diff options
Diffstat (limited to 'drivers/rtc/rtc-ds1302.c')
| -rw-r--r-- | drivers/rtc/rtc-ds1302.c | 255 |
1 files changed, 255 insertions, 0 deletions
diff --git a/drivers/rtc/rtc-ds1302.c b/drivers/rtc/rtc-ds1302.c new file mode 100644 index 000000000..6bef7a523 --- /dev/null +++ b/drivers/rtc/rtc-ds1302.c @@ -0,0 +1,255 @@ +/* + * 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/rtc.h> +#include <linux/io.h> +#include <linux/bcd.h> + +#define DRV_NAME "rtc-ds1302" +#define DRV_VERSION "0.1.1" + +#define RTC_CMD_READ 0x81 /* Read command */ +#define RTC_CMD_WRITE 0x80 /* Write command */ + +#define RTC_CMD_WRITE_ENABLE 0x00 /* Write enable */ +#define RTC_CMD_WRITE_DISABLE 0x80 /* Write disable */ + +#define RTC_ADDR_RAM0 0x20 /* Address of RAM0 */ +#define RTC_ADDR_TCR 0x08 /* Address of trickle charge register */ +#define RTC_ADDR_CTRL 0x07 /* Address of control 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 */ + +#ifdef CONFIG_SH_SECUREEDGE5410 +#include <asm/rtc.h> +#include <mach/secureedge5410.h> + +#define RTC_RESET 0x1000 +#define RTC_IODATA 0x0800 +#define RTC_SCLK 0x0400 + +#define set_dp(x) SECUREEDGE_WRITE_IOPORT(x, 0x1c00) +#define get_dp() SECUREEDGE_READ_IOPORT() +#define ds1302_set_tx() +#define ds1302_set_rx() + +static inline int ds1302_hw_init(void) +{ + return 0; +} + +static inline void ds1302_reset(void) +{ + set_dp(get_dp() & ~(RTC_RESET | RTC_IODATA | RTC_SCLK)); +} + +static inline void ds1302_clock(void) +{ + set_dp(get_dp() | RTC_SCLK); /* clock high */ + set_dp(get_dp() & ~RTC_SCLK); /* clock low */ +} + +static inline void ds1302_start(void) +{ + set_dp(get_dp() | RTC_RESET); +} + +static inline void ds1302_stop(void) +{ + set_dp(get_dp() & ~RTC_RESET); +} + +static inline void ds1302_txbit(int bit) +{ + set_dp((get_dp() & ~RTC_IODATA) | (bit ? RTC_IODATA : 0)); +} + +static inline int ds1302_rxbit(void) +{ + return !!(get_dp() & RTC_IODATA); +} + +#else +#error "Add support for your platform" +#endif + +static void ds1302_sendbits(unsigned int val) +{ + int i; + + ds1302_set_tx(); + + for (i = 8; (i); i--, val >>= 1) { + ds1302_txbit(val & 0x1); + ds1302_clock(); + } +} + +static unsigned int ds1302_recvbits(void) +{ + unsigned int val; + int i; + + ds1302_set_rx(); + + for (i = 0, val = 0; (i < 8); i++) { + val |= (ds1302_rxbit() << i); + ds1302_clock(); + } + + return val; +} + +static unsigned int ds1302_readbyte(unsigned int addr) +{ + unsigned int val; + + ds1302_reset(); + + ds1302_start(); + ds1302_sendbits(((addr & 0x3f) << 1) | RTC_CMD_READ); + val = ds1302_recvbits(); + ds1302_stop(); + + return val; +} + +static void ds1302_writebyte(unsigned int addr, unsigned int val) +{ + ds1302_reset(); + + ds1302_start(); + ds1302_sendbits(((addr & 0x3f) << 1) | RTC_CMD_WRITE); + ds1302_sendbits(val); + ds1302_stop(); +} + +static int ds1302_rtc_read_time(struct device *dev, struct rtc_time *tm) +{ + 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; + + 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); + + return rtc_valid_tm(tm); +} + +static int ds1302_rtc_set_time(struct device *dev, struct rtc_time *tm) +{ + ds1302_writebyte(RTC_ADDR_CTRL, RTC_CMD_WRITE_ENABLE); + /* 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); + + ds1302_writebyte(RTC_ADDR_CTRL, RTC_CMD_WRITE_DISABLE); + + 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: + { + int tcs_val; + + if (copy_from_user(&tcs_val, (int __user *)arg, sizeof(int))) + return -EFAULT; + + ds1302_writebyte(RTC_ADDR_TCR, (0xa0 | tcs_val * 0xf)); + 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 __init ds1302_rtc_probe(struct platform_device *pdev) +{ + struct rtc_device *rtc; + + if (ds1302_hw_init()) { + dev_err(&pdev->dev, "Failed to init communication channel"); + return -EINVAL; + } + + /* Reset */ + ds1302_reset(); + + /* 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) { + dev_err(&pdev->dev, "Failed to probe"); + return -ENODEV; + } + + rtc = devm_rtc_device_register(&pdev->dev, "ds1302", + &ds1302_rtc_ops, THIS_MODULE); + if (IS_ERR(rtc)) + return PTR_ERR(rtc); + + platform_set_drvdata(pdev, rtc); + + return 0; +} + +static struct platform_driver ds1302_platform_driver = { + .driver = { + .name = DRV_NAME, + }, +}; + +module_platform_driver_probe(ds1302_platform_driver, ds1302_rtc_probe); + +MODULE_DESCRIPTION("Dallas DS1302 RTC driver"); +MODULE_VERSION(DRV_VERSION); +MODULE_AUTHOR("Paul Mundt, David McCullough"); +MODULE_LICENSE("GPL v2"); |