海思平台HI35XX系列RTC驱动程序设计

    海思官方手册上说Hi3536CV100/Hi3536DV100/Hi3559AV100/Hi3559CV100 支持内核标准 RTC 驱动，内核编译默认打开 RTC 选项就可以了。HI35XX其它的设备就需要自己设计RTC驱动了。不管什么平台，海思SDK里面都有自带一个简单的rtc驱动，SDK的/drv/rtc/ 里面有详细的说明，这里不再重复。但是，官方自带的rtc驱动是不支持linux hwclock命令操作的。所以一般还是需要自己写。

    驱动程序模型分为三种：

    （1）传统模型，直接固定硬件资源

    （2）总线设备驱动模型，驱动不用改，不同的硬件注册不同的设备。

    （3）设备树模型，最新的模型，简便高效    

    我有两款设备Hi3520DV300和Hi3520DV400,V400是使用设备树来管理硬件，但V300还是使用传统的方式。为了兼容，这里采用了总线设备驱动模型。

---

（一）配置内核

    (1)修改linux-3.18.y/drivers/rtc/ 下的Kconfig ,最后面添加：

comment "HI3520DV400 RTC drivers"
config RTC_HI3520DV400
    bool "HI3520DV400 RTC SET"
    help
        If you say Y here you will get support for the Hypervisor
        based RTC on SUN4V systems.


endif # RTC_CLASS 

    (2)修改linux-3.18.y/drivers/rtc/ 下的Makefile ,最后面添加：

obj-$(CONFIG_RTC_HI3520DV400)   += hi_rtc_drv.o
obj-$(CONFIG_RTC_HI3520DV400)   += hi_rtc_dev.o 

   (3)配置内核，支持RTC功能，并选中我们自己的驱动,我这里是HI3520DV400

（二）创建设备文件

    在RTC目录下创建设备文件：hi_rtc_dev.c

#include 
#include 
#include 
#include 
#include 
#include 
#include 

#define RTC_SPI_BASE_ADDR	IO_ADDRESS(0x120b0000)
#define RTC_SPI_CLK_DIV		(RTC_SPI_BASE_ADDR + 0x000)
#define RTC_SPI_RW			(RTC_SPI_BASE_ADDR + 0x004)
#define HI_RTC_IRQ			(37)	

static struct resource  rtc_resource[] = {
	[0] = {
		.start = RTC_SPI_BASE_ADDR,
		.end   = RTC_SPI_RW,
		.flags = IORESOURCE_MEM,
	},
	[1] = {
	.start = HI_RTC_IRQ,
	.end   = HI_RTC_IRQ,
	.flags = IORESOURCE_IRQ,
	},
};

static struct platform_device wisdom_device_rtc = {
	.name = "biao_rtc",
	.id   = 0,
	.resource = rtc_resource,
	.num_resources = ARRAY_SIZE(rtc_resource),
};


static int biao_rtc_dev_init(void)
{
	platform_device_register(&wisdom_device_rtc);
	return 0;
}

static void biao_rtc_dev_exit(void)
{
	platform_device_unregister(&wisdom_device_rtc);
}

module_init(biao_rtc_dev_init);
module_exit(biao_rtc_dev_exit);

MODULE_LICENSE("GPL");

（三）创建驱动文件

    在RTC目录下创建驱动程序：hi_rtc_drv.c

/*
 * DS1286 Real Time Clock interface for Linux
 *
 * Copyright (C) 1998, 1999, 2000 Ralf Baechle
 * Copyright (C) 2008 Thomas Bogendoerfer
 *
 * Based on code written by Paul Gortmaker.
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the
 * Free Software Foundation; either version 2 of the License, or (at your
 * option) any later version.
 */

#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include  
#define DRV_VERSION		"1.0"

/* RTC Control over SPI */
#define RTC_SPI_BASE_ADDR	IO_ADDRESS(0x120b0000)
#define SPI_CLK_DIV			(RTC_SPI_BASE_ADDR + 0x000)
#define SPI_RW				(RTC_SPI_BASE_ADDR + 0x004)

