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500 lines
12 KiB
500 lines
12 KiB
// SPDX-License-Identifier: GPL-2.0-only |
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/* |
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* An rtc driver for the Dallas DS1511 |
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* |
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* Copyright (C) 2006 Atsushi Nemoto <[email protected]> |
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* Copyright (C) 2007 Andrew Sharp <[email protected]> |
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* |
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* Real time clock driver for the Dallas 1511 chip, which also |
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* contains a watchdog timer. There is a tiny amount of code that |
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* platform code could use to mess with the watchdog device a little |
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* bit, but not a full watchdog driver. |
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*/ |
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#include <linux/bcd.h> |
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#include <linux/init.h> |
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#include <linux/kernel.h> |
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#include <linux/gfp.h> |
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#include <linux/delay.h> |
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#include <linux/interrupt.h> |
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#include <linux/rtc.h> |
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#include <linux/platform_device.h> |
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#include <linux/io.h> |
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#include <linux/module.h> |
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enum ds1511reg { |
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DS1511_SEC = 0x0, |
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DS1511_MIN = 0x1, |
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DS1511_HOUR = 0x2, |
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DS1511_DOW = 0x3, |
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DS1511_DOM = 0x4, |
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DS1511_MONTH = 0x5, |
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DS1511_YEAR = 0x6, |
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DS1511_CENTURY = 0x7, |
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DS1511_AM1_SEC = 0x8, |
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DS1511_AM2_MIN = 0x9, |
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DS1511_AM3_HOUR = 0xa, |
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DS1511_AM4_DATE = 0xb, |
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DS1511_WD_MSEC = 0xc, |
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DS1511_WD_SEC = 0xd, |
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DS1511_CONTROL_A = 0xe, |
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DS1511_CONTROL_B = 0xf, |
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DS1511_RAMADDR_LSB = 0x10, |
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DS1511_RAMDATA = 0x13 |
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}; |
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#define DS1511_BLF1 0x80 |
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#define DS1511_BLF2 0x40 |
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#define DS1511_PRS 0x20 |
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#define DS1511_PAB 0x10 |
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#define DS1511_TDF 0x08 |
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#define DS1511_KSF 0x04 |
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#define DS1511_WDF 0x02 |
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#define DS1511_IRQF 0x01 |
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#define DS1511_TE 0x80 |
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#define DS1511_CS 0x40 |
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#define DS1511_BME 0x20 |
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#define DS1511_TPE 0x10 |
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#define DS1511_TIE 0x08 |
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#define DS1511_KIE 0x04 |
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#define DS1511_WDE 0x02 |
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#define DS1511_WDS 0x01 |
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#define DS1511_RAM_MAX 0x100 |
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#define RTC_CMD DS1511_CONTROL_B |
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#define RTC_CMD1 DS1511_CONTROL_A |
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#define RTC_ALARM_SEC DS1511_AM1_SEC |
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#define RTC_ALARM_MIN DS1511_AM2_MIN |
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#define RTC_ALARM_HOUR DS1511_AM3_HOUR |
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#define RTC_ALARM_DATE DS1511_AM4_DATE |
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#define RTC_SEC DS1511_SEC |
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#define RTC_MIN DS1511_MIN |
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#define RTC_HOUR DS1511_HOUR |
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#define RTC_DOW DS1511_DOW |
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#define RTC_DOM DS1511_DOM |
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#define RTC_MON DS1511_MONTH |
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#define RTC_YEAR DS1511_YEAR |
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#define RTC_CENTURY DS1511_CENTURY |
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#define RTC_TIE DS1511_TIE |
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#define RTC_TE DS1511_TE |
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struct rtc_plat_data { |
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struct rtc_device *rtc; |
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void __iomem *ioaddr; /* virtual base address */ |
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int irq; |
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unsigned int irqen; |
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int alrm_sec; |
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int alrm_min; |
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int alrm_hour; |
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int alrm_mday; |
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spinlock_t lock; |
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}; |
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static DEFINE_SPINLOCK(ds1511_lock); |
