diff options
Diffstat (limited to 'drivers/rtc/rtc-ds1511.c')
| -rw-r--r-- | drivers/rtc/rtc-ds1511.c | 500 |
1 files changed, 500 insertions, 0 deletions
diff --git a/drivers/rtc/rtc-ds1511.c b/drivers/rtc/rtc-ds1511.c new file mode 100644 index 000000000..1109cad83 --- /dev/null +++ b/drivers/rtc/rtc-ds1511.c @@ -0,0 +1,500 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * An rtc driver for the Dallas DS1511 + * + * Copyright (C) 2006 Atsushi Nemoto <anemo@mba.ocn.ne.jp> + * Copyright (C) 2007 Andrew Sharp <andy.sharp@lsi.com> + * + * Real time clock driver for the Dallas 1511 chip, which also + * contains a watchdog timer. There is a tiny amount of code that + * platform code could use to mess with the watchdog device a little + * bit, but not a full watchdog driver. + */ + +#include <linux/bcd.h> +#include <linux/init.h> +#include <linux/kernel.h> +#include <linux/gfp.h> +#include <linux/delay.h> +#include <linux/interrupt.h> +#include <linux/rtc.h> +#include <linux/platform_device.h> +#include <linux/io.h> +#include <linux/module.h> + +enum ds1511reg { + DS1511_SEC = 0x0, + DS1511_MIN = 0x1, + DS1511_HOUR = 0x2, + DS1511_DOW = 0x3, + DS1511_DOM = 0x4, + DS1511_MONTH = 0x5, + DS1511_YEAR = 0x6, + DS1511_CENTURY = 0x7, + DS1511_AM1_SEC = 0x8, + DS1511_AM2_MIN = 0x9, + DS1511_AM3_HOUR = 0xa, + DS1511_AM4_DATE = 0xb, + DS1511_WD_MSEC = 0xc, + DS1511_WD_SEC = 0xd, + DS1511_CONTROL_A = 0xe, + DS1511_CONTROL_B = 0xf, + DS1511_RAMADDR_LSB = 0x10, + DS1511_RAMDATA = 0x13 +}; + +#define DS1511_BLF1 0x80 +#define DS1511_BLF2 0x40 +#define DS1511_PRS 0x20 +#define DS1511_PAB 0x10 +#define DS1511_TDF 0x08 +#define DS1511_KSF 0x04 +#define DS1511_WDF 0x02 +#define DS1511_IRQF 0x01 +#define DS1511_TE 0x80 +#define DS1511_CS 0x40 +#define DS1511_BME 0x20 +#define DS1511_TPE 0x10 +#define DS1511_TIE 0x08 +#define DS1511_KIE 0x04 +#define DS1511_WDE 0x02 +#define DS1511_WDS 0x01 +#define DS1511_RAM_MAX 0x100 + +#define RTC_CMD DS1511_CONTROL_B +#define RTC_CMD1 DS1511_CONTROL_A + +#define RTC_ALARM_SEC DS1511_AM1_SEC +#define RTC_ALARM_MIN DS1511_AM2_MIN +#define RTC_ALARM_HOUR DS1511_AM3_HOUR +#define RTC_ALARM_DATE DS1511_AM4_DATE + +#define RTC_SEC DS1511_SEC +#define RTC_MIN DS1511_MIN +#define RTC_HOUR DS1511_HOUR +#define RTC_DOW DS1511_DOW +#define RTC_DOM DS1511_DOM +#define RTC_MON DS1511_MONTH +#define RTC_YEAR DS1511_YEAR +#define RTC_CENTURY DS1511_CENTURY + +#define RTC_TIE DS1511_TIE +#define RTC_TE DS1511_TE + +struct rtc_plat_data { + struct rtc_device *rtc; + void __iomem *ioaddr; /* virtual base address */ + int irq; + unsigned int irqen; + int alrm_sec; + int alrm_min; + int alrm_hour; + int alrm_mday; + spinlock_t lock; +}; + +static DEFINE_SPINLOCK(ds1511_lock); + +static __iomem char *ds1511_base; +static u32 reg_spacing = 1; + +static noinline void +rtc_write(uint8_t val, uint32_t reg) +{ + writeb(val, ds1511_base + (reg * reg_spacing)); +} + +static noinline uint8_t +rtc_read(enum ds1511reg reg) +{ + return readb(ds1511_base + (reg * reg_spacing)); +} + +static inline void +rtc_disable_update(void) +{ + rtc_write((rtc_read(RTC_CMD) & ~RTC_TE), RTC_CMD); +} + +static void +rtc_enable_update(void) +{ + rtc_write((rtc_read(RTC_CMD) | RTC_TE), RTC_CMD); +} + +/* + * #define DS1511_WDOG_RESET_SUPPORT + * + * Uncomment this if you want to use these routines in + * some platform code. + */ +#ifdef DS1511_WDOG_RESET_SUPPORT +/* + * just enough code to set the watchdog timer so that it + * will reboot the system + */ +void +ds1511_wdog_set(unsigned long deciseconds) +{ + /* + * the wdog timer can take 99.99 seconds + */ + deciseconds %= 10000; + /* + * set the wdog values in the wdog registers + */ + rtc_write(bin2bcd(deciseconds % 100), DS1511_WD_MSEC); + rtc_write(bin2bcd(deciseconds / 100), DS1511_WD_SEC); + /* + * set wdog enable and wdog 'steering' bit to issue a reset + */ + rtc_write(rtc_read(RTC_CMD) | DS1511_WDE | DS1511_WDS, RTC_CMD); +} + +void +ds1511_wdog_disable(void) +{ + /* + * clear wdog enable and wdog 'steering' bits + */ + rtc_write(rtc_read(RTC_CMD) & ~(DS1511_WDE | DS1511_WDS), RTC_CMD); + /* + * clear the wdog counter + */ + rtc_write(0, DS1511_WD_MSEC); + rtc_write(0, DS1511_WD_SEC); +} +#endif + +/* + * set the rtc chip's idea of the time. + * stupidly, some callers call with year unmolested; + * and some call with year = year - 1900. thanks. + */ +static int ds1511_rtc_set_time(struct device *dev, struct rtc_time *rtc_tm) +{ + u8 mon, day, dow, hrs, min, sec, yrs, cen; + unsigned long flags; + + /* + * won't have to change this for a while + */ + if (rtc_tm->tm_year < 1900) + rtc_tm->tm_year += 1900; + + if (rtc_tm->tm_year < 1970) + return -EINVAL; + + yrs = rtc_tm->tm_year % 100; + cen = rtc_tm->tm_year / 100; + mon = rtc_tm->tm_mon + 1; /* tm_mon starts at zero */ + day = rtc_tm->tm_mday; + dow = rtc_tm->tm_wday & 0x7; /* automatic BCD */ + hrs = rtc_tm->tm_hour; + min = rtc_tm->tm_min; + sec = rtc_tm->tm_sec; + + if ((mon > 12) || (day == 0)) + return -EINVAL; + + if (day > rtc_month_days(rtc_tm->tm_mon, rtc_tm->tm_year)) + return -EINVAL; + + if ((hrs >= 24) || (min >= 60) || (sec >= 60)) + return -EINVAL; + + /* + * each register is a different number of valid bits + */ + sec = bin2bcd(sec) & 0x7f; + min = bin2bcd(min) & 0x7f; + hrs = bin2bcd(hrs) & 0x3f; + day = bin2bcd(day) & 0x3f; + mon = bin2bcd(mon) & 0x1f; + yrs = bin2bcd(yrs) & 0xff; + cen = bin2bcd(cen) & 0xff; + + spin_lock_irqsave(&ds1511_lock, flags); + rtc_disable_update(); + rtc_write(cen, RTC_CENTURY); + rtc_write(yrs, RTC_YEAR); + rtc_write((rtc_read(RTC_MON) & 0xe0) | mon, RTC_MON); + rtc_write(day, RTC_DOM); + rtc_write(hrs, RTC_HOUR); + rtc_write(min, RTC_MIN); + rtc_write(sec, RTC_SEC); + rtc_write(dow, RTC_DOW); + rtc_enable_update(); + spin_unlock_irqrestore(&ds1511_lock, flags); + + return 0; +} + +static int ds1511_rtc_read_time(struct device *dev, struct rtc_time *rtc_tm) +{ + unsigned int century; + unsigned long flags; + + spin_lock_irqsave(&ds1511_lock, flags); + rtc_disable_update(); + + rtc_tm->tm_sec = rtc_read(RTC_SEC) & 0x7f; + rtc_tm->tm_min = rtc_read(RTC_MIN) & 0x7f; + rtc_tm->tm_hour = rtc_read(RTC_HOUR) & 0x3f; + rtc_tm->tm_mday = rtc_read(RTC_DOM) & 0x3f; + rtc_tm->tm_wday = rtc_read(RTC_DOW) & 0x7; + rtc_tm->tm_mon = rtc_read(RTC_MON) & 0x1f; + rtc_tm->tm_year = rtc_read(RTC_YEAR) & 0x7f; + century = rtc_read(RTC_CENTURY); + + rtc_enable_update(); + spin_unlock_irqrestore(&ds1511_lock, flags); + + rtc_tm->tm_sec = bcd2bin(rtc_tm->tm_sec); + rtc_tm->tm_min = bcd2bin(rtc_tm->tm_min); + rtc_tm->tm_hour = bcd2bin(rtc_tm->tm_hour); + rtc_tm->tm_mday = bcd2bin(rtc_tm->tm_mday); + rtc_tm->tm_wday = bcd2bin(rtc_tm->tm_wday); + rtc_tm->tm_mon = bcd2bin(rtc_tm->tm_mon); + rtc_tm->tm_year = bcd2bin(rtc_tm->tm_year); + century = bcd2bin(century) * 100; + + /* + * Account for differences between how the RTC uses the values + * and how they are defined in a struct rtc_time; + */ + century += rtc_tm->tm_year; + rtc_tm->tm_year = century - 1900; + + rtc_tm->tm_mon--; + + return 0; +} + +/* + * write the alarm register settings + * + * we only have the use to interrupt every second, otherwise + * known as the update interrupt, or the interrupt if the whole + * date/hours/mins/secs matches. the ds1511 has many more + * permutations, but the kernel doesn't. + */ +static void +ds1511_rtc_update_alarm(struct rtc_plat_data *pdata) +{ + unsigned long flags; + + spin_lock_irqsave(&pdata->lock, flags); + rtc_write(pdata->alrm_mday < 0 || (pdata->irqen & RTC_UF) ? + 0x80 : bin2bcd(pdata->alrm_mday) & 0x3f, + RTC_ALARM_DATE); + rtc_write(pdata->alrm_hour < 0 || (pdata->irqen & RTC_UF) ? + 0x80 : bin2bcd(pdata->alrm_hour) & 0x3f, + RTC_ALARM_HOUR); + rtc_write(pdata->alrm_min < 0 || (pdata->irqen & RTC_UF) ? + 0x80 : bin2bcd(pdata->alrm_min) & 0x7f, + RTC_ALARM_MIN); + rtc_write(pdata->alrm_sec < 0 || (pdata->irqen & RTC_UF) ? + 0x80 : bin2bcd(pdata->alrm_sec) & 0x7f, + RTC_ALARM_SEC); + rtc_write(rtc_read(RTC_CMD) | (pdata->irqen ? RTC_TIE : 0), RTC_CMD); + rtc_read(RTC_CMD1); /* clear interrupts */ + spin_unlock_irqrestore(&pdata->lock, flags); +} + +static int +ds1511_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm) +{ + struct rtc_plat_data *pdata = dev_get_drvdata(dev); + + if (pdata->irq <= 0) + return -EINVAL; + + pdata->alrm_mday = alrm->time.tm_mday; + pdata->alrm_hour = alrm->time.tm_hour; + pdata->alrm_min = alrm->time.tm_min; + pdata->alrm_sec = alrm->time.tm_sec; + if (alrm->enabled) + pdata->irqen |= RTC_AF; + + ds1511_rtc_update_alarm(pdata); + return 0; +} + +static int +ds1511_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm) +{ + struct rtc_plat_data *pdata = dev_get_drvdata(dev); + + if (pdata->irq <= 0) + return -EINVAL; + + alrm->time.tm_mday = pdata->alrm_mday < 0 ? 0 : pdata->alrm_mday; + alrm->time.tm_hour = pdata->alrm_hour < 0 ? 0 : pdata->alrm_hour; + alrm->time.tm_min = pdata->alrm_min < 0 ? 0 : pdata->alrm_min; + alrm->time.tm_sec = pdata->alrm_sec < 0 ? 0 : pdata->alrm_sec; + alrm->enabled = (pdata->irqen & RTC_AF) ? 1 : 0; + return 0; +} + +static irqreturn_t +ds1511_interrupt(int irq, void *dev_id) +{ + struct platform_device *pdev = dev_id; + struct rtc_plat_data *pdata = platform_get_drvdata(pdev); + unsigned long events = 0; + + spin_lock(&pdata->lock); + /* + * read and clear interrupt + */ + if (rtc_read(RTC_CMD1) & DS1511_IRQF) { + events = RTC_IRQF; + if (rtc_read(RTC_ALARM_SEC) & 0x80) + events |= RTC_UF; + else + events |= RTC_AF; + rtc_update_irq(pdata->rtc, 1, events); + } + spin_unlock(&pdata->lock); + return