Part Number: AM3354
Tool/software: Linux
Hello,
We are using custom board with AM3354 (TI SDK 04.02).
We are facing an issue with RTC driver.
If we set the time and date as "30th July 2018 11:55 PM" (just before midnight), and power it off immediately, wait for more than 5 min ensuring RTC will change the date, after power on, the date jumps to future date or past date.
We observed this for 30th July, 30th May only. It works well for 30th August or any other dates.
Failed Scenario (Consistent):
Step-1: Set the time at "30th July 2018 11:55 PM".
Step-2: Power off the board.
Step-3: After 12 minutes, power on, the time and date is not proper (May go for future date or Past date)
Board 1: Sample Output after 12 min: "26th July 2018 10:15 AM"
Board 2: Sample Output after 12 min: "12th Aug 2018 00:15 AM"
Board 3: Sample Output after 12 min: "01st Aug 2018 00:07 AM"
Success Scenario:
Step-1: Set the time at "20th July 2018 11:55 PM".
Step-2: Power off the board.
Step-3: After 12 minutes, power on, the time and date is Proper i.e. "21st July 2018 00:07 AM"
FYI --> battery is working fine.Issue happens if we switch off the board just before midnight on 30th July. If we don't switch it off, it works well (date changes to 31st July).
The RTC driver we are using is attached.
Kindly support !
Thanks,
Thejes
/*
* SPI Driver for Microchip MCP795 RTC
*
* Copyright (C) Josef Gajdusek <atx@atx.name>
*
* based on other Linux RTC drivers
*
* Device datasheet:
* http://ww1.microchip.com/downloads/en/DeviceDoc/22280A.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/module.h>
#include <linux/kernel.h>
#include <linux/device.h>
#include <linux/printk.h>
#include <linux/spi/spi.h>
#include <linux/rtc.h>
#include <linux/of.h>
/* lnt changes */ /*goutham*/
#include <linux/io.h>
#include <linux/of.h>
/* MCP795 Instructions, see datasheet table 3-1 */
#define MCP795_EEREAD 0x03
#define MCP795_EEWRITE 0x02
#define MCP795_EEWRDI 0x04
#define MCP795_EEWREN 0x06
#define MCP795_SRREAD 0x05
#define MCP795_SRWRITE 0x01
#define MCP795_READ 0x13
#define MCP795_WRITE 0x12
#define MCP795_UNLOCK 0x14
#define MCP795_IDWRITE 0x32
#define MCP795_IDREAD 0x33
#define MCP795_CLRWDT 0x44
#define MCP795_CLRRAM 0x54
#define MCP795_ST_BIT 0x80
#define MCP795_24_BIT 0x40
/* lnt changes */ /*goutham*/
#define MCP795_VBATEN_BIT 0x08
#define MCP795_VBAT_BIT 0x10
static int mcp795_rtcc_read(struct device *dev, u8 addr, u8 *buf, u8 count)
{
struct spi_device *spi = to_spi_device(dev);
int ret;
u8 tx[2];
tx[0] = MCP795_READ;
tx[1] = addr;
ret = spi_write_then_read(spi, tx, sizeof(tx), buf, count);
if (ret)
dev_err(dev, "Failed reading %d bytes from address %x.\n",
count, addr);
return ret;
}
static int mcp795_rtcc_write(struct device *dev, u8 addr, u8 *data, u8 count)
{
struct spi_device *spi = to_spi_device(dev);
int ret;
u8 tx[2 + count];
tx[0] = MCP795_WRITE;
tx[1] = addr;
memcpy(&tx[2], data, count);
ret = spi_write(spi, tx, 2 + count);
if (ret)
dev_err(dev, "Failed to write %d bytes to address %x.\n",
count, addr);
return ret;
}
static int mcp795_rtcc_set_bits(struct device *dev, u8 addr, u8 mask, u8 state)
{
int ret;
u8 tmp;
ret = mcp795_rtcc_read(dev, addr, &tmp, 1);
if (ret)
return ret;
if ((tmp & mask) != state) {
tmp = (tmp & ~mask) | state;
ret = mcp795_rtcc_write(dev, addr, &tmp, 1);
}
return ret;
}
static int mcp795_set_time(struct device *dev, struct rtc_time *tim)
{
int ret;
u8 data[7];
/* Read first, so we can leave config bits untouched */
ret = mcp795_rtcc_read(dev, 0x01, data, sizeof(data));
