/*
* RTC Driver for X-Powers AC100
*
* Copyright (c) 2016 Chen-Yu Tsai
*
* Chen-Yu Tsai <wens@csie.org>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* 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/bcd.h>
#include <linux/device.h>
#include <linux/interrupt.h>
#include <linux/kernel.h>
#include <linux/mfd/ac100.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/regmap.h>
#include <linux/rtc.h>
#include <linux/types.h>
/* Control register */
#define AC100_RTC_CTRL_24HOUR BIT(0)
/* RTC */
#define AC100_RTC_SEC_MASK GENMASK(6, 0)
#define AC100_RTC_MIN_MASK GENMASK(6, 0)
#define AC100_RTC_HOU_MASK GENMASK(5, 0)
#define AC100_RTC_WEE_MASK GENMASK(2, 0)
#define AC100_RTC_DAY_MASK GENMASK(5, 0)
#define AC100_RTC_MON_MASK GENMASK(4, 0)
#define AC100_RTC_YEA_MASK GENMASK(7, 0)
#define AC100_RTC_YEA_LEAP BIT(15)
#define AC100_RTC_UPD_TRIGGER BIT(15)
/* Alarm (wall clock) */
#define AC100_ALM_INT_ENABLE BIT(0)
#define AC100_ALM_SEC_MASK GENMASK(6, 0)
#define AC100_ALM_MIN_MASK GENMASK(6, 0)
#define AC100_ALM_HOU_MASK GENMASK(5, 0)
#define AC100_ALM_WEE_MASK GENMASK(2, 0)
#define AC100_ALM_DAY_MASK GENMASK(5, 0)
#define AC100_ALM_MON_MASK GENMASK(4, 0)
#define AC100_ALM_YEA_MASK GENMASK(7, 0)
#define AC100_ALM_ENABLE_FLAG BIT(15)
#define AC100_ALM_UPD_TRIGGER BIT(15)
/*
* 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 - 2069. This range is selected to match Allwinner's
* driver.
*/
#define AC100_YEAR_MIN 1970
#define AC100_YEAR_MAX 2069
#define AC100_YEAR_OFF (AC100_YEAR_MIN - 1900)
struct ac100_rtc_dev {
struct rtc_device *rtc;
struct device *dev;
struct regmap *regmap;
int irq;
unsigned long alarm;
};
static int ac100_rtc_get_time(struct device *dev, struct rtc_time *rtc_tm)
{
struct ac100_rtc_dev *chip = dev_get_drvdata(dev);
struct regmap *regmap = chip->regmap;
u16 reg[7];
int ret;
ret = regmap_bulk_read(regmap, AC100_RTC_SEC, reg, 7);
if (ret)
return ret;
rtc_tm->tm_sec = bcd2bin(reg[0] & AC100_RTC_SEC_MASK);
rtc_tm->tm_min = bcd2bin(reg[1] & AC100_RTC_MIN_MASK);
rtc_tm->tm_hour = bcd2bin(reg[2] & AC100_RTC_HOU_MASK);
rtc_tm->tm_wday = bcd2bin(reg[3] & AC100_RTC_WEE_MASK);
rtc_tm->tm_mday = bcd2bin(reg[4] & AC100_RTC_DAY_MASK);
rtc_tm->tm_mon = bcd2bin(reg[5] & AC100_RTC_MON_MASK) - 1;
rtc_tm->tm_year = bcd2bin(reg[6] & AC100_RTC_YEA_MASK) +
AC100_YEAR_OFF;
return rtc_valid_tm(rtc_tm);
}
static int ac100_rtc_set_time(struct device *dev, struct rtc_time *rtc_tm)
{
struct ac100_rtc_dev *chip = dev_get_drvdata(dev);
struct regmap *regmap = chip->regmap;
int year;
u16 reg[8];
/* our RTC has a limited year range... */
year = rtc_tm->tm_year - AC100_YEAR_OFF;
if (year < 0 || year > (AC100_YEAR_MAX - 1900)) {
dev_err(dev, "rtc only supports year in range %d - %d\n",
