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u-boot/drivers/rtc/ds1307.c
Chris Packham c1a2afa408 rtc: ds1307: remove redundant code in rtc_reset 
As of commit 1a1fa2406689 ("rtc: Set valid date after reset") the
command "date reset" will set the date/time to 2000-01-01 0:00:00 after
calling rtc_reset(). This means that the ds1307 implementation of
rtc_reset() doesn't need to call rtc_set().

Signed-off-by: Chris Packham <judge.packham@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
2018-04-06 20:45:44 -04:00

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/*
* (C) Copyright 2001, 2002, 2003
* Wolfgang Denk, DENX Software Engineering, wd@denx.de.
* Keith Outwater, keith_outwater@mvis.com`
* Steven Scholz, steven.scholz@imc-berlin.de
*
* SPDX-License-Identifier: GPL-2.0+
*/
/*
* Date & Time support (no alarms) for Dallas Semiconductor (now Maxim)
* DS1307 and DS1338/9 Real Time Clock (RTC).
*
* based on ds1337.c
*/
#include <common.h>
#include <command.h>
#include <dm.h>
#include <rtc.h>
#include <i2c.h>
enum ds_type {
ds_1307,
ds_1337,
ds_1340,
mcp794xx,
};
/*
* RTC register addresses
*/
#define RTC_SEC_REG_ADDR 0x00
#define RTC_MIN_REG_ADDR 0x01
#define RTC_HR_REG_ADDR 0x02
#define RTC_DAY_REG_ADDR 0x03
#define RTC_DATE_REG_ADDR 0x04
#define RTC_MON_REG_ADDR 0x05
#define RTC_YR_REG_ADDR 0x06
#define RTC_CTL_REG_ADDR 0x07
#define RTC_SEC_BIT_CH 0x80 /* Clock Halt (in Register 0) */
#define RTC_CTL_BIT_RS0 0x01 /* Rate select 0 */
#define RTC_CTL_BIT_RS1 0x02 /* Rate select 1 */
#define RTC_CTL_BIT_SQWE 0x10 /* Square Wave Enable */
#define RTC_CTL_BIT_OUT 0x80 /* Output Control */
/* MCP7941X-specific bits */
#define MCP7941X_BIT_ST 0x80
#define MCP7941X_BIT_VBATEN 0x08
#ifndef CONFIG_DM_RTC
#if defined(CONFIG_CMD_DATE)
/*---------------------------------------------------------------------*/
#undef DEBUG_RTC
#ifdef DEBUG_RTC
#define DEBUGR(fmt, args...) printf(fmt, ##args)
#else
#define DEBUGR(fmt, args...)
#endif
/*---------------------------------------------------------------------*/
#ifndef CONFIG_SYS_I2C_RTC_ADDR
# define CONFIG_SYS_I2C_RTC_ADDR 0x68
#endif
#if defined(CONFIG_RTC_DS1307) && (CONFIG_SYS_I2C_SPEED > 100000)
# error The DS1307 is specified only up to 100kHz!
#endif
static uchar rtc_read (uchar reg);
static void rtc_write (uchar reg, uchar val);
/*
* Get the current time from the RTC
*/
int rtc_get (struct rtc_time *tmp)
{
int rel = 0;
uchar sec, min, hour, mday, wday, mon, year;
#ifdef CONFIG_RTC_MCP79411
read_rtc:
#endif
sec = rtc_read (RTC_SEC_REG_ADDR);
min = rtc_read (RTC_MIN_REG_ADDR);
hour = rtc_read (RTC_HR_REG_ADDR);
wday = rtc_read (RTC_DAY_REG_ADDR);
mday = rtc_read (RTC_DATE_REG_ADDR);
mon = rtc_read (RTC_MON_REG_ADDR);
year = rtc_read (RTC_YR_REG_ADDR);
DEBUGR ("Get RTC year: %02x mon: %02x mday: %02x wday: %02x "
"hr: %02x min: %02x sec: %02x\n",
year, mon, mday, wday, hour, min, sec);
#ifdef CONFIG_RTC_DS1307
if (sec & RTC_SEC_BIT_CH) {
printf ("### Warning: RTC oscillator has stopped\n");
/* clear the CH flag */
rtc_write (RTC_SEC_REG_ADDR,
rtc_read (RTC_SEC_REG_ADDR) & ~RTC_SEC_BIT_CH);