if (ret)
return ret;
data[0] = (data[0] & 0x80) | ((tim->tm_sec / 10) << 4) | (tim->tm_sec % 10);
data[1] = (data[1] & 0x80) | ((tim->tm_min / 10) << 4) | (tim->tm_min % 10);
data[2] = ((tim->tm_hour / 10) << 4) | (tim->tm_hour % 10);
data[4] = ((tim->tm_mday / 10) << 4) | ((tim->tm_mday) % 10);
//data[5] = (data[5] & 0x10) | (tim->tm_mon / 10) | (tim->tm_mon % 10); /*goutham*/
data[5] = (data[5] & 0x10) | ((tim->tm_mon / 10) << 4) | (tim->tm_mon % 10);
if (tim->tm_year > 100)
tim->tm_year -= 100;
data[6] = ((tim->tm_year / 10) << 4) | (tim->tm_year % 10);
ret = mcp795_rtcc_write(dev, 0x01, data, sizeof(data));
if (ret)
return ret;
//Commented by guru to debug
dev_dbg(dev, "Set mcp795: %04d-%02d-%02d %02d:%02d:%02d\n",
tim->tm_year + 1900, tim->tm_mon, tim->tm_mday,
tim->tm_hour, tim->tm_min, tim->tm_sec);
dev_err(dev, "Write RTC called.....!!!!!\n" );
return 0;
}
static int mcp795_read_time(struct device *dev, struct rtc_time *tim)
{
int ret;
u8 data[7];
ret = mcp795_rtcc_read(dev, 0x01, data, sizeof(data));
if (ret)
return ret;
tim->tm_sec = ((data[0] & 0x70) >> 4) * 10 + (data[0] & 0x0f);
tim->tm_min = ((data[1] & 0x70) >> 4) * 10 + (data[1] & 0x0f);
tim->tm_hour = ((data[2] & 0x30) >> 4) * 10 + (data[2] & 0x0f);
tim->tm_mday = ((data[4] & 0x30) >> 4) * 10 + (data[4] & 0x0f);
tim->tm_mon = ((data[5] & 0x10) >> 4) * 10 + (data[5] & 0x0f);
tim->tm_year = ((data[6] & 0xf0) >> 4) * 10 + (data[6] & 0x0f) + 100; /* Assume we are in 20xx */
dev_err(dev, "Read RTC called....!!!!\n" );
dev_dbg(dev, "Read from mcp795: %04d-%02d-%02d %02d:%02d:%02d\n",
tim->tm_year + 1900, tim->tm_mon, tim->tm_mday,
tim->tm_hour, tim->tm_min, tim->tm_sec);
return rtc_valid_tm(tim);
}
/* LNT changes */ /*goutham*/
#ifdef CONFIG_OF
static const struct of_device_id mcp795_rtc_match[] = {
{ .compatible = "microchip,mcp795-rtc", },
{},
};
MODULE_DEVICE_TABLE(of, mcp795_rtc_match);
#endif
static const struct rtc_class_ops mcp795_rtc_ops = {
.read_time = mcp795_read_time,
.set_time = mcp795_set_time
};
static int mcp795_probe(struct spi_device *spi)
{
struct rtc_device *rtc;
int ret;
spi->mode = SPI_MODE_0;
spi->bits_per_word = 8;
ret = spi_setup(spi);
if (ret) {
dev_err(&spi->dev, "Unable to setup SPI\n");
return ret;
}
dev_err(&spi->dev, "SPI-RTC setup done....\n");
/* Start the oscillator */
mcp795_rtcc_set_bits(&spi->dev, 0x01, MCP795_ST_BIT, MCP795_ST_BIT);
/* Clear the 12 hour mode flag*/
mcp795_rtcc_set_bits(&spi->dev, 0x03, MCP795_24_BIT, 0);
/* Enable VBATEN Bit to use the Battery supply in the absence of Vcc TEN_BIT */ /*goutham*/
mcp795_rtcc_set_bits(&spi->dev, 0x04, MCP795_VBATEN_BIT, MCP795_VBATEN_BIT);
/* clear VBAT Bit to use acknowledge the VCC powerfail */
mcp795_rtcc_set_bits(&spi->dev, 0x04, MCP795_VBAT_BIT, 0);
rtc = devm_rtc_device_register(&spi->dev, "rtc-mcp795",
&mcp795_rtc_ops, THIS_MODULE);
if (IS_ERR(rtc))
return PTR_ERR(rtc);
spi_set_drvdata(spi, rtc);
return 0;
}
#ifdef CONFIG_OF
static const struct of_device_id mcp795_of_match[] = {
{ .compatible = "maxim,mcp795" },
{ }
};
MODULE_DEVICE_TABLE(of, mcp795_of_match);
#endif
static struct spi_driver mcp795_driver = {
/* .driver = { *goutham*
.name = "rtc-mcp795",
.of_match_table = of_match_ptr(mcp795_of_match),
},
.probe = mcp795_probe,*/
.driver = {
.name = "rtc-mcp795",
.of_match_table = of_match_ptr(mcp795_rtc_match),
},
.probe = mcp795_probe,
};
module_spi_driver(mcp795_driver);
MODULE_DESCRIPTION("MCP795 RTC SPI Driver");
MODULE_AUTHOR("Josef Gajdusek <atx@atx.name>");
MODULE_LICENSE("GPL");
MODULE_ALIAS("spi:mcp795");