events ? IRQ_HANDLED : IRQ_NONE; +} + +static int ds1511_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled) +{ + struct rtc_plat_data *pdata = dev_get_drvdata(dev); + + if (pdata->irq <= 0) + return -EINVAL; + if (enabled) + pdata->irqen |= RTC_AF; + else + pdata->irqen &= ~RTC_AF; + ds1511_rtc_update_alarm(pdata); + return 0; +} + +static const struct rtc_class_ops ds1511_rtc_ops = { + .read_time = ds1511_rtc_read_time, + .set_time = ds1511_rtc_set_time, + .read_alarm = ds1511_rtc_read_alarm, + .set_alarm = ds1511_rtc_set_alarm, + .alarm_irq_enable = ds1511_rtc_alarm_irq_enable, +}; + +static int ds1511_nvram_read(void *priv, unsigned int pos, void *buf, + size_t size) +{ + int i; + + rtc_write(pos, DS1511_RAMADDR_LSB); + for (i = 0; i < size; i++) + *(char *)buf++ = rtc_read(DS1511_RAMDATA); + + return 0; +} + +static int ds1511_nvram_write(void *priv, unsigned int pos, void *buf, + size_t size) +{ + int i; + + rtc_write(pos, DS1511_RAMADDR_LSB); + for (i = 0; i < size; i++) + rtc_write(*(char *)buf++, DS1511_RAMDATA); + + return 0; +} + +static int ds1511_rtc_probe(struct platform_device *pdev) +{ + struct rtc_plat_data *pdata; + int ret = 0; + struct nvmem_config ds1511_nvmem_cfg = { + .name = "ds1511_nvram", + .word_size = 1, + .stride = 1, + .size = DS1511_RAM_MAX, + .reg_read = ds1511_nvram_read, + .reg_write = ds1511_nvram_write, + .priv = &pdev->dev, + }; + + pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL); + if (!pdata) + return -ENOMEM; + + ds1511_base = devm_platform_ioremap_resource(pdev, 0); + if (IS_ERR(ds1511_base)) + return PTR_ERR(ds1511_base); + pdata->ioaddr = ds1511_base; + pdata->irq = platform_get_irq(pdev, 0); + + /* + * turn on the clock and the crystal, etc. + */ + rtc_write(DS1511_BME, RTC_CMD); + rtc_write(0, RTC_CMD1); + /* + * clear the wdog counter + */ + rtc_write(0, DS1511_WD_MSEC); + rtc_write(0, DS1511_WD_SEC); + /* + * start the clock + */ + rtc_enable_update(); + + /* + * check for a dying bat-tree + */ + if (rtc_read(RTC_CMD1) & DS1511_BLF1) + dev_warn(&pdev->dev, "voltage-low detected.\n"); + + spin_lock_init(&pdata->lock); + platform_set_drvdata(pdev, pdata); + + pdata->rtc = devm_rtc_allocate_device(&pdev->dev); + if (IS_ERR(pdata->rtc)) + return PTR_ERR(pdata->rtc); + + pdata->rtc->ops = &ds1511_rtc_ops; + + ret = devm_rtc_register_device(pdata->rtc); + if (ret) + return ret; + + devm_rtc_nvmem_register(pdata->rtc, &ds1511_nvmem_cfg); + + /* + * if the platform has an interrupt in mind for this device, + * then by all means, set it + */ + if (pdata->irq > 0) { + rtc_read(RTC_CMD1); + if (devm_request_irq(&pdev->dev, pdata->irq, ds1511_interrupt, + IRQF_SHARED, pdev->name, pdev) < 0) { + + dev_warn(&pdev->dev, "interrupt not available.\n"); + pdata->irq = 0; + } + } + + return 0; +} + +/* work with hotplug and coldplug */ +MODULE_ALIAS("platform:ds1511"); + +static struct platform_driver ds1511_rtc_driver = { + .probe = ds1511_rtc_probe, + .driver = { + .name = "ds1511", + }, +}; + +module_platform_driver(ds1511_rtc_driver); + +MODULE_AUTHOR("Andrew Sharp <andy.sharp@lsi.com>"); +MODULE_DESCRIPTION("Dallas DS1511 RTC driver"); +MODULE_LICENSE("GPL"); |