HYM8563驱动分析

#include <linux/module.h>
#include <linux/i2c.h>
#include <linux/bcd.h>
#include <linux/rtc.h>
#include <linux/delay.h>
#include <linux/wakelock.h>
#include <linux/slab.h>
#include <mach/gpio.h>
#include <mach/iomux.h>
#include "rtc-HYM8563.h"
#include <mach/board.h>

#define RTC_SPEED 200 * 1000
#define pr_fmt(fmt) "rtc: %s: " fmt, __func__
struct hym8563 {
    int irq;
    struct i2c_client *client;
    struct work_struct work;
    struct mutex mutex;
    struct rtc_device *rtc;
    int exiting;
    struct rtc_wkalrm alarm;
    struct wake_lock wake_lock;
};
static struct i2c_client *gClient = NULL;

static int hym8563_i2c_read_regs(struct i2c_client *client, u8 reg, u8 buf[], unsigned len)
{
    int ret; 
    ret = i2c_master_reg8_recv(client, reg, buf, len, RTC_SPEED);
    return ret; 
}

static int hym8563_i2c_set_regs(struct i2c_client *client, u8 reg, u8 const buf[], __u16 len)
{
    int ret; 
    ret = i2c_master_reg8_send(client, reg, buf, (int)len, RTC_SPEED);
    return ret;
}


int hym8563_enable_count(struct i2c_client *client, int en)
{
    struct hym8563 *hym8563 = i2c_get_clientdata(client);   
    u8 regs[2];
    if (!hym8563)
        return -1;
    if (en) {
        hym8563_i2c_read_regs(client, RTC_CTL2, regs, 1);
        regs[0] |= TIE;
        hym8563_i2c_set_regs(client, RTC_CTL2, regs, 1);
        regs[0] = 0;
        regs[0] |= (TE | TD1);
        hym8563_i2c_set_regs(client, RTC_T_CTL, regs, 1);
    }
    else {
        hym8563_i2c_read_regs(client, RTC_CTL2, regs, 1);
        regs[0] &= ~TIE;
        hym8563_i2c_set_regs(client, RTC_CTL2, regs, 1);
        regs[0] = 0;
        regs[0] |= (TD0 | TD1);
        hym8563_i2c_set_regs(client, RTC_T_CTL, regs, 1);
    }
    return 0;
}

//0 < sec <=255
int hym8563_set_count(struct i2c_client *client, int sec)
{   
    struct hym8563 *hym8563 = i2c_get_clientdata(client);
    u8 regs[2];
    if (!hym8563)
        return -1;      
    if (sec >= 255)
        regs[0] = 255;
    else if (sec <= 1)
        regs[0] = 1;
    else
        regs[0] = sec;  
    hym8563_i2c_set_regs(client, RTC_T_COUNT, regs, 1); 
    return 0;
}


/*the init of the hym8563 at first time */
static int hym8563_init_device(struct i2c_client *client)   
{
    struct hym8563 *hym8563 = i2c_get_clientdata(client);
    u8 regs[2];
    int sr;
    mutex_lock(&hym8563->mutex);
    regs[0]=0;
    sr = hym8563_i2c_set_regs(client, RTC_CTL1, regs, 1);       
    if (sr < 0)
        goto exit;  
    //enable clkout
    regs[0] = 0x80;
    sr = hym8563_i2c_set_regs(client, RTC_CLKOUT, regs, 1);
    if (sr < 0)
        goto exit;
    /*enable alarm && count interrupt*/
    sr = hym8563_i2c_read_regs(client, RTC_CTL2, regs, 1);
    if (sr < 0)
        goto exit;
    regs[0] = 0x0;
    regs[0] |= (AIE | TIE);
    sr = hym8563_i2c_set_regs(client, RTC_CTL2, regs, 1);
    if (sr < 0)
        goto exit;
    sr = hym8563_i2c_read_regs(client, RTC_CTL2, regs, 1);
    if (sr < 0)
        goto exit;
    sr = hym8563_i2c_read_regs(client, RTC_CTL2, regs, 1);
    if (sr < 0) {
        pr_err("read CTL2 err\n");
        goto exit;
    }

