diff options
Diffstat (limited to 'drivers/rtc/rtc-sun6i.c')
| -rw-r--r-- | drivers/rtc/rtc-sun6i.c | 447 |
1 files changed, 447 insertions, 0 deletions
diff --git a/drivers/rtc/rtc-sun6i.c b/drivers/rtc/rtc-sun6i.c new file mode 100644 index 000000000000..c169a2cd4727 --- /dev/null +++ b/drivers/rtc/rtc-sun6i.c @@ -0,0 +1,447 @@ +/* + * An RTC driver for Allwinner A31/A23 + * + * Copyright (c) 2014, Chen-Yu Tsai <wens@csie.org> + * + * based on rtc-sunxi.c + * + * An RTC driver for Allwinner A10/A20 + * + * Copyright (c) 2013, Carlo Caione <carlo.caione@gmail.com> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, but WITHOUT + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for + * more details. + */ + +#include <linux/delay.h> +#include <linux/err.h> +#include <linux/fs.h> +#include <linux/init.h> +#include <linux/interrupt.h> +#include <linux/io.h> +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/of.h> +#include <linux/of_address.h> +#include <linux/of_device.h> +#include <linux/platform_device.h> +#include <linux/rtc.h> +#include <linux/types.h> + +/* Control register */ +#define SUN6I_LOSC_CTRL 0x0000 +#define SUN6I_LOSC_CTRL_ALM_DHMS_ACC BIT(9) +#define SUN6I_LOSC_CTRL_RTC_HMS_ACC BIT(8) +#define SUN6I_LOSC_CTRL_RTC_YMD_ACC BIT(7) +#define SUN6I_LOSC_CTRL_ACC_MASK GENMASK(9, 7) + +/* RTC */ +#define SUN6I_RTC_YMD 0x0010 +#define SUN6I_RTC_HMS 0x0014 + +/* Alarm 0 (counter) */ +#define SUN6I_ALRM_COUNTER 0x0020 +#define SUN6I_ALRM_CUR_VAL 0x0024 +#define SUN6I_ALRM_EN 0x0028 +#define SUN6I_ALRM_EN_CNT_EN BIT(0) +#define SUN6I_ALRM_IRQ_EN 0x002c +#define SUN6I_ALRM_IRQ_EN_CNT_IRQ_EN BIT(0) +#define SUN6I_ALRM_IRQ_STA 0x0030 +#define SUN6I_ALRM_IRQ_STA_CNT_IRQ_PEND BIT(0) + +/* Alarm 1 (wall clock) */ +#define SUN6I_ALRM1_EN 0x0044 +#define SUN6I_ALRM1_IRQ_EN 0x0048 +#define SUN6I_ALRM1_IRQ_STA 0x004c +#define SUN6I_ALRM1_IRQ_STA_WEEK_IRQ_PEND BIT(0) + +/* Alarm config */ +#define SUN6I_ALARM_CONFIG 0x0050 +#define SUN6I_ALARM_CONFIG_WAKEUP BIT(0) + +/* + * Get date values + */ +#define SUN6I_DATE_GET_DAY_VALUE(x) ((x) & 0x0000001f) +#define SUN6I_DATE_GET_MON_VALUE(x) (((x) & 0x00000f00) >> 8) +#define SUN6I_DATE_GET_YEAR_VALUE(x) (((x) & 0x003f0000) >> 16) +#define SUN6I_LEAP_GET_VALUE(x) (((x) & 0x00400000) >> 22) + +/* + * Get time values + */ +#define SUN6I_TIME_GET_SEC_VALUE(x) ((x) & 0x0000003f) +#define SUN6I_TIME_GET_MIN_VALUE(x) (((x) & 0x00003f00) >> 8) +#define SUN6I_TIME_GET_HOUR_VALUE(x) (((x) & 0x001f0000) >> 16) + +/* + * Set date values + */ +#define SUN6I_DATE_SET_DAY_VALUE(x) ((x) & 0x0000001f) +#define SUN6I_DATE_SET_MON_VALUE(x) ((x) << 8 & 0x00000f00) +#define SUN6I_DATE_SET_YEAR_VALUE(x) ((x) << 16 & 0x003f0000) +#define SUN6I_LEAP_SET_VALUE(x) ((x) << 22 & 0x00400000) + +/* + * Set time values + */ +#define SUN6I_TIME_SET_SEC_VALUE(x) ((x) & 0x0000003f) +#define SUN6I_TIME_SET_MIN_VALUE(x) ((x) << 8 & 0x00003f00) +#define SUN6I_TIME_SET_HOUR_VALUE(x) ((x) << 16 & 0x001f0000) + +/* + * The