AC100_YEAR_MIN, AC100_YEAR_MAX);
return -EINVAL;
}
/* convert to BCD */
reg[0] = bin2bcd(rtc_tm->tm_sec) & AC100_RTC_SEC_MASK;
reg[1] = bin2bcd(rtc_tm->tm_min) & AC100_RTC_MIN_MASK;
reg[2] = bin2bcd(rtc_tm->tm_hour) & AC100_RTC_HOU_MASK;
reg[3] = bin2bcd(rtc_tm->tm_wday) & AC100_RTC_WEE_MASK;
reg[4] = bin2bcd(rtc_tm->tm_mday) & AC100_RTC_DAY_MASK;
reg[5] = bin2bcd(rtc_tm->tm_mon + 1) & AC100_RTC_MON_MASK;
reg[6] = bin2bcd(year) & AC100_RTC_YEA_MASK;
/* trigger write */
reg[7] = AC100_RTC_UPD_TRIGGER;
/* Is it a leap year? */
if (is_leap_year(year + AC100_YEAR_OFF + 1900))
reg[6] |= AC100_RTC_YEA_LEAP;
return regmap_bulk_write(regmap, AC100_RTC_SEC, reg, 8);
}
static int ac100_rtc_alarm_irq_enable(struct device *dev, unsigned int en)
{
struct ac100_rtc_dev *chip = dev_get_drvdata(dev);
struct regmap *regmap = chip->regmap;
unsigned int val;
val = en ? AC100_ALM_INT_ENABLE : 0;
return regmap_write(regmap, AC100_ALM_INT_ENA, val);
}
static int ac100_rtc_get_alarm(struct device *dev, struct rtc_wkalrm *alrm)
{
struct ac100_rtc_dev *chip = dev_get_drvdata(dev);
struct regmap *regmap = chip->regmap;
struct rtc_time *alrm_tm = &alrm->time;
u16 reg[7];
unsigned int val;
int ret;
ret = regmap_read(regmap, AC100_ALM_INT_ENA, &val);
if (ret)
return ret;
alrm->enabled = !!(val & AC100_ALM_INT_ENABLE);
ret = regmap_bulk_read(regmap, AC100_ALM_SEC, reg, 7);
if (ret)
return ret;
alrm_tm->tm_sec = bcd2bin(reg[0] & AC100_ALM_SEC_MASK);
alrm_tm->tm_min = bcd2bin(reg[1] & AC100_ALM_MIN_MASK);
alrm_tm->tm_hour = bcd2bin(reg[2] & AC100_ALM_HOU_MASK);
alrm_tm->tm_wday = bcd2bin(reg[3] & AC100_ALM_WEE_MASK);
alrm_tm->tm_mday = bcd2bin(reg[4] & AC100_ALM_DAY_MASK);
alrm_tm->tm_mon = bcd2bin(reg[5] & AC100_ALM_MON_MASK) - 1;
alrm_tm->tm_year = bcd2bin(reg[6] & AC100_ALM_YEA_MASK) +
AC100_YEAR_OFF;
return 0;
}
static int ac100_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
{
struct ac100_rtc_dev *chip = dev_get_drvdata(dev);
struct regmap *regmap = chip->regmap;
struct rtc_time *alrm_tm = &alrm->time;
u16 reg[8];
int year;
int ret;
/* our alarm has a limited year range... */
year = alrm_tm->tm_year - AC100_YEAR_OFF;
if (year < 0 || year > (AC100_YEAR_MAX - 1900)) {
dev_err(dev, "alarm only supports year in range %d - %d\n",
AC100_YEAR_MIN, AC100_YEAR_MAX);
return -EINVAL;
}
/* convert to BCD */
reg[0] = (bin2bcd(alrm_tm->tm_sec) & AC100_ALM_SEC_MASK) |
AC100_ALM_ENABLE_FLAG;
reg[1] = (bin2bcd(alrm_tm->tm_min) & AC100_ALM_MIN_MASK) |
AC100_ALM_ENABLE_FLAG;
reg[2] = (bin2bcd(alrm_tm->tm_hour) & AC100_ALM_HOU_MASK) |
AC100_ALM_ENABLE_FLAG;
/* Do not enable weekday alarm */
reg[3] = bin2bcd(alrm_tm->tm_wday) & AC100_ALM_WEE_MASK;
reg[4] = (bin2bcd(alrm_tm->tm_mday) & AC100_ALM_DAY_MASK) |
