327 lines
6.8 KiB
C
327 lines
6.8 KiB
C
/*
|
|
* Copyright (C) 2012 Avionic Design GmbH
|
|
*
|
|
* 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/bcd.h>
|
|
#include <linux/i2c.h>
|
|
#include <linux/module.h>
|
|
#include <linux/rtc.h>
|
|
#include <linux/of.h>
|
|
|
|
#define DRIVER_NAME "rtc-pcf8523"
|
|
|
|
#define REG_CONTROL1 0x00
|
|
#define REG_CONTROL1_CAP_SEL (1 << 7)
|
|
#define REG_CONTROL1_STOP (1 << 5)
|
|
|
|
#define REG_CONTROL3 0x02
|
|
#define REG_CONTROL3_PM_BLD (1 << 7) /* battery low detection disabled */
|
|
#define REG_CONTROL3_PM_VDD (1 << 6) /* switch-over disabled */
|
|
#define REG_CONTROL3_PM_DSM (1 << 5) /* direct switching mode */
|
|
#define REG_CONTROL3_PM_MASK 0xe0
|
|
|
|
#define REG_SECONDS 0x03
|
|
#define REG_SECONDS_OS (1 << 7)
|
|
|
|
#define REG_MINUTES 0x04
|
|
#define REG_HOURS 0x05
|
|
#define REG_DAYS 0x06
|
|
#define REG_WEEKDAYS 0x07
|
|
#define REG_MONTHS 0x08
|
|
#define REG_YEARS 0x09
|
|
|
|
struct pcf8523 {
|
|
struct rtc_device *rtc;
|
|
};
|
|
|
|
static int pcf8523_read(struct i2c_client *client, u8 reg, u8 *valuep)
|
|
{
|
|
struct i2c_msg msgs[2];
|
|
u8 value = 0;
|
|
int err;
|
|
|
|
msgs[0].addr = client->addr;
|
|
msgs[0].flags = 0;
|
|
msgs[0].len = sizeof(reg);
|
|
msgs[0].buf = ®
|
|
|
|
msgs[1].addr = client->addr;
|
|
msgs[1].flags = I2C_M_RD;
|
|
msgs[1].len = sizeof(value);
|
|
msgs[1].buf = &value;
|
|
|
|
err = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
|
|
if (err < 0)
|
|
return err;
|
|
|
|
*valuep = value;
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int pcf8523_write(struct i2c_client *client, u8 reg, u8 value)
|
|
{
|
|
u8 buffer[2] = { reg, value };
|
|
struct i2c_msg msg;
|
|
int err;
|
|
|
|
msg.addr = client->addr;
|
|
msg.flags = 0;
|
|
msg.len = sizeof(buffer);
|
|
msg.buf = buffer;
|
|
|
|
err = i2c_transfer(client->adapter, &msg, 1);
|
|
if (err < 0)
|
|
return err;
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int pcf8523_select_capacitance(struct i2c_client *client, bool high)
|
|
{
|
|
u8 value;
|
|
int err;
|
|
|
|
err = pcf8523_read(client, REG_CONTROL1, &value);
|
|
if (err < 0)
|
|
return err;
|
|
|
|
if (!high)
|
|
value &= ~REG_CONTROL1_CAP_SEL;
|
|
else
|
|
value |= REG_CONTROL1_CAP_SEL;
|
|
|
|
err = pcf8523_write(client, REG_CONTROL1, value);
|
|
if (err < 0)
|
|
return err;
|
|
|
|
return err;
|
|
}
|
|
|
|
static int pcf8523_set_pm(struct i2c_client *client, u8 pm)
|
|
{
|
|
u8 value;
|
|
int err;
|
|
|
|
err = pcf8523_read(client, REG_CONTROL3, &value);
|
|
if (err < 0)
|
|
return err;
|
|
|
|
value = (value & ~REG_CONTROL3_PM_MASK) | pm;
|
|
|
|
err = pcf8523_write(client, REG_CONTROL3, value);
|
|
if (err < 0)
|
|
return err;
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int pcf8523_stop_rtc(struct i2c_client *client)
|
|
{
|
|
u8 value;
|
|
int err;
|
|
|
|
err = pcf8523_read(client, REG_CONTROL1, &value);
|
|
if (err < 0)
|
|
return err;
|
|
|
|
value |= REG_CONTROL1_STOP;
|
|
|
|
err = pcf8523_write(client, REG_CONTROL1, value);
|
|
if (err < 0)
|
|
return err;
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int pcf8523_start_rtc(struct i2c_client *client)
|
|
{
|
|
u8 value;
|
|
int err;
|
|
|
|
err = pcf8523_read(client, REG_CONTROL1, &value);
|
|
if (err < 0)
|
|
return err;
|
|
|
|
value &= ~REG_CONTROL1_STOP;
|
|
|
|
err = pcf8523_write(client, REG_CONTROL1, value);
|
|
if (err < 0)
|
|
return err;
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int pcf8523_rtc_read_time(struct device *dev, struct rtc_time *tm)
|
|
{
|
|
struct i2c_client *client = to_i2c_client(dev);
|
|
u8 start = REG_SECONDS, regs[7];
|
|
struct i2c_msg msgs[2];
|
|
int err;
|
|
|
|
msgs[0].addr = client->addr;
|
|
msgs[0].flags = 0;
|
|
msgs[0].len = 1;
|
|
msgs[0].buf = &start;
|
|
|
|
msgs[1].addr = client->addr;
|
|
msgs[1].flags = I2C_M_RD;
|
|
msgs[1].len = sizeof(regs);
|
|
msgs[1].buf = regs;
|
|
|
|
err = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
|
|
if (err < 0)
|
|
return err;
|
|
|
|
if (regs[0] & REG_SECONDS_OS) {
|
|
/*
|
|
* If the oscillator was stopped, try to clear the flag. Upon
|
|
* power-up the flag is always set, but if we cannot clear it
|
|
* the oscillator isn't running properly for some reason. The
|
|
* sensible thing therefore is to return an error, signalling
|
|
* that the clock cannot be assumed to be correct.
