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// SPDX-License-Identifier: GPL-2.0-only
/*
* An rtc/i2c driver for the EM Microelectronic EM3027
* Copyright 2011 CompuLab, Ltd.
*
* Author: Mike Rapoport <mike@compulab.co.il>
*
* Based on rtc-ds1672.c by Alessandro Zummo <a.zummo@towertech.it>
*/
#include <linux/i2c.h>
#include <linux/rtc.h>
#include <linux/bcd.h>
#include <linux/module.h>
#include <linux/of.h>
/* Registers */
#define EM3027_REG_ON_OFF_CTRL 0x00
#define EM3027_REG_IRQ_CTRL 0x01
#define EM3027_REG_IRQ_FLAGS 0x02
#define EM3027_REG_STATUS 0x03
#define EM3027_REG_RST_CTRL 0x04
#define EM3027_REG_WATCH_SEC 0x08
#define EM3027_REG_WATCH_MIN 0x09
#define EM3027_REG_WATCH_HOUR 0x0a
#define EM3027_REG_WATCH_DATE 0x0b
#define EM3027_REG_WATCH_DAY 0x0c
#define EM3027_REG_WATCH_MON 0x0d
#define EM3027_REG_WATCH_YEAR 0x0e
#define EM3027_REG_ALARM_SEC 0x10
#define EM3027_REG_ALARM_MIN 0x11
#define EM3027_REG_ALARM_HOUR 0x12
#define EM3027_REG_ALARM_DATE 0x13
#define EM3027_REG_ALARM_DAY 0x14
#define EM3027_REG_ALARM_MON 0x15
#define EM3027_REG_ALARM_YEAR 0x16
static struct i2c_driver em3027_driver;
static int em3027_get_time(struct device *dev, struct rtc_time *tm)
{
struct i2c_client *client = to_i2c_client(dev);
unsigned char addr = EM3027_REG_WATCH_SEC;
unsigned char buf[7];
struct i2c_msg msgs[] = {
{/* setup read addr */
.addr = client->addr,
.len = 1,
.buf = &addr
},
{/* read time/date */
.addr = client->addr,
.flags = I2C_M_RD,
.len = 7,
.buf = buf
},
};
/* read time/date registers */
if ((i2c_transfer(client->adapter, &msgs[0], 2)) != 2) {
dev_err(&client->dev, "%s: read error\n", __func__);
return -EIO;
}
tm->tm_sec = bcd2bin(buf[0]);
tm->tm_min = bcd2bin(buf[1]);
tm->tm_hour = bcd2bin(buf[2]);
tm->tm_mday = bcd2bin(buf[3]);
tm->tm_wday = bcd2bin(buf[4]);
tm->tm_mon = bcd2bin(buf[5]) - 1;
tm->tm_year = bcd2bin(buf[6]) + 100;
return 0;
}
static int em3027_set_time(struct device *dev, struct rtc_time *tm)
{
struct i2c_client *client = to_i2c_client(dev);
unsigned char buf[8];
struct i2c_msg msg = {
.addr = client->addr,
.len = 8,
.buf = buf, /* write time/date */
};
buf[0] = EM3027_REG_WATCH_SEC;
buf[1] = bin2bcd(tm->tm_sec);
buf[2] = bin2bcd(tm->tm_min);
buf[3] = bin2bcd(tm->tm_hour);
buf[4] = bin2bcd(tm->tm_mday);
buf[5] = bin2bcd(tm->tm_wday);
buf[6] = bin2bcd(tm->tm_mon + 1);
buf[7] = bin2bcd(tm->tm_year % 100);
/* write time/date registers */
if ((i2c_transfer(client->adapter, &msg, 1)) != 1) {
dev_err(&client->dev, "%s: write error\n", __func__);
return -EIO;
}
return 0;
}
static const struct rtc_class_ops em3027_rtc_ops = {
.read_time = em3027_get_time,
.set_time = em3027_set_time,
};
static int em3027_probe(struct i2c_client *client)
{
struct rtc_device *rtc;
if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
return -ENODEV;
rtc = devm_rtc_device_register(&client->dev, em3027_driver.driver.name,
&em3027_rtc_ops, THIS_MODULE);
if (IS_ERR(rtc))
return PTR_ERR(rtc);
i2c_set_clientdata(client, rtc);
return 0;
}
static const struct i2c_device_id em3027_id[] = {
{ "em3027", 0 },
{ }
};
MODULE_DEVICE_TABLE(i2c, em3027_id);
#ifdef CONFIG_OF
static const struct of_device_id em3027_of_match[] = {
{ .compatible = "emmicro,em3027", },
{}
};
MODULE_DEVICE_TABLE(of, em3027_of_match);
#endif
static struct i2c_driver em3027_driver = {
.driver = {
.name = "rtc-em3027",
.of_match_table = of_match_ptr(em3027_of_match),
},
.probe = em3027_probe,
.id_table = em3027_id,
};
module_i2c_driver(em3027_driver);
MODULE_AUTHOR("Mike Rapoport <mike@compulab.co.il>");
MODULE_DESCRIPTION("EM Microelectronic EM3027 RTC driver");
MODULE_LICENSE("GPL");
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