    if(regs[0] & (AF|TF))
    {
        regs[0] &= ~(AF|TF);
        sr = hym8563_i2c_set_regs(client, RTC_CTL2, regs, 1);
    }

exit:
    mutex_unlock(&hym8563->mutex);

    return sr;
}

static int hym8563_read_datetime(struct i2c_client *client, struct rtc_time *tm)
{
    struct hym8563 *hym8563 = i2c_get_clientdata(client);
    u8 i,regs[HYM8563_RTC_SECTION_LEN] = { 0, };
    mutex_lock(&hym8563->mutex);
// for (i = 0; i < HYM8563_RTC_SECTION_LEN; i++) {
// hym8563_i2c_read_regs(client, RTC_SEC+i, &regs[i], 1);
// }
    hym8563_i2c_read_regs(client, RTC_SEC, regs, HYM8563_RTC_SECTION_LEN);

    mutex_unlock(&hym8563->mutex);

    tm->tm_sec = bcd2bin(regs[0x00] & 0x7F);
    tm->tm_min = bcd2bin(regs[0x01] & 0x7F);
    tm->tm_hour = bcd2bin(regs[0x02] & 0x3F);
    tm->tm_mday = bcd2bin(regs[0x03] & 0x3F);
    tm->tm_wday = bcd2bin(regs[0x04] & 0x07);   

    tm->tm_mon = bcd2bin(regs[0x05] & 0x1F) ; 
    tm->tm_mon -= 1;            //inorder to cooperate the systerm time

    tm->tm_year = bcd2bin(regs[0x06] & 0xFF);
    if(regs[5] & 0x80)
        tm->tm_year += 1900;
    else
        tm->tm_year += 2000;

    tm->tm_yday = rtc_year_days(tm->tm_mday, tm->tm_mon, tm->tm_year);  
    tm->tm_year -= 1900;            //inorder to cooperate the systerm time 
    if(tm->tm_year < 0)
        tm->tm_year = 0;    
    tm->tm_isdst = 0;   

    pr_debug("%4d-%02d-%02d(%d) %02d:%02d:%02d\n",
        1900 + tm->tm_year, tm->tm_mon + 1, tm->tm_mday, tm->tm_wday,
        tm->tm_hour, tm->tm_min, tm->tm_sec);

    return 0;
}

static int hym8563_rtc_read_time(struct device *dev, struct rtc_time *tm)
{
    return hym8563_read_datetime(to_i2c_client(dev), tm);
}

static int hym8563_set_time(struct i2c_client *client, struct rtc_time *tm) 
{
    struct hym8563 *hym8563 = i2c_get_clientdata(client);
    u8 regs[HYM8563_RTC_SECTION_LEN] = { 0, };
    u8 mon_day,i;
    u8 ret = 0;

    pr_debug("%4d-%02d-%02d(%d) %02d:%02d:%02d\n",
        1900 + tm->tm_year, tm->tm_mon + 1, tm->tm_mday, tm->tm_wday,
        tm->tm_hour, tm->tm_min, tm->tm_sec);

    mon_day = rtc_month_days((tm->tm_mon), tm->tm_year + 1900);

    if(tm->tm_sec >= 60 || tm->tm_sec < 0 )     //set sec
        regs[0x00] = bin2bcd(0x00);
    else
        regs[0x00] = bin2bcd(tm->tm_sec);

    if(tm->tm_min >= 60 || tm->tm_min < 0 )     //set min 
        regs[0x01] = bin2bcd(0x00);
    else
        regs[0x01] = bin2bcd(tm->tm_min);

    if(tm->tm_hour >= 24 || tm->tm_hour < 0 )       //set hour
        regs[0x02] = bin2bcd(0x00);
    else
        regs[0x02] = bin2bcd(tm->tm_hour);

    if((tm->tm_mday) > mon_day)             //if the input month day is bigger than the biggest day of this month, set the biggest day 
        regs[0x03] = bin2bcd(mon_day);
    else if((tm->tm_mday) > 0)
        regs[0x03] = bin2bcd(tm->tm_mday);
    else if((tm->tm_mday) <= 0)
        regs[0x03] = bin2bcd(0x01);