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static __iomem char *ds1511_base; |
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static u32 reg_spacing = 1; |
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static noinline void |
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rtc_write(uint8_t val, uint32_t reg) |
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{ |
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writeb(val, ds1511_base + (reg * reg_spacing)); |
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} |
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static noinline uint8_t |
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rtc_read(enum ds1511reg reg) |
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{ |
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return readb(ds1511_base + (reg * reg_spacing)); |
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} |
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static inline void |
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rtc_disable_update(void) |
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{ |
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rtc_write((rtc_read(RTC_CMD) & ~RTC_TE), RTC_CMD); |
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} |
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static void |
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rtc_enable_update(void) |
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{ |
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rtc_write((rtc_read(RTC_CMD) | RTC_TE), RTC_CMD); |
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} |
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/* |
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* #define DS1511_WDOG_RESET_SUPPORT |
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* |
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* Uncomment this if you want to use these routines in |
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* some platform code. |
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*/ |
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#ifdef DS1511_WDOG_RESET_SUPPORT |
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/* |
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* just enough code to set the watchdog timer so that it |
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* will reboot the system |
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*/ |
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void |
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ds1511_wdog_set(unsigned long deciseconds) |
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{ |
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/* |
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* the wdog timer can take 99.99 seconds |
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*/ |
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deciseconds %= 10000; |
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/* |
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* set the wdog values in the wdog registers |
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*/ |
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rtc_write(bin2bcd(deciseconds % 100), DS1511_WD_MSEC); |
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rtc_write(bin2bcd(deciseconds / 100), DS1511_WD_SEC); |
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/* |
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* set wdog enable and wdog 'steering' bit to issue a reset |
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*/ |
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rtc_write(rtc_read(RTC_CMD) | DS1511_WDE | DS1511_WDS, RTC_CMD); |
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} |
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void |
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ds1511_wdog_disable(void) |
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{ |
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/* |
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* clear wdog enable and wdog 'steering' bits |
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*/ |
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rtc_write(rtc_read(RTC_CMD) & ~(DS1511_WDE | DS1511_WDS), RTC_CMD); |
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/* |
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* clear the wdog counter |
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*/ |
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rtc_write(0, DS1511_WD_MSEC); |
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rtc_write(0, DS1511_WD_SEC); |
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} |
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#endif |
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/* |
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* set the rtc chip's idea of the time. |
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* stupidly, some callers call with year unmolested; |
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* and some call with year = year - 1900. thanks. |
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*/ |
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static int ds1511_rtc_set_time(struct device *dev, struct rtc_time *rtc_tm) |
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{ |
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u8 mon, day, dow, hrs, min, sec, yrs, cen; |
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unsigned long flags; |
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/* |
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* won't have to change this for a while |
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*/ |
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if (rtc_tm->tm_year < 1900) |
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rtc_tm->tm_year += 1900; |
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if (rtc_tm->tm_year < 1970) |
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return -EINVAL; |
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yrs = rtc_tm->tm_year % 100; |
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cen = rtc_tm->tm_year / 100; |
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mon = rtc_tm->tm_mon + 1; /* tm_mon starts at zero */ |
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day = rtc_tm->tm_mday; |
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dow = rtc_tm->tm_wday & 0x7; /* automatic BCD */ |
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hrs = rtc_tm->tm_hour; |
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min = rtc_tm->tm_min; |
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sec = rtc_tm->tm_sec; |
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if ((mon > 12) || (day == 0)) |
