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rtc: mediatek: add driver for RTC on MT7622 SoC 

This patch introduces the driver for the RTC on MT7622 SoC.

Signed-off-by: Sean Wang <sean.wang@mediatek.com>
Reviewed-by: Yingjoe Chen <yingjoe.chen@mediatek.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
This commit is contained in:
Sean Wang 2017-10-23 15:16:45 +08:00 committed by Alexandre Belloni
parent 1901142ba8
commit ba5d018135
3 changed files with 433 additions and 0 deletions
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10
drivers/rtc/Kconfig
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@ -1715,6 +1715,16 @@ config RTC_DRV_MT6397
If you want to use Mediatek(R) RTC interface, select Y or M here.
config RTC_DRV_MT7622
tristate "MediaTek SoC based RTC"
depends on ARCH_MEDIATEK || COMPILE_TEST
help
This enables support for the real time clock built in the MediaTek
SoCs.
This drive can also be built as a module. If so, the module
will be called rtc-mt7622.
config RTC_DRV_XGENE
tristate "APM X-Gene RTC"
depends on HAS_IOMEM

1
drivers/rtc/Makefile
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@ -102,6 +102,7 @@ obj-$(CONFIG_RTC_DRV_MPC5121) += rtc-mpc5121.o
obj-$(CONFIG_RTC_DRV_VRTC) += rtc-mrst.o
obj-$(CONFIG_RTC_DRV_MSM6242) += rtc-msm6242.o
obj-$(CONFIG_RTC_DRV_MT6397) += rtc-mt6397.o
obj-$(CONFIG_RTC_DRV_MT7622) += rtc-mt7622.o
obj-$(CONFIG_RTC_DRV_MV) += rtc-mv.o
obj-$(CONFIG_RTC_DRV_MXC) += rtc-mxc.o
obj-$(CONFIG_RTC_DRV_NUC900) += rtc-nuc900.o

422
drivers/rtc/rtc-mt7622.c Normal file
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@ -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");