/* * Dallas DS1302 RTC Support * * Copyright (C) 2002 David McCullough * Copyright (C) 2003 - 2007 Paul Mundt * * This file is subject to the terms and conditions of the GNU General Public * License version 2. See the file "COPYING" in the main directory of * this archive for more details. */ #include <linux/init.h> #include <linux/module.h> #include <linux/kernel.h> #include <linux/platform_device.h> #include <linux/time.h> #include <linux/rtc.h> #include <linux/spinlock.h> #include <linux/io.h> #include <linux/bcd.h> #include <asm/rtc.h> #define DRV_NAME "rtc-ds1302" #define DRV_VERSION "0.1.0" #define RTC_CMD_READ 0x81 /* Read command */ #define RTC_CMD_WRITE 0x80 /* Write command */ #define RTC_ADDR_RAM0 0x20 /* Address of RAM0 */ #define RTC_ADDR_TCR 0x08 /* Address of trickle charge register */ #define RTC_ADDR_YEAR 0x06 /* Address of year register */ #define RTC_ADDR_DAY 0x05 /* Address of day of week register */ #define RTC_ADDR_MON 0x04 /* Address of month register */ #define RTC_ADDR_DATE 0x03 /* Address of day of month register */ #define RTC_ADDR_HOUR 0x02 /* Address of hour register */ #define RTC_ADDR_MIN 0x01 /* Address of minute register */ #define RTC_ADDR_SEC 0x00 /* Address of second register */ #define RTC_RESET 0x1000 #define RTC_IODATA 0x0800 #define RTC_SCLK 0x0400 #ifdef CONFIG_SH_SECUREEDGE5410 #include <asm/snapgear.h> #define set_dp(x) SECUREEDGE_WRITE_IOPORT(x, 0x1c00) #define get_dp() SECUREEDGE_READ_IOPORT() #else #error "Add support for your platform" #endif struct ds1302_rtc { struct rtc_device *rtc_dev; spinlock_t lock; }; static void ds1302_sendbits(unsigned int val) { int i; for (i = 8; (i); i--, val >>= 1) { set_dp((get_dp() & ~RTC_IODATA) | ((val & 0x1) ? RTC_IODATA : 0)); set_dp(get_dp() | RTC_SCLK); /* clock high */ set_dp(get_dp() & ~RTC_SCLK); /* clock low */ } } static unsigned int ds1302_recvbits(void) { unsigned int val; int i; for (i = 0, val = 0; (i < 8); i++) { val |= (((get_dp() & RTC_IODATA) ? 1 : 0) << i); set_dp(get_dp() | RTC_SCLK); /* clock high */ set_dp(get_dp() & ~RTC_SCLK); /* clock low */ } return val; } static unsigned int ds1302_readbyte(unsigned int addr) { unsigned int val; set_dp(get_dp() & ~(RTC_RESET | RTC_IODATA | RTC_SCLK)); set_dp(get_dp() | RTC_RESET); ds1302_sendbits(((addr & 0x3f) << 1) | RTC_CMD_READ); val = ds1302_recvbits(); set_dp(get_dp() & ~RTC_RESET); return val; } static void ds1302_writebyte(unsigned int addr, unsigned int val) { set_dp(get_dp() & ~(RTC_RESET | RTC_IODATA | RTC_SCLK)); set_dp(get_dp() | RTC_RESET); ds1302_sendbits(((addr & 0x3f) << 1) | RTC_CMD_WRITE); ds1302_sendbits(val); set_dp(get_dp() & ~RTC_RESET); } static int ds1302_rtc_read_time(struct device *dev, struct rtc_time *tm) { struct ds1302_rtc *rtc = dev_get_drvdata(dev); spin_lock_irq(&rtc->lock); tm->tm_sec = BCD2BIN(ds1302_readbyte(RTC_ADDR_SEC)); tm->tm_min = BCD2BIN(ds1302_readbyte(RTC_ADDR_MIN)); tm->tm_hour = BCD2BIN(ds1302_readbyte(RTC_ADDR_HOUR)); tm->tm_wday = BCD2BIN(ds1302_readbyte(RTC_ADDR_DAY)); tm->tm_mday = BCD2BIN(ds1302_readbyte(RTC_ADDR_DATE)); tm->tm_mon = BCD2BIN(ds1302_readbyte(RTC_ADDR_MON)) - 1; tm->tm_year = BCD2BIN(ds1302_readbyte(RTC_ADDR_YEAR)); if (tm->tm_year < 70) tm->tm_year += 100; spin_unlock_irq(&rtc->lock); dev_dbg(dev, "%s: tm is secs=%d, mins=%d, hours=%d, " "mday=%d, mon=%d, year=%d, wday=%d\n", __func__, tm->tm_sec, tm->tm_min, tm->tm_hour, tm->tm_mday, tm->tm_mon + 1, tm->tm_year, tm->tm_wday); if (rtc_valid_tm(tm) < 0) dev_err(dev, "invalid date\n"); return 0; } static int ds1302_rtc_set_time(struct device *dev, struct rtc_time *tm) { struct ds1302_rtc *rtc = dev_get_drvdata(dev); spin_lock_irq(&rtc->lock); /* Stop RTC */ ds1302_writebyte(RTC_ADDR_SEC, ds1302_readbyte(RTC_ADDR_SEC) | 0x80); ds1302_writebyte(RTC_ADDR_SEC, BIN2BCD(tm->tm_sec)); ds1302_writebyte(RTC_ADDR_MIN, BIN2BCD(tm->tm_min)); ds1302_writebyte(RTC_ADDR_HOUR, BIN2BCD(tm->tm_hour)); ds1302_writebyte(RTC_ADDR_DAY, BIN2BCD(tm->tm_wday)); ds1302_writebyte(RTC_ADDR_DATE, BIN2BCD(tm->tm_mday)); ds1302_writebyte(RTC_ADDR_MON, BIN2BCD(tm->tm_mon + 1)); ds1302_writebyte(RTC_ADDR_YEAR, BIN2BCD(tm->tm_year % 100)); /* Start RTC */ ds1302_writebyte(RTC_ADDR_SEC, ds1302_readbyte(RTC_ADDR_SEC) & ~0x80); spin_unlock_irq(&rtc->lock); return 0; } static int ds1302_rtc_ioctl(struct device *dev, unsigned int cmd, unsigned long arg) { switch (cmd) { #ifdef RTC_SET_CHARGE case RTC_SET_CHARGE: { struct ds1302_rtc *rtc = dev_get_drvdata(dev); int tcs_val; if (copy_from_user(&tcs_val, (int __user *)arg, sizeof(int))) return -EFAULT; spin_lock_irq(&rtc->lock); ds1302_writebyte(RTC_ADDR_TCR, (0xa0 | tcs_val * 0xf)); spin_unlock_irq(&rtc->lock); return 0; } #endif } return -ENOIOCTLCMD; } static struct rtc_class_ops ds1302_rtc_ops = { .read_time = ds1302_rtc_read_time, .set_time = ds1302_rtc_set_time, .ioctl = ds1302_rtc_ioctl, }; static int __devinit ds1302_rtc_probe(struct platform_device *pdev) { struct ds1302_rtc *rtc; int ret; /* Reset */ set_dp(get_dp() & ~(RTC_RESET | RTC_IODATA | RTC_SCLK)); /* Write a magic value to the DS1302 RAM, and see if it sticks. */ ds1302_writebyte(RTC_ADDR_RAM0, 0x42); if (ds1302_readbyte(RTC_ADDR_RAM0) != 0x42) return -ENODEV; rtc = kzalloc(sizeof(struct ds1302_rtc), GFP_KERNEL); if (unlikely(!rtc)) return -ENOMEM; spin_lock_init(&rtc->lock); rtc->rtc_dev = rtc_device_register("ds1302", &pdev->dev, &ds1302_rtc_ops, THIS_MODULE); if (IS_ERR(rtc->rtc_dev)) { ret = PTR_ERR(rtc->rtc_dev); goto out; } platform_set_drvdata(pdev, rtc); return 0; out: kfree(rtc); return ret; } static int __devexit ds1302_rtc_remove(struct platform_device *pdev) { struct ds1302_rtc *rtc = platform_get_drvdata(pdev); if (likely(rtc->rtc_dev)) rtc_device_unregister(rtc->rtc_dev); platform_set_drvdata(pdev, NULL); kfree(rtc); return 0; } static struct platform_driver ds1302_platform_driver = { .driver = { .name = DRV_NAME, .owner = THIS_MODULE, }, .probe = ds1302_rtc_probe, .remove = __devexit_p(ds1302_rtc_remove), }; static int __init ds1302_rtc_init(void) { return platform_driver_register(&ds1302_platform_driver); } static void __exit ds1302_rtc_exit(void) { platform_driver_unregister(&ds1302_platform_driver); } module_init(ds1302_rtc_init); module_exit(ds1302_rtc_exit); MODULE_DESCRIPTION("Dallas DS1302 RTC driver"); MODULE_VERSION(DRV_VERSION); MODULE_AUTHOR("Paul Mundt, David McCullough"); MODULE_LICENSE("GPL v2");