|
|
*/
|
|
|
|
regs[0] &= ~REG_SECONDS_OS;
|
|
|
|
err = pcf8523_write(client, REG_SECONDS, regs[0]);
|
|
if (err < 0)
|
|
return err;
|
|
|
|
err = pcf8523_read(client, REG_SECONDS, ®s[0]);
|
|
if (err < 0)
|
|
return err;
|
|
|
|
if (regs[0] & REG_SECONDS_OS)
|
|
return -EAGAIN;
|
|
}
|
|
|
|
tm->tm_sec = bcd2bin(regs[0] & 0x7f);
|
|
tm->tm_min = bcd2bin(regs[1] & 0x7f);
|
|
tm->tm_hour = bcd2bin(regs[2] & 0x3f);
|
|
tm->tm_mday = bcd2bin(regs[3] & 0x3f);
|
|
tm->tm_wday = regs[4] & 0x7;
|
|
tm->tm_mon = bcd2bin(regs[5] & 0x1f);
|
|
tm->tm_year = bcd2bin(regs[6]) + 100;
|
|
|
|
return rtc_valid_tm(tm);
|
|
}
|
|
|
|
static int pcf8523_rtc_set_time(struct device *dev, struct rtc_time *tm)
|
|
{
|
|
struct i2c_client *client = to_i2c_client(dev);
|
|
struct i2c_msg msg;
|
|
u8 regs[8];
|
|
int err;
|
|
|
|
err = pcf8523_stop_rtc(client);
|
|
if (err < 0)
|
|
return err;
|
|
|
|
regs[0] = REG_SECONDS;
|
|
regs[1] = bin2bcd(tm->tm_sec);
|
|
regs[2] = bin2bcd(tm->tm_min);
|
|
regs[3] = bin2bcd(tm->tm_hour);
|
|
regs[4] = bin2bcd(tm->tm_mday);
|
|
regs[5] = tm->tm_wday;
|
|
regs[6] = bin2bcd(tm->tm_mon);
|
|
regs[7] = bin2bcd(tm->tm_year - 100);
|
|
|
|
msg.addr = client->addr;
|
|
msg.flags = 0;
|
|
msg.len = sizeof(regs);
|
|
msg.buf = regs;
|
|
|
|
err = i2c_transfer(client->adapter, &msg, 1);
|
|
if (err < 0) {
|
|
/*
|
|
* If the time cannot be set, restart the RTC anyway. Note
|
|
* that errors are ignored if the RTC cannot be started so
|
|
* that we have a chance to propagate the original error.
|
|
*/
|
|
pcf8523_start_rtc(client);
|
|
return err;
|
|
}
|
|
|
|
return pcf8523_start_rtc(client);
|
|
}
|
|
|
|
static const struct rtc_class_ops pcf8523_rtc_ops = {
|
|
.read_time = pcf8523_rtc_read_time,
|
|
.set_time = pcf8523_rtc_set_time,
|
|
};
|
|
|
|
static int pcf8523_probe(struct i2c_client *client,
|
|
const struct i2c_device_id *id)
|
|
{
|
|
struct pcf8523 *pcf;
|
|
int err;
|
|
|
|
if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
|
|
return -ENODEV;
|
|
|
|
pcf = devm_kzalloc(&client->dev, sizeof(*pcf), GFP_KERNEL);
|
|
if (!pcf)
|
|
return -ENOMEM;
|
|
|
|
err = pcf8523_select_capacitance(client, true);
|
|
if (err < 0)
|
|
return err;
|
|
|
|
err = pcf8523_set_pm(client, 0);
|
|
if (err < 0)
|
|
return err;
|
|
|
|
pcf->rtc = rtc_device_register(DRIVER_NAME, &client->dev,
|
|
&pcf8523_rtc_ops, THIS_MODULE);
|
|
if (IS_ERR(pcf->rtc))
|
|
return PTR_ERR(pcf->rtc);
|
|
|
|
i2c_set_clientdata(client, pcf);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int pcf8523_remove(struct i2c_client *client)
|
|
{
|
|
struct pcf8523 *pcf = i2c_get_clientdata(client);
|
|
|
|
rtc_device_unregister(pcf->rtc);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static const struct i2c_device_id pcf8523_id[] = {
|
|
{ "pcf8523", 0 },
|
|
{ }
|
|
};
|
|
MODULE_DEVICE_TABLE(i2c, pcf8523_id);
|
|
|
|
#ifdef CONFIG_OF
|
|
static const struct of_device_id pcf8523_of_match[] = {
|
|
{ .compatible = "nxp,pcf8523" },
|
|
{ }
|
|
};
|
|
MODULE_DEVICE_TABLE(of, pcf8523_of_match);
|
|
#endif
|
|
|
|
static struct i2c_driver pcf8523_driver = {
|
|
.driver = {
|
|
.name = DRIVER_NAME,
|
|
.owner = THIS_MODULE,
|
|
.of_match_table = of_match_ptr(pcf8523_of_match),
|
|
},
|
|
.probe = pcf8523_probe,
|
|
.remove = pcf8523_remove,
|
|
.id_table = pcf8523_id,
|
|
};
|
|
module_i2c_driver(pcf8523_driver);
|
|
|
|
MODULE_AUTHOR("Thierry Reding <thierry.reding@avionic-design.de>");
|
|
MODULE_DESCRIPTION("NXP PCF8523 RTC driver");
|
|
MODULE_LICENSE("GPL v2");
|