    if( tm->tm_year >= 200)     // year >= 2100
        regs[0x06] = bin2bcd(99);   //year = 2099
    else if(tm->tm_year >= 100)         // 2000 <= year < 2100
        regs[0x06] = bin2bcd(tm->tm_year - 100);
    else if(tm->tm_year >= 0){              // 1900 <= year < 2000
        regs[0x06] = bin2bcd(tm->tm_year);  
        regs[0x05] |= 0x80; 
    }else{                                  // year < 1900
        regs[0x06] = bin2bcd(0);    //year = 1900 
        regs[0x05] |= 0x80; 
    }   
    regs[0x04] = bin2bcd(tm->tm_wday);      //set the weekday
    regs[0x05] = (regs[0x05] & 0x80)| (bin2bcd(tm->tm_mon + 1) & 0x7F);     //set the month

    mutex_lock(&hym8563->mutex);
// for(i=0;i<HYM8563_RTC_SECTION_LEN;i++){
// ret = hym8563_i2c_set_regs(client, RTC_SEC+i, &regs[i], 1);
// }
    hym8563_i2c_set_regs(client, RTC_SEC, regs, HYM8563_RTC_SECTION_LEN);
    mutex_unlock(&hym8563->mutex);
    return 0;
}

static int hym8563_rtc_set_time(struct device *dev, struct rtc_time *tm)
{
    return hym8563_set_time(to_i2c_client(dev), tm);
}

static int hym8563_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *tm)
{
    struct i2c_client *client = to_i2c_client(dev);
    struct hym8563 *hym8563 = i2c_get_clientdata(client);
    u8 regs[4] = { 0, };    
    pr_debug("enter\n");
    mutex_lock(&hym8563->mutex);
    hym8563_i2c_read_regs(client, RTC_A_MIN, regs, 4);
    regs[0] = 0x0;
    regs[0] |= TIE;
    hym8563_i2c_set_regs(client, RTC_CTL2, regs, 1);
    mutex_unlock(&hym8563->mutex);
    return 0;
}

static int hym8563_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)
{   
    struct i2c_client *client = to_i2c_client(dev);
    struct hym8563 *hym8563 = i2c_get_clientdata(client);
    struct rtc_time now, *tm = &alarm->time;
    u8 regs[4] = { 0, };
    u8 mon_day; 
    unsigned long   alarm_sec, now_sec;
    int diff_sec = 0;

    pr_debug("%4d-%02d-%02d(%d) %02d:%02d:%02d enabled %d\n",
        1900 + tm->tm_year, tm->tm_mon + 1, tm->tm_mday, tm->tm_wday,
        tm->tm_hour, tm->tm_min, tm->tm_sec, alarm->enabled);       
    hym8563_read_datetime(client, &now);    
    mutex_lock(&hym8563->mutex);
    rtc_tm_to_time(tm, &alarm_sec);
    rtc_tm_to_time(&now, &now_sec); 
    diff_sec = alarm_sec - now_sec; 
    if((diff_sec > 0) && (diff_sec < 256))
    {   
        printk("%s:diff_sec= %ds , use time\n",__func__, diff_sec);
        hym8563_enable_count(client, 1);                
        hym8563_set_count(client, diff_sec);
    }
    else
    {               
        printk("%s:diff_sec= %ds , use alarm\n",__func__, diff_sec);
        hym8563_enable_count(client, 0);        
        if(tm->tm_sec > 0)
        {
            rtc_tm_to_time(tm, &alarm_sec);
            rtc_time_to_tm(alarm_sec, tm);
        }
        hym8563->alarm = *alarm;
        regs[0] = 0x0;
        hym8563_i2c_set_regs(client, RTC_CTL2, regs, 1);
        mon_day = rtc_month_days(tm->tm_mon, tm->tm_year + 1900);
        hym8563_i2c_read_regs(client, RTC_A_MIN, regs, 4);
        if (tm->tm_min >= 60 || tm->tm_min < 0)     //set min
        regs[0x00] = bin2bcd(0x00) & 0x7f;
        else
        regs[0x00] = bin2bcd(tm->tm_min) & 0x7f;
        if (tm->tm_hour >= 24 || tm->tm_hour < 0)   //set hour
        regs[0x01] = bin2bcd(0x00) & 0x7f;
        else
        regs[0x01] = bin2bcd(tm->tm_hour) & 0x7f;
        regs[0x03] = bin2bcd (tm->tm_wday) & 0x7f;