AC100_ALM_ENABLE_FLAG;
reg[5] = (bin2bcd(alrm_tm->tm_mon + 1) & AC100_ALM_MON_MASK) |
AC100_ALM_ENABLE_FLAG;
reg[6] = (bin2bcd(year) & AC100_ALM_YEA_MASK) |
AC100_ALM_ENABLE_FLAG;
/* trigger write */
reg[7] = AC100_ALM_UPD_TRIGGER;
ret = regmap_bulk_write(regmap, AC100_ALM_SEC, reg, 8);
if (ret)
return ret;
return ac100_rtc_alarm_irq_enable(dev, alrm->enabled);
}
static irqreturn_t ac100_rtc_irq(int irq, void *data)
{
struct ac100_rtc_dev *chip = data;
struct regmap *regmap = chip->regmap;
unsigned int val = 0;
int ret;
mutex_lock(&chip->rtc->ops_lock);
/* read status */
ret = regmap_read(regmap, AC100_ALM_INT_STA, &val);
if (ret)
goto out;
if (val & AC100_ALM_INT_ENABLE) {
/* signal rtc framework */
rtc_update_irq(chip->rtc, 1, RTC_AF | RTC_IRQF);
/* clear status */
ret = regmap_write(regmap, AC100_ALM_INT_STA, val);
if (ret)
goto out;
/* disable interrupt */
ret = ac100_rtc_alarm_irq_enable(chip->dev, 0);
if (ret)
goto out;
}
out:
mutex_unlock(&chip->rtc->ops_lock);
return IRQ_HANDLED;
}
static const struct rtc_class_ops ac100_rtc_ops = {
.read_time = ac100_rtc_get_time,
.set_time = ac100_rtc_set_time,
.read_alarm = ac100_rtc_get_alarm,
.set_alarm = ac100_rtc_set_alarm,
.alarm_irq_enable = ac100_rtc_alarm_irq_enable,
};
static int ac100_rtc_probe(struct platform_device *pdev)
{
struct ac100_dev *ac100 = dev_get_drvdata(pdev->dev.parent);
struct ac100_rtc_dev *chip;
int ret;
chip = devm_kzalloc(&pdev->dev, sizeof(*chip), GFP_KERNEL);
platform_set_drvdata(pdev, chip);
chip->dev = &pdev->dev;
chip->regmap = ac100->regmap;
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_threaded_irq(&pdev->dev, chip->irq, NULL,
ac100_rtc_irq,
IRQF_SHARED | IRQF_ONESHOT,
dev_name(&pdev->dev), chip);
if (ret) {
dev_err(&pdev->dev, "Could not request IRQ\n");
return ret;
}
/* always use 24 hour mode */
regmap_write_bits(chip->regmap, AC100_RTC_CTRL, AC100_RTC_CTRL_24HOUR,
AC100_RTC_CTRL_24HOUR);
/* disable counter alarm interrupt */
regmap_write(chip->regmap, AC100_ALM_INT_ENA, 0);
/* clear counter alarm pending interrupts */
regmap_write(chip->regmap, AC100_ALM_INT_STA, AC100_ALM_INT_ENABLE);
chip->rtc = devm_rtc_device_register(&pdev->dev, "rtc-ac100",
&ac100_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 const struct of_device_id ac100_rtc_match[] = {
{ .compatible = "x-powers,ac100-rtc" },
{ },
};
MODULE_DEVICE_TABLE(of, ac100_rtc_match);
static struct platform_driver ac100_rtc_driver = {
.probe = ac100_rtc_probe,
.driver = {
.name = "ac100-rtc",
.of_match_table = of_match_ptr(ac100_rtc_match),
},
};
module_platform_driver(ac100_rtc_driver);
MODULE_DESCRIPTION("X-Powers AC100 RTC driver");
MODULE_AUTHOR("Chen-Yu Tsai <wens@csie.org>");
MODULE_LICENSE("GPL v2");
