字符设备驱动实例（PWM和RTC）

目录

五、PWM

六、RTC

---

五、PWM

        PWM(Pulse Width Modulation，脉宽调制器)，顾名思义就是一个输出脉冲宽度可以调整的硬件器件，其实它不仅脉冲宽度可调，频率也可以调整。它的核心部件是一个硬件定时器，其工作原理可以用下图来说明。

        PWM 管脚默认输出高电平，在图中的时刻1将数值设为 109，比较值设为109，在时刻2启动定时器，PWM 立即输出低电平，在时钟的作用下，计数器开始做减法计数，当计数值减到和比较值一致时(时刻 3)，输出翻转，之后一直输出高电平。当计数到达0后(时刻4)，再完成一次计数，在时刻5 重新从 109 开始计数，输出再次变成低电平，如此周而复始就形成一个矩形波。波形的周期由计数值决定，占空比由比较值决定。在图中，占空比为 110/160，如果用于计数的时钟频率为 freq，那么波形的频率就为freg/160。
        FS4412使用了其中一路PWM 输出 (PWMO，对应管脚是GPD0.0)接蜂鸣器，其电路原理图如图所示。

PWM0的内部结构如图所示。


        PWM 的输入时钟是 PCLK，经过8位的预分频后再经过第二次分频的时钟最终给到PWMO所对应的计数器0。TCNTB0是计数值寄存器，用于控制PWM输出波形的频率TCMPB0是比较寄存器，用于控制 PWM 输出波形的占空比，其输出还可以选择是否反向，是否有死区控制等(关于死区暂时不做介绍，感兴趣的同学可以了解一下电机控制)。
        接下来以PWM0为例，来讨论 PWM 的各寄存器（重点关注相关位)

 

 TCON寄存器主要用timer0

        TCON寄存器的比特1比较特殊，当要手动更新TCNTBO或TCMPBO的值时，先将对应的值写入寄存器，然后将 TCON 寄存器的比特1先置1再清0，这样新的值才会生效。
        设备树节点的源码如下。

    beep@139D0000 {compatible = "fs4412,fspwm";reg=<0x139D0000 0x24>;clocks=<&clock 336>;clock-names="timers";pinctrl-0=<pwm0 out>;pinctrI-names ="default";
};

        因为 PWM 使用到了一个时钟，在这里的 clocks 属性指定了 PWM 所使用的时钟clock-names 属性则给该时钟取了一个名字叫 timers，方便在驱动中获取该时钟。时钟的编号可以查看Documentation/devicetree/bindings/clock/exynos4-clock.txt内核文档。pinctrl-0属性则描述了PWM使用的GPIO管脚，它指定管脚是pwm0_out，相应的设备树节点定义在arch/arm/boot/dts/exynos4x12-pinctrldtsi，内容如下。

    pwm0_out:pwm0-out {samsung,pins = "gpd0-0";samsung,pin-function = <2>;samsung,pin-drv = <0>;samsung,pin-drv=<0>;};

        有了这个节点的定义后，我们在驱动中可以利用 pinctrl 子系统的API接口函数快捷地将对应管脚设置为想要的配置方式(我们这里就不详细讨论 pinctrl 子系统，但最常用的一个API将会在后面说明)。上面的节点表示将 GPD0.0管脚配置为功能2，即PWM0 的输出不上拉，驱动强度为最低级别。pinctrl-names 属性是给管脚命名，方便在驱动中获取。

        下面就是时钟子系统和 pinctrl 子系统中最常用的函数。

struct cik *clk_get(struct device *dev, const char *id);
void clk_put (struct clk *clk);
unsigned long clk_get_rate(strut clk *clk);
int clk_set_rate(struct clk *clk, unsigned long rate);
int clk_prepare_enable(struct clk *clk);
void clk_disable_unprepare(struct clk *clk);
struct pinctrl * devm_pinctrl_get_select_default(struct device *dev);

        cik_get: 从dev 中的设备节点中获取名字为 id 的时钟，返回 structclk 结构对象地址，用ISERR宏判断是否错误，用PTR ERR返回错误代码。

        clkput:释放clk。
        clk_get_rate:获取时钟 clk 的频率.

        clk_set_rate:设置时钟clk 的频率。

        clk_prepare_enable:使能时钟。
        clk_disable_unprepare:禁止时钟。
        devm_pinctrl_get_select_default: 从 dev 中的设备节点中获取 pinctrl 管脚，并进行指定的配置。
        有了上面的基础之后，就可以编写相应的驱动代码了。下面的驱动用于驱动蜂鸣器发声，所以应用层应该能够启动 PWM、停止PWM、设置 PWM 输出波形的频率，占空比恒定为50%。关于频率的设置可以利用下面的公式:

out freg= PCIK /(Prescaler0 +1)/ Divider MUX0 / (TCNTBO+1)

主要的代码如下

 

