[PATCH] rtc: cpcap: fix range

[PATCH] rtc: cpcap: fix range

[Sebastian Reichel]

Unbreak CPCAP driver, which has one more bit in the day counter
increasing the max. range from 2014 to 2058. The original commit
introducing the range limit was obviously wrong, since the driver
has only been written in 2017 (3 years after 14 bits would have
run out).

Reported-by: Sicelo A. Mhlongo <absicsz@gmail.com>
Reported-by: Dev Null <devnull@uvos.xyz>
Fixes: d2377f8cc5a7 ("rtc: cpcap: set range")
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>
---
 drivers/rtc/rtc-cpcap.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/rtc/rtc-cpcap.c b/drivers/rtc/rtc-cpcap.c
index a603f1f21125..800667d73a6f 100644
--- a/drivers/rtc/rtc-cpcap.c
+++ b/drivers/rtc/rtc-cpcap.c
@@ -261,7 +261,7 @@ static int cpcap_rtc_probe(struct platform_device *pdev)
 		return PTR_ERR(rtc->rtc_dev);
 
 	rtc->rtc_dev->ops = &cpcap_rtc_ops;
-	rtc->rtc_dev->range_max = (1 << 14) * SECS_PER_DAY - 1;
+	rtc->rtc_dev->range_max = (timeu64_t) (DAY_MASK + 1) * SECS_PER_DAY - 1;
 
 	err = cpcap_get_vendor(dev, rtc->regmap, &rtc->vendor);
 	if (err)
-- 
2.27.0

Re: [PATCH] rtc: cpcap: fix range

[Tony Lindgren]

* Sebastian Reichel <sebastian.reichel@collabora.com> [200629 11:42]:
> Unbreak CPCAP driver, which has one more bit in the day counter
> increasing the max. range from 2014 to 2058. The original commit
> introducing the range limit was obviously wrong, since the driver
> has only been written in 2017 (3 years after 14 bits would have
> run out).

So I guess with 14 bits vs 15 bits we have these date ranges:

1970 + (0x3fff / 365) = 2014
1970 + (0x7fff / 365) = 2059

Meaning we can't do the whole year for 2059 and it's only 2058
compatible like you say above :)

Acked-by: Tony Lindgren <tony@atomide.com>

Re: [PATCH] rtc: cpcap: fix range

[Merlijn Wajer]

Hi,

On 29/06/2020 13:41, Sebastian Reichel wrote:
> Unbreak CPCAP driver, which has one more bit in the day counter
> increasing the max. range from 2014 to 2058. The original commit
> introducing the range limit was obviously wrong, since the driver
> has only been written in 2017 (3 years after 14 bits would have
> run out).

This seems to work for me, thanks.

Please add as you deem appropriate:

Tested-by: Merlijn Wajer <merlijn@wizzup.org>
Acked-by: Merlijn Wajer <merlijn@wizzup.org>

Cheers,
Merlijn

Re: [PATCH] rtc: cpcap: fix range

[Alexandre Belloni]

On Mon, 29 Jun 2020 13:41:23 +0200, Sebastian Reichel wrote:
> Unbreak CPCAP driver, which has one more bit in the day counter
> increasing the max. range from 2014 to 2058. The original commit
> introducing the range limit was obviously wrong, since the driver
> has only been written in 2017 (3 years after 14 bits would have
> run out).

Applied, thanks!

What happen is that I can't count bits and so I though PCAP had 13 bits and
CPCAP 14 bits while it is indeed 14 and 15. I did the correct thing in the PCAP
driver though.

Thanks for the fix!

[1/1] rtc: cpcap: fix range
      commit: d6ac11f677ded28180fc9e59b01db79036c3ec31

Best regards,
-- 
Alexandre Belloni <alexandre.belloni@bootlin.com>