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/*
* An I2C driver for the PCF85063 RTC
* Copyright 2014 Rose Technology
*
* Author: Søren Andersen <san@rosetechnology.dk>
* Maintainers: http://www.nslu2-linux.org/
*
* based on the other drivers in this same directory.
*
* 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.
*/
#include <linux/i2c.h>
#include <linux/bcd.h>
#include <linux/rtc.h>
#include <linux/module.h>
#define PCF85063_REG_CTRL1 0x00 /* status */
#define PCF85063_REG_CTRL1_STOP BIT(5)
#define PCF85063_REG_CTRL2 0x01
#define PCF85063_REG_SC 0x04 /* datetime */
#define PCF85063_REG_SC_OS 0x80
#define PCF85063_REG_MN 0x05
#define PCF85063_REG_HR 0x06
#define PCF85063_REG_DM 0x07
#define PCF85063_REG_DW 0x08
#define PCF85063_REG_MO 0x09
#define PCF85063_REG_YR 0x0A
static struct i2c_driver pcf85063_driver;
struct pcf85063 {
struct rtc_device *rtc;
int voltage_low; /* indicates if a low_voltage was detected */
};
static int pcf85063_stop_clock(struct i2c_client *client, u8 *ctrl1)
{
s32 ret;
ret = i2c_smbus_read_byte_data(client, PCF85063_REG_CTRL1);
if (ret < 0) {
dev_err(&client->dev, "Failing to stop the clock\n");
return -EIO;
}
/* stop the clock */
ret |= PCF85063_REG_CTRL1_STOP;
ret = i2c_smbus_write_byte_data(client, PCF85063_REG_CTRL1, ret);
if (ret < 0) {
dev_err(&client->dev, "Failing to stop the clock\n");
return -EIO;
}
*ctrl1 = ret;
return 0;
}
/*
* In the routines that deal directly with the pcf85063 hardware, we use
* rtc_time -- month 0-11, hour 0-23, yr = calendar year-epoch.
*/
static int pcf85063_get_datetime(struct i2c_client *client, struct rtc_time *tm)
{
int rc;
u8 regs[7];
/*
* while reading, the time/date registers are blocked and not updated
* anymore until the access is finished. To not lose a second
* event, the access must be finished within one second. So, read all
* time/date registers in one turn.
*/
rc = i2c_smbus_read_i2c_block_data(client, PCF85063_REG_SC,
sizeof(regs), regs);
if (rc != sizeof(regs)) {
dev_err(&client->dev, "date/time register read error\n");
return -EIO;
}
/* if the clock has lost its power it makes no sense to use its time */
if (regs[0] & PCF85063_REG_SC_OS) {
dev_warn(&client->dev, "Power loss detected, invalid time\n");
return -EINVAL;
}
tm->tm_sec = bcd2bin(regs[0] & 0x7F);
tm->tm_min = bcd2bin(regs[1] & 0x7F);
tm->tm_hour = bcd2bin(regs[2] & 0x3F); /* rtc hr 0-23 */
tm->tm_mday = bcd2bin(regs[3] & 0x3F);
tm->tm_wday = regs[4] & 0x07;
tm->tm_mon = bcd2bin(regs[5] & 0x1F) - 1; /* rtc mn 1-12 */
tm->tm_year = bcd2bin(regs[6]);
if (tm->tm_year < 70)
tm->tm_year += 100; /* assume we are in 1970...2069 */
return rtc_valid_tm(tm);
}
static int pcf85063_set_datetime(struct i2c_client *client, struct rtc_time *tm)
{
int rc;
u8 regs[8];
/*
* to accurately set the time, reset the divider chain and keep it in
* reset state until all time/date registers are written
*/
rc = pcf85063_stop_clock(client, ®s[7]);
if (rc != 0)
return rc;
/* hours, minutes and seconds */
regs[0] = bin2bcd(tm->tm_sec) & 0x7F; /* clear OS flag */
regs[1] = bin2bcd(tm->tm_min);
regs[2] = bin2bcd(tm->tm_hour);
/* Day of month, 1 - 31 */
regs[3] = bin2bcd(tm->tm_mday);
/* Day, 0 - 6 */
regs[4] = tm->tm_wday & 0x07;
/* month, 1 - 12 */
regs[5] = bin2bcd(tm->tm_mon + 1);
/* year and century */
regs[6] = bin2bcd(tm->tm_year % 100);
/*
* after all time/date registers are written, let the 'address auto
* increment' feature wrap around and write register CTRL1 to re-enable
* the clock divider chain again
*/
regs[7] &= ~PCF85063_REG_CTRL1_STOP;
/* write all registers at once */
rc = i2c_smbus_write_i2c_block_data(client, PCF85063_REG_SC,
sizeof(regs), regs);
if (rc < 0) {
dev_err(&client->dev, "date/time register write error\n");
return rc;
}
return 0;
}
static int pcf85063_rtc_read_time(struct device *dev, struct rtc_time *tm)
{
return pcf85063_get_datetime(to_i2c_client(dev), tm);
}
static int pcf85063_rtc_set_time(struct device *dev, struct rtc_time *tm)
{
return pcf85063_set_datetime(to_i2c_client(dev), tm);
}
static const struct rtc_class_ops pcf85063_rtc_ops = {
.read_time = pcf85063_rtc_read_time,
.set_time = pcf85063_rtc_set_time
};
static int pcf85063_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
struct pcf85063 *pcf85063;
dev_dbg(&client->dev, "%s\n", __func__);
if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
return -ENODEV;
pcf85063 = devm_kzalloc(&client->dev, sizeof(struct pcf85063),
GFP_KERNEL);
if (!pcf85063)
return -ENOMEM;
i2c_set_clientdata(client, pcf85063);
pcf85063->rtc = devm_rtc_device_register(&client->dev,
pcf85063_driver.driver.name,
&pcf85063_rtc_ops, THIS_MODULE);
return PTR_ERR_OR_ZERO(pcf85063->rtc);
}
static const struct i2c_device_id pcf85063_id[] = {
{ "pcf85063", 0 },
{ }
};
MODULE_DEVICE_TABLE(i2c, pcf85063_id);
#ifdef CONFIG_OF
static const struct of_device_id pcf85063_of_match[] = {
{ .compatible = "nxp,pcf85063" },
{}
};
MODULE_DEVICE_TABLE(of, pcf85063_of_match);
#endif
static struct i2c_driver pcf85063_driver = {
.driver = {
.name = "rtc-pcf85063",
.of_match_table = of_match_ptr(pcf85063_of_match),
},
.probe = pcf85063_probe,
.id_table = pcf85063_id,
};
module_i2c_driver(pcf85063_driver);
MODULE_AUTHOR("Søren Andersen <san@rosetechnology.dk>");
MODULE_DESCRIPTION("PCF85063 RTC driver");
MODULE_LICENSE("GPL");
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