#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>#include <linux/fs.h>
#include <linux/cdev.h>#include <linux/slab.h>
#include <linux/ioctl.h>
#include <linux/uaccess.h>#include <linux/io.h>
#include <linux/ioport.h>
#include <linux/platform_device.h>#include <linux/of.h>
#include <linux/clk.h>
#include <linux/pinctrl/consumer.h>#include "fspwm.h"#define FSPWM_MAJOR	256
#define FSPWM_MINOR	7
#define FSPWM_DEV_NAME	"fspwm"struct fspwm_dev {unsigned int __iomem *tcfg0;unsigned int __iomem *tcfg1;unsigned int __iomem *tcon;unsigned int __iomem *tcntb0;unsigned int __iomem *tcmpb0;unsigned int __iomem *tcnto0;struct clk *clk;unsigned long freq;struct pinctrl	*pctrl;atomic_t available;struct cdev cdev;
};static int fspwm_open(struct inode *inode, struct file *filp)
{struct fspwm_dev *fspwm = container_of(inode->i_cdev, struct fspwm_dev, cdev);filp->private_data = fspwm;if (atomic_dec_and_test(&fspwm->available))return 0;else {atomic_inc(&fspwm->available);return -EBUSY;}
}static int fspwm_release(struct inode *inode, struct file *filp)
{struct fspwm_dev *fspwm = filp->private_data;atomic_inc(&fspwm->available);return 0;
}static long fspwm_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
{struct fspwm_dev *fspwm = filp->private_data;unsigned int div;if (_IOC_TYPE(cmd) != FSPWM_MAGIC)return -ENOTTY;switch (cmd) {case FSPWM_START:writel(readl(fspwm->tcon) | 0x1, fspwm->tcon);break;case FSPWM_STOP:writel(readl(fspwm->tcon) & ~0x1, fspwm->tcon);break;case FSPWM_SET_FREQ:if (arg > fspwm->freq || arg == 0)return -ENOTTY;div = fspwm->freq / arg - 1;writel(div, fspwm->tcntb0);writel(div / 2, fspwm->tcmpb0);writel(readl(fspwm->tcon) | 0x2, fspwm->tcon);writel(readl(fspwm->tcon) & ~0x2, fspwm->tcon);break;default:return -ENOTTY;}return 0;
}static struct file_operations fspwm_ops = {.owner = THIS_MODULE,.open = fspwm_open,.release = fspwm_release,.unlocked_ioctl = fspwm_ioctl,
};static int fspwm_probe(struct platform_device *pdev)
{int ret;dev_t dev;struct fspwm_dev *fspwm;struct resource *res;unsigned int prescaler0;dev = MKDEV(FSPWM_MAJOR, FSPWM_MINOR);ret = register_chrdev_region(dev, 1, FSPWM_DEV_NAME);if (ret)goto reg_err;fspwm = kzalloc(sizeof(struct fspwm_dev), GFP_KERNEL);if (!fspwm) {ret = -ENOMEM;goto mem_err;}platform_set_drvdata(pdev, fspwm);cdev_init(&fspwm->cdev, &fspwm_ops);fspwm->cdev.owner = THIS_MODULE;ret = cdev_add(&fspwm->cdev, dev, 1);if (ret)goto add_err;res = platform_get_resource(pdev, IORESOURCE_MEM, 0);if (!res) {ret = -ENOENT;goto res_err;}fspwm->tcfg0 = ioremap(res->start, resource_size(res));if (!fspwm->tcfg0) {ret = -EBUSY;goto map_err;}fspwm->tcfg1  = fspwm->tcfg0 + 1;fspwm->tcon   = fspwm->tcfg0 + 2;fspwm->tcntb0 = fspwm->tcfg0 + 3;fspwm->tcmpb0 = fspwm->tcfg0 + 4;fspwm->tcnto0 = fspwm->tcfg0 + 5;fspwm->clk = clk_get(&pdev->dev, "timers");if (IS_ERR(fspwm->clk)) {ret =  PTR_ERR(fspwm->clk);goto get_clk_err;}ret = clk_prepare_enable(fspwm->clk);if (ret < 0)goto enable_clk_err;fspwm->freq = clk_get_rate(fspwm->clk);prescaler0 = readl(fspwm->tcfg0) & 0xFF;writel((readl(fspwm->tcfg1) & ~0xF) | 0x4, fspwm->tcfg1); 	/* 1/16 */fspwm->freq /= (prescaler0 + 1) * 16;				/* 3125000 */writel((readl(fspwm->tcon) & ~0xF) | 0x8, fspwm->tcon);		/* auto-reload */fspwm->pctrl = devm_pinctrl_get_select_default(&pdev->dev);atomic_set(&fspwm->available, 1);return 0;enable_clk_err:clk_put(fspwm->clk);
get_clk_err:iounmap(fspwm->tcfg0);
map_err:
res_err:cdev_del(&fspwm->cdev);
add_err:kfree(fspwm);
mem_err:unregister_chrdev_region(dev, 1);
reg_err:return ret;
}static int fspwm_remove(struct platform_device *pdev)
{dev_t dev;struct fspwm_dev *fspwm = platform_get_drvdata(pdev);dev = MKDEV(FSPWM_MAJOR, FSPWM_MINOR);clk_disable_unprepare(fspwm->clk);clk_put(fspwm->clk);iounmap(fspwm->tcfg0);cdev_del(&fspwm->cdev);kfree(fspwm);unregister_chrdev_region(dev, 1);return 0;
}static const struct of_device_id fspwm_of_matches[] = {{ .compatible = "fs4412,fspwm", },{ /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, fspwm_of_matches);struct platform_driver fspwm_drv = { .driver = { .name    = "fspwm",.owner   = THIS_MODULE,.of_match_table = of_match_ptr(fspwm_of_matches),},  .probe   = fspwm_probe,.remove  = fspwm_remove,
};module_platform_driver(fspwm_drv);MODULE_LICENSE("GPL");
MODULE_AUTHOR("name <e-mail>");
MODULE_DESCRIPTION("PWM driver");

#ifndef _FSPWM_H
#define _FSPWM_H#define FSPWM_MAGIC	'f'#define FSPWM_START	_IO(FSPWM_MAGIC, 0)
#define FSPWM_STOP	_IO(FSPWM_MAGIC, 1)
#define FSPWM_SET_FREQ	_IOW(FSPWM_MAGIC, 2, unsigned int)#endif