        /* if the input month day is bigger than the biggest day of this month, set the biggest day */
        if (tm->tm_mday > mon_day)
        regs[0x02] = bin2bcd(mon_day) & 0x7f;
        else if (tm->tm_mday > 0)
        regs[0x02] = bin2bcd(tm->tm_mday) & 0x7f;
        else if (tm->tm_mday <= 0)
        regs[0x02] = bin2bcd(0x01) & 0x7f;

        hym8563_i2c_set_regs(client, RTC_A_MIN, regs, 4);   
        hym8563_i2c_read_regs(client, RTC_A_MIN, regs, 4);  
        hym8563_i2c_read_regs(client, RTC_CTL2, regs, 1);
        if (alarm->enabled == 1)
        regs[0] |= AIE;
        else
        regs[0] &= 0x0;
        regs[0] |= TIE;
        hym8563_i2c_set_regs(client, RTC_CTL2, regs, 1);
        hym8563_i2c_read_regs(client, RTC_CTL2, regs, 1);

        if(diff_sec <= 0)
        {       
            pr_info("alarm sec <= now sec\n");
        }           
    }   
    mutex_unlock(&hym8563->mutex);
    return 0;
}

#if defined(CONFIG_RTC_INTF_DEV) || defined(CONFIG_RTC_INTF_DEV_MODULE)
static int hym8563_i2c_open_alarm(struct i2c_client *client)
{
    u8 data;    
    hym8563_i2c_read_regs(client, RTC_CTL2, &data, 1);
    data |= AIE;
    hym8563_i2c_set_regs(client, RTC_CTL2, &data, 1);
    return 0;
}

static int hym8563_i2c_close_alarm(struct i2c_client *client)
{
    u8 data;    
    hym8563_i2c_read_regs(client, RTC_CTL2, &data, 1);
    data &= ~AIE;
    hym8563_i2c_set_regs(client, RTC_CTL2, &data, 1);
    return 0;
}

static int hym8563_rtc_ioctl(struct device *dev, unsigned int cmd, unsigned long arg)
{
    struct i2c_client *client = to_i2c_client(dev);

    switch (cmd) {
    case RTC_AIE_OFF:
        if(hym8563_i2c_close_alarm(client) < 0)
            goto err;
        break;
    case RTC_AIE_ON:
        if(hym8563_i2c_open_alarm(client))
            goto err;
        break;
    default:
        return -ENOIOCTLCMD;
    }   
    return 0;
err:
    return -EIO;
}
#else
#define hym8563_rtc_ioctl NULL
#endif

#if defined(CONFIG_RTC_INTF_PROC) || defined(CONFIG_RTC_INTF_PROC_MODULE)
static int hym8563_rtc_proc(struct device *dev, struct seq_file *seq)
{
    return 0;
}
#else
#define hym8563_rtc_proc NULL
#endif

static irqreturn_t hym8563_wakeup_irq(int irq, void *data)
{
    struct hym8563 *hym8563 = data; 
    struct i2c_client *client = hym8563->client;    
    u8 value;

    mutex_lock(&hym8563->mutex);
    hym8563_i2c_read_regs(client, RTC_CTL2, &value, 1);
    value &= ~(AF|TF);
    hym8563_i2c_set_regs(client, RTC_CTL2, &value, 1);  
    mutex_unlock(&hym8563->mutex);

    rtc_update_irq(hym8563->rtc, 1, RTC_IRQF | RTC_AF | RTC_UF);

