On Wed, Sep 14, 2016 at 04:02:29PM +0300, Grygorii Strashko wrote:
> @@ -35,6 +33,8 @@ Optional properties:
> For example in dra72x-evm, pcf gpio has to be
> driven low so that cpsw slave 0 and phy data
> lines are connected via mux.
> +- cpts_clock_mult : Numerator to convert input clock ticks into
> nanoseconds
> +- cpts_clock_shift : Denominator to convert input clock ticks into
> nanoseconds
You should explain to the reader how these will be calculated when the
properties are missing.
> diff --git a/drivers/net/ethernet/ti/cpts.c b/drivers/net/ethernet/ti/cpts.c
> index ff8bb85..8046a21 100644
> --- a/drivers/net/ethernet/ti/cpts.c
> +++ b/drivers/net/ethernet/ti/cpts.c
> @@ -418,18 +418,60 @@ void cpts_unregister(struct cpts *cpts)
> clk_disable(cpts->refclk);
> }
>
> +static void cpts_calc_mult_shift(struct cpts *cpts)
> +{
> + u64 maxsec;
> + u32 freq;
> + u32 mult;
> + u32 shift;
> + u64 ns;
> + u64 frac;
Why so many new lines? This isn't good style. Please combine
variables of the same type into one line and sort the lists
alphabetically.
> + if (cpts->cc_mult || cpts->cc.shift)
> + return;
> +
> + 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)
> + maxsec = 1;
> + else if (maxsec > 600 && cpts->cc.mask > UINT_MAX)
> + maxsec = 600;
> +
> + clocks_calc_mult_shift(&mult, &shift, freq, NSEC_PER_SEC, maxsec);
> +
> + cpts->cc_mult = mult;
> + cpts->cc.mult = mult;
> + cpts->cc.shift = shift;
> + /* Check calculations and inform if not precise */
Contrary to this comment, you are not making any kind of judgment
about whether the calculations are precise or not.
> + frac = 0;
> + ns = cyclecounter_cyc2ns(&cpts->cc, freq, cpts->cc.mask, &frac);
> +
> + dev_info(cpts->dev,
> + "CPTS: ref_clk_freq:%u calc_mult:%u calc_shift:%u error:%lld
> nsec/sec\n",
> + freq, cpts->cc_mult, cpts->cc.shift, (ns - NSEC_PER_SEC));
> +}
> +
Thanks,
Richard
