410 lines
9.8 KiB
C
410 lines
9.8 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* Driver for MediaTek SoC based RTC
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*
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* Copyright (C) 2017 Sean Wang <sean.wang@mediatek.com>
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*/
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#include <linux/clk.h>
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#include <linux/interrupt.h>
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#include <linux/module.h>
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#include <linux/of_address.h>
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#include <linux/of_device.h>
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#include <linux/platform_device.h>
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#include <linux/rtc.h>
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#define MTK_RTC_DEV KBUILD_MODNAME
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#define MTK_RTC_PWRCHK1 0x4
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#define RTC_PWRCHK1_MAGIC 0xc6
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#define MTK_RTC_PWRCHK2 0x8
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#define RTC_PWRCHK2_MAGIC 0x9a
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#define MTK_RTC_KEY 0xc
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#define RTC_KEY_MAGIC 0x59
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#define MTK_RTC_PROT1 0x10
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#define RTC_PROT1_MAGIC 0xa3
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#define MTK_RTC_PROT2 0x14
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#define RTC_PROT2_MAGIC 0x57
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#define MTK_RTC_PROT3 0x18
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#define RTC_PROT3_MAGIC 0x67
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#define MTK_RTC_PROT4 0x1c
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#define RTC_PROT4_MAGIC 0xd2
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#define MTK_RTC_CTL 0x20
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#define RTC_RC_STOP BIT(0)
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#define MTK_RTC_DEBNCE 0x2c
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#define RTC_DEBNCE_MASK GENMASK(2, 0)
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#define MTK_RTC_INT 0x30
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#define RTC_INT_AL_STA BIT(4)
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/*
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* Ranges from 0x40 to 0x78 provide RTC time setup for year, month,
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* day of month, day of week, hour, minute and second.
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*/
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#define MTK_RTC_TREG(_t, _f) (0x40 + (0x4 * (_f)) + ((_t) * 0x20))
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#define MTK_RTC_AL_CTL 0x7c
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#define RTC_AL_EN BIT(0)
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#define RTC_AL_ALL GENMASK(7, 0)
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/*
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* The offset is used in the translation for the year between in struct
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* rtc_time and in hardware register MTK_RTC_TREG(x,MTK_YEA)
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*/
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#define MTK_RTC_TM_YR_OFFSET 100
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/*
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* The lowest value for the valid tm_year. RTC hardware would take incorrectly
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* tm_year 100 as not a leap year and thus it is also required being excluded
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* from the valid options.
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*/
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#define MTK_RTC_TM_YR_L (MTK_RTC_TM_YR_OFFSET + 1)
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/*
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* The most year the RTC can hold is 99 and the next to 99 in year register
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* would be wraparound to 0, for MT7622.
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*/
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#define MTK_RTC_HW_YR_LIMIT 99
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/* The highest value for the valid tm_year */
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#define MTK_RTC_TM_YR_H (MTK_RTC_TM_YR_OFFSET + MTK_RTC_HW_YR_LIMIT)
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/* Simple macro helps to check whether the hardware supports the tm_year */
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#define MTK_RTC_TM_YR_VALID(_y) ((_y) >= MTK_RTC_TM_YR_L && \
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(_y) <= MTK_RTC_TM_YR_H)
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/* Types of the function the RTC provides are time counter and alarm. */
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enum {
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MTK_TC,
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MTK_AL,
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};
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/* Indexes are used for the pointer to relevant registers in MTK_RTC_TREG */
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enum {
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MTK_YEA,
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MTK_MON,
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MTK_DOM,
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MTK_DOW,
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MTK_HOU,
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MTK_MIN,