year parameter passed to the driver is usually an offset relative to + * the year 1900. This macro is used to convert this offset to another one + * relative to the minimum year allowed by the hardware. + * + * The year range is 1970 - 2033. This range is selected to match Allwinner's + * driver, even though it is somewhat limited. + */ +#define SUN6I_YEAR_MIN 1970 +#define SUN6I_YEAR_MAX 2033 +#define SUN6I_YEAR_OFF (SUN6I_YEAR_MIN - 1900) + +struct sun6i_rtc_dev { + struct rtc_device *rtc; + struct device *dev; + void __iomem *base; + int irq; + unsigned long alarm; +}; + +static irqreturn_t sun6i_rtc_alarmirq(int irq, void *id) +{ + struct sun6i_rtc_dev *chip = (struct sun6i_rtc_dev *) id; + u32 val; + + val = readl(chip->base + SUN6I_ALRM_IRQ_STA); + + if (val & SUN6I_ALRM_IRQ_STA_CNT_IRQ_PEND) { + val |= SUN6I_ALRM_IRQ_STA_CNT_IRQ_PEND; + writel(val, chip->base + SUN6I_ALRM_IRQ_STA); + + rtc_update_irq(chip->rtc, 1, RTC_AF | RTC_IRQF); + + return IRQ_HANDLED; + } + + return IRQ_NONE; +} + +static void sun6i_rtc_setaie(int to, struct sun6i_rtc_dev *chip) +{ + u32 alrm_val = 0; + u32 alrm_irq_val = 0; + u32 alrm_wake_val = 0; + + if (to) { + alrm_val = SUN6I_ALRM_EN_CNT_EN; + alrm_irq_val = SUN6I_ALRM_IRQ_EN_CNT_IRQ_EN; + alrm_wake_val = SUN6I_ALARM_CONFIG_WAKEUP; + } else { + writel(SUN6I_ALRM_IRQ_STA_CNT_IRQ_PEND, + chip->base + SUN6I_ALRM_IRQ_STA); + } + + writel(alrm_val, chip->base + SUN6I_ALRM_EN); + writel(alrm_irq_val, chip->base + SUN6I_ALRM_IRQ_EN); + writel(alrm_wake_val, chip->base + SUN6I_ALARM_CONFIG); +} + +static int sun6i_rtc_gettime(struct device *dev, struct rtc_time *rtc_tm) +{ + struct sun6i_rtc_dev *chip = dev_get_drvdata(dev); + u32 date, time; + + /* + * read again in case it changes + */ + do { + date = readl(chip->base + SUN6I_RTC_YMD); + time = readl(chip->base + SUN6I_RTC_HMS); + } while ((date != readl(chip->base + SUN6I_RTC_YMD)) || + (time != readl(chip->base + SUN6I_RTC_HMS))); + + rtc_tm->tm_sec = SUN6I_TIME_GET_SEC_VALUE(time); + rtc_tm->tm_min = SUN6I_TIME_GET_MIN_VALUE(time); + rtc_tm->tm_hour = SUN6I_TIME_GET_HOUR_VALUE(time); + + rtc_tm->tm_mday = SUN6I_DATE_GET_DAY_VALUE(date); + rtc_tm->tm_mon = SUN6I_DATE_GET_MON_VALUE(date); + rtc_tm->tm_year = SUN6I_DATE_GET_YEAR_VALUE(date); + + rtc_tm->tm_mon -= 1; + + /* + * switch from (data_year->min)-relative offset to + * a (1900)-relative one + */ + rtc_tm->tm_year += SUN6I_YEAR_OFF; + + return rtc_valid_tm(rtc_tm); +} + +static int sun6i_rtc_getalarm(struct device *dev, struct rtc_wkalrm *wkalrm) +{ + struct sun6i_rtc_dev *chip = dev_get_drvdata(dev); + u32 alrm_st; + u32 alrm_en; + + alrm_en = readl(chip->base + SUN6I_ALRM_IRQ_EN); + alrm_st = readl(chip->base + SUN6I_ALRM_IRQ_STA); + wkalrm->enabled = !!(alrm_en & SUN6I_ALRM_EN_CNT_EN); + wkalrm->pending = !!