    //printk("%s:irq=%d\n",__func__,irq);
    return IRQ_HANDLED;
}

static const struct rtc_class_ops hym8563_rtc_ops = {
    .read_time  = hym8563_rtc_read_time,
    .set_time   = hym8563_rtc_set_time,
    .read_alarm = hym8563_rtc_read_alarm,
    .set_alarm  = hym8563_rtc_set_alarm,
    .ioctl      = hym8563_rtc_ioctl,
    .proc       = hym8563_rtc_proc
};

static int __devinit hym8563_probe(struct i2c_client *client, const struct i2c_device_id *id)
{
    int rc = 0;
    u8 reg = 0;
    struct hym8563 *hym8563;
    struct rtc_device *rtc = NULL;
    struct rtc_time tm_read, tm = {
        .tm_wday = 6,
        .tm_year = 111,
        .tm_mon = 0,
        .tm_mday = 1,
        .tm_hour = 12,
        .tm_min = 0,
        .tm_sec = 0,
    };  

    if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
        return -ENODEV;

    hym8563 = kzalloc(sizeof(struct hym8563), GFP_KERNEL);
    if (!hym8563) {
        return -ENOMEM;
    }

    gClient = client;   
    hym8563->client = client;
    hym8563->alarm.enabled = 0;
    mutex_init(&hym8563->mutex);
    wake_lock_init(&hym8563->wake_lock, WAKE_LOCK_SUSPEND, "rtc_hym8563");
    i2c_set_clientdata(client, hym8563);

    hym8563_init_device(client);    //时钟模块初始化
    hym8563_enable_count(client, 0);//关闭计时 

    // check power down 
    hym8563_i2c_read_regs(client,RTC_SEC,&reg,1);
    if (reg&0x80) {
        dev_info(&client->dev, "clock/calendar information is no longer guaranteed\n");
        hym8563_set_time(client, &tm);
    }

    hym8563_read_datetime(client, &tm_read);    //read time from hym8563

    if(((tm_read.tm_year < 70) | (tm_read.tm_year > 137 )) | (tm_read.tm_mon == -1) | (rtc_valid_tm(&tm_read) != 0)) //if the hym8563 haven't initialized
    {
        hym8563_set_time(client, &tm);  //initialize the hym8563 
    }   

    if(gpio_request(client->irq, "rtc gpio"))
    {
        dev_err(&client->dev, "gpio request fail\n");
        gpio_free(client->irq);
        goto exit;
    }

    hym8563->irq = gpio_to_irq(client->irq);
    gpio_pull_updown(client->irq,GPIOPullUp);
    if (request_threaded_irq(hym8563->irq, NULL, hym8563_wakeup_irq, IRQF_TRIGGER_LOW | IRQF_ONESHOT, client->dev.driver->name, hym8563) < 0)
    {
        printk("unable to request rtc irq\n");
        goto exit;
    }   
    enable_irq_wake(hym8563->irq);

    rtc = rtc_device_register(client->name, &client->dev,
                  &hym8563_rtc_ops, THIS_MODULE);
    if (IS_ERR(rtc)) {
        rc = PTR_ERR(rtc);
        rtc = NULL;
        goto exit;
    }
    hym8563->rtc = rtc;

    return 0;

exit:
    if (rtc)
        rtc_device_unregister(rtc);
    if (hym8563) {
        wake_lock_destroy(&hym8563->wake_lock);
        kfree(hym8563);
    }
    return rc;
}

static int __devexit hym8563_remove(struct i2c_client *client)
{
    struct hym8563 *hym8563 = i2c_get_clientdata(client);

    if (hym8563->irq > 0) {
        mutex_lock(&hym8563->mutex);
        hym8563->exiting = 1;
        mutex_unlock(&hym8563->mutex);

        free_irq(hym8563->irq, hym8563);
        cancel_work_sync(&hym8563->work);
    }
    rtc_device_unregister(hym8563->rtc);
    wake_lock_destroy(&hym8563->wake_lock);
    kfree(hym8563);
    hym8563 = NULL;
    return 0;
}

void hym8563_shutdown(struct i2c_client * client)
{   u8 regs[2]; 
    int ret;    
    //disable clkout 
    regs[0] = 0x00; 
    ret=hym8563_i2c_set_regs(client, RTC_CLKOUT, regs, 1);  
    if(ret<0)   
        printk("rtc shutdown is error\n");
}



static const struct i2c_device_id hym8563_id[] = {
    { "rtc_hym8563", 0 },
    { }
};
MODULE_DEVICE_TABLE(i2c, hym8563_id);