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MTK_SEC
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};
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struct mtk_rtc {
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struct rtc_device *rtc;
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void __iomem *base;
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int irq;
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struct clk *clk;
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};
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static void mtk_w32(struct mtk_rtc *rtc, u32 reg, u32 val)
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{
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writel_relaxed(val, rtc->base + reg);
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}
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static u32 mtk_r32(struct mtk_rtc *rtc, u32 reg)
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{
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return readl_relaxed(rtc->base + reg);
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}
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static void mtk_rmw(struct mtk_rtc *rtc, u32 reg, u32 mask, u32 set)
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{
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u32 val;
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val = mtk_r32(rtc, reg);
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val &= ~mask;
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val |= set;
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mtk_w32(rtc, reg, val);
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}
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static void mtk_set(struct mtk_rtc *rtc, u32 reg, u32 val)
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{
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mtk_rmw(rtc, reg, 0, val);
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}
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static void mtk_clr(struct mtk_rtc *rtc, u32 reg, u32 val)
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{
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mtk_rmw(rtc, reg, val, 0);
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}
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static void mtk_rtc_hw_init(struct mtk_rtc *hw)
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{
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/* The setup of the init sequence is for allowing RTC got to work */
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mtk_w32(hw, MTK_RTC_PWRCHK1, RTC_PWRCHK1_MAGIC);
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mtk_w32(hw, MTK_RTC_PWRCHK2, RTC_PWRCHK2_MAGIC);
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mtk_w32(hw, MTK_RTC_KEY, RTC_KEY_MAGIC);
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mtk_w32(hw, MTK_RTC_PROT1, RTC_PROT1_MAGIC);
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mtk_w32(hw, MTK_RTC_PROT2, RTC_PROT2_MAGIC);
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mtk_w32(hw, MTK_RTC_PROT3, RTC_PROT3_MAGIC);
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mtk_w32(hw, MTK_RTC_PROT4, RTC_PROT4_MAGIC);
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mtk_rmw(hw, MTK_RTC_DEBNCE, RTC_DEBNCE_MASK, 0);
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mtk_clr(hw, MTK_RTC_CTL, RTC_RC_STOP);
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}
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static void mtk_rtc_get_alarm_or_time(struct mtk_rtc *hw, struct rtc_time *tm,
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int time_alarm)
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{
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u32 year, mon, mday, wday, hour, min, sec;
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/*
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* Read again until the field of the second is not changed which
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* ensures all fields in the consistent state. Note that MTK_SEC must
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* be read first. In this way, it guarantees the others remain not
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* changed when the results for two MTK_SEC consecutive reads are same.
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*/
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do {
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sec = mtk_r32(hw, MTK_RTC_TREG(time_alarm, MTK_SEC));
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min = mtk_r32(hw, MTK_RTC_TREG(time_alarm, MTK_MIN));
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hour = mtk_r32(hw, MTK_RTC_TREG(time_alarm, MTK_HOU));
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wday = mtk_r32(hw, MTK_RTC_TREG(time_alarm, MTK_DOW));
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mday = mtk_r32(hw, MTK_RTC_TREG(time_alarm, MTK_DOM));
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mon = mtk_r32(hw, MTK_RTC_TREG(time_alarm, MTK_MON));
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year = mtk_r32(hw, MTK_RTC_TREG(time_alarm, MTK_YEA));
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} while (sec != mtk_r32(hw, MTK_RTC_TREG(time_alarm, MTK_SEC)));
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tm->tm_sec = sec;
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tm->tm_min = min;
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tm->tm_hour = hour;
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tm->tm_wday = wday;
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tm->tm_mday = mday;
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tm->tm_mon = mon - 1;
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/* Rebase to the absolute year which userspace queries */
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tm->tm_year = year + MTK_RTC_TM_YR_OFFSET;
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}