        代码第 27 行至第 32 行是对应的寄存器虚拟地址成员变量。代码第 33 行是获得的PCLK时钟对象指针。代码第 34 行是计算后得到的送入定时器0的时钟频率。代码第35行是PWM输出管脚所对应的pinctrl对象指针。
        在 fspwm_probe 函数中，和前面一样也是注册字符设备、获取IO资源并进行映射等操作。代码第 142行至第 151 行是获取 PCLK 时钟，然后使能和获取频率的代码。代码第 153 行获得了预分频值。代码第 154 行将二级分频设置为 16，代码第 155 行则计算得到了输入到定时器0的时钟频率。代码第 156 行将定时器设置为自动重装模式，用于持续输出PWM 波形。代码第158 行将 GPDO.0管脚设置为 PWMO的输出。
        在fspwm_ioctl 函数中，FSPWM_START 是启动 PWM 的命令，将TCON 的比特0置1即可。FSPWM_STOP 是停止 PWM 的命令，将 TCON 的比特0清0即可FSPWM_SET_FREQ 是设置频率的命令，首先判断了要设置的频率是否超过了范围和是否合法，接下来根据前面的公式计算出了计数值，然后设置了 TCNTBO和TCMPBO，最后根据前面的描述操作 TCON 的比特 1更新新的计数值和比较值。
测试的应用层头文件代码如下。 

#ifndef _MUSIC_H
#define _MUSIC_Htypedef struct
{int pitch; int dimation;
} note;// 1		2		3		4		5		6       7
// C		D		E		F		G		A	B
// 261.6256	293.6648	329.6276	349.2282	391.9954	440	493.8833// C调
#define DO	262
#define RE	294
#define MI	330
#define FA	349
#define SOL	392
#define LA	440
#define SI	494#define BEAT	(60000000 / 120)const note HappyNewYear[] = {{DO,   BEAT/2}, {DO,   BEAT/2}, {DO,   BEAT}, {SOL/2, BEAT},{MI,   BEAT/2}, {MI,   BEAT/2}, {MI,   BEAT}, {DO,    BEAT},{DO,   BEAT/2}, {MI,   BEAT/2}, {SOL,  BEAT}, {SOL,    BEAT},{FA,   BEAT/2}, {MI,   BEAT/2}, {RE,   BEAT}, {RE,    BEAT},{RE,   BEAT/2}, {MI,   BEAT/2}, {FA,   BEAT}, {FA,    BEAT},{MI,   BEAT/2}, {RE,   BEAT/2}, {MI,   BEAT}, {DO,    BEAT},{DO,   BEAT/2}, {MI,   BEAT/2}, {RE,   BEAT}, {SOL/2, BEAT},{SI/2, BEAT/2}, {RE,   BEAT/2}, {DO,   BEAT}, {DO,    BEAT},
};#endif

        note 表示的是一个音符，pitch 表示音高，dimation 表示音符演奏的时间HappyNewYear是《新年好》歌曲的各音符表示。测试的应用层代码如下

#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/ioctl.h>
#include <fcntl.h>
#include <errno.h>#include "fspwm.h"
#include "music.h"#define ARRAY_SIZE(a)	(sizeof(a) / sizeof(a[0]))int main(int argc, char *argv[])
{int i;int fd;int ret;unsigned int freq;fd = open("/dev/pwm", O_RDWR);if (fd == -1)goto fail;ret = ioctl(fd, FSPWM_START);if (ret == -1)goto fail;for (i = 0; i < ARRAY_SIZE(HappyNewYear); i++) {ret = ioctl(fd, FSPWM_SET_FREQ, HappyNewYear[i].pitch);if (ret == -1)goto fail;usleep(HappyNewYear[i].dimation);}ret = ioctl(fd, FSPWM_STOP);if (ret == -1)goto fail;exit(EXIT_SUCCESS);
fail:perror("pwm test");exit(EXIT_FAILURE);
}

        代码中首先打开了设备，然后启动了 PWM 输出，在 for 循环中依次取出乐曲中的各个音符，然后设置频率，再延时指定的时间，这就完成了乐曲的演奏，最后停止了 PWM。

        编译和测试的命令如下，如果工作正常会听到《新年好》的音乐声。

 效果我发了个视频还没审核过感兴趣的可以后面看我在csdn上的视频

六、RTC

        RTC(Real Time Clock，实时时钟) 用于产生年、月、日、时、分、秒的硬件器件。现在的计算机系统上几乎都包含了这个器件，有的 RTC 还带闹钟功能。它的工作原理也非常简单，就是将 1Hz 的时钟用于计数，按照不同的进制产生进位，从而生成上面的时间。
        Exynos4412 上自带一个RTC，带闹钟的功能，为了简单，我们省略对这部分内容的讨论，只关心和时间相关的寄存器，见下表。

        上面只列出了秒时间的寄存器，类似的还有分、天、月等。上面涉及一个BCD 码,所谓的BCD码就是用十六进制来表示十进制，比如0x59就是十进制的59。Linux内核提供了两者之间相互转换的宏，bcd2bin 是将 BCD码转换成一般的整形数，bin2bcd 则相反。
        下面是RTC的设备树节点。

    rtc@100700000 {compatible = "fs4412,fsrtc"；reg = <0x10070000 0x100>;clocks = <&clock 346>;clock-names ="rtc";status = "okay";};

        时钟属性请参照 Documentation/devicetree/bindings/clock/exynos4-clock.txt 内核文档status属性设定为okay，是因为该节点在arch/arm/boot/dts/exynos4.dtsi中已经定义过了在那里status 的值为 disabled，表示禁止，要使能该节点就需要将 status 属性改为 okay。

        驱动的实现比较简单，在时间的设置方面，首先将 RTCCON 寄存器的比特0置1然后将时间值转换成 BCD 码再写入到相应的寄存器，最后将 RTCCON 寄存器的比特0清0即可。时间获取则读出寄存器的值，然后将 BCD码转成一般的整数即可。关于时间定义了一个结构 struct rtc_time，请参见源码的头文件。关键的驱动代码如下
 