/* Define the union SPI_RW */
typedef union {
	struct {
		unsigned int spi_wdata		: 8; /* [7:0] */
		unsigned int spi_rdata		: 8; /* [15:8] */
		unsigned int spi_addr		: 7; /* [22:16] */
		unsigned int spi_rw		    : 1; /* [23] */
		unsigned int spi_start		: 1; /* [24] */
		unsigned int reserved		: 6; /* [30:25] */
		unsigned int spi_busy		: 1; /* [31] */
	} bits;
	/* Define an unsigned member */
	unsigned int u32;
} U_SPI_RW;

#define SPI_WRITE		(0)
#define SPI_READ		(1)

#define RTC_IRQ			(37)	

/* RTC REG */
#define RTC_10MS_COUN	0x00
#define RTC_S_COUNT  	0x01
#define RTC_M_COUNT  	0x02  
#define RTC_H_COUNT  	0x03
#define RTC_D_COUNT_L	0x04
#define RTC_D_COUNT_H	0x05
#define RTC_MR_10MS		0x06
#define RTC_MR_S		0x07
#define RTC_MR_M		0x08
#define RTC_MR_H		0x09
#define RTC_MR_D_L		0x0A
#define RTC_MR_D_H		0x0B
#define RTC_LR_10MS		0x0C
#define RTC_LR_S		0x0D
#define RTC_LR_M		0x0E
#define RTC_LR_H		0x0F
#define RTC_LR_D_L		0x10
#define RTC_LR_D_H		0x11
#define RTC_LORD		0x12
#define RTC_IMSC		0x13
#define RTC_INT_CLR		0x14
#define RTC_INT_MASK	0x15
#define RTC_INT_RAW		0x16
#define RTC_CLK			0x17
#define RTC_POR_N		0x18
#define RTC_SAR_CTRL	0x1A

#define RTC_FREQ_H		0x51
#define RTC_FREQ_L		0x52

#define RETRY_CNT 100

#define FREQ_MAX_VAL	3277000
#define FREQ_MIN_VAL	3276000

static DEFINE_MUTEX(hirtc_lock);

struct biao_rtc_priv {
	struct rtc_device *rtc;
	u32 __iomem *rtcregs;
	spinlock_t lock;
};
static int spi_write(char reg, char val)
{
	U_SPI_RW w_data, r_data;
	r_data.u32 = 0;
	w_data.u32 = 0;
	
	w_data.bits.spi_wdata = val;
	w_data.bits.spi_addr = reg;
	w_data.bits.spi_rw = SPI_WRITE;
	w_data.bits.spi_start = 0x1;
	writel(w_data.u32, (volatile void __iomem *)SPI_RW);

	do {
		r_data.u32 = readl((volatile void __iomem *)SPI_RW);
	} while (r_data.bits.spi_busy);

	return 0;
}

static int spi_rtc_write(char reg, char val)
{
	mutex_lock(&hirtc_lock);
	spi_write(reg, val);
	mutex_unlock(&hirtc_lock);
	
	return 0;
}

static int spi_read(char reg, char *val)
{
	U_SPI_RW w_data, r_data;

	r_data.u32 = 0;
	w_data.u32 = 0;
	w_data.bits.spi_addr = reg;
	w_data.bits.spi_rw = SPI_READ;
	w_data.bits.spi_start = 0x1;
	

	writel(w_data.u32, (volatile void __iomem *)SPI_RW);

	do {
		r_data.u32 = readl((volatile void __iomem *)SPI_RW);
	} while (r_data.bits.spi_busy);
	
	*val = r_data.bits.spi_rdata;

	return 0;
}

static int spi_rtc_read(char reg, char *val)
{
	mutex_lock(&hirtc_lock);
	spi_read(reg, val);
	mutex_unlock(&hirtc_lock);

	return 0;
}

static int hirtc_get_alarm(struct device *dev, struct rtc_wkalrm *alm)
{
	unsigned char dayl, dayh;
	unsigned char second, minute, hour;
	unsigned long seconds = 0;
	unsigned int day;

	spi_rtc_read(RTC_MR_S, &second);
	spi_rtc_read(RTC_MR_M, &minute);
	spi_rtc_read(RTC_MR_H, &hour);
	spi_rtc_read(RTC_MR_D_L, &dayl);
	spi_rtc_read(RTC_MR_D_H, &dayh);
	day = (unsigned int)(dayl | (dayh << 8)); 
	seconds = second + minute*60 + hour*60*60 + day*24*60*60;
	rtc_time_to_tm(seconds,&(alm->time));

