- 根目录:
- drivers
- rtc
- rtc-pcf2127.c
/*
* An I2C driver for the NXP PCF2127 RTC
* Copyright 2013 Til-Technologies
*
* Author: Renaud Cerrato <r.cerrato@til-technologies.fr>
*
* based on the other drivers in this same directory.
*
* http://www.nxp.com/documents/data_sheet/PCF2127AT.pdf
*
* 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/slab.h>
#include <linux/module.h>
#include <linux/of.h>
#define DRV_VERSION "0.0.1"
#define PCF2127_REG_CTRL1 (0x00) /* Control Register 1 */
#define PCF2127_REG_CTRL2 (0x01) /* Control Register 2 */
#define PCF2127_REG_CTRL3 (0x02) /* Control Register 3 */
#define PCF2127_REG_SC (0x03) /* datetime */
#define PCF2127_REG_MN (0x04)
#define PCF2127_REG_HR (0x05)
#define PCF2127_REG_DM (0x06)
#define PCF2127_REG_DW (0x07)
#define PCF2127_REG_MO (0x08)
#define PCF2127_REG_YR (0x09)
static struct i2c_driver pcf2127_driver;
struct pcf2127 {
struct rtc_device *rtc;
int voltage_low; /* indicates if a low_voltage was detected */
};
/*
* In the routines that deal directly with the pcf2127 hardware, we use
* rtc_time -- month 0-11, hour 0-23, yr = calendar year-epoch.
*/
static int pcf2127_get_datetime(struct i2c_client *client, struct rtc_time *tm)
{
struct pcf2127 *pcf2127 = i2c_get_clientdata(client);
unsigned char buf[10] = { PCF2127_REG_CTRL1 };
/* read registers */
if (i2c_master_send(client, buf, 1) != 1 ||
i2c_master_recv(client, buf, sizeof(buf)) != sizeof(buf)) {
dev_err(&client->dev, "%s: read error\n", __func__);
return -EIO;
}
if (buf[PCF2127_REG_CTRL3] & 0x04) {
pcf2127->voltage_low = 1;
dev_info(&client->dev,
"low voltage detected, date/time is not reliable.\n");
}
dev_dbg(&client->dev,
"%s: raw data is cr1=%02x, cr2=%02x, cr3=%02x, "
"sec=%02x, min=%02x, hr=%02x, "
"mday=%02x, wday=%02x, mon=%02x, year=%02x\n",
__func__,
buf[0], buf[1], buf[2],
buf[3], buf[4], buf[5],
buf[6], buf[7], buf[8], buf[9]);
tm->tm_sec = bcd2bin(buf[PCF2127_REG_SC] & 0x7F);
tm->tm_min = bcd2bin(buf[PCF2127_REG_MN] & 0x7F);
tm->tm_hour = bcd2bin(buf[PCF2127_REG_HR] & 0x3F); /* rtc hr 0-23 */
tm->tm_mday = bcd2bin(buf[PCF2127_REG_DM] & 0x3F);
tm->tm_wday = buf[PCF2127_REG_DW] & 0x07;
tm->tm_mon = bcd2bin(buf[PCF2127_REG_MO] & 0x1F) - 1; /* rtc mn 1-12 */
tm->tm_year = bcd2bin(buf[PCF2127_REG_YR]);
if (tm->tm_year < 70)
tm->tm_year += 100; /* assume we are in 1970...2069 */
dev_dbg(&client->dev, "%s: tm is secs=%d, mins=%d, hours=%d, "
"mday=%d, mon=%d, year=%d, wday=%d\n",
__func__,
tm->tm_sec, tm->tm_min, tm->tm_hour,
tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
/* the clock can give out invalid datetime, but we cannot return
* -EINVAL otherwise hwclock will refuse to set the time on bootup.