#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>#include <linux/fs.h>
#include <linux/cdev.h>#include <linux/slab.h>
#include <linux/ioctl.h>
#include <linux/uaccess.h>#include <linux/io.h>
#include <linux/ioport.h>
#include <linux/platform_device.h>#include <linux/of.h>
#include <linux/clk.h>
#include <linux/pinctrl/consumer.h>
#include <linux/bcd.h>#include "fsrtc.h"#define FSRTC_MAJOR	256
#define FSRTC_MINOR	8
#define FSRTC_DEV_NAME	"fsrtc"struct fsrtc_dev {unsigned int __iomem *rtccon;unsigned int __iomem *bcdsec;unsigned int __iomem *bcdmin;unsigned int __iomem *bcdhour;unsigned int __iomem *bcdday;unsigned int __iomem *bcdmon;unsigned int __iomem *bcdyear;struct clk *clk;atomic_t available;struct cdev cdev;
};static int fsrtc_open(struct inode *inode, struct file *filp)
{struct fsrtc_dev *fsrtc = container_of(inode->i_cdev, struct fsrtc_dev, cdev);filp->private_data = fsrtc;if (atomic_dec_and_test(&fsrtc->available))return 0;else {atomic_inc(&fsrtc->available);return -EBUSY;}
}static int fsrtc_release(struct inode *inode, struct file *filp)
{struct fsrtc_dev *fsrtc = filp->private_data;atomic_inc(&fsrtc->available);return 0;
}static long fsrtc_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
{struct fsrtc_dev *fsrtc = filp->private_data;struct rtc_time time;if (_IOC_TYPE(cmd) != FSRTC_MAGIC)return -ENOTTY;switch (cmd) {case FSRTC_SET:if (copy_from_user(&time, (struct rtc_time __user *)arg, sizeof(struct rtc_time)))return -ENOTTY;writel(readl(fsrtc->rtccon) | 0x1, fsrtc->rtccon);writel(bin2bcd(time.tm_sec ),  fsrtc->bcdsec);writel(bin2bcd(time.tm_min ),  fsrtc->bcdmin);writel(bin2bcd(time.tm_hour),  fsrtc->bcdhour);writel(bin2bcd(time.tm_mday),  fsrtc->bcdday);writel(bin2bcd(time.tm_mon ),  fsrtc->bcdmon);writel(bin2bcd(time.tm_year - 2000),  fsrtc->bcdyear);writel(readl(fsrtc->rtccon) & ~0x1, fsrtc->rtccon);break;case FSRTC_GET:time.tm_sec  = bcd2bin(readl(fsrtc->bcdsec));time.tm_min  = bcd2bin(readl(fsrtc->bcdmin));time.tm_hour = bcd2bin(readl(fsrtc->bcdhour));time.tm_mday = bcd2bin(readl(fsrtc->bcdday));time.tm_mon  = bcd2bin(readl(fsrtc->bcdmon));time.tm_year = bcd2bin(readl(fsrtc->bcdyear)) + 2000;if (copy_to_user((struct rtc_time __user *)arg, &time, sizeof(struct rtc_time)))return -ENOTTY;break;default:return -ENOTTY;}return 0;
}static struct file_operations fsrtc_ops = {.owner = THIS_MODULE,.open = fsrtc_open,.release = fsrtc_release,.unlocked_ioctl = fsrtc_ioctl,
};static int fsrtc_probe(struct platform_device *pdev)
{int ret;dev_t dev;struct fsrtc_dev *fsrtc;struct resource *res;unsigned int __iomem *regbase;dev = MKDEV(FSRTC_MAJOR, FSRTC_MINOR);ret = register_chrdev_region(dev, 1, FSRTC_DEV_NAME);if (ret)goto reg_err;fsrtc = kzalloc(sizeof(struct fsrtc_dev), GFP_KERNEL);if (!fsrtc) {ret = -ENOMEM;goto mem_err;}platform_set_drvdata(pdev, fsrtc);cdev_init(&fsrtc->cdev, &fsrtc_ops);fsrtc->cdev.owner = THIS_MODULE;ret = cdev_add(&fsrtc->cdev, dev, 1);if (ret)goto add_err;res = platform_get_resource(pdev, IORESOURCE_MEM, 0);if (!res) {ret = -ENOENT;goto res_err;}regbase = ioremap(res->start, resource_size(res));if (!regbase) {ret = -EBUSY;goto map_err;}fsrtc->rtccon     = regbase + 16;fsrtc->bcdsec     = regbase + 28;fsrtc->bcdmin     = regbase + 29;fsrtc->bcdhour    = regbase + 30;fsrtc->bcdday     = regbase + 31;fsrtc->bcdmon     = regbase + 33;fsrtc->bcdyear    = regbase + 34;fsrtc->clk = clk_get(&pdev->dev, "rtc");if (IS_ERR(fsrtc->clk)) {ret =  PTR_ERR(fsrtc->clk);goto get_clk_err;}ret = clk_prepare_enable(fsrtc->clk);if (ret < 0)goto enable_clk_err;writel(0, fsrtc->rtccon);atomic_set(&fsrtc->available, 1);return 0;enable_clk_err:clk_put(fsrtc->clk);
get_clk_err:iounmap(fsrtc->rtccon - 16);
map_err:
res_err:cdev_del(&fsrtc->cdev);
add_err:kfree(fsrtc);
mem_err:unregister_chrdev_region(dev, 1);
reg_err:return ret;
}static int fsrtc_remove(struct platform_device *pdev)
{dev_t dev;struct fsrtc_dev *fsrtc = platform_get_drvdata(pdev);dev = MKDEV(FSRTC_MAJOR, FSRTC_MINOR);clk_disable_unprepare(fsrtc->clk);clk_put(fsrtc->clk);iounmap(fsrtc->rtccon - 16);cdev_del(&fsrtc->cdev);kfree(fsrtc);unregister_chrdev_region(dev, 1);return 0;
}static const struct of_device_id fsrtc_of_matches[] = {{ .compatible = "fs4412,fsrtc", },{ /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, fsrtc_of_matches);struct platform_driver fsrtc_drv = { .driver = { .name    = "fsrtc",.owner   = THIS_MODULE,.of_match_table = of_match_ptr(fsrtc_of_matches),},  .probe   = fsrtc_probe,.remove  = fsrtc_remove,
};module_platform_driver(fsrtc_drv);MODULE_LICENSE("GPL");
MODULE_AUTHOR("name <e-mail>");
MODULE_DESCRIPTION("RTC driver");

