linux-kernel - Re: [PATCH 2/2] rtc: brcmstb-waketimer: Add Broadcom STB wake-timer

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Date:   Mon, 26 Jun 2017 10:15:46 -0700
From:   Florian Fainelli <f.fainelli@...il.com>
To:     Alexandre Belloni <alexandre.belloni@...e-electrons.com>
Cc:     linux-kernel@...r.kernel.org,
        Brian Norris <computersforpeace@...il.com>,
        Markus Mayer <mmayer@...adcom.com>,
        Alessandro Zummo <a.zummo@...ertech.it>,
        Rob Herring <robh+dt@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        Gregory Fong <gregory.0xf0@...il.com>,
        "maintainer:BROADCOM BCM7XXX ARM ARCHITECTURE" 
        <bcm-kernel-feedback-list@...adcom.com>,
        "open list:REAL TIME CLOCK (RTC) SUBSYSTEM" 
        <rtc-linux@...glegroups.com>,
        "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" 
        <devicetree@...r.kernel.org>,
        "moderated list:BROADCOM BCM7XXX ARM ARCHITECTURE" 
        <linux-arm-kernel@...ts.infradead.org>
Subject: Re: [PATCH 2/2] rtc: brcmstb-waketimer: Add Broadcom STB wake-timer

On 06/24/2017 11:59 AM, Alexandre Belloni wrote:
> Hi,
> 
> This seems mostly good.
> 
> On 15/06/2017 at 12:59:04 -0700, Florian Fainelli wrote:
>> +static void wktmr_read(struct brcmstb_waketmr *timer,
>> +		       struct wktmr_time *t)
>> +{
>> +	u32 tmp;
>> +
> 
> To be sure, is this IP always 32bit, even on 64bit platforms?

Correct, it's only 32-bit capable (saw the recent discussions about the
2038yr "problem"...).

> 
>> +	do {
>> +		t->sec = readl_relaxed(timer->base + BRCMSTB_WKTMR_COUNTER);
>> +		tmp = readl_relaxed(timer->base + BRCMSTB_WKTMR_PRESCALER_VAL);
>> +	} while (tmp >= timer->rate);
>> +
>> +	t->pre = timer->rate - tmp;
>> +}
>> +
> 
> [...]
> 
>> +static int brcmstb_waketmr_settime(struct device *dev,
>> +				   struct rtc_time *tm)
>> +{
>> +	struct brcmstb_waketmr *timer = dev_get_drvdata(dev);
>> +	unsigned long sec;
>> +	int ret;
>> +
>> +	ret = rtc_valid_tm(tm);
>> +	if (ret)
>> +		return ret;
>> +
> 
> There is no way this function can be called without a valid tm. The only
> caller checks before calling.

OK.

> 
>> +	rtc_tm_to_time(tm, &sec);
>> +
>> +	dev_dbg(dev, "%s: sec=%ld\n", __func__, sec);
>> +	writel_relaxed(sec, timer->base + BRCMSTB_WKTMR_COUNTER);
>> +
>> +	return 0;
>> +}
>> +
>> +static int brcmstb_waketmr_getalarm(struct device *dev,
>> +				    struct rtc_wkalrm *alarm)
>> +{
>> +	struct brcmstb_waketmr *timer = dev_get_drvdata(dev);
>> +	unsigned long sec;
>> +	u32 reg;
>> +
>> +	sec = readl_relaxed(timer->base + BRCMSTB_WKTMR_ALARM);
>> +	if (sec == 0) {
>> +		/* Alarm is disabled */
>> +		alarm->enabled = 0;
>> +		alarm->time.tm_mon = -1;
>> +		alarm->time.tm_mday = -1;
>> +		alarm->time.tm_year = -1;
>> +		alarm->time.tm_hour = -1;
>> +		alarm->time.tm_min = -1;
>> +		alarm->time.tm_sec = -1;
> 
> This is not needed since d68778b80dd7

Great, I will take that out.

Do you care whether some dev_dbg() prints are left in the driver or
should I remove those in v2?

> 
>> +		dev_dbg(dev, "%s: alarm is disabled\n", __func__);
>> +	} else {
>> +		/* Alarm is enabled */
>> +		alarm->enabled = 1;
>> +		rtc_time_to_tm(sec, &alarm->time);
>> +		dev_dbg(dev, "%s: alarm is enabled\n", __func__);
>> +	}
>> +
>> +	reg = readl_relaxed(timer->base + BRCMSTB_WKTMR_EVENT);
>> +	alarm->pending = !!(reg & 1);
>> +	dev_dbg(dev, "%s: alarm pending=%d\n", __func__, alarm->pending);
>> +
>> +	return 0;
>> +}
> 


-- 
Florian