mirror of
https://github.com/torvalds/linux.git
synced 2025-11-04 02:30:34 +02:00
435af89786
With this driver, mainline Linux can keep its time and date in sync with the vendor kernel. Advanced functionality like alarm and automatic power-on is not yet supported. Signed-off-by: Jonathan Neuschäfer <j.neuschaefer@gmx.net> Acked-by: Alexandre Belloni <alexandre.belloni@bootlin.com> Signed-off-by: Lee Jones <lee.jones@linaro.org>
145 lines
3.9 KiB
C
145 lines
3.9 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
|
|
/*
|
|
* The Netronix embedded controller is a microcontroller found in some
|
|
* e-book readers designed by the original design manufacturer Netronix, Inc.
|
|
* It contains RTC, battery monitoring, system power management, and PWM
|
|
* functionality.
|
|
*
|
|
* This driver implements access to the RTC time and date.
|
|
*
|
|
* Copyright 2020 Jonathan Neuschäfer <j.neuschaefer@gmx.net>
|
|
*/
|
|
|
|
#include <linux/mfd/ntxec.h>
|
|
#include <linux/module.h>
|
|
#include <linux/platform_device.h>
|
|
#include <linux/regmap.h>
|
|
#include <linux/rtc.h>
|
|
#include <linux/types.h>
|
|
|
|
struct ntxec_rtc {
|
|
struct device *dev;
|
|
struct ntxec *ec;
|
|
};
|
|
|
|
#define NTXEC_REG_WRITE_YEAR 0x10
|
|
#define NTXEC_REG_WRITE_MONTH 0x11
|
|
#define NTXEC_REG_WRITE_DAY 0x12
|
|
#define NTXEC_REG_WRITE_HOUR 0x13
|
|
#define NTXEC_REG_WRITE_MINUTE 0x14
|
|
#define NTXEC_REG_WRITE_SECOND 0x15
|
|
|
|
#define NTXEC_REG_READ_YEAR_MONTH 0x20
|
|
#define NTXEC_REG_READ_MDAY_HOUR 0x21
|
|
#define NTXEC_REG_READ_MINUTE_SECOND 0x23
|
|
|
|
static int ntxec_read_time(struct device *dev, struct rtc_time *tm)
|
|
{
|
|
struct ntxec_rtc *rtc = dev_get_drvdata(dev);
|
|
unsigned int value;
|
|
int res;
|
|
|
|
retry:
|
|
res = regmap_read(rtc->ec->regmap, NTXEC_REG_READ_MINUTE_SECOND, &value);
|
|
if (res < 0)
|
|
return res;
|
|
|
|
tm->tm_min = value >> 8;
|
|
tm->tm_sec = value & 0xff;
|
|
|
|
res = regmap_read(rtc->ec->regmap, NTXEC_REG_READ_MDAY_HOUR, &value);
|
|
if (res < 0)
|
|
return res;
|
|
|
|
tm->tm_mday = value >> 8;
|
|
tm->tm_hour = value & 0xff;
|
|
|
|
res = regmap_read(rtc->ec->regmap, NTXEC_REG_READ_YEAR_MONTH, &value);
|
|
if (res < 0)
|
|
return res;
|
|
|
|
tm->tm_year = (value >> 8) + 100;
|
|
tm->tm_mon = (value & 0xff) - 1;
|
|
|
|
/*
|
|
* Read the minutes/seconds field again. If it changed since the first
|
|
* read, we can't assume that the values read so far are consistent,
|
|
* and should start from the beginning.
|
|
*/
|
|
res = regmap_read(rtc->ec->regmap, NTXEC_REG_READ_MINUTE_SECOND, &value);
|
|
if (res < 0)
|
|
return res;
|
|
|
|
if (tm->tm_min != value >> 8 || tm->tm_sec != (value & 0xff))
|
|
goto retry;
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int ntxec_set_time(struct device *dev, struct rtc_time *tm)
|
|
{
|
|
struct ntxec_rtc *rtc = dev_get_drvdata(dev);
|
|
|
|
/*
|
|
* To avoid time overflows while we're writing the full date/time,
|
|
* set the seconds field to zero before doing anything else. For the
|
|
* next 59 seconds (plus however long it takes until the RTC's next
|
|
* update of the second field), the seconds field will not overflow
|
|
* into the other fields.
|
|
*/
|
|
struct reg_sequence regs[] = {
|
|
{ NTXEC_REG_WRITE_SECOND, ntxec_reg8(0) },
|
|
{ NTXEC_REG_WRITE_YEAR, ntxec_reg8(tm->tm_year - 100) },
|
|
{ NTXEC_REG_WRITE_MONTH, ntxec_reg8(tm->tm_mon + 1) },
|
|
{ NTXEC_REG_WRITE_DAY, ntxec_reg8(tm->tm_mday) },
|
|
{ NTXEC_REG_WRITE_HOUR, ntxec_reg8(tm->tm_hour) },
|
|
{ NTXEC_REG_WRITE_MINUTE, ntxec_reg8(tm->tm_min) },
|
|
{ NTXEC_REG_WRITE_SECOND, ntxec_reg8(tm->tm_sec) },
|
|
};
|
|
|
|
return regmap_multi_reg_write(rtc->ec->regmap, regs, ARRAY_SIZE(regs));
|
|
}
|
|
|
|
static const struct rtc_class_ops ntxec_rtc_ops = {
|
|
.read_time = ntxec_read_time,
|
|
.set_time = ntxec_set_time,
|
|
};
|
|
|
|
static int ntxec_rtc_probe(struct platform_device *pdev)
|
|
{
|
|
struct rtc_device *dev;
|
|
struct ntxec_rtc *rtc;
|
|
|
|
pdev->dev.of_node = pdev->dev.parent->of_node;
|
|
|
|
rtc = devm_kzalloc(&pdev->dev, sizeof(*rtc), GFP_KERNEL);
|
|
if (!rtc)
|
|
return -ENOMEM;
|
|
|
|
rtc->dev = &pdev->dev;
|
|
rtc->ec = dev_get_drvdata(pdev->dev.parent);
|
|
platform_set_drvdata(pdev, rtc);
|
|
|
|
dev = devm_rtc_allocate_device(&pdev->dev);
|
|
if (IS_ERR(dev))
|
|
return PTR_ERR(dev);
|
|
|
|
dev->ops = &ntxec_rtc_ops;
|
|
dev->range_min = RTC_TIMESTAMP_BEGIN_2000;
|
|
dev->range_max = 9025257599LL; /* 2255-12-31 23:59:59 */
|
|
|
|
return devm_rtc_register_device(dev);
|
|
}
|
|
|
|
static struct platform_driver ntxec_rtc_driver = {
|
|
.driver = {
|
|
.name = "ntxec-rtc",
|
|
},
|
|
.probe = ntxec_rtc_probe,
|
|
};
|
|
module_platform_driver(ntxec_rtc_driver);
|
|
|
|
MODULE_AUTHOR("Jonathan Neuschäfer <j.neuschaefer@gmx.net>");
|
|
MODULE_DESCRIPTION("RTC driver for Netronix EC");
|
|
MODULE_LICENSE("GPL");
|
|
MODULE_ALIAS("platform:ntxec-rtc");
|