 

#ifndef _FSRTC_H
#define _FSRTC_Hstruct rtc_time {int tm_sec;int tm_min;int tm_hour;int tm_mday;int tm_mon;int tm_year;int tm_wday;int tm_yday;
};#define FSRTC_MAGIC	'f'#define FSRTC_SET	_IOW(FSRTC_MAGIC, 0, struct rtc_time)
#define FSRTC_GET	_IOR(FSRTC_MAGIC, 1, struct rtc_time)#endif

        上面的代码比较简单，在此不再多解释。需要注意的是，手册给出的 BCDDAYWEEK和BCDDAY 两个寄存器的地址交换了，需要交换过来。另外，寄存器存放的年份只有3位，所以固定添加了 2000 的偏移。应用层的测试代码也请参见下载资源里面的源码。
        测试的结果如下。

        其实 Linux 内核针对 RTC有一个现成的框架，类似于输入子系统一样，我们只需要使用相应的API，然后再实现要求的接口函数即可。Exynos4412的 RTC 驱动在内核中也已经实现好了，请参见内核源码 drivers/rtc/rtc-s3c.c，这个源码留给大家自己去分析。那么我们要如何使用这个驱动呢?首先将设备树节点改为下面的样子。


        没错，确实这么简单，因为在arch/arm/boot/dts/exynos4.dtsi中已经定义过该节点了现在只需要使能该节点即可。另外就是要确认内核中驱动已经被选配，参见下面的面置项。

 

        重新编译设备树和内核后，复制文件到 TFTP 服务器指定的目录，启动开发板，使用下面的命令可以确认驱动工作正常。

 

 

