From: Chen-Yu Tsai <wens@csie.org>
To: Michael Turquette <mturquette@baylibre.com>
Cc: Chen-Yu Tsai <wens@csie.org>, Lee Jones <lee.jones@linaro.org>,
Alessandro Zummo <a.zummo@towertech.it>,
Alexandre Belloni <alexandre.belloni@free-electrons.com>,
Rob Herring <robh+dt@kernel.org>,
Mark Rutland <mark.rutland@arm.com>,
Maxime Ripard <maxime.ripard@free-electrons.com>,
Stephen Boyd <sboyd@codeaurora.org>,
linux-arm-kernel <linux-arm-kernel@lists.infradead.org>,
rtc-linux@googlegroups.com, linux-clk <linux-clk@vger.kernel.org>,
devicetree <devicetree@vger.kernel.org>,
linux-kernel <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v4 4/7] rtc: ac100: Add clk output support
Date: Fri, 22 Jul 2016 09:22:25 +0800 [thread overview]
Message-ID: <CAGb2v65x_3b84mRJMkt2e7-rbbyYQ3Zz05hS3GuH=P9v8ecwpA@mail.gmail.com> (raw)
In-Reply-To: <146914709427.8780.16475894348537760808@resonance>
On Fri, Jul 22, 2016 at 8:24 AM, Michael Turquette
<mturquette@baylibre.com> wrote:
> Quoting Chen-Yu Tsai (2016-07-13 20:34:34)
>> On Sat, Jul 9, 2016 at 2:36 AM, Michael Turquette
>> <mturquette@baylibre.com> wrote:
>> > Quoting Chen-Yu Tsai (2016-06-30 08:58:48)
>> >> +static long ac100_clkout_round_rate(struct clk_hw *hw, unsigned long rate,
>> >> + unsigned long prate)
>> >> +{
>> >> + unsigned long best_rate = 0, tmp_rate, tmp_prate;
>> >> + int i;
>> >> +
>> >> + if (prate == AC100_RTC_32K_RATE)
>> >> + return divider_round_rate(hw, rate, &prate, NULL,
>> >> + AC100_CLKOUT_DIV_WIDTH,
>> >> + CLK_DIVIDER_POWER_OF_TWO);
>> >> +
>> >> + for (i = 0; ac100_clkout_prediv[i].div; i++) {
>> >> + tmp_prate = DIV_ROUND_UP(prate, ac100_clkout_prediv[i].val);
>> >> + tmp_rate = divider_round_rate(hw, rate, &tmp_prate, NULL,
>> >> + AC100_CLKOUT_DIV_WIDTH,
>> >> + CLK_DIVIDER_POWER_OF_TWO);
>> >> +
>> >> + if (tmp_rate > rate)
>> >> + continue;
>> >> + if (rate - tmp_rate < best_rate - tmp_rate)
>> >> + best_rate = tmp_rate;
>> >> + }
>> >> +
>> >> + return best_rate;
>> >> +}
>> >> +
>> >> +static int ac100_clkout_determine_rate(struct clk_hw *hw,
>> >> + struct clk_rate_request *req)
>> >> +{
>> >> + struct clk_hw *best_parent;
>> >> + unsigned long best = 0;
>> >> + int i, num_parents = clk_hw_get_num_parents(hw);
>> >> +
>> >> + for (i = 0; i < num_parents; i++) {
>> >> + struct clk_hw *parent = clk_hw_get_parent_by_index(hw, i);
>> >> + unsigned long tmp, prate = clk_hw_get_rate(parent);
>> >> +
>> >> + tmp = ac100_clkout_round_rate(hw, req->rate, prate);
>> >> +
>> >> + if (tmp > req->rate)
>> >> + continue;
>> >> + if (req->rate - tmp < req->rate - best) {
>> >> + best = tmp;
>> >> + best_parent = parent;
>> >> + }
>> >> + }
>> >> +
>> >> + if (!best)
>> >> + return -EINVAL;
>> >> +
>> >> + req->best_parent_hw = best_parent;
>> >> + req->best_parent_rate = best;
>> >> + req->rate = best;
>> >> +
>> >> + return 0;
>> >> +}
>> >
>> > You only need one of the two functions above. Keep the .determine_rate
>> > callback and drop .round_rate.
>>
>> Only .round_rate is set in the clk_ops. ac100_clkout_round_rate just
>> serves to split out some of the calculations done per parent.
>
> If you only use .round_rate, shouldn't you drop .determine_rate then?
Oops! I meant we only set .determine_rate. ac100_clkout_round_rate is
called in the per parent loop in .determine_rate.
ChenYu
>
> Regards,
> Mike
>
>>
>> > Otherwise the rest of the clk support looks great to me. Feel free to
>> > add:
>> >
>> > Reviewed-by: Michael Turquette <mturquette@baylibre.com>
>>
>> Thanks!
>>
>> ChenYu
next prev parent reply other threads:[~2016-07-22 1:22 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-06-30 15:58 [PATCH v4 0/7] mfd: ac100: Add support for X-Powers AC100 audio codec / RTC combo IC Chen-Yu Tsai
2016-06-30 15:58 ` [PATCH v4 1/7] mfd: ac100: Add device tree bindings for X-Powers AC100 codec/RTC " Chen-Yu Tsai
2016-07-01 2:48 ` Rob Herring
2016-07-01 8:40 ` Lee Jones
2016-06-30 15:58 ` [PATCH v4 2/7] mfd: ac100: Add driver for X-Powers AC100 audio codec / RTC " Chen-Yu Tsai
2016-06-30 15:58 ` [PATCH v4 3/7] rtc: ac100: Add RTC driver for X-Powers AC100 Chen-Yu Tsai
2016-06-30 15:58 ` [PATCH v4 4/7] rtc: ac100: Add clk output support Chen-Yu Tsai
2016-07-08 18:36 ` Michael Turquette
2016-07-14 3:34 ` Chen-Yu Tsai
[not found] ` <146914709427.8780.16475894348537760808@resonance>
2016-07-22 1:22 ` Chen-Yu Tsai [this message]
2016-06-30 15:58 ` [PATCH v4 5/7] ARM: dts: sun9i: a80-optimus: Add device node for AC100 Chen-Yu Tsai
2016-06-30 15:58 ` [PATCH v4 6/7] ARM: dts: sun9i: cubieboard4: " Chen-Yu Tsai
2016-06-30 15:58 ` [PATCH v4 7/7] ARM: dts: sun9i: Switch to the AC100 RTC clock outputs for osc32k Chen-Yu Tsai
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