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SubjectRe: [rtc-linux] Re: invalid default values in RTC chip
David Brownell wrote:
> On Thursday 23 October 2008, Jüri Reitel wrote:
>
>> I included patch that just removes the RTC time registers check, when i
>> compiled the module and booted up with invalid values in RTC then system
>> automatically set system time and RTC time to 1.1.2000 (this is nice
>> because i dont have to use date and hwclock manually)
>>
>
> I wouldn't rely on the initial time setting being valid;
> it's not guaranteed by specs for all the chips, as I recall.
>
>
>
>> i checked the rtc_valid_tm function and saw that it also checks for the
>> year value among others but in ds1307_read_alarm (now this function is
>> renamed to ds1337_read_alarm) year is set to -1 with some other fields
>> so rtc_valid_tm function can not be used in ds1337_read_alarm function.
>>
>
> Right. I forget what alarm issues I was thinking of, but
> that wasn't it ... other code in the RTC framework handles
> morphing that time into a valid date.
>
>
>
>> This patch removes rtc date time values check in probe function
>>
>
> Thanks. This looks OK ... got a Signed-off-By for us?
>
>
>
>> --- a/drivers/rtc/rtc-ds1307.c
>> +++ b/drivers/rtc/rtc-ds1307.c
>> @@ -298,7 +298,7 @@ static int ds1307_set_time(struct device *dev,
>> struct rtc_time *t)
>> return 0;
>> }
>>
>> -static int ds1307_read_alarm(struct device *dev, struct rtc_wkalrm *t)
>> +static int ds1337_read_alarm(struct device *dev, struct rtc_wkalrm *t)
>> {
>> struct i2c_client *client = to_i2c_client(dev);
>> struct ds1307 *ds1307 = i2c_get_clientdata(client);
>> @@ -353,7 +353,7 @@ static int ds1307_read_alarm(struct device *dev,
>> struct rtc_wkalrm *t)
>> return 0;
>> }
>>
>> -static int ds1307_set_alarm(struct device *dev, struct rtc_wkalrm *t)
>> +static int ds1337_set_alarm(struct device *dev, struct rtc_wkalrm *t)
>> {
>> struct i2c_client *client = to_i2c_client(dev);
>> struct ds1307 *ds1307 = i2c_get_clientdata(client);
>> @@ -475,8 +475,8 @@ static int ds1307_ioctl(struct device *dev, unsigned
>> int cmd, unsigned long arg)
>> static const struct rtc_class_ops ds13xx_rtc_ops = {
>> .read_time = ds1307_get_time,
>> .set_time = ds1307_set_time,
>> - .read_alarm = ds1307_read_alarm,
>> - .set_alarm = ds1307_set_alarm,
>> + .read_alarm = ds1337_read_alarm,
>> + .set_alarm = ds1337_set_alarm,
>> .ioctl = ds1307_ioctl,
>> };
>>
>> @@ -707,22 +707,6 @@ read_rtc:
>> break;
>> }
>>
>> - tmp = ds1307->regs[DS1307_REG_SECS];
>> - tmp = bcd2bin(tmp & 0x7f);
>> - if (tmp > 60)
>> - goto exit_bad;
>> - tmp = bcd2bin(ds1307->regs[DS1307_REG_MIN] & 0x7f);
>> - if (tmp > 60)
>> - goto exit_bad;
>> -
>> - tmp = bcd2bin(ds1307->regs[DS1307_REG_MDAY] & 0x3f);
>> - if (tmp == 0 || tmp > 31)
>> - goto exit_bad;
>> -
>> - tmp = bcd2bin(ds1307->regs[DS1307_REG_MONTH] & 0x1f);
>> - if (tmp == 0 || tmp > 12)
>> - goto exit_bad;
>> -
>> tmp = ds1307->regs[DS1307_REG_HOUR];
>> switch (ds1307->type) {
>> case ds_1340:
>> @@ -779,13 +763,6 @@ read_rtc:
>>
>> return 0;
>>
>> -exit_bad:
>> - dev_dbg(&client->dev, "%s: %02x %02x %02x %02x %02x %02x %02x\n",
>> - "bogus register",
>> - ds1307->regs[0], ds1307->regs[1],
>> - ds1307->regs[2], ds1307->regs[3],
>> - ds1307->regs[4], ds1307->regs[5],
>> - ds1307->regs[6]);
>> exit_irq:
>> if (ds1307->rtc)
>> rtc_device_unregister(ds1307->rtc);
>>
>>
>
>
>
>
>
Thank you pointing to not rely on random values on RTC chip, i had luck
when reinserted battery from/to RTC in random initial values (that gave
me 1.1.2000).

Signed-off-by: Jüri Reitel <juri.reitel@liewenthal.ee>

JR

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