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Subject[PATCH 10/10] rtc: ds1347: handle century register
Date
The DS1347 can handle years from 0 to 9999, add century register support.

Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
---
drivers/rtc/rtc-ds1347.c | 37 ++++++++++++++++++++++++-------------
1 file changed, 24 insertions(+), 13 deletions(-)

diff --git a/drivers/rtc/rtc-ds1347.c b/drivers/rtc/rtc-ds1347.c
index a49ce9991916..7025cf3fb9f8 100644
--- a/drivers/rtc/rtc-ds1347.c
+++ b/drivers/rtc/rtc-ds1347.c
@@ -26,6 +26,7 @@
#define DS1347_DAY_REG 0x0B
#define DS1347_YEAR_REG 0x0D
#define DS1347_CONTROL_REG 0x0F
+#define DS1347_CENTURY_REG 0x13
#define DS1347_STATUS_REG 0x17
#define DS1347_CLOCK_BURST 0x3F

@@ -49,9 +50,9 @@ static const struct regmap_access_table ds1347_access_table = {
static int ds1347_read_time(struct device *dev, struct rtc_time *dt)
{
struct regmap *map = dev_get_drvdata(dev);
- unsigned int status;
- int err;
+ unsigned int status, century, secs;
unsigned char buf[8];
+ int err;

err = regmap_read(map, DS1347_STATUS_REG, &status);
if (err)
@@ -60,9 +61,19 @@ static int ds1347_read_time(struct device *dev, struct rtc_time *dt)
if (status & DS1347_OSF_BIT)
return -EINVAL;

- err = regmap_bulk_read(map, DS1347_CLOCK_BURST, buf, 8);
- if (err)
- return err;
+ do {
+ err = regmap_bulk_read(map, DS1347_CLOCK_BURST, buf, 8);
+ if (err)
+ return err;
+
+ err = regmap_read(map, DS1347_CENTURY_REG, &century);
+ if (err)
+ return err;
+
+ err = regmap_read(map, DS1347_SECONDS_REG, &secs);
+ if (err)
+ return err;
+ } while (buf[0] != secs);

dt->tm_sec = bcd2bin(buf[0]);
dt->tm_min = bcd2bin(buf[1] & 0x7f);
@@ -70,7 +81,7 @@ static int ds1347_read_time(struct device *dev, struct rtc_time *dt)
dt->tm_mday = bcd2bin(buf[3]);
dt->tm_mon = bcd2bin(buf[4]) - 1;
dt->tm_wday = bcd2bin(buf[5]) - 1;
- dt->tm_year = bcd2bin(buf[6]) + 100;
+ dt->tm_year = (bcd2bin(century) * 100) + bcd2bin(buf[6]) - 1900;

return 0;
}
@@ -78,6 +89,7 @@ static int ds1347_read_time(struct device *dev, struct rtc_time *dt)
static int ds1347_set_time(struct device *dev, struct rtc_time *dt)
{
struct regmap *map = dev_get_drvdata(dev);
+ unsigned int century;
unsigned char buf[8];
int err;

@@ -92,19 +104,18 @@ static int ds1347_set_time(struct device *dev, struct rtc_time *dt)
buf[3] = bin2bcd(dt->tm_mday);
buf[4] = bin2bcd(dt->tm_mon + 1);
buf[5] = bin2bcd(dt->tm_wday + 1);
-
- /* year in linux is from 1900 i.e in range of 100
- in rtc it is from 00 to 99 */
- dt->tm_year = dt->tm_year % 100;
-
- buf[6] = bin2bcd(dt->tm_year);
+ buf[6] = bin2bcd(dt->tm_year % 100);
buf[7] = bin2bcd(0x00);

- /* write the rtc settings */
err = regmap_bulk_write(map, DS1347_CLOCK_BURST, buf, 8);
if (err)
return err;

+ century = (dt->tm_year / 100) + 19;
+ err = regmap_write(map, DS1347_CENTURY_REG, century);
+ if (err)
+ return err;
+
return regmap_update_bits(map, DS1347_STATUS_REG,
DS1347_NEOSC_BIT | DS1347_OSF_BIT, 0);
}
--
2.21.0
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