Messages in this thread | | | Subject | Re: [PATCH v2 2/4] rtc: Add support for the MediaTek MT2712 RTC | From | Ran Bi <> | Date | Thu, 22 Aug 2019 20:34:14 +0800 |
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Hi,
> > + > > +#define MTK_RTC_DEV KBUILD_MODNAME > > You probably shouldn't do that and have a static string for the driver > name. I probably doesn't matter much though because DT is used to probe > the driver. >
Will change it at next patch.
> > +/* we map HW YEAR 0 to 2000 because 2000 is the leap year */ > > +#define MT2712_MIN_YEAR 2000 > > +#define MT2712_BASE_YEAR 1900 > > +#define MT2712_MIN_YEAR_OFFSET (MT2712_MIN_YEAR - MT2712_BASE_YEAR) > > +#define MT2712_MAX_YEAR_OFFSET (MT2712_MIN_YEAR_OFFSET + 127) > > + > > All those defines are unecessary, see below. >
Will change it at next patch.
> > +struct mt2712_rtc { > > + struct device *dev; > > Looking at the code closely, it seems this is only used for debug and > error messages. Maybe you could use rtc_dev->dev instead. >
Will change it at next patch.
> > + mutex_lock(&rtc->rtc_dev->ops_lock); > > + > > + irqsta = mt2712_readl(rtc, MT2712_IRQ_STA); > > Do you have to lock that read? Is the register cleared on read? >
Yes, this register is read clear register.
> > + do { > > + __mt2712_rtc_read_time(rtc, tm, &sec); > > + } while (sec < tm->tm_sec); /* SEC has carried */ > > Shouldn't that be while (tm->tm_sec < sec)? >
In __mt2712_rtc_read_time function, we read tm->tm_sec before read sec. Sometimes we can meet situation like "tm->tm_sec == 59" and "sec == 0". It means that TC_SEC has carried and we need to reload the tm struct. I suppose it was correct that using "while (sec < tm->tm_sec)"
> > + > > + /* HW register use 7 bits to store year data, minus > > + * MT2712_MIN_YEAR_OFFSET brfore write year data to register, and plus > > + * MT2712_MIN_YEAR_OFFSET back after read year from register > > + */ > > + tm->tm_year += MT2712_MIN_YEAR_OFFSET; > > Simply add 100 in __mt2712_rtc_read_time >
Will change it at next patch.
> > + > > + /* HW register start mon from one, but tm_mon start from zero. */ > > + tm->tm_mon--; > > + > > You can also do that in __mt2712_rtc_read_time. >
Will change it at next patch.
> > + if (rtc_valid_tm(tm)) { > > This check is unnecessary, the validity is always checked by the core. >
Will remove this at next patch.
> > + if (tm->tm_year > MT2712_MAX_YEAR_OFFSET) { > > + dev_dbg(rtc->dev, "Set year %d out of range. (%d - %d)\n", > > + 1900 + tm->tm_year, 1900 + MT2712_MIN_YEAR_OFFSET, > > + 1900 + MT2712_MAX_YEAR_OFFSET); > > + return -EINVAL; > > + } > > This check is unnecessary, see below. >
Will change it at next patch.
> > + > > + tm->tm_year -= MT2712_MIN_YEAR_OFFSET; > > + tm->tm_mon++; > > You should probably avoid modifying tm, move the substraction and > addition in the mt2712_writel calls. >
Will change it at next patch.
> > + if (tm->tm_year > MT2712_MAX_YEAR_OFFSET) { > > + dev_dbg(rtc->dev, "Set year %d out of range. (%d - %d)\n", > > + 1900 + tm->tm_year, 1900 + MT2712_MIN_YEAR_OFFSET, > > + 1900 + MT2712_MAX_YEAR_OFFSET); > > + return -EINVAL; > > + } > > + > > Unnecessary check. >
Will change it at next patch.
> > + p1 = mt2712_readl(rtc, MT2712_POWERKEY1); > > + p2 = mt2712_readl(rtc, MT2712_POWERKEY2); > > + if (p1 != MT2712_POWERKEY1_KEY || p2 != MT2712_POWERKEY2_KEY) > > + dev_dbg(rtc->dev, "powerkey not set (lost power)\n"); > > + > > This info is valuable, you should check that when reading the time and > return -EINVAL if power was lost. >
Will change it at next patch.
> > > + /* RTC need POWERKEY1/2 match, then goto normal work mode */ > > + mt2712_writel(rtc, MT2712_POWERKEY1, MT2712_POWERKEY1_KEY); > > + mt2712_writel(rtc, MT2712_POWERKEY2, MT2712_POWERKEY2_KEY); > > This should be written when setting the time after power was lost. >
I suppose we can move this into mt2712_rtc_read_time function's "if (p1 != MT2712_POWERKEY1_KEY || p2 != MT2712_POWERKEY2_KEY)" condition which will be added at next patch. We need additional flag to mark this condition or another if condition in mt2712_rtc_set_time fucntion if we put these code in mt2712_rtc_set_time function.
> > +static const struct rtc_class_ops mt2712_rtc_ops = { > > + .read_time = mt2712_rtc_read_time, > > + .set_time = mt2712_rtc_set_time, > > + .read_alarm = mt2712_rtc_read_alarm, > > + .set_alarm = mt2712_rtc_set_alarm, > > For proper operations, you should also provide the .alarm_irq_enable > callback. >
Will change it at next patch.
> > + rtc->rtc_dev->ops = &mt2712_rtc_ops; > > If you set the range properly here using rtc_dev->range_min and > rtc_dev->range_max, then the core will be able to do range checking and > will also take care of the year offset/windowing calculations instead of > having to hardcode that in the driver. >
Will change it at next patch.
Best Regards, Ran
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