diff options
Diffstat (limited to 'qemu/roms/u-boot/drivers/rtc/ds3231.c')
| -rw-r--r-- | qemu/roms/u-boot/drivers/rtc/ds3231.c | 161 |
1 files changed, 161 insertions, 0 deletions
diff --git a/qemu/roms/u-boot/drivers/rtc/ds3231.c b/qemu/roms/u-boot/drivers/rtc/ds3231.c new file mode 100644 index 000000000..c84bbc647 --- /dev/null +++ b/qemu/roms/u-boot/drivers/rtc/ds3231.c @@ -0,0 +1,161 @@ +/* + * (C) Copyright 2006 + * Markus Klotzbuecher, mk@denx.de + * + * SPDX-License-Identifier: GPL-2.0+ + */ + +/* + * Date & Time support (no alarms) for Dallas Semiconductor (now Maxim) + * Extremly Accurate DS3231 Real Time Clock (RTC). + * + * copied from ds1337.c + */ + +#include <common.h> +#include <command.h> +#include <rtc.h> +#include <i2c.h> + +#if defined(CONFIG_CMD_DATE) + +/* + * RTC register addresses + */ +#define RTC_SEC_REG_ADDR 0x0 +#define RTC_MIN_REG_ADDR 0x1 +#define RTC_HR_REG_ADDR 0x2 +#define RTC_DAY_REG_ADDR 0x3 +#define RTC_DATE_REG_ADDR 0x4 +#define RTC_MON_REG_ADDR 0x5 +#define RTC_YR_REG_ADDR 0x6 +#define RTC_CTL_REG_ADDR 0x0e +#define RTC_STAT_REG_ADDR 0x0f + + +/* + * RTC control register bits + */ +#define RTC_CTL_BIT_A1IE 0x1 /* Alarm 1 interrupt enable */ +#define RTC_CTL_BIT_A2IE 0x2 /* Alarm 2 interrupt enable */ +#define RTC_CTL_BIT_INTCN 0x4 /* Interrupt control */ +#define RTC_CTL_BIT_RS1 0x8 /* Rate select 1 */ +#define RTC_CTL_BIT_RS2 0x10 /* Rate select 2 */ +#define RTC_CTL_BIT_DOSC 0x80 /* Disable Oscillator */ + +/* + * RTC status register bits + */ +#define RTC_STAT_BIT_A1F 0x1 /* Alarm 1 flag */ +#define RTC_STAT_BIT_A2F 0x2 /* Alarm 2 flag */ +#define RTC_STAT_BIT_OSF 0x80 /* Oscillator stop flag */ + + +static uchar rtc_read (uchar reg); +static void rtc_write (uchar reg, uchar val); + + +/* + * Get the current time from the RTC + */ +int rtc_get (struct rtc_time *tmp) +{ + int rel = 0; + uchar sec, min, hour, mday, wday, mon_cent, year, control, status; + + control = rtc_read (RTC_CTL_REG_ADDR); + status = rtc_read (RTC_STAT_REG_ADDR); + sec = rtc_read (RTC_SEC_REG_ADDR); + min = rtc_read (RTC_MIN_REG_ADDR); + hour = rtc_read (RTC_HR_REG_ADDR); + wday = rtc_read (RTC_DAY_REG_ADDR); + mday = rtc_read (RTC_DATE_REG_ADDR); + mon_cent = rtc_read (RTC_MON_REG_ADDR); + year = rtc_read (RTC_YR_REG_ADDR); + + debug("Get RTC year: %02x mon/cent: %02x mday: %02x wday: %02x " + "hr: %02x min: %02x sec: %02x control: %02x status: %02x\n", + year, mon_cent, mday, wday, hour, min, sec, control, status); + + if (status & RTC_STAT_BIT_OSF) { + printf ("### Warning: RTC oscillator has stopped\n"); + /* clear the OSF flag */ + rtc_write (RTC_STAT_REG_ADDR, + rtc_read (RTC_STAT_REG_ADDR) & ~RTC_STAT_BIT_OSF); + rel = -1; + } + + tmp->tm_sec = bcd2bin (sec & 0x7F); + tmp->tm_min = bcd2bin (min & 0x7F); + tmp->tm_hour = bcd2bin (hour & 0x3F); + tmp->tm_mday = bcd2bin (mday & 0x3F); + tmp->tm_mon = bcd2bin (mon_cent & 0x1F); + tmp->tm_year = bcd2bin (year) + ((mon_cent & 0x80) ? 2000 : 1900); + tmp->tm_wday = bcd2bin ((wday - 1) & 0x07); + tmp->tm_yday = 0; + tmp->tm_isdst= 0; + + debug("Get DATE: %4d-%02d-%02d (wday=%d) TIME: %2d:%02d:%02d\n", + tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday, + tmp->tm_hour, tmp->tm_min, tmp->tm_sec); + + return rel; +} + + +/* + * Set the RTC + */ +int rtc_set (struct rtc_time *tmp) +{ + uchar century; + + debug("Set DATE: %4d-%02d-%02d (wday=%d) TIME: %2d:%02d:%02d\n", + tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday, + tmp->tm_hour, tmp->tm_min, tmp->tm_sec); + + rtc_write (RTC_YR_REG_ADDR, bin2bcd (tmp->tm_year % 100)); + + century = (tmp->tm_year >= 2000) ? 0x80 : 0; + rtc_write (RTC_MON_REG_ADDR, bin2bcd (tmp->tm_mon) | century); + + rtc_write (RTC_DAY_REG_ADDR, bin2bcd (tmp->tm_wday + 1)); + rtc_write (RTC_DATE_REG_ADDR, bin2bcd (tmp->tm_mday)); + rtc_write (RTC_HR_REG_ADDR, bin2bcd (tmp->tm_hour)); + rtc_write (RTC_MIN_REG_ADDR, bin2bcd (tmp->tm_min)); + rtc_write (RTC_SEC_REG_ADDR, bin2bcd (tmp->tm_sec)); + + return 0; +} + + +/* + * Reset the RTC. We also enable the oscillator output on the + * SQW/INTB* pin and program it for 32,768 Hz output. Note that + * according to the datasheet, turning on the square wave output + * increases the current drain on the backup battery from about + * 600 nA to 2uA. + */ +void rtc_reset (void) +{ + rtc_write (RTC_CTL_REG_ADDR, RTC_CTL_BIT_RS1 | RTC_CTL_BIT_RS2); +} + + +/* + * Helper functions + */ + +static +uchar rtc_read (uchar reg) +{ + return (i2c_reg_read (CONFIG_SYS_I2C_RTC_ADDR, reg)); +} + + +static void rtc_write (uchar reg, uchar val) +{ + i2c_reg_write (CONFIG_SYS_I2C_RTC_ADDR, reg, val); +} + +#endif |