	return 0;
}

static int hirtc_set_alarm(struct device *dev, struct rtc_wkalrm *alm)
{
	unsigned int days;
	unsigned long seconds = 0;

	if(rtc_valid_tm(&alm->time))
		return -1;
    
    rtc_tm_to_time(&alm->time,&seconds);
	days = seconds/(60*60*24);

	spi_rtc_write(RTC_MR_10MS, 0);
	spi_rtc_write(RTC_MR_S, alm->time.tm_sec);
	spi_rtc_write(RTC_MR_M, alm->time.tm_min);
	spi_rtc_write(RTC_MR_H, alm->time.tm_hour);
	spi_rtc_write(RTC_MR_D_L, (days & 0xFF));
	spi_rtc_write(RTC_MR_D_H, (days >> 8));

	return 0;
}
static int hirtc_get_time(struct device *dev, struct rtc_time *tm)
{
	unsigned char dayl, dayh;
	unsigned char second, minute, hour;
	unsigned long seconds = 0;
	unsigned int day;
	
    unsigned char raw_value;
    
    spi_rtc_read(RTC_LORD, &raw_value);
    if(raw_value & 0x4)
    {
        spi_rtc_write(RTC_LORD, (~(1<<2)) & raw_value);
    }

	spi_rtc_read(RTC_LORD, &raw_value);
    spi_rtc_write(RTC_LORD, (1<<1) | raw_value);//lock the time

    do
    {
        spi_rtc_read(RTC_LORD, &raw_value);
    }while(raw_value & 0x2);
	udelay(1000);
	spi_rtc_read(RTC_S_COUNT, &second);
	spi_rtc_read(RTC_M_COUNT, &minute);
	spi_rtc_read(RTC_H_COUNT, &hour);
	spi_rtc_read(RTC_D_COUNT_L, &dayl);
	spi_rtc_read(RTC_D_COUNT_H, &dayh);
	day = (dayl | (dayh << 8));
	seconds = second + minute*60 + hour*60*60 + day*24*60*60;
	rtc_time_to_tm(seconds, tm);
    printk("[FJW]:hirtc_get_time [year %d] [mon %d] [mday %d] [hour %d] [min %d] [sec %d] \n"
        ,tm->tm_year,tm->tm_mon,tm->tm_mday,tm->tm_hour,tm->tm_min,tm->tm_sec);

	return 0;
}

static int hirtc_set_time(struct device *dev, struct rtc_time *tm)
{
	unsigned char ret;
	unsigned int days;
	unsigned long seconds = 0;
	unsigned int cnt = 0;
    
	if(rtc_valid_tm(tm))
		return -1;
    
    rtc_tm_to_time(tm,&seconds);
	days = seconds/(60*60*24);
    
    printk("[FJW]:hirtc_set_time [year %d] [mon %d] [mday %d] [hour %d] [min %d] [sec %d] \n"
        ,tm->tm_year,tm->tm_mon,tm->tm_mday,tm->tm_hour,tm->tm_min,tm->tm_sec);
    
	do {
		spi_rtc_read(RTC_LORD, &ret);
		udelay(1000);
		cnt++;
	} while ( (ret&0x1) && (cnt < RETRY_CNT));
	
	if (cnt >= RETRY_CNT) {
		printk(KERN_ERR "check state error!\n");
		return -1;
	}
	spi_rtc_write(RTC_LR_10MS, 0);
	spi_rtc_write(RTC_LR_S, tm->tm_sec);
	spi_rtc_write(RTC_LR_M, tm->tm_min);
	spi_rtc_write(RTC_LR_H, tm->tm_hour);
	spi_rtc_write(RTC_LR_D_L, (days & 0xFF));
	spi_rtc_write(RTC_LR_D_H, (days >> 8));
	spi_rtc_write(RTC_LORD, (ret|0x1));
	return 0;
}

static const struct rtc_class_ops hi_rtc_ops = {
	.read_time	= hirtc_get_time,
	.set_time	= hirtc_set_time,
	.read_alarm	= hirtc_get_alarm,
	.set_alarm	= hirtc_set_alarm,
};