*/
if (rtc_valid_tm(tm) < 0)
dev_err(&client->dev, "retrieved date/time is not valid.\n");
return 0;
}
static int pcf2127_set_datetime(struct i2c_client *client, struct rtc_time *tm)
{
unsigned char buf[8];
int i = 0, err;
dev_dbg(&client->dev, "%s: secs=%d, mins=%d, hours=%d, "
"mday=%d, mon=%d, year=%d, wday=%d\n",
__func__,
tm->tm_sec, tm->tm_min, tm->tm_hour,
tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
/* start register address */
buf[i++] = PCF2127_REG_SC;
/* hours, minutes and seconds */
buf[i++] = bin2bcd(tm->tm_sec);
buf[i++] = bin2bcd(tm->tm_min);
buf[i++] = bin2bcd(tm->tm_hour);
buf[i++] = bin2bcd(tm->tm_mday);
buf[i++] = tm->tm_wday & 0x07;
/* month, 1 - 12 */
buf[i++] = bin2bcd(tm->tm_mon + 1);
/* year */
buf[i++] = bin2bcd(tm->tm_year % 100);
/* write register's data */
err = i2c_master_send(client, buf, i);
if (err != i) {
dev_err(&client->dev,
"%s: err=%d", __func__, err);
return -EIO;
}
return 0;
}
#ifdef CONFIG_RTC_INTF_DEV
static int pcf2127_rtc_ioctl(struct device *dev,
unsigned int cmd, unsigned long arg)
{
struct pcf2127 *pcf2127 = i2c_get_clientdata(to_i2c_client(dev));
switch (cmd) {
case RTC_VL_READ:
if (pcf2127->voltage_low)
dev_info(dev, "low voltage detected, date/time is not reliable.\n");
if (copy_to_user((void __user *)arg, &pcf2127->voltage_low,
sizeof(int)))
return -EFAULT;
return 0;
default:
return -ENOIOCTLCMD;
}
}
#else
#define pcf2127_rtc_ioctl NULL
#endif
static int pcf2127_rtc_read_time(struct device *dev, struct rtc_time *tm)
{
return pcf2127_get_datetime(to_i2c_client(dev), tm);
}
static int pcf2127_rtc_set_time(struct device *dev, struct rtc_time *tm)
{
return pcf2127_set_datetime(to_i2c_client(dev), tm);
}
static const struct rtc_class_ops pcf2127_rtc_ops = {
.ioctl = pcf2127_rtc_ioctl,
.read_time = pcf2127_rtc_read_time,
.set_time = pcf2127_rtc_set_time,
};
static int pcf2127_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
struct pcf2127 *pcf2127;
dev_dbg(&client->dev, "%s\n", __func__);
if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
return -ENODEV;
pcf2127 = devm_kzalloc(&client->dev, sizeof(struct pcf2127),
GFP_KERNEL);
if (!pcf2127)
return -ENOMEM;
dev_info(&client->dev, "chip found, driver version " DRV_VERSION "\n");
i2c_set_clientdata(client, pcf2127);
pcf2127->rtc = devm_rtc_device_register(&client->dev,
pcf2127_driver.driver.name,
&pcf2127_rtc_ops, THIS_MODULE);
return PTR_ERR_OR_ZERO(pcf2127->rtc);
}
static const struct i2c_device_id pcf2127_id[] = {
{ "pcf2127", 0 },
{ }
};
MODULE_DEVICE_TABLE(i2c, pcf2127_id);
#ifdef CONFIG_OF
static const struct of_device_id pcf2127_of_match[] = {
{ .compatible = "nxp,pcf2127" },
{}
};
MODULE_DEVICE_TABLE(of, pcf2127_of_match);
#endif
static struct i2c_driver pcf2127_driver = {
.driver = {
.name = "rtc-pcf2127",
.owner = THIS_MODULE,
.of_match_table = of_match_ptr(pcf2127_of_match),
},
.probe = pcf2127_probe,
.id_table = pcf2127_id,
};
module_i2c_driver(pcf2127_driver);
MODULE_AUTHOR("Renaud Cerrato <r.cerrato@til-technologies.fr>");
MODULE_DESCRIPTION("NXP PCF2127 RTC driver");
MODULE_LICENSE("GPL");
MODULE_VERSION(DRV_VERSION);