(alrm_st & SUN6I_ALRM_EN_CNT_EN); + rtc_time_to_tm(chip->alarm, &wkalrm->time); + + return 0; +} + +static int sun6i_rtc_setalarm(struct device *dev, struct rtc_wkalrm *wkalrm) +{ + struct sun6i_rtc_dev *chip = dev_get_drvdata(dev); + struct rtc_time *alrm_tm = &wkalrm->time; + struct rtc_time tm_now; + unsigned long time_now = 0; + unsigned long time_set = 0; + unsigned long time_gap = 0; + int ret = 0; + + ret = sun6i_rtc_gettime(dev, &tm_now); + if (ret < 0) { + dev_err(dev, "Error in getting time\n"); + return -EINVAL; + } + + rtc_tm_to_time(alrm_tm, &time_set); + rtc_tm_to_time(&tm_now, &time_now); + if (time_set <= time_now) { + dev_err(dev, "Date to set in the past\n"); + return -EINVAL; + } + + time_gap = time_set - time_now; + + if (time_gap > U32_MAX) { + dev_err(dev, "Date too far in the future\n"); + return -EINVAL; + } + + sun6i_rtc_setaie(0, chip); + writel(0, chip->base + SUN6I_ALRM_COUNTER); + usleep_range(100, 300); + + writel(time_gap, chip->base + SUN6I_ALRM_COUNTER); + chip->alarm = time_set; + + sun6i_rtc_setaie(wkalrm->enabled, chip); + + return 0; +} + +static int sun6i_rtc_wait(struct sun6i_rtc_dev *chip, int offset, + unsigned int mask, unsigned int ms_timeout) +{ + const unsigned long timeout = jiffies + msecs_to_jiffies(ms_timeout); + u32 reg; + + do { + reg = readl(chip->base + offset); + reg &= mask; + + if (!reg) + return 0; + + } while (time_before(jiffies, timeout)); + + return -ETIMEDOUT; +} + +static int sun6i_rtc_settime(struct device *dev, struct rtc_time *rtc_tm) +{ + struct sun6i_rtc_dev *chip = dev_get_drvdata(dev); + u32 date = 0; + u32 time = 0; + int year; + + year = rtc_tm->tm_year + 1900; + if (year < SUN6I_YEAR_MIN || year > SUN6I_YEAR_MAX) { + dev_err(dev, "rtc only supports year in range %d - %d\n", + SUN6I_YEAR_MIN, SUN6I_YEAR_MAX); + return -EINVAL; + } + + rtc_tm->tm_year -= SUN6I_YEAR_OFF; + rtc_tm->tm_mon += 1; + + date = SUN6I_DATE_SET_DAY_VALUE(rtc_tm->tm_mday) | + SUN6I_DATE_SET_MON_VALUE(rtc_tm->tm_mon) | + SUN6I_DATE_SET_YEAR_VALUE(rtc_tm->tm_year); + + if (is_leap_year(year)) + date |= SUN6I_LEAP_SET_VALUE(1); + + time = SUN6I_TIME_SET_SEC_VALUE(rtc_tm->tm_sec) | + SUN6I_TIME_SET_MIN_VALUE(rtc_tm->tm_min) | + SUN6I_TIME_SET_HOUR_VALUE(rtc_tm->tm_hour); + + /* Check whether registers are writable */ + if (sun6i_rtc_wait(chip, SUN6I_LOSC_CTRL, + SUN6I_LOSC_CTRL_ACC_MASK, 50)) { + dev_err(dev, "rtc is still busy.\n"); + return -EBUSY; + } + + writel(time, chip->base + SUN6I_RTC_HMS); + + /* + * After writing the RTC HH-MM-SS register, the + * SUN6I_LOSC_CTRL_RTC_HMS_ACC bit is set and it will not + * be cleared until the real writing operation is finished + */ + + if (sun6i_rtc_wait(chip, SUN6I_LOSC_CTRL, + SUN6I_LOSC_CTRL_RTC_HMS_ACC, 50)) { + dev_err(dev, "Failed to set rtc time.\n"); + return -ETIMEDOUT; + } + + writel(date, chip->base + SUN6I_RTC_YMD); + + /* + * After writing the RTC YY-MM-DD register, the + * SUN6I_LOSC_CTRL_RTC_YMD_ACC bit is set and it will not + * be cleared until the real writing operation is finished + */ + + if (sun6i_rtc_wait(chip, SUN6I_LOSC_CTRL, + SUN6I_LOSC_CTRL_RTC_YMD_ACC, 50)) { + dev_err(dev, "Failed to set rtc time.