static int hi_rtc_probe(struct platform_device *pdev)
{
	struct rtc_device *rtc;
	struct resource *res;
	struct biao_rtc_priv *priv;
	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	if (!res)
		return -ENODEV;
	priv = devm_kzalloc(&pdev->dev, sizeof(struct biao_rtc_priv), GFP_KERNEL);
	if (!priv)
		return -ENOMEM;
	priv->rtcregs = devm_ioremap_resource(&pdev->dev, res);
	if (IS_ERR(priv->rtcregs))
		return PTR_ERR(priv->rtcregs);
	spin_lock_init(&priv->lock);
	platform_set_drvdata(pdev, priv);
	rtc = devm_rtc_device_register(&pdev->dev, "biao_rtc", &hi_rtc_ops,THIS_MODULE);
	if (IS_ERR(rtc))
		return PTR_ERR(rtc);
	priv->rtc = rtc;
	return 0;
}

static int hi_rtc_remove(struct platform_device *pdev)
{
	return 0;
}

static struct platform_driver hi_biao_rtc_platform_driver = {
	.driver		= {
		.name	= "biao_rtc",
		.owner	= THIS_MODULE,
	},
	.probe		= hi_rtc_probe,
	.remove		= hi_rtc_remove,
};

module_platform_driver(hi_biao_rtc_platform_driver);

MODULE_AUTHOR("Caibiao Lee");
MODULE_DESCRIPTION("biao_rtc RTC driver");
MODULE_LICENSE("GPL");
MODULE_VERSION(DRV_VERSION);
MODULE_ALIAS("platform:biao_rtc");

（四）添加头文件

    在/include/linux/ 下面创建文件：hi_rtc.h

/*
 * include/hi_rtc.h for Linux .
 *
 * This file defines hi_rtc micro-definitions for driver developer.
 *
 * History:
 *      10-April-2006 create this file
 */

#ifndef __HI_RTC__
#define __HI_RTC__

typedef struct {
        unsigned int  year;
        unsigned int  month;
        unsigned int  date;
        unsigned int  hour;
        unsigned int  minute;
        unsigned int  second;
        unsigned int  weekday;
} rtc_time_t;

typedef	struct {
	unsigned char reg;
	unsigned char val;
} reg_data_t;

typedef enum temp_sel_mode {
	TEMP_SEL_FIXMODE  = 0,
	TEMP_SEL_OUTSIDE,
	TEMP_SEL_INTERNAL,
} temp_sel_mode;

typedef struct {
	temp_sel_mode mode;
	int value;
} reg_temp_mode_t; 

typedef struct {
	unsigned int freq_l;
} rtc_freq_t;

#define HI_RTC_AIE_ON		_IO('p', 0x01)
#define HI_RTC_AIE_OFF		_IO('p', 0x02)

#define HI_RTC_BM_ON		_IO('p', 0x03)
#define HI_RTC_BM_OFF		_IO('p', 0x04)

#define HI_RTC_GET_FREQ		_IOR('P', 0x05, rtc_freq_t)
#define HI_RTC_SET_FREQ		_IOW('p', 0x06, rtc_freq_t)

#define HI_RTC_ALM_SET		_IOW('p', 0x07,  rtc_time_t)
#define HI_RTC_ALM_READ		_IOR('p', 0x08,  rtc_time_t)
#define HI_RTC_RD_TIME		_IOR('p', 0x09,  rtc_time_t)
#define HI_RTC_SET_TIME		_IOW('p', 0x0a,  rtc_time_t)
#define HI_RTC_RESET		_IOW('p', 0x0b,  rtc_time_t)
#define HI_RTC_REG_SET		_IOW('p', 0x0c,  reg_data_t)
#define HI_RTC_REG_READ		_IOR('p', 0x0d,  reg_data_t)

#endif

（五）编译运行：

    如果驱动正常加载，会在/dev 下生成rtc0的设备文件。使用hwclock命令测试RTC是否正常。

~ # date
Tue Jan 29 17:32:10 CST 2019
~ # date 11062112
Wed Nov  6 21:12:00 CST 2019
~ # date
Wed Nov  6 21:12:02 CST 2019
~ # hwclock 
Tue Jan 29 17:33:36 2019  0.000000 seconds
~ # hwclock -w
~ # hwclock 
Wed Nov  6 21:12:20 2019  0.000000 seconds
~ # 
~ # hwclock 
Wed Nov  6 21:16:24 2019  0.000000 seconds
~ # 

        可以看到时间的设置和读取都是正常的。

    代码文件下载路径：Hi3520DV400 RTC 驱动程序