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static void mtk_rtc_set_alarm_or_time(struct mtk_rtc *hw, struct rtc_time *tm,
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int time_alarm)
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{
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u32 year;
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/* Rebase to the relative year which RTC hardware requires */
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year = tm->tm_year - MTK_RTC_TM_YR_OFFSET;
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mtk_w32(hw, MTK_RTC_TREG(time_alarm, MTK_YEA), year);
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mtk_w32(hw, MTK_RTC_TREG(time_alarm, MTK_MON), tm->tm_mon + 1);
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mtk_w32(hw, MTK_RTC_TREG(time_alarm, MTK_DOW), tm->tm_wday);
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mtk_w32(hw, MTK_RTC_TREG(time_alarm, MTK_DOM), tm->tm_mday);
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mtk_w32(hw, MTK_RTC_TREG(time_alarm, MTK_HOU), tm->tm_hour);
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mtk_w32(hw, MTK_RTC_TREG(time_alarm, MTK_MIN), tm->tm_min);
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mtk_w32(hw, MTK_RTC_TREG(time_alarm, MTK_SEC), tm->tm_sec);
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}
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static irqreturn_t mtk_rtc_alarmirq(int irq, void *id)
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{
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struct mtk_rtc *hw = (struct mtk_rtc *)id;
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u32 irq_sta;
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irq_sta = mtk_r32(hw, MTK_RTC_INT);
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if (irq_sta & RTC_INT_AL_STA) {
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/* Stop alarm also implicitly disables the alarm interrupt */
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mtk_w32(hw, MTK_RTC_AL_CTL, 0);
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rtc_update_irq(hw->rtc, 1, RTC_IRQF | RTC_AF);
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/* Ack alarm interrupt status */
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mtk_w32(hw, MTK_RTC_INT, RTC_INT_AL_STA);
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return IRQ_HANDLED;
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}
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return IRQ_NONE;
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}
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static int mtk_rtc_gettime(struct device *dev, struct rtc_time *tm)
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{
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struct mtk_rtc *hw = dev_get_drvdata(dev);
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mtk_rtc_get_alarm_or_time(hw, tm, MTK_TC);
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return 0;
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}
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static int mtk_rtc_settime(struct device *dev, struct rtc_time *tm)
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{
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struct mtk_rtc *hw = dev_get_drvdata(dev);
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if (!MTK_RTC_TM_YR_VALID(tm->tm_year))
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return -EINVAL;
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/* Stop time counter before setting a new one*/
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mtk_set(hw, MTK_RTC_CTL, RTC_RC_STOP);
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mtk_rtc_set_alarm_or_time(hw, tm, MTK_TC);
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/* Restart the time counter */
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mtk_clr(hw, MTK_RTC_CTL, RTC_RC_STOP);
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return 0;
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}
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static int mtk_rtc_getalarm(struct device *dev, struct rtc_wkalrm *wkalrm)
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{
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struct mtk_rtc *hw = dev_get_drvdata(dev);
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struct rtc_time *alrm_tm = &wkalrm->time;
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mtk_rtc_get_alarm_or_time(hw, alrm_tm, MTK_AL);
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wkalrm->enabled = !!(mtk_r32(hw, MTK_RTC_AL_CTL) & RTC_AL_EN);
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wkalrm->pending = !!(mtk_r32(hw, MTK_RTC_INT) & RTC_INT_AL_STA);
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return 0;
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}
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static int mtk_rtc_setalarm(struct device *dev, struct rtc_wkalrm *wkalrm)
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{
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struct mtk_rtc *hw = dev_get_drvdata(dev);
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struct rtc_time *alrm_tm = &wkalrm->time;
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if (!MTK_RTC_TM_YR_VALID(alrm_tm->tm_year))
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return -EINVAL;
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/*
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* Stop the alarm also implicitly including disables interrupt before
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* setting a new one.
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*/
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mtk_clr(hw, MTK_RTC_AL_CTL, RTC_AL_EN);
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/*
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* Avoid contention between mtk_rtc_setalarm and IRQ handler so that
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* disabling the interrupt and awaiting for pending IRQ handler to
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* complete.
