diff options
Diffstat (limited to 'drivers/rtc/rtc-stk17ta8.c')
| -rw-r--r-- | drivers/rtc/rtc-stk17ta8.c | 337 |
1 files changed, 337 insertions, 0 deletions
diff --git a/drivers/rtc/rtc-stk17ta8.c b/drivers/rtc/rtc-stk17ta8.c new file mode 100644 index 000000000..7cb6be1b7 --- /dev/null +++ b/drivers/rtc/rtc-stk17ta8.c @@ -0,0 +1,337 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * A RTC driver for the Simtek STK17TA8 + * + * By Thomas Hommel <thomas.hommel@ge.com> + * + * Based on the DS1553 driver from + * Atsushi Nemoto <anemo@mba.ocn.ne.jp> + */ + +#include <linux/bcd.h> +#include <linux/init.h> +#include <linux/kernel.h> +#include <linux/gfp.h> +#include <linux/delay.h> +#include <linux/jiffies.h> +#include <linux/interrupt.h> +#include <linux/rtc.h> +#include <linux/platform_device.h> +#include <linux/io.h> +#include <linux/module.h> + +#define RTC_REG_SIZE 0x20000 +#define RTC_OFFSET 0x1fff0 + +#define RTC_FLAGS (RTC_OFFSET + 0) +#define RTC_CENTURY (RTC_OFFSET + 1) +#define RTC_SECONDS_ALARM (RTC_OFFSET + 2) +#define RTC_MINUTES_ALARM (RTC_OFFSET + 3) +#define RTC_HOURS_ALARM (RTC_OFFSET + 4) +#define RTC_DATE_ALARM (RTC_OFFSET + 5) +#define RTC_INTERRUPTS (RTC_OFFSET + 6) +#define RTC_WATCHDOG (RTC_OFFSET + 7) +#define RTC_CALIBRATION (RTC_OFFSET + 8) +#define RTC_SECONDS (RTC_OFFSET + 9) +#define RTC_MINUTES (RTC_OFFSET + 10) +#define RTC_HOURS (RTC_OFFSET + 11) +#define RTC_DAY (RTC_OFFSET + 12) +#define RTC_DATE (RTC_OFFSET + 13) +#define RTC_MONTH (RTC_OFFSET + 14) +#define RTC_YEAR (RTC_OFFSET + 15) + +#define RTC_SECONDS_MASK 0x7f +#define RTC_DAY_MASK 0x07 +#define RTC_CAL_MASK 0x3f + +/* Bits in the Calibration register */ +#define RTC_STOP 0x80 + +/* Bits in the Flags register */ +#define RTC_FLAGS_AF 0x40 +#define RTC_FLAGS_PF 0x20 +#define RTC_WRITE 0x02 +#define RTC_READ 0x01 + +/* Bits in the Interrupts register */ +#define RTC_INTS_AIE 0x40 + +struct rtc_plat_data { + struct rtc_device *rtc; + void __iomem *ioaddr; + unsigned long last_jiffies; + int irq; + unsigned int irqen; + int alrm_sec; + int alrm_min; + int alrm_hour; + int alrm_mday; + spinlock_t lock; +}; + +static int stk17ta8_rtc_set_time(struct device *dev, struct rtc_time *tm) +{ + struct rtc_plat_data *pdata = dev_get_drvdata(dev); + void __iomem *ioaddr = pdata->ioaddr; + u8 flags; + + flags = readb(pdata->ioaddr + RTC_FLAGS); + writeb(flags | RTC_WRITE, pdata->ioaddr + RTC_FLAGS); + + writeb(bin2bcd(tm->tm_year % 100), ioaddr + RTC_YEAR); + writeb(bin2bcd(tm->tm_mon + 1), ioaddr + RTC_MONTH); + writeb(bin2bcd(tm->tm_wday) & RTC_DAY_MASK, ioaddr + RTC_DAY); + writeb(bin2bcd(tm->tm_mday), ioaddr + RTC_DATE); + writeb(bin2bcd(tm->tm_hour), ioaddr + RTC_HOURS); + writeb(bin2bcd(tm->tm_min), ioaddr + RTC_MINUTES); + writeb(bin2bcd(tm->tm_sec) & RTC_SECONDS_MASK, ioaddr + RTC_SECONDS); + writeb(bin2bcd((tm->tm_year + 1900) / 100), ioaddr + RTC_CENTURY); + + writeb(flags & ~RTC_WRITE, pdata->ioaddr + RTC_FLAGS); + return 