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// SPDX-License-Identifier: GPL-2.0-only
#include <linux/limits.h>
#include <linux/mod_devicetable.h>
#include <linux/platform_device.h>
#include <linux/rtc.h>
#include <linux/mfd/88pm886.h>
/*
* Time is calculated as the sum of a 32-bit read-only advancing counter and a
* writeable constant offset stored in the chip's spare registers.
*/
static int pm886_rtc_read_time(struct device *dev, struct rtc_time *tm)
{
struct regmap *regmap = dev_get_drvdata(dev);
u32 time;
u32 buf;
int ret;
ret = regmap_bulk_read(regmap, PM886_REG_RTC_SPARE1, &buf, 4);
if (ret)
return ret;
time = buf;
ret = regmap_bulk_read(regmap, PM886_REG_RTC_CNT1, &buf, 4);
if (ret)
return ret;
time += buf;
rtc_time64_to_tm(time, tm);
return 0;
}
static int pm886_rtc_set_time(struct device *dev, struct rtc_time *tm)
{
struct regmap *regmap = dev_get_drvdata(dev);
u32 buf;
int ret;
ret = regmap_bulk_read(regmap, PM886_REG_RTC_CNT1, &buf, 4);
if (ret)
return ret;
buf = rtc_tm_to_time64(tm) - buf;
return regmap_bulk_write(regmap, PM886_REG_RTC_SPARE1, &buf, 4);
}
static const struct rtc_class_ops pm886_rtc_ops = {
.read_time = pm886_rtc_read_time,
.set_time = pm886_rtc_set_time,
};
static int pm886_rtc_probe(struct platform_device *pdev)
{
struct pm886_chip *chip = dev_get_drvdata(pdev->dev.parent);
struct device *dev = &pdev->dev;
struct rtc_device *rtc;
int ret;
platform_set_drvdata(pdev, chip->regmap);
rtc = devm_rtc_allocate_device(dev);
if (IS_ERR(rtc))
return dev_err_probe(dev, PTR_ERR(rtc),
"Failed to allocate RTC device\n");
rtc->ops = &pm886_rtc_ops;
rtc->range_max = U32_MAX;
ret = devm_rtc_register_device(rtc);
if (ret)
return dev_err_probe(dev, ret, "Failed to register RTC device\n");
return 0;
}
static const struct platform_device_id pm886_rtc_id_table[] = {
{ "88pm886-rtc", },
{ }
};
MODULE_DEVICE_TABLE(platform, pm886_rtc_id_table);
static struct platform_driver pm886_rtc_driver = {
.driver = {
.name = "88pm886-rtc",
},
.probe = pm886_rtc_probe,
.id_table = pm886_rtc_id_table,
};
module_platform_driver(pm886_rtc_driver);
MODULE_DESCRIPTION("Marvell 88PM886 RTC driver");
MODULE_AUTHOR("Karel Balej <balejk@matfyz.cz>");
MODULE_LICENSE("GPL");
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