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return -EINVAL; |
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if (day > rtc_month_days(rtc_tm->tm_mon, rtc_tm->tm_year)) |
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return -EINVAL; |
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if ((hrs >= 24) || (min >= 60) || (sec >= 60)) |
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return -EINVAL; |
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/* |
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* each register is a different number of valid bits |
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*/ |
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sec = bin2bcd(sec) & 0x7f; |
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min = bin2bcd(min) & 0x7f; |
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hrs = bin2bcd(hrs) & 0x3f; |
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day = bin2bcd(day) & 0x3f; |
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mon = bin2bcd(mon) & 0x1f; |
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yrs = bin2bcd(yrs) & 0xff; |
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cen = bin2bcd(cen) & 0xff; |
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spin_lock_irqsave(&ds1511_lock, flags); |
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rtc_disable_update(); |
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rtc_write(cen, RTC_CENTURY); |
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rtc_write(yrs, RTC_YEAR); |
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rtc_write((rtc_read(RTC_MON) & 0xe0) | mon, RTC_MON); |
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rtc_write(day, RTC_DOM); |
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rtc_write(hrs, RTC_HOUR); |
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rtc_write(min, RTC_MIN); |
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rtc_write(sec, RTC_SEC); |
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rtc_write(dow, RTC_DOW); |
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rtc_enable_update(); |
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spin_unlock_irqrestore(&ds1511_lock, flags); |
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return 0; |
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} |
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static int ds1511_rtc_read_time(struct device *dev, struct rtc_time *rtc_tm) |
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{ |
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unsigned int century; |
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unsigned long flags; |
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spin_lock_irqsave(&ds1511_lock, flags); |
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rtc_disable_update(); |
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rtc_tm->tm_sec = rtc_read(RTC_SEC) & 0x7f; |
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rtc_tm->tm_min = rtc_read(RTC_MIN) & 0x7f; |
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rtc_tm->tm_hour = rtc_read(RTC_HOUR) & 0x3f; |
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rtc_tm->tm_mday = rtc_read(RTC_DOM) & 0x3f; |
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rtc_tm->tm_wday = rtc_read(RTC_DOW) & 0x7; |
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rtc_tm->tm_mon = rtc_read(RTC_MON) & 0x1f; |
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rtc_tm->tm_year = rtc_read(RTC_YEAR) & 0x7f; |
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century = rtc_read(RTC_CENTURY); |
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rtc_enable_update(); |
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spin_unlock_irqrestore(&ds1511_lock, flags); |
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rtc_tm->tm_sec = bcd2bin(rtc_tm->tm_sec); |
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rtc_tm->tm_min = bcd2bin(rtc_tm->tm_min); |
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rtc_tm->tm_hour = bcd2bin(rtc_tm->tm_hour); |
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rtc_tm->tm_mday = bcd2bin(rtc_tm->tm_mday); |
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rtc_tm->tm_wday = bcd2bin(rtc_tm->tm_wday); |
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rtc_tm->tm_mon = bcd2bin(rtc_tm->tm_mon); |
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rtc_tm->tm_year = bcd2bin(rtc_tm->tm_year); |
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century = bcd2bin(century) * 100; |
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/* |
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* Account for differences between how the RTC uses the values |
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* and how they are defined in a struct rtc_time; |
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*/ |
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century += rtc_tm->tm_year; |
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rtc_tm->tm_year = century - 1900; |
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rtc_tm->tm_mon--; |
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return 0; |
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} |
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/* |
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* write the alarm register settings |
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* |
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* we only have the use to interrupt every second, otherwise |
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* known as the update interrupt, or the interrupt if the whole |
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* date/hours/mins/secs matches. the ds1511 has many more |
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* permutations, but the kernel doesn't. |
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*/ |
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static void |
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ds1511_rtc_update_alarm(struct rtc_plat_data *pdata) |
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{ |
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unsigned long flags; |
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spin_lock_irqsave(&pdata->lock, flags); |
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rtc_write(pdata->alrm_mday < 0 || (pdata->irqen & RTC_UF) ? |
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0x80 : bin2bcd(pdata->alrm_mday) & 0x3f, |
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RTC_ALARM_DATE); |
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rtc_write(pdata->alrm_hour < 0 || (pdata->irqen & RTC_UF) ? |
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0x80 : bin2bcd(pdata->alrm_hour) & 0x3f, |
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RTC_ALARM_HOUR); |
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rtc_write(pdata->alrm_min < 0 || (pdata->irqen & RTC_UF) ? |