rel = -1;
}
#endif
#ifdef CONFIG_RTC_MCP79411
/* make sure that the backup battery is enabled */
if (!(wday & MCP7941X_BIT_VBATEN)) {
rtc_write(RTC_DAY_REG_ADDR,
wday | MCP7941X_BIT_VBATEN);
}
/* clock halted? turn it on, so clock can tick. */
if (!(sec & MCP7941X_BIT_ST)) {
rtc_write(RTC_SEC_REG_ADDR, MCP7941X_BIT_ST);
printf("Started RTC\n");
goto read_rtc;
}
#endif
tmp->tm_sec = bcd2bin (sec & 0x7F);
tmp->tm_min = bcd2bin (min & 0x7F);
tmp->tm_hour = bcd2bin (hour & 0x3F);
tmp->tm_mday = bcd2bin (mday & 0x3F);
tmp->tm_mon = bcd2bin (mon & 0x1F);
tmp->tm_year = bcd2bin (year) + ( bcd2bin (year) >= 70 ? 1900 : 2000);
tmp->tm_wday = bcd2bin ((wday - 1) & 0x07);
tmp->tm_yday = 0;
tmp->tm_isdst= 0;
DEBUGR ("Get DATE: %4d-%02d-%02d (wday=%d) TIME: %2d:%02d:%02d\n",
tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday,
tmp->tm_hour, tmp->tm_min, tmp->tm_sec);
return rel;
}
/*
* Set the RTC
*/
int rtc_set (struct rtc_time *tmp)
{
DEBUGR ("Set DATE: %4d-%02d-%02d (wday=%d) TIME: %2d:%02d:%02d\n",
tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday,
tmp->tm_hour, tmp->tm_min, tmp->tm_sec);
if (tmp->tm_year < 1970 || tmp->tm_year > 2069)
printf("WARNING: year should be between 1970 and 2069!\n");
rtc_write (RTC_YR_REG_ADDR, bin2bcd (tmp->tm_year % 100));
rtc_write (RTC_MON_REG_ADDR, bin2bcd (tmp->tm_mon));
#ifdef CONFIG_RTC_MCP79411
rtc_write (RTC_DAY_REG_ADDR,
bin2bcd (tmp->tm_wday + 1) | MCP7941X_BIT_VBATEN);
#else
rtc_write (RTC_DAY_REG_ADDR, bin2bcd (tmp->tm_wday + 1));
#endif
rtc_write (RTC_DATE_REG_ADDR, bin2bcd (tmp->tm_mday));
rtc_write (RTC_HR_REG_ADDR, bin2bcd (tmp->tm_hour));
rtc_write (RTC_MIN_REG_ADDR, bin2bcd (tmp->tm_min));
#ifdef CONFIG_RTC_MCP79411
rtc_write (RTC_SEC_REG_ADDR, bin2bcd (tmp->tm_sec) | MCP7941X_BIT_ST);
#else
rtc_write (RTC_SEC_REG_ADDR, bin2bcd (tmp->tm_sec));
#endif
return 0;
}
/*
* Reset the RTC. We setting the date back to 1970-01-01.
* We also enable the oscillator output on the SQW/OUT pin and program
* it for 32,768 Hz output. Note that according to the datasheet, turning
* on the square wave output increases the current drain on the backup
* battery to something between 480nA and 800nA.
*/
void rtc_reset (void)
{
rtc_write (RTC_SEC_REG_ADDR, 0x00); /* clearing Clock Halt */
rtc_write (RTC_CTL_REG_ADDR, RTC_CTL_BIT_SQWE | RTC_CTL_BIT_RS1 | RTC_CTL_BIT_RS0);
}
/*
* Helper functions
*/
static
uchar rtc_read (uchar reg)
{
return (i2c_reg_read (CONFIG_SYS_I2C_RTC_ADDR, reg));
}
static void rtc_write (uchar reg, uchar val)
{
i2c_reg_write (CONFIG_SYS_I2C_RTC_ADDR, reg, val);
}
#endif /* CONFIG_CMD_DATE*/
#endif /* !CONFIG_DM_RTC */
#ifdef CONFIG_DM_RTC
static int ds1307_rtc_set(struct udevice *dev, const struct rtc_time *tm)
{
int ret;
uchar buf[7];
enum ds_type type = dev_get_driver_data(dev);
debug("Set DATE: %4d-%02d-%02d (wday=%d) TIME: %2d:%02d:%02d\n",
tm->tm_year, tm->tm_mon, tm->tm_mday, tm->tm_wday,
tm->tm_hour, tm->tm_min, tm->tm_sec);
if (tm->tm_year < 1970 || tm->tm_year > 2069)
printf("WARNING: year should be between 1970 and 2069!\n");
buf[RTC_YR_REG_ADDR] = bin2bcd(tm->tm_year % 100);