//构建i2c_driver
static struct i2c_driver hym8563_driver = {
    .driver     = {
        .name   = "rtc_hym8563",
        .owner  = THIS_MODULE,
    },
    .probe      = hym8563_probe,
    .remove     = __devexit_p(hym8563_remove),
#if defined(CONFIG_ARCH_RK3066B) || defined(CONFIG_ARCH_RK3188) || defined(CONFIG_ARCH_RKPX3)
    //.shutdown=hym8563_shutdown,
#else
    .shutdown=hym8563_shutdown,
#endif
    .id_table   = hym8563_id,
};

//注册i2c_driver
static int __init hym8563_init(void)
{
    return i2c_add_driver(&hym8563_driver);
}

static void __exit hym8563_exit(void)
{
    i2c_del_driver(&hym8563_driver);
}

MODULE_AUTHOR("lhh [email protected]");
MODULE_DESCRIPTION("HYM8563 RTC driver");
MODULE_LICENSE("GPL");

module_init(hym8563_init);
module_exit(hym8563_exit);

关于IIC驱动的介绍，可查阅
http://www.cnblogs.com/liugf05/archive/2012/12/05/2803795.html
http://www.cnblogs.com/simonshi/archive/2011/02/24/1963426.html

某些关键函数分析
注册平台驱动的函数为platform_driver_register()详见
http://blog.csdn.net/yili_xie/article/details/5193609
对应IIC设备，对应的注册IIC驱动的函数为i2c_add_driver();
http://blog.csdn.net/zclongembedded/article/details/8207722

i2c_check_functionality用来判定设配器的能力

wake_lock_init()用于初始化一个新锁，type参数指定了锁的类型,详看
http://blog.csdn.net/g_salamander/article/details/7978772
gpio_request(client->irq, “rtc gpio”)//申请该gpio，并设置名字为rtc gpio
hym8563->irq = gpio_to_irq(client->irq);//将申请到的io口设置中断功能
gpio_pull_updown(client->irq,GPIOPullUp);//上拉该gpio。
该gpio在板级文件kernel/arm/mach-rkpx3/board-rkpx3-sdk. c中定义。

static struct i2c_board_info __initdata i2c1_info[] = {
#if defined (CONFIG_RTC_HYM8563)
    {
        .type           = "rtc_hym8563",
        .addr           = 0x51,
        .flags          = 0,
        .irq            = RK30_PIN0_PB5,
    },
#endif
}
i2c_register_board_info(1, i2c1_info, ARRAY_SIZE(i2c1_info));
}

request_threaded_irq申请线程中断，为什么不用request_irq,请查阅
http://www.cnblogs.com/leaven/archive/2010/09/09/1822018.html

request_threaded_irq(hym8563->irq, NULL, hym8563_wakeup_irq, IRQF_TRIGGER_LOW | IRQF_ONESHOT, client->dev.driver->name, hym8563)
//IRQF_TRIGGER_LOW电平触发，IRQF_ONESHOT代表只触发一次，详细介绍见
http://www.wowotech.net/linux_kenrel/request_threaded_irq.html
static irqreturn_t hym8563_wakeup_irq(int irq, void *data)
{
    struct hym8563 *hym8563 = data; 
    struct i2c_client *client = hym8563->client;    
    u8 value;

    mutex_lock(&hym8563->mutex);
    hym8563_i2c_read_regs(client, RTC_CTL2, &value, 1);
    value &= ~(AF|TF);
    hym8563_i2c_set_regs(client, RTC_CTL2, &value, 1);  
    mutex_unlock(&hym8563->mutex);

    rtc_update_irq(hym8563->rtc, 1, RTC_IRQF | RTC_AF | RTC_UF);

    //printk("%s:irq=%d\n",__func__,irq);
    return IRQ_HANDLED;
}

enable_irq_wake(hym8563->irq);//时能中断唤醒
我的理解是当我们设好闹钟后，关闭屏幕（休眠），时间到了触发了中断，开屏幕响铃。
详见http://blog.csdn.net/njuitjf/article/details/21475405

rtc = rtc_device_register(client->name, &client->dev,&hym8563_rtc_ops, THIS_MODULE);//向linux系统注册RTC设备，并成生proc、sys目录下的属性文件
详见http://blog.csdn.net/fanqipin/article/details/8089995

参考
http://blog.csdn.net/airk000/article/details/22655171