/* drivers/rtc/rtc-s3c.c** Copyright (c) 2010 Samsung Electronics Co., Ltd.*		http://www.samsung.com/** 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 <linux/log2.h>
#include <linux/slab.h>
#include <linux/of.h>
#include <linux/uaccess.h>
#include <linux/io.h>#include <asm/irq.h>
#include "rtc-s3c.h"enum s3c_cpu_type {TYPE_S3C2410,TYPE_S3C2416,TYPE_S3C2443,TYPE_S3C64XX,
};struct s3c_rtc_drv_data {int cpu_type;
};/* I have yet to find an S3C implementation with more than one* of these rtc blocks in */static struct clk *rtc_clk;
static void __iomem *s3c_rtc_base;
static int s3c_rtc_alarmno = NO_IRQ;
static int s3c_rtc_tickno  = NO_IRQ;
static enum s3c_cpu_type s3c_rtc_cpu_type;static DEFINE_SPINLOCK(s3c_rtc_pie_lock);static void s3c_rtc_alarm_clk_enable(bool enable)
{static DEFINE_SPINLOCK(s3c_rtc_alarm_clk_lock);static bool alarm_clk_enabled;unsigned long irq_flags;spin_lock_irqsave(&s3c_rtc_alarm_clk_lock, irq_flags);if (enable) {if (!alarm_clk_enabled) {clk_enable(rtc_clk);alarm_clk_enabled = true;}} else {if (alarm_clk_enabled) {clk_disable(rtc_clk);alarm_clk_enabled = false;}}spin_unlock_irqrestore(&s3c_rtc_alarm_clk_lock, irq_flags);
}/* IRQ Handlers */static irqreturn_t s3c_rtc_alarmirq(int irq, void *id)
{struct rtc_device *rdev = id;clk_enable(rtc_clk);rtc_update_irq(rdev, 1, RTC_AF | RTC_IRQF);if (s3c_rtc_cpu_type == TYPE_S3C64XX)writeb(S3C2410_INTP_ALM, s3c_rtc_base + S3C2410_INTP);clk_disable(rtc_clk);s3c_rtc_alarm_clk_enable(false);return IRQ_HANDLED;
}static irqreturn_t s3c_rtc_tickirq(int irq, void *id)
{struct rtc_device *rdev = id;clk_enable(rtc_clk);rtc_update_irq(rdev, 1, RTC_PF | RTC_IRQF);if (s3c_rtc_cpu_type == TYPE_S3C64XX)writeb(S3C2410_INTP_TIC, s3c_rtc_base + S3C2410_INTP);clk_disable(rtc_clk);return IRQ_HANDLED;
}/* Update control registers */
static int s3c_rtc_setaie(struct device *dev, unsigned int enabled)
{unsigned int tmp;dev_dbg(dev, "%s: aie=%d\n", __func__, enabled);clk_enable(rtc_clk);tmp = readb(s3c_rtc_base + S3C2410_RTCALM) & ~S3C2410_RTCALM_ALMEN;if (enabled)tmp |= S3C2410_RTCALM_ALMEN;writeb(tmp, s3c_rtc_base + S3C2410_RTCALM);clk_disable(rtc_clk);s3c_rtc_alarm_clk_enable(enabled);return 0;
}static int s3c_rtc_setfreq(struct device *dev, int freq)
{struct platform_device *pdev = to_platform_device(dev);struct rtc_device *rtc_dev = platform_get_drvdata(pdev);unsigned int tmp = 0;int val;if (!is_power_of_2(freq))return -EINVAL;clk_enable(rtc_clk);spin_lock_irq(&s3c_rtc_pie_lock);if (s3c_rtc_cpu_type != TYPE_S3C64XX) {tmp = readb(s3c_rtc_base + S3C2410_TICNT);tmp &= S3C2410_TICNT_ENABLE;}val = (rtc_dev->max_user_freq / freq) - 1;if (s3c_rtc_cpu_type == TYPE_S3C2416 || s3c_rtc_cpu_type == TYPE_S3C2443) {tmp |= S3C2443_TICNT_PART(val);writel(S3C2443_TICNT1_PART(val), s3c_rtc_base + S3C2443_TICNT1);if (s3c_rtc_cpu_type == TYPE_S3C2416)writel(S3C2416_TICNT2_PART(val), s3c_rtc_base + S3C2416_TICNT2);} else {tmp |= val;}writel(tmp, s3c_rtc_base + S3C2410_TICNT);spin_unlock_irq(&s3c_rtc_pie_lock);clk_disable(rtc_clk);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;clk_enable(rtc_clk);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 whether 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;}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;dev_dbg(dev, "read time %04d.%02d.%02d %02d:%02d:%02d\n",1900 + 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_mon -= 1;clk_disable(rtc_clk);return rtc_valid_tm(rtc_tm);
}static int s3c_rtc_settime(struct device *dev, struct rtc_time *tm)
{void __iomem *base = s3c_rtc_base;int year = tm->tm_year - 100;dev_dbg(dev, "set time %04d.%02d.%02d %02d:%02d:%02d\n",1900 + 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;}clk_enable(rtc_clk);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);clk_disable(rtc_clk);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;clk_enable(rtc_clk);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;dev_dbg(dev, "read alarm %d, %04d.%02d.%02d %02d:%02d:%02d\n",alm_en,1900 + 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)alm_tm->tm_sec = bcd2bin(alm_tm->tm_sec);elsealm_tm->tm_sec = -1;if (alm_en & S3C2410_RTCALM_MINEN)alm_tm->tm_min = bcd2bin(alm_tm->tm_min);elsealm_tm->tm_min = -1;if (alm_en & S3C2410_RTCALM_HOUREN)alm_tm->tm_hour = bcd2bin(alm_tm->tm_hour);elsealm_tm->tm_hour = -1;if (alm_en & S3C2410_RTCALM_DAYEN)alm_tm->tm_mday = bcd2bin(alm_tm->tm_mday);elsealm_tm->tm_mday = -1;if (alm_en & S3C2410_RTCALM_MONEN) {alm_tm->tm_mon = bcd2bin(alm_tm->tm_mon);alm_tm->tm_mon -= 1;} else {alm_tm->tm_mon = -1;}if (alm_en & S3C2410_RTCALM_YEAREN)alm_tm->tm_year = bcd2bin(alm_tm->tm_year);elsealm_tm->tm_year = -1;clk_disable(rtc_clk);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;clk_enable(rtc_clk);dev_dbg(dev, "s3c_rtc_setalarm: %d, %04d.%02d.%02d %02d:%02d:%02d\n",alrm->enabled,1900 + tm->tm_year, tm->tm_mon + 1, tm->tm_mday,tm->tm_hour, tm->tm_min, 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);}dev_dbg(dev, "setting S3C2410_RTCALM to %08x\n", alrm_en);writeb(alrm_en, base + S3C2410_RTCALM);s3c_rtc_setaie(dev, alrm->enabled);clk_disable(rtc_clk);return 0;
}static int s3c_rtc_proc(struct device *dev, struct seq_file *seq)
{unsigned int ticnt;clk_enable(rtc_clk);if (s3c_rtc_cpu_type == TYPE_S3C64XX) {ticnt = readw(s3c_rtc_base + S3C2410_RTCCON);ticnt &= S3C64XX_RTCCON_TICEN;} else {ticnt = readb(s3c_rtc_base + S3C2410_TICNT);ticnt &= S3C2410_TICNT_ENABLE;}seq_printf(seq, "periodic_IRQ\t: %s\n", ticnt  ? "yes" : "no");clk_disable(rtc_clk);return 0;
}static const struct rtc_class_ops s3c_rtcops = {.read_time	= s3c_rtc_gettime,.set_time	= s3c_rtc_settime,.read_alarm	= s3c_rtc_getalarm,.set_alarm	= s3c_rtc_setalarm,.proc		= s3c_rtc_proc,.alarm_irq_enable = s3c_rtc_setaie,
