From: Grygorii Strashko <grygorii.strashko@ti.com>
To: Richard Cochran <richardcochran@gmail.com>
Cc: "David S. Miller" <davem@davemloft.net>, <netdev@vger.kernel.org>,
Mugunthan V N <mugunthanvnm@ti.com>, Sekhar Nori <nsekhar@ti.com>,
<linux-kernel@vger.kernel.org>, <linux-omap@vger.kernel.org>,
Rob Herring <robh+dt@kernel.org>, <devicetree@vger.kernel.org>,
Murali Karicheri <m-karicheri2@ti.com>,
Wingman Kwok <w-kwok2@ti.com>,
John Stultz <john.stultz@linaro.org>,
Thomas Gleixner <tglx@linutronix.de>
Subject: Re: [PATCH v2 12/13] net: ethernet: ti: cpts: calc mult and shift from refclk freq
Date: Tue, 29 Nov 2016 10:22:21 -0600 [thread overview]
Message-ID: <cfa767c3-9ff4-d1b3-14a2-2f2118356bf1@ti.com> (raw)
In-Reply-To: <20161129103453.GJ3110@localhost.localdomain>
On 11/29/2016 04:34 AM, Richard Cochran wrote:
> On Mon, Nov 28, 2016 at 05:03:36PM -0600, Grygorii Strashko wrote:
>> +static void cpts_calc_mult_shift(struct cpts *cpts)
>> +{
>> + u64 frac, maxsec, ns;
>> + u32 freq, mult, shift;
>> +
>> + freq = clk_get_rate(cpts->refclk);
>> +
>> + /* Calc the maximum number of seconds which we can run before
>> + * wrapping around.
>> + */
>> + maxsec = cpts->cc.mask;
>> + do_div(maxsec, freq);
>> + if (maxsec > 600 && cpts->cc.mask > UINT_MAX)
>> + maxsec = 600;
>
> The reason for this test is not obvious. Why check cc.mask against
> UINT_MAX? Please use the comment to explain it.
>
Yeah. This is copy paste from __clocksource_update_freq_scale(), but
I'm going to limit it to 10 sec for now, because otherwise it will result in too small
mult in case of 64bit counter.
if (maxsec > 10)
maxsec = 10;
--
regards,
-grygorii
next prev parent reply other threads:[~2016-11-29 16:22 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-11-28 23:03 [PATCH v2 00/13] net: ethernet: ti: cpts: update and fixes Grygorii Strashko
2016-11-28 23:03 ` [PATCH v2 01/13] net: ethernet: ti: cpts: switch to readl/writel_relaxed() Grygorii Strashko
2016-11-29 9:38 ` Richard Cochran
2016-11-28 23:03 ` [PATCH v2 02/13] net: ethernet: ti: allow cpts to be built separately Grygorii Strashko
2016-11-29 9:37 ` Richard Cochran
2016-11-28 23:03 ` [PATCH v2 03/13] net: ethernet: ti: cpsw: minimize direct access to struct cpts Grygorii Strashko
2016-11-28 23:03 ` [PATCH v2 04/13] net: ethernet: ti: cpts: fix unbalanced clk api usage in cpts_register/unregister Grygorii Strashko
2016-11-29 9:48 ` Richard Cochran
2016-11-28 23:03 ` [PATCH v2 05/13] net: ethernet: ti: cpts: fix registration order Grygorii Strashko
2016-11-29 9:48 ` Richard Cochran
2016-11-28 23:03 ` [PATCH v2 06/13] net: ethernet: ti: cpts: disable cpts when unregistered Grygorii Strashko
2016-11-29 9:49 ` Richard Cochran
2016-11-28 23:03 ` [PATCH v2 07/13] net: ethernet: ti: cpts: rework initialization/deinitialization Grygorii Strashko
2016-11-29 10:07 ` Richard Cochran
2016-11-29 15:50 ` Grygorii Strashko
2016-11-30 18:30 ` Grygorii Strashko
2016-11-28 23:03 ` [PATCH v2 08/13] net: ethernet: ti: cpts: move dt props parsing to cpts driver Grygorii Strashko
2016-11-29 10:11 ` Richard Cochran
2016-11-29 15:54 ` Grygorii Strashko
2016-11-28 23:03 ` [PATCH v2 09/13] net: ethernet: ti: cpts: clean up event list if event pool is empty Grygorii Strashko
2016-11-29 10:13 ` Richard Cochran
2016-11-28 23:03 ` [PATCH v2 10/13] net: ethernet: ti: cpts: drop excessive writes to CTRL and INT_EN regs Grygorii Strashko
2016-11-29 10:14 ` Richard Cochran
2016-11-28 23:03 ` [PATCH v2 11/13] clocksource: export the clocks_calc_mult_shift to use by timestamp code Grygorii Strashko
2016-11-29 9:08 ` Thomas Gleixner
2016-11-28 23:03 ` [PATCH v2 12/13] net: ethernet: ti: cpts: calc mult and shift from refclk freq Grygorii Strashko
2016-11-29 10:34 ` Richard Cochran
2016-11-29 16:22 ` Grygorii Strashko [this message]
2016-11-28 23:03 ` [PATCH v2 13/13] net: ethernet: ti: cpts: fix overflow check period Grygorii Strashko
2016-11-30 9:12 ` Richard Cochran
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