You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
232 lines
6.1 KiB
232 lines
6.1 KiB
/* |
|
* 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);
|
|
|