buf[RTC_MON_REG_ADDR] = bin2bcd(tm->tm_mon);
buf[RTC_DAY_REG_ADDR] = bin2bcd(tm->tm_wday + 1);
buf[RTC_DATE_REG_ADDR] = bin2bcd(tm->tm_mday);
buf[RTC_HR_REG_ADDR] = bin2bcd(tm->tm_hour);
buf[RTC_MIN_REG_ADDR] = bin2bcd(tm->tm_min);
buf[RTC_SEC_REG_ADDR] = bin2bcd(tm->tm_sec);
if (type == mcp794xx) {
buf[RTC_DAY_REG_ADDR] |= MCP7941X_BIT_VBATEN;
buf[RTC_SEC_REG_ADDR] |= MCP7941X_BIT_ST;
}
ret = dm_i2c_write(dev, 0, buf, sizeof(buf));
if (ret < 0)
return ret;
return 0;
}
static int ds1307_rtc_get(struct udevice *dev, struct rtc_time *tm)
{
int ret;
uchar buf[7];
enum ds_type type = dev_get_driver_data(dev);
read_rtc:
ret = dm_i2c_read(dev, 0, buf, sizeof(buf));
if (ret < 0)
return ret;
if (type == ds_1307) {
if (buf[RTC_SEC_REG_ADDR] & RTC_SEC_BIT_CH) {
printf("### Warning: RTC oscillator has stopped\n");
/* clear the CH flag */
buf[RTC_SEC_REG_ADDR] &= ~RTC_SEC_BIT_CH;
dm_i2c_reg_write(dev, RTC_SEC_REG_ADDR,
buf[RTC_SEC_REG_ADDR]);
return -1;
}
}
if (type == mcp794xx) {
/* make sure that the backup battery is enabled */
if (!(buf[RTC_DAY_REG_ADDR] & MCP7941X_BIT_VBATEN)) {
dm_i2c_reg_write(dev, RTC_DAY_REG_ADDR,
buf[RTC_DAY_REG_ADDR] |
MCP7941X_BIT_VBATEN);
}
/* clock halted? turn it on, so clock can tick. */
if (!(buf[RTC_SEC_REG_ADDR] & MCP7941X_BIT_ST)) {
dm_i2c_reg_write(dev, RTC_SEC_REG_ADDR,
MCP7941X_BIT_ST);
printf("Started RTC\n");
goto read_rtc;
}
}
tm->tm_sec = bcd2bin(buf[RTC_SEC_REG_ADDR] & 0x7F);
tm->tm_min = bcd2bin(buf[RTC_MIN_REG_ADDR] & 0x7F);
tm->tm_hour = bcd2bin(buf[RTC_HR_REG_ADDR] & 0x3F);
tm->tm_mday = bcd2bin(buf[RTC_DATE_REG_ADDR] & 0x3F);
tm->tm_mon = bcd2bin(buf[RTC_MON_REG_ADDR] & 0x1F);
tm->tm_year = bcd2bin(buf[RTC_YR_REG_ADDR]) +
(bcd2bin(buf[RTC_YR_REG_ADDR]) >= 70 ?
1900 : 2000);
tm->tm_wday = bcd2bin((buf[RTC_DAY_REG_ADDR] - 1) & 0x07);
tm->tm_yday = 0;
tm->tm_isdst = 0;
debug("Get DATE: %4d-%02d-%02d (wday=%d) TIME: %2d:%02d:%02d\n",
tm->tm_year, tm->tm_mon, tm->tm_mday, tm->tm_wday,
tm->tm_hour, tm->tm_min, tm->tm_sec);
return 0;
}
static int ds1307_rtc_reset(struct udevice *dev)
{
int ret;
/* clear Clock Halt */
ret = dm_i2c_reg_write(dev, RTC_SEC_REG_ADDR, 0x00);
if (ret < 0)
return ret;
ret = dm_i2c_reg_write(dev, RTC_CTL_REG_ADDR,
RTC_CTL_BIT_SQWE | RTC_CTL_BIT_RS1 |
RTC_CTL_BIT_RS0);
if (ret < 0)
return ret;
return 0;
}
static int ds1307_probe(struct udevice *dev)
{
i2c_set_chip_flags(dev, DM_I2C_CHIP_RD_ADDRESS |
DM_I2C_CHIP_WR_ADDRESS);
return 0;
}
static const struct rtc_ops ds1307_rtc_ops = {
.get = ds1307_rtc_get,
.set = ds1307_rtc_set,
.reset = ds1307_rtc_reset,
};
static const struct udevice_id ds1307_rtc_ids[] = {
{ .compatible = "dallas,ds1307", .data = ds_1307 },
{ .compatible = "dallas,ds1337", .data = ds_1337 },
{ .compatible = "dallas,ds1340", .data = ds_1340 },
{ .compatible = "microchip,mcp7941x", .data = mcp794xx },
{ }
};
U_BOOT_DRIVER(rtc_ds1307) = {
.name = "rtc-ds1307",
.id = UCLASS_RTC,
.probe = ds1307_probe,
.of_match = ds1307_rtc_ids,
.ops = &ds1307_rtc_ops,
};
#endif /* CONFIG_DM_RTC */
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