linux/drivers/rtc/rtc-pcf85063.c
Chris DeBruin 0d981f81e0 rtc: pcf85063: Add support for the PCF85063A device
The current rtc-pcf85063 driver only supports the PCF85063TP device.
Using the existing driver on a PCF85063A will result in the time being
set correctly into the RTC, but the RTC is held in the stopped state.
Therefore, the time will no longer advance and no error is indicated.

The PCF85063A device has a bigger memory map than the PCF85063TP.
The existing driver make use of an address rollover condition,
but the rollover point is different in the two devices.

Signed-off-by: Chris DeBruin <cdeb5783@gmail.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
2016-07-19 19:11:54 +02:00

235 lines
5.7 KiB
C

/*
* 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>
/*
* Information for this driver was pulled from the following datasheets.
*
* http://www.nxp.com/documents/data_sheet/PCF85063A.pdf
* http://www.nxp.com/documents/data_sheet/PCF85063TP.pdf
*
* PCF85063A -- Rev. 6 — 18 November 2015
* PCF85063TP -- Rev. 4 — 6 May 2015
*/
#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;
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;
}
static int pcf85063_start_clock(struct i2c_client *client, u8 ctrl1)
{
s32 ret;
/* start the clock */
ctrl1 &= PCF85063_REG_CTRL1_STOP;
ret = i2c_smbus_write_byte_data(client, PCF85063_REG_CTRL1, ctrl1);
if (ret < 0) {
dev_err(&client->dev, "Failing to start the clock\n");
return -EIO;
}
return 0;
}
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]);
tm->tm_year += 100;
return rtc_valid_tm(tm);
}
static int pcf85063_set_datetime(struct i2c_client *client, struct rtc_time *tm)
{
int rc;
u8 regs[7];
u8 ctrl1;
if ((tm->tm_year < 100) || (tm->tm_year > 199))
return -EINVAL;
/*
* 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, &ctrl1);
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);
/* 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;
}
/*
* Write the control register as a separate action since the size of
* the register space is different between the PCF85063TP and
* PCF85063A devices. The rollover point can not be used.
*/
rc = pcf85063_start_clock(client, ctrl1);
if (rc != 0)
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 rtc_device *rtc;
dev_dbg(&client->dev, "%s\n", __func__);
if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
return -ENODEV;
rtc = devm_rtc_device_register(&client->dev,
pcf85063_driver.driver.name,
&pcf85063_rtc_ops, THIS_MODULE);
return PTR_ERR_OR_ZERO(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");