mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-25 18:30:06 +00:00
![Mirza Krak](/assets/img/avatar_default.png)
Add a sanity check to see if chip is present. If we can not communicate with the chip there is no point in registering a RTC device. Signed-off-by: Mirza Krak <mirza.krak@hostmobility.com> Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
241 lines
5.9 KiB
C
241 lines
5.9 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;
|
|
int err;
|
|
|
|
dev_dbg(&client->dev, "%s\n", __func__);
|
|
|
|
if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
|
|
return -ENODEV;
|
|
|
|
err = i2c_smbus_read_byte_data(client, PCF85063_REG_CTRL1);
|
|
if (err < 0) {
|
|
dev_err(&client->dev, "RTC chip is not present\n");
|
|
return err;
|
|
}
|
|
|
|
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");
|