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*/
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synchronize_irq(hw->irq);
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mtk_rtc_set_alarm_or_time(hw, alrm_tm, MTK_AL);
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/* Restart the alarm with the new setup */
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mtk_w32(hw, MTK_RTC_AL_CTL, RTC_AL_ALL);
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return 0;
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}
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static const struct rtc_class_ops mtk_rtc_ops = {
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.read_time = mtk_rtc_gettime,
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.set_time = mtk_rtc_settime,
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.read_alarm = mtk_rtc_getalarm,
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.set_alarm = mtk_rtc_setalarm,
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};
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static const struct of_device_id mtk_rtc_match[] = {
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{ .compatible = "mediatek,mt7622-rtc" },
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{ .compatible = "mediatek,soc-rtc" },
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{},
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};
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MODULE_DEVICE_TABLE(of, mtk_rtc_match);
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static int mtk_rtc_probe(struct platform_device *pdev)
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{
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struct mtk_rtc *hw;
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int ret;
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hw = devm_kzalloc(&pdev->dev, sizeof(*hw), GFP_KERNEL);
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if (!hw)
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return -ENOMEM;
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platform_set_drvdata(pdev, hw);
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hw->base = devm_platform_ioremap_resource(pdev, 0);
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if (IS_ERR(hw->base))
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return PTR_ERR(hw->base);
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hw->clk = devm_clk_get(&pdev->dev, "rtc");
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if (IS_ERR(hw->clk)) {
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dev_err(&pdev->dev, "No clock\n");
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return PTR_ERR(hw->clk);
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}
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ret = clk_prepare_enable(hw->clk);
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if (ret)
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return ret;
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hw->irq = platform_get_irq(pdev, 0);
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if (hw->irq < 0) {
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ret = hw->irq;
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goto err;
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}
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ret = devm_request_irq(&pdev->dev, hw->irq, mtk_rtc_alarmirq,
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0, dev_name(&pdev->dev), hw);
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if (ret) {
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dev_err(&pdev->dev, "Can't request IRQ\n");
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goto err;
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}
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mtk_rtc_hw_init(hw);
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device_init_wakeup(&pdev->dev, true);
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hw->rtc = devm_rtc_device_register(&pdev->dev, pdev->name,
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&mtk_rtc_ops, THIS_MODULE);
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if (IS_ERR(hw->rtc)) {
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ret = PTR_ERR(hw->rtc);
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dev_err(&pdev->dev, "Unable to register device\n");
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goto err;
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}
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return 0;
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err:
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clk_disable_unprepare(hw->clk);
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return ret;
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}
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static void mtk_rtc_remove(struct platform_device *pdev)
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{
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struct mtk_rtc *hw = platform_get_drvdata(pdev);
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clk_disable_unprepare(hw->clk);
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}
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#ifdef CONFIG_PM_SLEEP
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static int mtk_rtc_suspend(struct device *dev)
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{
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struct mtk_rtc *hw = dev_get_drvdata(dev);
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if (device_may_wakeup(dev))
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enable_irq_wake(hw->irq);
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return 0;
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}
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static int mtk_rtc_resume(struct device *dev)
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{
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struct mtk_rtc *hw = dev_get_drvdata(dev);
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if (device_may_wakeup(dev))
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disable_irq_wake(hw->irq);
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return 0;
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}
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static SIMPLE_DEV_PM_OPS(mtk_rtc_pm_ops, mtk_rtc_suspend, mtk_rtc_resume);
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#define MTK_RTC_PM_OPS (&mtk_rtc_pm_ops)
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#else /* CONFIG_PM */
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#define MTK_RTC_PM_OPS NULL
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#endif /* CONFIG_PM */
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static struct platform_driver mtk_rtc_driver = {
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.probe = mtk_rtc_probe,
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.remove_new = mtk_rtc_remove,
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.driver = {
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.name = MTK_RTC_DEV,
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.of_match_table = mtk_rtc_match,
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.pm = MTK_RTC_PM_OPS,
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},
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};
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module_platform_driver(mtk_rtc_driver);
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MODULE_DESCRIPTION("MediaTek SoC based RTC Driver");
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MODULE_AUTHOR("Sean Wang <sean.wang@mediatek.com>");
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MODULE_LICENSE("GPL");
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