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u-boot/drivers/rtc/m41t62.c
Max Yang 92cf458f8a rtc: m41t62: fix wrong register use for set/reset ST bit 
Fix wrong register use when set/reset ST bit.
ST bit is in register M41T62_REG_SEC not in M41T62_REG_ALARM_HOUR.

I have not actually tested this. But this seemed buggy from inspection.

Fixes: 9bbe210512c4539 ("rtc: m41t62: add oscillator fail bit reset support")
Signed-off-by: Max Yang <max.yang@deltaww.com>
2021-07-15 19:06:49 -04:00

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// SPDX-License-Identifier: GPL-2.0+
/*
* (C) Copyright 2018
* Lukasz Majewski, DENX Software Engineering, lukma@denx.de.
*
* (C) Copyright 2008
* Stefan Roese, DENX Software Engineering, sr@denx.de.
*
* based on a the Linux rtc-m41t80.c driver which is:
* Alexander Bigga <ab@mycable.de>, 2006 (c) mycable GmbH
*/
/*
* Date & Time support for STMicroelectronics M41T62
*/
/* #define DEBUG */
#include <common.h>
#include <command.h>
#include <dm.h>
#include <log.h>
#include <rtc.h>
#include <i2c.h>
#include <linux/log2.h>
#include <linux/delay.h>
#define M41T62_REG_SSEC 0
#define M41T62_REG_SEC 1
#define M41T62_REG_MIN 2
#define M41T62_REG_HOUR 3
#define M41T62_REG_WDAY 4
#define M41T62_REG_DAY 5
#define M41T62_REG_MON 6
#define M41T62_REG_YEAR 7
#define M41T62_REG_ALARM_MON 0xa
#define M41T62_REG_ALARM_DAY 0xb
#define M41T62_REG_ALARM_HOUR 0xc
#define M41T62_REG_ALARM_MIN 0xd
#define M41T62_REG_ALARM_SEC 0xe
#define M41T62_REG_FLAGS 0xf
#define M41T62_DATETIME_REG_SIZE (M41T62_REG_YEAR + 1)
#define M41T62_ALARM_REG_SIZE \
(M41T62_REG_ALARM_SEC + 1 - M41T62_REG_ALARM_MON)
#define M41T62_SEC_ST (1 << 7) /* ST: Stop Bit */
#define M41T62_ALMON_AFE (1 << 7) /* AFE: AF Enable Bit */
#define M41T62_ALMON_SQWE (1 << 6) /* SQWE: SQW Enable Bit */
#define M41T62_ALHOUR_HT (1 << 6) /* HT: Halt Update Bit */
#define M41T62_FLAGS_AF (1 << 6) /* AF: Alarm Flag Bit */
#define M41T62_FLAGS_OF (1 << 2) /* OF: Oscillator Flag Bit */
#define M41T62_FLAGS_BATT_LOW (1 << 4) /* BL: Battery Low Bit */
#define M41T62_WDAY_SQW_FREQ_MASK 0xf0
#define M41T62_WDAY_SQW_FREQ_SHIFT 4
#define M41T62_SQW_MAX_FREQ 32768
#define M41T62_FEATURE_HT (1 << 0)
#define M41T62_FEATURE_BL (1 << 1)
#define M41T80_ALHOUR_HT (1 << 6) /* HT: Halt Update Bit */
static void m41t62_update_rtc_time(struct rtc_time *tm, u8 *buf)
{
debug("%s: raw read data - sec=%02x, min=%02x, hr=%02x, "
"mday=%02x, mon=%02x, year=%02x, wday=%02x, y2k=%02x\n",
__FUNCTION__,
buf[0], buf[1], buf[2], buf[3],
buf[4], buf[5], buf[6], buf[7]);
tm->tm_sec = bcd2bin(buf[M41T62_REG_SEC] & 0x7f);
tm->tm_min = bcd2bin(buf[M41T62_REG_MIN] & 0x7f);
tm->tm_hour = bcd2bin(buf[M41T62_REG_HOUR] & 0x3f);
