(0);s3c_rtc_setaie(0);iounmap(s3c_rtc_base);release_resource(s3c_rtc_mem);kfree(s3c_rtc_mem);return 0;}static int s3c_rtc_probe(struct platform_device *pdev){struct rtc_device *rtc;struct resource *res;int ret;pr_debug("%s: probe=%p\n", __FUNCTION__, 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;}s3c_rtc_alarmno = platform_get_irq(pdev, 0);if (s3c_rtc_alarmno < 0) {dev_err(&pdev->dev, "no irq for alarm\n");return -ENOENT;}pr_debug("s3c2410_rtc: tick irq %d, alarm irq %d\n", s3c_rtc_tickno, s3c_rtc_alarmno);/* 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(s3c_rtc_freq);/* 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;}#ifdef CONFIG_PM/* RTC Power management control */static int ticnt_save;static int s3c_rtc_suspend(struct platform_device *pdev, pm_message_t state){/* save TICNT for anyone using periodic interrupts */ticnt_save = readb(s3c_rtc_base + S3C2410_TICNT);s3c_rtc_enable(pdev, 0);return 0;}static int s3c_rtc_resume(struct platform_device *pdev){s3c_rtc_enable(pdev, 1);writeb(ticnt_save, s3c_rtc_base + S3C2410_TICNT);return 0;}#else#define s3c_rtc_suspend NULL#define s3c_rtc_resume  NULL#endifstatic struct platform_driver s3c2410_rtcdrv = {.probe= s3c_rtc_probe,.remove= s3c_rtc_remove,.suspend= s3c_rtc_suspend,.resume= s3c_rtc_resume,.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_rtcdrv);}static void __exit s3c_rtc_exit(void){platform_driver_unregister(&s3c2410_rtcdrv);}module_init(s3c_rtc_init);module_exit(s3c_rtc_exit);MODULE_DESCRIPTION("Samsung S3C RTC Driver");MODULE_AUTHOR("Ben Dooks <[e-mail]>");MODULE_LICENSE("GPL");

   

分析如下

1.数据结构

 平台数据

static struct resource s3c_rtc_resource[] = {
 [0] = {
  .start = S3C24XX_PA_RTC,
  .end   = S3C24XX_PA_RTC + 0xff,
  .flags = IORESOURCE_MEM,
 },
 [1] = {
  .start = IRQ_RTC,
  .end   = IRQ_RTC,
  .flags = IORESOURCE_IRQ,
 },
 [2] = {
  .start = IRQ_TICK,
  .end   = IRQ_TICK,
  .flags = IORESOURCE_IRQ
 }
};

struct platform_device s3c_device_rtc = {
 .name    = "s3c2410-rtc",
 .id    = -1,
 .num_resources   = ARRAY_SIZE(s3c_rtc_resource),
 .resource   = s3c_rtc_resource,
};

static struct platform_driver s3c2410_rtc_driver = {
 .probe  = s3c_rtc_probe,
 .remove  = __devexit_p(s3c_rtc_remove),
 .suspend = s3c_rtc_suspend,
 .resume  = s3c_rtc_resume,
 .driver  = {
  .name = "s3c2410-rtc",
  .owner = THIS_MODULE,
 },
};

RTC设备

rtc_device

2.驱动分析

A.平台驱动

1.探测函数主要做了如下的事情

  a.从平台资源中取出相关的配置信息(中断，地址)

  b.内存和端口的映射

  c.使能时钟和设置频率，设置device_init_wakeup

  d.完成实时时钟驱动注册，rtc_device_register，关联相关操作

   e.设置最大频率，并将RTC设备添加到平台设备中。

2.移除函数

      将RTc从平台设备中移除，注销RTC设备

       禁止使能RTC

       禁止告警使能

       IO端口反映射

       释放内存

       内存反映射

B.RTC驱动

   1.文件操作指针结构赋值

    2.完成相应操作

RTC驱动模型分析

 

在文件interface.c中对函数集s3c_rtcops中的各函数进行包装，以供上层函数调用。

rtc-dev.c ：该文件主要实现了RTC字符设备的操作函数集：

static const struct file_operations rtc_dev_fops = {

                                    .owner = THIS_MODULE,

                                    .llseek = no_llseek,

                                    .read = rtc_dev_read,

                                    .poll = rtc_dev_poll,

                                    .unlocked_ioctl = rtc_dev_ioctl,

                                    .open = rtc_dev_open,

                                    .release = rtc_dev_release,

                                    .fasync = rtc_dev_fasync,

                           };

文件interface.c对函数集s3c_rtcops中的各函数进行包装，RTC字符设备函数集rtc_dev_fops 中的操作函数就是通过调用这些被包装后的函数实现对硬件的操作的。