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0x80 : bin2bcd(pdata->alrm_min) & 0x7f, |
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RTC_ALARM_MIN); |
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rtc_write(pdata->alrm_sec < 0 || (pdata->irqen & RTC_UF) ? |
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0x80 : bin2bcd(pdata->alrm_sec) & 0x7f, |
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RTC_ALARM_SEC); |
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rtc_write(rtc_read(RTC_CMD) | (pdata->irqen ? RTC_TIE : 0), RTC_CMD); |
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rtc_read(RTC_CMD1); /* clear interrupts */ |
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spin_unlock_irqrestore(&pdata->lock, flags); |
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} |
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static int |
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ds1511_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm) |
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{ |
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struct rtc_plat_data *pdata = dev_get_drvdata(dev); |
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if (pdata->irq <= 0) |
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return -EINVAL; |
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pdata->alrm_mday = alrm->time.tm_mday; |
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pdata->alrm_hour = alrm->time.tm_hour; |
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pdata->alrm_min = alrm->time.tm_min; |
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pdata->alrm_sec = alrm->time.tm_sec; |
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if (alrm->enabled) |
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pdata->irqen |= RTC_AF; |
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ds1511_rtc_update_alarm(pdata); |
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return 0; |
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} |
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static int |
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ds1511_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm) |
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{ |
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struct rtc_plat_data *pdata = dev_get_drvdata(dev); |
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if (pdata->irq <= 0) |
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return -EINVAL; |
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alrm->time.tm_mday = pdata->alrm_mday < 0 ? 0 : pdata->alrm_mday; |
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alrm->time.tm_hour = pdata->alrm_hour < 0 ? 0 : pdata->alrm_hour; |
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alrm->time.tm_min = pdata->alrm_min < 0 ? 0 : pdata->alrm_min; |
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alrm->time.tm_sec = pdata->alrm_sec < 0 ? 0 : pdata->alrm_sec; |
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alrm->enabled = (pdata->irqen & RTC_AF) ? 1 : 0; |
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return 0; |
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} |
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static irqreturn_t |
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ds1511_interrupt(int irq, void *dev_id) |
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{ |
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struct platform_device *pdev = dev_id; |
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struct rtc_plat_data *pdata = platform_get_drvdata(pdev); |
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unsigned long events = 0; |
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spin_lock(&pdata->lock); |
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/* |
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* read and clear interrupt |
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*/ |
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if (rtc_read(RTC_CMD1) & DS1511_IRQF) { |
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events = RTC_IRQF; |
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if (rtc_read(RTC_ALARM_SEC) & 0x80) |
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events |= RTC_UF; |
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else |
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events |= RTC_AF; |
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rtc_update_irq(pdata->rtc, 1, events); |
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} |
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spin_unlock(&pdata->lock); |
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return events ? IRQ_HANDLED : IRQ_NONE; |
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} |
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static int ds1511_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled) |
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{ |
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struct rtc_plat_data *pdata = dev_get_drvdata(dev); |
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if (pdata->irq <= 0) |
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return -EINVAL; |
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if (enabled) |
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pdata->irqen |= RTC_AF; |
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else |
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pdata->irqen &= ~RTC_AF; |
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ds1511_rtc_update_alarm(pdata); |
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return 0; |
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} |
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static const struct rtc_class_ops ds1511_rtc_ops = { |
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.read_time = ds1511_rtc_read_time, |
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.set_time = ds1511_rtc_set_time, |
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.read_alarm = ds1511_rtc_read_alarm, |
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.set_alarm = ds1511_rtc_set_alarm, |
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.alarm_irq_enable = ds1511_rtc_alarm_irq_enable, |
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}; |
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static int ds1511_nvram_read(void *priv, unsigned int pos, void *buf, |
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size_t size) |
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{ |
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int i; |
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rtc_write(pos, DS1511_RAMADDR_LSB); |
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for (i = 0; i < size; i++) |