};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;clk_enable(rtc_clk);if (!en) {tmp = readw(base + S3C2410_RTCCON);if (s3c_rtc_cpu_type == TYPE_S3C64XX)tmp &= ~S3C64XX_RTCCON_TICEN;tmp &= ~S3C2410_RTCCON_RTCEN;writew(tmp, base + S3C2410_RTCCON);if (s3c_rtc_cpu_type != TYPE_S3C64XX) {tmp = readb(base + S3C2410_TICNT);tmp &= ~S3C2410_TICNT_ENABLE;writeb(tmp, base + S3C2410_TICNT);}} else {/* re-enable the device, and check it is ok */if ((readw(base+S3C2410_RTCCON) & S3C2410_RTCCON_RTCEN) == 0) {dev_info(&pdev->dev, "rtc disabled, re-enabling\n");tmp = readw(base + S3C2410_RTCCON);writew(tmp | S3C2410_RTCCON_RTCEN,base + S3C2410_RTCCON);}if ((readw(base + S3C2410_RTCCON) & S3C2410_RTCCON_CNTSEL)) {dev_info(&pdev->dev, "removing RTCCON_CNTSEL\n");tmp = readw(base + S3C2410_RTCCON);writew(tmp & ~S3C2410_RTCCON_CNTSEL,base + S3C2410_RTCCON);}if ((readw(base + S3C2410_RTCCON) & S3C2410_RTCCON_CLKRST)) {dev_info(&pdev->dev, "removing RTCCON_CLKRST\n");tmp = readw(base + S3C2410_RTCCON);writew(tmp & ~S3C2410_RTCCON_CLKRST,base + S3C2410_RTCCON);}}clk_disable(rtc_clk);
}static int s3c_rtc_remove(struct platform_device *dev)
{s3c_rtc_setaie(&dev->dev, 0);clk_unprepare(rtc_clk);rtc_clk = NULL;return 0;
}static const struct of_device_id s3c_rtc_dt_match[];static inline int s3c_rtc_get_driver_data(struct platform_device *pdev)
{
#ifdef CONFIG_OFstruct s3c_rtc_drv_data *data;if (pdev->dev.of_node) {const struct of_device_id *match;match = of_match_node(s3c_rtc_dt_match, pdev->dev.of_node);data = (struct s3c_rtc_drv_data *) match->data;return data->cpu_type;}
#endifreturn platform_get_device_id(pdev)->driver_data;
}static int s3c_rtc_probe(struct platform_device *pdev)
{struct rtc_device *rtc;struct rtc_time rtc_tm;struct resource *res;int ret;int tmp;dev_dbg(&pdev->dev, "%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 s3c_rtc_tickno;}s3c_rtc_alarmno = platform_get_irq(pdev, 0);if (s3c_rtc_alarmno < 0) {dev_err(&pdev->dev, "no irq for alarm\n");return s3c_rtc_alarmno;}dev_dbg(&pdev->dev, "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);s3c_rtc_base = devm_ioremap_resource(&pdev->dev, res);if (IS_ERR(s3c_rtc_base))return PTR_ERR(s3c_rtc_base);rtc_clk = devm_clk_get(&pdev->dev, "rtc");if (IS_ERR(rtc_clk)) {dev_err(&pdev->dev, "failed to find rtc clock source\n");ret = PTR_ERR(rtc_clk);rtc_clk = NULL;return ret;}clk_prepare_enable(rtc_clk);/* check to see if everything is setup correctly */s3c_rtc_enable(pdev, 1);dev_dbg(&pdev->dev, "s3c2410_rtc: RTCCON=%02x\n",readw(s3c_rtc_base + S3C2410_RTCCON));device_init_wakeup(&pdev->dev, 1);/* register RTC and exit */rtc = devm_rtc_device_register(&pdev->dev, "s3c", &s3c_rtcops,THIS_MODULE);if (IS_ERR(rtc)) {dev_err(&pdev->dev, "cannot attach rtc\n");ret = PTR_ERR(rtc);goto err_nortc;}s3c_rtc_cpu_type = s3c_rtc_get_driver_data(pdev);/* Check RTC Time */s3c_rtc_gettime(NULL, &rtc_tm);if (rtc_valid_tm(&rtc_tm)) {rtc_tm.tm_year	= 100;rtc_tm.tm_mon	= 0;rtc_tm.tm_mday	= 1;rtc_tm.tm_hour	= 0;rtc_tm.tm_min	= 0;rtc_tm.tm_sec	= 0;s3c_rtc_settime(NULL, &rtc_tm);dev_warn(&pdev->dev, "warning: invalid RTC value so initializing it\n");}if (s3c_rtc_cpu_type != TYPE_S3C2410)rtc->max_user_freq = 32768;elsertc->max_user_freq = 128;if (s3c_rtc_cpu_type == TYPE_S3C2416 || s3c_rtc_cpu_type == TYPE_S3C2443) {tmp = readw(s3c_rtc_base + S3C2410_RTCCON);tmp |= S3C2443_RTCCON_TICSEL;writew(tmp, s3c_rtc_base + S3C2410_RTCCON);}platform_set_drvdata(pdev, rtc);s3c_rtc_setfreq(&pdev->dev, 1);ret = devm_request_irq(&pdev->dev, s3c_rtc_alarmno, s3c_rtc_alarmirq,0,  "s3c2410-rtc alarm", rtc);if (ret) {dev_err(&pdev->dev, "IRQ%d error %d\n", s3c_rtc_alarmno, ret);goto err_nortc;}ret = devm_request_irq(&pdev->dev, s3c_rtc_tickno, s3c_rtc_tickirq,0,  "s3c2410-rtc tick", rtc);if (ret) {dev_err(&pdev->dev, "IRQ%d error %d\n", s3c_rtc_tickno, ret);goto err_nortc;}clk_disable(rtc_clk);return 0;err_nortc:s3c_rtc_enable(pdev, 0);clk_disable_unprepare(rtc_clk);return ret;
}#ifdef CONFIG_PM_SLEEP
/* RTC Power management control */static int ticnt_save, ticnt_en_save;
static bool wake_en;static int s3c_rtc_suspend(struct device *dev)
{struct platform_device *pdev = to_platform_device(dev);clk_enable(rtc_clk);/* save TICNT for anyone using periodic interrupts */if (s3c_rtc_cpu_type == TYPE_S3C64XX) {ticnt_en_save = readw(s3c_rtc_base + S3C2410_RTCCON);ticnt_en_save &= S3C64XX_RTCCON_TICEN;ticnt_save = readl(s3c_rtc_base + S3C2410_TICNT);} else {ticnt_save = readb(s3c_rtc_base + S3C2410_TICNT);}s3c_rtc_enable(pdev, 0);if (device_may_wakeup(dev) && !wake_en) {if (enable_irq_wake(s3c_rtc_alarmno) == 0)wake_en = true;elsedev_err(dev, "enable_irq_wake failed\n");}clk_disable(rtc_clk);return 0;
}static int s3c_rtc_resume(struct device *dev)
{struct platform_device *pdev = to_platform_device(dev);unsigned int tmp;clk_enable(rtc_clk);s3c_rtc_enable(pdev, 1);if (s3c_rtc_cpu_type == TYPE_S3C64XX) {writel(ticnt_save, s3c_rtc_base + S3C2410_TICNT);if (ticnt_en_save) {tmp = readw(s3c_rtc_base + S3C2410_RTCCON);writew(tmp | ticnt_en_save,s3c_rtc_base + S3C2410_RTCCON);}} else {writeb(ticnt_save, s3c_rtc_base + S3C2410_TICNT);}if (device_may_wakeup(dev) && wake_en) {disable_irq_wake(s3c_rtc_alarmno);wake_en = false;}clk_disable(rtc_clk);return 0;
}
#endifstatic SIMPLE_DEV_PM_OPS(s3c_rtc_pm_ops, s3c_rtc_suspend, s3c_rtc_resume);#ifdef CONFIG_OF
static struct s3c_rtc_drv_data s3c_rtc_drv_data_array[] = {[TYPE_S3C2410] = { TYPE_S3C2410 },[TYPE_S3C2416] = { TYPE_S3C2416 },[TYPE_S3C2443] = { TYPE_S3C2443 },[TYPE_S3C64XX] = { TYPE_S3C64XX },
};static const struct of_device_id s3c_rtc_dt_match[] = {{.compatible = "samsung,s3c2410-rtc",.data = &s3c_rtc_drv_data_array[TYPE_S3C2410],}, {.compatible = "samsung,s3c2416-rtc",.data = &s3c_rtc_drv_data_array[TYPE_S3C2416],}, {.compatible = "samsung,s3c2443-rtc",.data = &s3c_rtc_drv_data_array[TYPE_S3C2443],}, {.compatible = "samsung,s3c6410-rtc",.data = &s3c_rtc_drv_data_array[TYPE_S3C64XX],},{},
};
MODULE_DEVICE_TABLE(of, s3c_rtc_dt_match);
#endifstatic struct platform_device_id s3c_rtc_driver_ids[] = {{.name		= "s3c2410-rtc",.driver_data	= TYPE_S3C2410,}, {.name		= "s3c2416-rtc",.driver_data	= TYPE_S3C2416,}, {.name		= "s3c2443-rtc",.driver_data	= TYPE_S3C2443,}, {.name		= "s3c64xx-rtc",.driver_data	= TYPE_S3C64XX,},{ }
};MODULE_DEVICE_TABLE(platform, s3c_rtc_driver_ids);static struct platform_driver s3c_rtc_driver = {.probe		= s3c_rtc_probe,.remove		= s3c_rtc_remove,.id_table	= s3c_rtc_driver_ids,.driver		= {.name	= "s3c-rtc",.owner	= THIS_MODULE,.pm	= &s3c_rtc_pm_ops,.of_match_table	= of_match_ptr(s3c_rtc_dt_match),},
};module_platform_driver(s3c_rtc_driver);MODULE_DESCRIPTION("Samsung S3C RTC Driver");
MODULE_AUTHOR("Ben Dooks <[e-mail]>");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:s3c2410-rtc");