\n"); + return -ETIMEDOUT; + } + + return 0; +} + +static int sun6i_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled) +{ + struct sun6i_rtc_dev *chip = dev_get_drvdata(dev); + + if (!enabled) + sun6i_rtc_setaie(enabled, chip); + + return 0; +} + +static const struct rtc_class_ops sun6i_rtc_ops = { + .read_time = sun6i_rtc_gettime, + .set_time = sun6i_rtc_settime, + .read_alarm = sun6i_rtc_getalarm, + .set_alarm = sun6i_rtc_setalarm, + .alarm_irq_enable = sun6i_rtc_alarm_irq_enable +}; + +static int sun6i_rtc_probe(struct platform_device *pdev) +{ + struct sun6i_rtc_dev *chip; + struct resource *res; + int ret; + + chip = devm_kzalloc(&pdev->dev, sizeof(*chip), GFP_KERNEL); + if (!chip) + return -ENOMEM; + + platform_set_drvdata(pdev, chip); + chip->dev = &pdev->dev; + + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); + chip->base = devm_ioremap_resource(&pdev->dev, res); + if (IS_ERR(chip->base)) + return PTR_ERR(chip->base); + + chip->irq = platform_get_irq(pdev, 0); + if (chip->irq < 0) { + dev_err(&pdev->dev, "No IRQ resource\n"); + return chip->irq; + } + + ret = devm_request_irq(&pdev->dev, chip->irq, sun6i_rtc_alarmirq, + 0, dev_name(&pdev->dev), chip); + if (ret) { + dev_err(&pdev->dev, "Could not request IRQ\n"); + return ret; + } + + /* clear the alarm counter value */ + writel(0, chip->base + SUN6I_ALRM_COUNTER); + + /* disable counter alarm */ + writel(0, chip->base + SUN6I_ALRM_EN); + + /* disable counter alarm interrupt */ + writel(0, chip->base + SUN6I_ALRM_IRQ_EN); + + /* disable week alarm */ + writel(0, chip->base + SUN6I_ALRM1_EN); + + /* disable week alarm interrupt */ + writel(0, chip->base + SUN6I_ALRM1_IRQ_EN); + + /* clear counter alarm pending interrupts */ + writel(SUN6I_ALRM_IRQ_STA_CNT_IRQ_PEND, + chip->base + SUN6I_ALRM_IRQ_STA); + + /* clear week alarm pending interrupts */ + writel(SUN6I_ALRM1_IRQ_STA_WEEK_IRQ_PEND, + chip->base + SUN6I_ALRM1_IRQ_STA); + + /* disable alarm wakeup */ + writel(0, chip->base + SUN6I_ALARM_CONFIG); + + chip->rtc = rtc_device_register("rtc-sun6i", &pdev->dev, + &sun6i_rtc_ops, THIS_MODULE); + if (IS_ERR(chip->rtc)) { + dev_err(&pdev->dev, "unable to register device\n"); + return PTR_ERR(chip->rtc); + } + + dev_info(&pdev->dev, "RTC enabled\n"); + + return 0; +} + +static int sun6i_rtc_remove(struct platform_device *pdev) +{ + struct sun6i_rtc_dev *chip = platform_get_drvdata(pdev); + + rtc_device_unregister(chip->rtc); + + return 0; +} + +static const struct of_device_id sun6i_rtc_dt_ids[] = { + { .compatible = "allwinner,sun6i-a31-rtc" }, + { /* sentinel */ }, +}; +MODULE_DEVICE_TABLE(of, sun6i_rtc_dt_ids); + +static struct platform_driver sun6i_rtc_driver = { + .probe = sun6i_rtc_probe, + .remove = sun6i_rtc_remove, + .driver = { + .name = "sun6i-rtc", + .of_match_table = sun6i_rtc_dt_ids, + }, +}; + +module_platform_driver(sun6i_rtc_driver); + +MODULE_DESCRIPTION("sun6i RTC driver"); +MODULE_AUTHOR("Chen-Yu Tsai <wens@csie.org>"); +MODULE_LICENSE("GPL"); |