diff options
Diffstat (limited to 'drivers/rtc/rtc-mt7622.c')
| -rw-r--r-- | drivers/rtc/rtc-mt7622.c | 422 |
1 files changed, 422 insertions, 0 deletions
diff --git a/drivers/rtc/rtc-mt7622.c b/drivers/rtc/rtc-mt7622.c new file mode 100644 index 000000000000..d79b9ae4d237 --- /dev/null +++ b/drivers/rtc/rtc-mt7622.c @@ -0,0 +1,422 @@ +/* + * Driver for MediaTek SoC based RTC + * + * Copyright (C) 2017 Sean Wang <sean.wang@mediatek.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/clk.h> +#include <linux/interrupt.h> +#include <linux/module.h> +#include <linux/of_address.h> +#include <linux/of_device.h> +#include <linux/platform_device.h> +#include <linux/rtc.h> + +#define MTK_RTC_DEV KBUILD_MODNAME + +#define MTK_RTC_PWRCHK1 0x4 +#define RTC_PWRCHK1_MAGIC 0xc6 + +#define MTK_RTC_PWRCHK2 0x8 +#define RTC_PWRCHK2_MAGIC 0x9a + +#define MTK_RTC_KEY 0xc +#define RTC_KEY_MAGIC 0x59 + +#define MTK_RTC_PROT1 0x10 +#define RTC_PROT1_MAGIC 0xa3 + +#define MTK_RTC_PROT2 0x14 +#define RTC_PROT2_MAGIC 0x57 + +#define MTK_RTC_PROT3 0x18 +#define RTC_PROT3_MAGIC 0x67 + +#define MTK_RTC_PROT4 0x1c +#define RTC_PROT4_MAGIC 0xd2 + +#define MTK_RTC_CTL 0x20 +#define RTC_RC_STOP BIT(0) + +#define MTK_RTC_DEBNCE 0x2c +#define RTC_DEBNCE_MASK GENMASK(2, 0) + +#define MTK_RTC_INT 0x30 +#define RTC_INT_AL_STA BIT(4) + +/* + * Ranges from 0x40 to 0x78 provide RTC time setup for year, month, + * day of month, day of week, hour, minute and second. + */ +#define MTK_RTC_TREG(_t, _f) (0x40 + (0x4 * (_f)) + ((_t) * 0x20)) + +#define MTK_RTC_AL_CTL 0x7c +#define RTC_AL_EN BIT(0) +#define RTC_AL_ALL GENMASK(7, 0) + +/* + * The offset is used in the translation for the year between in struct + * rtc_time and in hardware register MTK_RTC_TREG(x,MTK_YEA) + */ +#define MTK_RTC_TM_YR_OFFSET 100 + +/* + * The lowest value for the valid tm_year. RTC hardware would take incorrectly + * tm_year 100 as not a leap year and thus it is also required being excluded + * from the valid options. + */ +#define MTK_RTC_TM_YR_L (MTK_RTC_TM_YR_OFFSET + 1) + +/* + * The most year the RTC can hold is 99 and the next to 99 in year register + * would be wraparound to 0, for MT7622. + */ +#define MTK_RTC_HW_YR_LIMIT 99 + +/* The highest value for the valid tm_year */ +#define MTK_RTC_TM_YR_H (MTK_RTC_TM_YR_OFFSET + MTK_RTC_HW_YR_LIMIT) + +/* Simple macro helps to check whether the hardware supports the tm_year */ +#define MTK_RTC_TM_YR_VALID(_y) ((_y) >= MTK_RTC_TM_YR_L && \ + (_y) <= MTK_RTC_TM_YR_H) + +/* Types of the function the RTC provides are time counter and alarm. */ +enum { + MTK_TC, + MTK_AL, +}; + +/* Indexes are used for the pointer to relevant registers in MTK_RTC_TREG */ +enum { + MTK_YEA, + MTK_MON, + MTK_DOM, + MTK_DOW, + MTK_HOU, + MTK_MIN, + MTK_SEC +}; + +struct mtk_rtc { + struct rtc_device *rtc; + void __iomem *base; + int irq; + struct clk *clk; +}; + +static void mtk_w32(struct mtk_rtc *rtc, u32 reg, u32 val) +{ + writel_relaxed(val, rtc->base + reg); +} + +static u32 mtk_r32(struct mtk_rtc *rtc, u32 reg) +{ + return readl_relaxed(rtc->base + reg); +} + +static void mtk_rmw(struct mtk_rtc *rtc, u32 reg, u32 mask, u32 set) +{ + u32 val; + + val = mtk_r32(rtc, reg); + val &= ~mask; + val |= set; + mtk_w32(rtc, reg, val); +} + +static void mtk_set(struct mtk_rtc *rtc, u32 reg, u32 val) +{ + mtk_rmw(rtc, reg, 0, val); +} + +static void mtk_clr(struct mtk_rtc *rtc, u32 reg, u32 val) +{ + mtk_rmw(rtc, reg, val, 0); +} + +static void mtk_rtc_hw_init(struct mtk_rtc *hw) +{ + /* The setup of the init sequence is for allowing RTC got to work */ + mtk_w32(hw, MTK_RTC_PWRCHK1, RTC_PWRCHK1_MAGIC); + mtk_w32(hw, MTK_RTC_PWRCHK2, RTC_PWRCHK2_MAGIC); + mtk_w32(hw, MTK_RTC_KEY, RTC_KEY_MAGIC); + mtk_w32(hw, MTK_RTC_PROT1, RTC_PROT1_MAGIC); + mtk_w32(hw, MTK_RTC_PROT2, RTC_PROT2_MAGIC); + mtk_w32(hw, MTK_RTC_PROT3, RTC_PROT3_MAGIC); + mtk_w32(hw, MTK_RTC_PROT4, RTC_PROT4_MAGIC); + mtk_rmw(hw, MTK_RTC_DEBNCE, RTC_DEBNCE_MASK, 0); + mtk_clr(hw, MTK_RTC_CTL, RTC_RC_STOP); +} + +static void mtk_rtc_get_alarm_or_time(struct mtk_rtc *hw, struct rtc_time *tm, + int time_alarm) +{ + u32 year, mon, mday, wday, hour, min, sec; + + /* + * Read again until the field of the second is not changed which + * ensures all fields in the consistent state. Note that MTK_SEC must + * be read first. In this way, it guarantees the others remain not + * changed when the results for two MTK_SEC consecutive reads are same. + */ + do { + sec = mtk_r32(hw, MTK_RTC_TREG(time_alarm, MTK_SEC)); + min = mtk_r32(hw, MTK_RTC_TREG(time_alarm, MTK_MIN)); + hour = mtk_r32(hw, MTK_RTC_TREG(time_alarm, MTK_HOU)); + wday = mtk_r32(hw, MTK_RTC_TREG(time_alarm, MTK_DOW)); + mday = mtk_r32(hw, MTK_RTC_TREG(time_alarm, MTK_DOM)); + mon = mtk_r32(hw, MTK_RTC_TREG(time_alarm, MTK_MON)); + year = mtk_r32(hw, MTK_RTC_TREG(time_alarm, MTK_YEA)); + } while (sec != mtk_r32(hw, MTK_RTC_TREG(time_alarm, MTK_SEC))); + + tm->tm_sec = sec; + tm->tm_min = min; + tm->tm_hour = hour; + tm->tm_wday = wday; + tm->tm_mday = mday; + tm->tm_mon = mon - 1; + + /* Rebase to the absolute year which userspace queries */ + tm->tm_year = year + MTK_RTC_TM_YR_OFFSET; +} + +static void mtk_rtc_set_alarm_or_time(struct mtk_rtc *hw, struct rtc_time *tm, + int time_alarm) +{ + u32 year; + + /* Rebase to the relative year which RTC hardware requires */ + year = tm->tm_year - MTK_RTC_TM_YR_OFFSET; + + mtk_w32(hw, MTK_RTC_TREG(time_alarm, MTK_YEA), year); + mtk_w32(hw, MTK_RTC_TREG(time_alarm, MTK_MON), tm->tm_mon + 1); + mtk_w32(hw, MTK_RTC_TREG(time_alarm, MTK_DOW), tm->tm_wday); + mtk_w32(hw, MTK_RTC_TREG(time_alarm, MTK_DOM), tm->tm_mday); + mtk_w32(hw, MTK_RTC_TREG(time_alarm, MTK_HOU), tm->tm_hour); + mtk_w32(hw, MTK_RTC_TREG(time_alarm, MTK_MIN), tm->tm_min); + mtk_w32(hw, MTK_RTC_TREG(time_alarm, MTK_SEC), tm->tm_sec); +} + +static irqreturn_t mtk_rtc_alarmirq(int irq, void *id) +{ + struct mtk_rtc *hw = (struct mtk_rtc *)id; + u32 irq_sta; + + irq_sta = mtk_r32(hw, MTK_RTC_INT); + if (irq_sta & RTC_INT_AL_STA) { + /* Stop alarm also implicitly disables the alarm interrupt */ + mtk_w32(hw, MTK_RTC_AL_CTL, 0); + rtc_update_irq(hw->rtc, 1, RTC_IRQF | RTC_AF); + + /* Ack alarm interrupt status */ + mtk_w32(hw, MTK_RTC_INT, RTC_INT_AL_STA); + return IRQ_HANDLED; + } + + return IRQ_NONE; +} + +static int mtk_rtc_gettime(struct device *dev, struct rtc_time *tm) +{ + struct mtk_rtc *hw = dev_get_drvdata(dev); + + mtk_rtc_get_alarm_or_time(hw, tm, MTK_TC); + + return rtc_valid_tm(tm); +} + +static int mtk_rtc_settime(struct device *dev, struct rtc_time *tm) +{ + struct mtk_rtc *hw = dev_get_drvdata(dev); + + if (!MTK_RTC_TM_YR_VALID(tm->tm_year)) + return -EINVAL; + + /* Stop time counter before setting a new one*/ + mtk_set(hw, MTK_RTC_CTL, RTC_RC_STOP); + + mtk_rtc_set_alarm_or_time(hw, tm, MTK_TC); + + /* Restart the time counter */ + mtk_clr(hw, MTK_RTC_CTL, RTC_RC_STOP); + + return 0; +} + +static int mtk_rtc_getalarm(struct device *dev, struct rtc_wkalrm *wkalrm) +{ + struct mtk_rtc *hw = dev_get_drvdata(dev); + struct rtc_time *alrm_tm = &wkalrm->time; + + mtk_rtc_get_alarm_or_time(hw, alrm_tm, MTK_AL); + + wkalrm->enabled = !!(mtk_r32(hw, MTK_RTC_AL_CTL) & RTC_AL_EN); + wkalrm->pending = !!(mtk_r32(hw, MTK_RTC_INT) & RTC_INT_AL_STA); + + return 0; +} + +static int mtk_rtc_setalarm(struct device *dev, struct rtc_wkalrm *wkalrm) +{ + struct mtk_rtc *hw = dev_get_drvdata(dev); + struct rtc_time *alrm_tm = &wkalrm->time; + + if (!MTK_RTC_TM_YR_VALID(alrm_tm->tm_year)) + return -EINVAL; + + /* + * Stop the alarm also implicitly including disables interrupt before + * setting a new one. + */ + mtk_clr(hw, MTK_RTC_AL_CTL, RTC_AL_EN); + + /* + * Avoid contention between mtk_rtc_setalarm and IRQ handler so that + * disabling the interrupt and awaiting for pending IRQ handler to + * complete. + */ + synchronize_irq(hw->irq); + + mtk_rtc_set_alarm_or_time(hw, alrm_tm, MTK_AL); + + /* Restart the alarm with the new setup */ + mtk_w32(hw, MTK_RTC_AL_CTL, RTC_AL_ALL); + + return 0; +} + +static const struct rtc_class_ops mtk_rtc_ops = { + .read_time = mtk_rtc_gettime, + .set_time = mtk_rtc_settime, + .read_alarm = mtk_rtc_getalarm, + .set_alarm = mtk_rtc_setalarm, +}; + +static const struct of_device_id mtk_rtc_match[] = { + { .compatible = "mediatek,mt7622-rtc" }, + { .compatible = "mediatek,soc-rtc" }, + {}, +}; + +static int mtk_rtc_probe(struct platform_device *pdev) +{ + struct mtk_rtc *hw; + struct resource *res; + int ret; + + hw = devm_kzalloc(&pdev->dev, sizeof(*hw), GFP_KERNEL); + if (!hw) + return -ENOMEM; + + platform_set_drvdata(pdev, hw); + + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); + hw->base = devm_ioremap_resource(&pdev->dev, res); + if (IS_ERR(hw->base)) + return PTR_ERR(hw->base); + + hw->clk = devm_clk_get(&pdev->dev, "rtc"); + if (IS_ERR(hw->clk)) { + dev_err(&pdev->dev, "No clock\n"); + return PTR_ERR(hw->clk); + } + + ret = clk_prepare_enable(hw->clk); + if (ret) + return ret; + + hw->irq = platform_get_irq(pdev, 0); + if (hw->irq < 0) { + dev_err(&pdev->dev, "No IRQ resource\n"); + ret = hw->irq; + goto err; + } + + ret = devm_request_irq(&pdev->dev, hw->irq, mtk_rtc_alarmirq, + 0, dev_name(&pdev->dev), hw); + if (ret) { + dev_err(&pdev->dev, "Can't request IRQ\n"); + goto err; + } + + mtk_rtc_hw_init(hw); + + device_init_wakeup(&pdev->dev, true); + + hw->rtc = devm_rtc_device_register(&pdev->dev, pdev->name, + &mtk_rtc_ops, THIS_MODULE); + if (IS_ERR(hw->rtc)) { + ret = PTR_ERR(hw->rtc); + dev_err(&pdev->dev, "Unable to register device\n"); + goto err; + } + + return 0; +err: + clk_disable_unprepare(hw->clk); + + return ret; +} + +static int mtk_rtc_remove(struct platform_device *pdev) +{ + struct mtk_rtc *hw = platform_get_drvdata(pdev); + + clk_disable_unprepare(hw->clk); + + return 0; +} + +#ifdef CONFIG_PM_SLEEP +static int mtk_rtc_suspend(struct device *dev) +{ + struct mtk_rtc *hw = dev_get_drvdata(dev); + + if (device_may_wakeup(dev)) + enable_irq_wake(hw->irq); + + return 0; +} + +static int mtk_rtc_resume(struct device *dev) +{ + struct mtk_rtc *hw = dev_get_drvdata(dev); + + if (device_may_wakeup(dev)) + disable_irq_wake(hw->irq); + + return 0; +} + +static SIMPLE_DEV_PM_OPS(mtk_rtc_pm_ops, mtk_rtc_suspend, mtk_rtc_resume); + +#define MTK_RTC_PM_OPS (&mtk_rtc_pm_ops) +#else /* CONFIG_PM */ +#define MTK_RTC_PM_OPS NULL +#endif /* CONFIG_PM */ + +static struct platform_driver mtk_rtc_driver = { + .probe = mtk_rtc_probe, + .remove = mtk_rtc_remove, + .driver = { + .name = MTK_RTC_DEV, + .of_match_table = mtk_rtc_match, + .pm = MTK_RTC_PM_OPS, + }, +}; + +module_platform_driver(mtk_rtc_driver); + +MODULE_DESCRIPTION("MediaTek SoC based RTC Driver"); +MODULE_AUTHOR("Sean Wang <sean.wang@mediatek.com>"); +MODULE_LICENSE("GPL"); |