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*(char *)buf++ = rtc_read(DS1511_RAMDATA); |
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return 0; |
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} |
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static int ds1511_nvram_write(void *priv, unsigned int pos, void *buf, |
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size_t size) |
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{ |
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int i; |
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rtc_write(pos, DS1511_RAMADDR_LSB); |
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for (i = 0; i < size; i++) |
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rtc_write(*(char *)buf++, DS1511_RAMDATA); |
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return 0; |
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} |
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static int ds1511_rtc_probe(struct platform_device *pdev) |
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{ |
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struct rtc_plat_data *pdata; |
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int ret = 0; |
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struct nvmem_config ds1511_nvmem_cfg = { |
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.name = "ds1511_nvram", |
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.word_size = 1, |
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.stride = 1, |
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.size = DS1511_RAM_MAX, |
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.reg_read = ds1511_nvram_read, |
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.reg_write = ds1511_nvram_write, |
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.priv = &pdev->dev, |
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}; |
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pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL); |
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if (!pdata) |
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return -ENOMEM; |
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ds1511_base = devm_platform_ioremap_resource(pdev, 0); |
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if (IS_ERR(ds1511_base)) |
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return PTR_ERR(ds1511_base); |
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pdata->ioaddr = ds1511_base; |
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pdata->irq = platform_get_irq(pdev, 0); |
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/* |
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* turn on the clock and the crystal, etc. |
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*/ |
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rtc_write(DS1511_BME, RTC_CMD); |
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rtc_write(0, RTC_CMD1); |
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/* |
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* clear the wdog counter |
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*/ |
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rtc_write(0, DS1511_WD_MSEC); |
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rtc_write(0, DS1511_WD_SEC); |
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/* |
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* start the clock |
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*/ |
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rtc_enable_update(); |
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/* |
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* check for a dying bat-tree |
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*/ |
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if (rtc_read(RTC_CMD1) & DS1511_BLF1) |
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dev_warn(&pdev->dev, "voltage-low detected.\n"); |
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spin_lock_init(&pdata->lock); |
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platform_set_drvdata(pdev, pdata); |
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pdata->rtc = devm_rtc_allocate_device(&pdev->dev); |
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if (IS_ERR(pdata->rtc)) |
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return PTR_ERR(pdata->rtc); |
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pdata->rtc->ops = &ds1511_rtc_ops; |
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ret = devm_rtc_register_device(pdata->rtc); |
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if (ret) |
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return ret; |
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devm_rtc_nvmem_register(pdata->rtc, &ds1511_nvmem_cfg); |
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/* |
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* if the platform has an interrupt in mind for this device, |
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* then by all means, set it |
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*/ |
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if (pdata->irq > 0) { |
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rtc_read(RTC_CMD1); |
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if (devm_request_irq(&pdev->dev, pdata->irq, ds1511_interrupt, |
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IRQF_SHARED, pdev->name, pdev) < 0) { |
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dev_warn(&pdev->dev, "interrupt not available.\n"); |
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pdata->irq = 0; |
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} |
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} |
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return 0; |
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} |
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/* work with hotplug and coldplug */ |
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MODULE_ALIAS("platform:ds1511"); |
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static struct platform_driver ds1511_rtc_driver = { |
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.probe = ds1511_rtc_probe, |
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.driver = { |
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.name = "ds1511", |
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}, |
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}; |
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module_platform_driver(ds1511_rtc_driver); |
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MODULE_AUTHOR("Andrew Sharp <[email protected]>"); |
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MODULE_DESCRIPTION("Dallas DS1511 RTC driver"); |
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MODULE_LICENSE("GPL");
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