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Commit bcebd81d authored by Stefan Christ's avatar Stefan Christ Committed by Alexandre Belloni
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rtc: m41t80: avoid out of range year values 



Avoid saving an out of range year value to the RTC. Reading that value
from the RTC again returns a totally wrong time value. For Example

    $ timedatectl set-ntp no
    $ timedatectl set-time "1990-01-01 12:12:00"
    # Reboot
    rtc-m41t80 0-0068: setting system clock to 2090-01-01 12:12:35 UTC (3786955955)

Signed-off-by: default avatarStefan Christ <s.christ@phytec.de>
Signed-off-by: default avatarAlexandre Belloni <alexandre.belloni@free-electrons.com>
parent ae6e00b4

drivers/rtc/rtc-m41t80.c

+6 −0
Original line number Original line Diff line number Diff line
@@ -176,7 +176,13 @@ static int m41t80_set_datetime(struct i2c_client *client, struct rtc_time *tm) 
		bin2bcd(tm->tm_mday) | (buf[M41T80_REG_DAY] & ~0x3f);

		bin2bcd(tm->tm_mday) | (buf[M41T80_REG_DAY] & ~0x3f);

	buf[M41T80_REG_MON] =

	buf[M41T80_REG_MON] =

		bin2bcd(tm->tm_mon + 1) | (buf[M41T80_REG_MON] & ~0x1f);

		bin2bcd(tm->tm_mon + 1) | (buf[M41T80_REG_MON] & ~0x1f);



	/* assume 20YY not 19YY */

	/* assume 20YY not 19YY */

	if (tm->tm_year < 100 || tm->tm_year > 199) {

		dev_err(&client->dev, "Year must be between 2000 and 2099. It's %d.\n",

			tm->tm_year + 1900);

		return -EINVAL;

	}

	buf[M41T80_REG_YEAR] = bin2bcd(tm->tm_year % 100);

	buf[M41T80_REG_YEAR] = bin2bcd(tm->tm_year % 100);





	if (i2c_transfer(client->adapter, msgs, 1) != 1) {

	if (i2c_transfer(client->adapter, msgs, 1) != 1) {