0; +} + +static int stk17ta8_rtc_read_time(struct device *dev, struct rtc_time *tm) +{ + struct rtc_plat_data *pdata = dev_get_drvdata(dev); + void __iomem *ioaddr = pdata->ioaddr; + unsigned int year, month, day, hour, minute, second, week; + unsigned int century; + u8 flags; + + /* give enough time to update RTC in case of continuous read */ + if (pdata->last_jiffies == jiffies) + msleep(1); + pdata->last_jiffies = jiffies; + + flags = readb(pdata->ioaddr + RTC_FLAGS); + writeb(flags | RTC_READ, ioaddr + RTC_FLAGS); + second = readb(ioaddr + RTC_SECONDS) & RTC_SECONDS_MASK; + minute = readb(ioaddr + RTC_MINUTES); + hour = readb(ioaddr + RTC_HOURS); + day = readb(ioaddr + RTC_DATE); + week = readb(ioaddr + RTC_DAY) & RTC_DAY_MASK; + month = readb(ioaddr + RTC_MONTH); + year = readb(ioaddr + RTC_YEAR); + century = readb(ioaddr + RTC_CENTURY); + writeb(flags & ~RTC_READ, ioaddr + RTC_FLAGS); + tm->tm_sec = bcd2bin(second); + tm->tm_min = bcd2bin(minute); + tm->tm_hour = bcd2bin(hour); + tm->tm_mday = bcd2bin(day); + tm->tm_wday = bcd2bin(week); + tm->tm_mon = bcd2bin(month) - 1; + /* year is 1900 + tm->tm_year */ + tm->tm_year = bcd2bin(year) + bcd2bin(century) * 100 - 1900; + + return 0; +} + +static void stk17ta8_rtc_update_alarm(struct rtc_plat_data *pdata) +{ + void __iomem *ioaddr = pdata->ioaddr; + unsigned long irqflags; + u8 flags; + + spin_lock_irqsave(&pdata->lock, irqflags); + + flags = readb(ioaddr + RTC_FLAGS); + writeb(flags | RTC_WRITE, ioaddr + RTC_FLAGS); + + writeb(pdata->alrm_mday < 0 || (pdata->irqen & RTC_UF) ? + 0x80 : bin2bcd(pdata->alrm_mday), + ioaddr + RTC_DATE_ALARM); + writeb(pdata->alrm_hour < 0 || (pdata->irqen & RTC_UF) ? + 0x80 : bin2bcd(pdata->alrm_hour), + ioaddr + RTC_HOURS_ALARM); + writeb(pdata->alrm_min < 0 || (pdata->irqen & RTC_UF) ? + 0x80 : bin2bcd(pdata->alrm_min), + ioaddr + RTC_MINUTES_ALARM); + writeb(pdata->alrm_sec < 0 || (pdata->irqen & RTC_UF) ? + 0x80 : bin2bcd(pdata->alrm_sec), + ioaddr + RTC_SECONDS_ALARM); + writeb(pdata->irqen ? RTC_INTS_AIE : 0, ioaddr + RTC_INTERRUPTS); + readb(ioaddr + RTC_FLAGS); /* clear interrupts */ + writeb(flags & ~RTC_WRITE, ioaddr + RTC_FLAGS); + spin_unlock_irqrestore(&pdata->lock, irqflags); +} + +static int stk17ta8_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; + stk17ta8_rtc_update_alarm(pdata); + return 0; +} + +static int stk17ta8_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 stk17ta8_rtc_interrupt(int irq, void *dev_id) +{ + struct platform_device *pdev = dev_id; + struct rtc_plat_data *pdata = platform_get_drvdata(pdev); + void __iomem *ioaddr = pdata->ioaddr; + unsigned long events = 0; + + spin_lock(&pdata->lock); + /* read and clear interrupt */ + if (readb(ioaddr + RTC_FLAGS) & RTC_FLAGS_AF) { + events = RTC_IRQF; + if (readb(ioaddr + RTC_SECONDS_ALARM) & 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 stk17ta8_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; + stk17ta8_rtc_update_alarm(pdata); + return 