tm->tm_mday = bcd2bin(buf[M41T62_REG_DAY] & 0x3f);
tm->tm_wday = buf[M41T62_REG_WDAY] & 0x07;
tm->tm_mon = bcd2bin(buf[M41T62_REG_MON] & 0x1f);
/* assume 20YY not 19YY, and ignore the Century Bit */
/* U-Boot needs to add 1900 here */
tm->tm_year = bcd2bin(buf[M41T62_REG_YEAR]) + 100 + 1900;
debug("%s: tm is secs=%d, mins=%d, hours=%d, "
"mday=%d, mon=%d, year=%d, wday=%d\n",
__FUNCTION__,
tm->tm_sec, tm->tm_min, tm->tm_hour,
tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
}
static void m41t62_set_rtc_buf(const struct rtc_time *tm, u8 *buf)
{
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);
/* Merge time-data and register flags into buf[0..7] */
buf[M41T62_REG_SSEC] = 0;
buf[M41T62_REG_SEC] =
bin2bcd(tm->tm_sec) | (buf[M41T62_REG_SEC] & ~0x7f);
buf[M41T62_REG_MIN] =
bin2bcd(tm->tm_min) | (buf[M41T62_REG_MIN] & ~0x7f);
buf[M41T62_REG_HOUR] =
bin2bcd(tm->tm_hour) | (buf[M41T62_REG_HOUR] & ~0x3f) ;
buf[M41T62_REG_WDAY] =
(tm->tm_wday & 0x07) | (buf[M41T62_REG_WDAY] & ~0x07);
buf[M41T62_REG_DAY] =
bin2bcd(tm->tm_mday) | (buf[M41T62_REG_DAY] & ~0x3f);
buf[M41T62_REG_MON] =
bin2bcd(tm->tm_mon) | (buf[M41T62_REG_MON] & ~0x1f);
/* assume 20YY not 19YY */
buf[M41T62_REG_YEAR] = bin2bcd(tm->tm_year % 100);
}
#ifdef CONFIG_DM_RTC
static int m41t62_rtc_get(struct udevice *dev, struct rtc_time *tm)
{
u8 buf[M41T62_DATETIME_REG_SIZE];
int ret;
ret = dm_i2c_read(dev, 0, buf, sizeof(buf));
if (ret)
return ret;
m41t62_update_rtc_time(tm, buf);
return 0;
}
static int m41t62_rtc_set(struct udevice *dev, const struct rtc_time *tm)
{
u8 buf[M41T62_DATETIME_REG_SIZE];
int ret;
ret = dm_i2c_read(dev, 0, buf, sizeof(buf));
if (ret)
return ret;
m41t62_set_rtc_buf(tm, buf);
ret = dm_i2c_write(dev, 0, buf, sizeof(buf));
if (ret) {
printf("I2C write failed in %s()\n", __func__);
return ret;
}
return 0;
}
static int m41t62_sqw_enable(struct udevice *dev, bool enable)
{
u8 val;
int ret;
ret = dm_i2c_read(dev, M41T62_REG_ALARM_MON, &val, sizeof(val));
if (ret)
return ret;
if (enable)
val |= M41T62_ALMON_SQWE;
else
val &= ~M41T62_ALMON_SQWE;
return dm_i2c_write(dev, M41T62_REG_ALARM_MON, &val, sizeof(val));
}
static int m41t62_sqw_set_rate(struct udevice *dev, unsigned int rate)
{
u8 val, newval, sqwrateval;
int ret;
if (rate >= M41T62_SQW_MAX_FREQ)
sqwrateval = 1;
else if (rate >= M41T62_SQW_MAX_FREQ / 4)
sqwrateval = 2;
else if (rate)
sqwrateval = 15 - ilog2(rate);
ret = dm_i2c_read(dev, M41T62_REG_WDAY, &val, sizeof(val));
if (ret)
return ret;
newval = val;
newval &= ~M41T62_WDAY_SQW_FREQ_MASK;
newval |= (sqwrateval << M41T62_WDAY_SQW_FREQ_SHIFT);
/*
* Try to avoid writing unchanged values. Writing to this register
* will reset the internal counter pipeline and thus affect system
* time.