 

/** Copyright (c) 2003 Simtec Electronics <[e-mail]>*		      http://www.simtec.co.uk/products/SWLINUX/** 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 Internal RTC register definition
*/#ifndef __ASM_ARCH_REGS_RTC_H
#define __ASM_ARCH_REGS_RTC_H __FILE__#define S3C2410_RTCREG(x) (x)
#define S3C2410_INTP		S3C2410_RTCREG(0x30)
#define S3C2410_INTP_ALM	(1 << 1)
#define S3C2410_INTP_TIC	(1 << 0)#define S3C2410_RTCCON		S3C2410_RTCREG(0x40)
#define S3C2410_RTCCON_RTCEN	(1 << 0)
#define S3C2410_RTCCON_CNTSEL	(1 << 2)
#define S3C2410_RTCCON_CLKRST	(1 << 3)
#define S3C2443_RTCCON_TICSEL	(1 << 4)
#define S3C64XX_RTCCON_TICEN	(1 << 8)#define S3C2410_TICNT		S3C2410_RTCREG(0x44)
#define S3C2410_TICNT_ENABLE	(1 << 7)/* S3C2443: tick count is 15 bit wide* TICNT[6:0] contains upper 7 bits* TICNT1[7:0] contains lower 8 bits*/
#define S3C2443_TICNT_PART(x)	((x & 0x7f00) >> 8)
#define S3C2443_TICNT1		S3C2410_RTCREG(0x4C)
#define S3C2443_TICNT1_PART(x)	(x & 0xff)/* S3C2416: tick count is 32 bit wide* TICNT[6:0] contains bits [14:8]* TICNT1[7:0] contains lower 8 bits* TICNT2[16:0] contains upper 17 bits*/
#define S3C2416_TICNT2		S3C2410_RTCREG(0x48)
#define S3C2416_TICNT2_PART(x)	((x & 0xffff8000) >> 15)#define S3C2410_RTCALM		S3C2410_RTCREG(0x50)
#define S3C2410_RTCALM_ALMEN	(1 << 6)
#define S3C2410_RTCALM_YEAREN	(1 << 5)
#define S3C2410_RTCALM_MONEN	(1 << 4)
#define S3C2410_RTCALM_DAYEN	(1 << 3)
#define S3C2410_RTCALM_HOUREN	(1 << 2)
#define S3C2410_RTCALM_MINEN	(1 << 1)
#define S3C2410_RTCALM_SECEN	(1 << 0)#define S3C2410_ALMSEC		S3C2410_RTCREG(0x54)
#define S3C2410_ALMMIN		S3C2410_RTCREG(0x58)
#define S3C2410_ALMHOUR		S3C2410_RTCREG(0x5c)#define S3C2410_ALMDATE		S3C2410_RTCREG(0x60)
#define S3C2410_ALMMON		S3C2410_RTCREG(0x64)
#define S3C2410_ALMYEAR		S3C2410_RTCREG(0x68)#define S3C2410_RTCSEC		S3C2410_RTCREG(0x70)
#define S3C2410_RTCMIN		S3C2410_RTCREG(0x74)
#define S3C2410_RTCHOUR		S3C2410_RTCREG(0x78)
#define S3C2410_RTCDATE		S3C2410_RTCREG(0x7c)
#define S3C2410_RTCMON		S3C2410_RTCREG(0x84)
#define S3C2410_RTCYEAR		S3C2410_RTCREG(0x88)#endif /* __ASM_ARCH_REGS_RTC_H */