0; +} + +static const struct rtc_class_ops stk17ta8_rtc_ops = { + .read_time = stk17ta8_rtc_read_time, + .set_time = stk17ta8_rtc_set_time, + .read_alarm = stk17ta8_rtc_read_alarm, + .set_alarm = stk17ta8_rtc_set_alarm, + .alarm_irq_enable = stk17ta8_rtc_alarm_irq_enable, +}; + +static int stk17ta8_nvram_read(void *priv, unsigned int pos, void *val, + size_t bytes) +{ + struct rtc_plat_data *pdata = priv; + void __iomem *ioaddr = pdata->ioaddr; + u8 *buf = val; + + for (; bytes; bytes--) + *buf++ = readb(ioaddr + pos++); + return 0; +} + +static int stk17ta8_nvram_write(void *priv, unsigned int pos, void *val, + size_t bytes) +{ + struct rtc_plat_data *pdata = priv; + void __iomem *ioaddr = pdata->ioaddr; + u8 *buf = val; + + for (; bytes; bytes--) + writeb(*buf++, ioaddr + pos++); + return 0; +} + +static int stk17ta8_rtc_probe(struct platform_device *pdev) +{ + unsigned int cal; + unsigned int flags; + struct rtc_plat_data *pdata; + void __iomem *ioaddr; + int ret = 0; + struct nvmem_config nvmem_cfg = { + .name = "stk17ta8_nvram", + .word_size = 1, + .stride = 1, + .size = RTC_OFFSET, + .reg_read = stk17ta8_nvram_read, + .reg_write = stk17ta8_nvram_write, + }; + + pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL); + if (!pdata) + return -ENOMEM; + + ioaddr = devm_platform_ioremap_resource(pdev, 0); + if (IS_ERR(ioaddr)) + return PTR_ERR(ioaddr); + pdata->ioaddr = ioaddr; + pdata->irq = platform_get_irq(pdev, 0); + + /* turn RTC on if it was not on */ + cal = readb(ioaddr + RTC_CALIBRATION); + if (cal & RTC_STOP) { + cal &= RTC_CAL_MASK; + flags = readb(ioaddr + RTC_FLAGS); + writeb(flags | RTC_WRITE, ioaddr + RTC_FLAGS); + writeb(cal, ioaddr + RTC_CALIBRATION); + writeb(flags & ~RTC_WRITE, ioaddr + RTC_FLAGS); + } + if (readb(ioaddr + RTC_FLAGS) & RTC_FLAGS_PF) + dev_warn(&pdev->dev, "voltage-low detected.\n"); + + spin_lock_init(&pdata->lock); + pdata->last_jiffies = jiffies; + platform_set_drvdata(pdev, pdata); + if (pdata->irq > 0) { + writeb(0, ioaddr + RTC_INTERRUPTS); + if (devm_request_irq(&pdev->dev, pdata->irq, + stk17ta8_rtc_interrupt, + IRQF_SHARED, + pdev->name, pdev) < 0) { + dev_warn(&pdev->dev, "interrupt not available.\n"); + pdata->irq = 0; + } + } + + pdata->rtc = devm_rtc_allocate_device(&pdev->dev); + if (IS_ERR(pdata->rtc)) + return PTR_ERR(pdata->rtc); + + pdata->rtc->ops = &stk17ta8_rtc_ops; + + nvmem_cfg.priv = pdata; + ret = devm_rtc_nvmem_register(pdata->rtc, &nvmem_cfg); + if (ret) + return ret; + + return devm_rtc_register_device(pdata->rtc); +} + +/* work with hotplug and coldplug */ +MODULE_ALIAS("platform:stk17ta8"); + +static struct platform_driver stk17ta8_rtc_driver = { + .probe = stk17ta8_rtc_probe, + .driver = { + .name = "stk17ta8", + }, +}; + +module_platform_driver(stk17ta8_rtc_driver); + +MODULE_AUTHOR("Thomas Hommel <thomas.hommel@ge.com>"); +MODULE_DESCRIPTION("Simtek STK17TA8 RTC driver"); +MODULE_LICENSE("GPL"); |