*/
if (newval == val)
return 0;
return dm_i2c_write(dev, M41T62_REG_WDAY, &newval, sizeof(newval));
}
static int m41t62_rtc_restart_osc(struct udevice *dev)
{
u8 val;
int ret;
/* 0. check if oscillator failure happened */
ret = dm_i2c_read(dev, M41T62_REG_FLAGS, &val, sizeof(val));
if (ret)
return ret;
if (!(val & M41T62_FLAGS_OF))
return 0;
ret = dm_i2c_read(dev, M41T62_REG_SEC, &val, sizeof(val));
if (ret)
return ret;
/* 1. Set stop bit */
val |= M41T62_SEC_ST;
ret = dm_i2c_write(dev, M41T62_REG_SEC, &val, sizeof(val));
if (ret)
return ret;
/* 2. Clear stop bit */
val &= ~M41T62_SEC_ST;
ret = dm_i2c_write(dev, M41T62_REG_SEC, &val, sizeof(val));
if (ret)
return ret;
/* 3. wait 4 seconds */
mdelay(4000);
ret = dm_i2c_read(dev, M41T62_REG_FLAGS, &val, sizeof(val));
if (ret)
return ret;
/* 4. clear M41T62_FLAGS_OF bit */
val &= ~M41T62_FLAGS_OF;
ret = dm_i2c_write(dev, M41T62_REG_FLAGS, &val, sizeof(val));
if (ret)
return ret;
return 0;
}
static int m41t62_rtc_clear_ht(struct udevice *dev)
{
u8 val;
int ret;
/*
* M41T82: Make sure HT (Halt Update) bit is cleared.
* This bit is 0 in M41T62 so its save to clear it always.
*/
ret = dm_i2c_read(dev, M41T62_REG_ALARM_HOUR, &val, sizeof(val));
if (ret)
return ret;
val &= ~M41T80_ALHOUR_HT;
ret = dm_i2c_write(dev, M41T62_REG_ALARM_HOUR, &val, sizeof(val));
if (ret)
return ret;
return 0;
}
static int m41t62_rtc_reset(struct udevice *dev)
{
int ret;
ret = m41t62_rtc_restart_osc(dev);
if (ret)
return ret;
ret = m41t62_rtc_clear_ht(dev);
if (ret)
return ret;
/*
* Some boards feed the square wave as clock input into
* the SoC. This enables a 32.768kHz square wave, which is
* also the hardware default after power-loss.
*/
ret = m41t62_sqw_set_rate(dev, 32768);
if (ret)
return ret;
return m41t62_sqw_enable(dev, true);
}
/*
* Make sure HT bit is cleared. This bit is set on entering battery backup
* mode, so do this before the first read access.
*/
static int m41t62_rtc_probe(struct udevice *dev)
{
return m41t62_rtc_clear_ht(dev);
}
static const struct rtc_ops m41t62_rtc_ops = {
.get = m41t62_rtc_get,
.set = m41t62_rtc_set,
.reset = m41t62_rtc_reset,
};
static const struct udevice_id m41t62_rtc_ids[] = {
{ .compatible = "st,m41t62" },
{ .compatible = "st,m41t82" },
{ .compatible = "st,m41st87" },
{ .compatible = "microcrystal,rv4162" },
{ }
};
U_BOOT_DRIVER(rtc_m41t62) = {
.name = "rtc-m41t62",
.id = UCLASS_RTC,
.of_match = m41t62_rtc_ids,
.ops = &m41t62_rtc_ops,
.probe = &m41t62_rtc_probe,
};
#else /* NON DM RTC code - will be removed */
int rtc_get(struct rtc_time *tm)
{
u8 buf[M41T62_DATETIME_REG_SIZE];
i2c_read(CONFIG_SYS_I2C_RTC_ADDR, 0, 1, buf, M41T62_DATETIME_REG_SIZE);
m41t62_update_rtc_time(tm, buf);
return 0;
}
int rtc_set(struct rtc_time *tm)
{
u8 buf[M41T62_DATETIME_REG_SIZE];
i2c_read(CONFIG_SYS_I2C_RTC_ADDR, 0, 1, buf, M41T62_DATETIME_REG_SIZE);
m41t62_set_rtc_buf(tm, buf);
if (i2c_write(CONFIG_SYS_I2C_RTC_ADDR, 0, 1, buf,
M41T62_DATETIME_REG_SIZE)) {
printf("I2C write failed in %s()\n", __func__);
return -1;
}
return 0;
}
void rtc_reset(void)
{
u8 val;
/*
* M41T82: Make sure HT (Halt Update) bit is cleared.
* This bit is 0 in M41T62 so its save to clear it always.
*/
i2c_read(CONFIG_SYS_I2C_RTC_ADDR, M41T62_REG_ALARM_HOUR, 1, &val, 1);
val &= ~M41T80_ALHOUR_HT;
i2c_write(CONFIG_SYS_I2C_RTC_ADDR, M41T62_REG_ALARM_HOUR, 1, &val, 1);
}
#endif /* CONFIG_DM_RTC */
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