linux-kernel - Re: [PATCH] rtc: cpcap: fix range

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Message-ID: <20200629143454.GP37466@atomide.com>
Date:   Mon, 29 Jun 2020 07:34:54 -0700
From:   Tony Lindgren <tony@...mide.com>
To:     Sebastian Reichel <sebastian.reichel@...labora.com>
Cc:     Sebastian Reichel <sre@...nel.org>,
        Alexandre Belloni <alexandre.belloni@...tlin.com>,
        Dev Null <devnull@...s.xyz>, Pavel Machek <pavel@....cz>,
        Merlijn Wajer <merlijn@...zup.org>,
        linux-kernel@...r.kernel.org, linux-omap@...r.kernel.org,
        linux-rtc@...r.kernel.org, "Sicelo A . Mhlongo" <absicsz@...il.com>
Subject: Re: [PATCH] rtc: cpcap: fix range

* Sebastian Reichel <sebastian.reichel@...labora.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@...mide.com>