From: Pi-Cheng Chen <pi-cheng.chen@linaro.org>
To: Sascha Hauer <s.hauer@pengutronix.de>
Cc: Mike Turquette <mturquette@linaro.org>,
Stephen Boyd <sboyd@codeaurora.org>,
Matthias Brugger <matthias.bgg@gmail.com>,
Rob Herring <robh+dt@kernel.org>, Pawel Moll <pawel.moll@arm.com>,
Mark Rutland <mark.rutland@arm.com>,
Ian Campbell <ijc+devicetree@hellion.org.uk>,
Kumar Gala <galak@codeaurora.org>,
Henry Chen <henryc.chen@mediatek.com>,
James Liao <jamesjj.liao@mediatek.com>,
Chen Fan <fan.chen@mediatek.com>,
Eddie Huang <eddie.huang@mediatek.com>,
"Joe.C" <yingjoe.chen@mediatek.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>,
devicetree@vger.kernel.org,
Linaro Kernel Mailman List <linaro-kernel@lists.linaro.org>,
linux-mediatek@lists.infradead.org
Subject: Re: [PATCH] clk: mediatek: Export CPU mux clocks for CPU frequency control
Date: Thu, 5 Mar 2015 10:43:21 +0800 [thread overview]
Message-ID: <CALx668WKKmifhuODsV+Uaoq4ggcmB1=wbpLzXBnjEtxbuB4qig@mail.gmail.com> (raw)
In-Reply-To: <20150304112109.GB11010@pengutronix.de>
Hi Sascha,
On 4 March 2015 at 19:21, Sascha Hauer <s.hauer@pengutronix.de> wrote:
> On Wed, Mar 04, 2015 at 06:49:11PM +0800, pi-cheng.chen wrote:
>> This patch adds CPU mux clocks which are used by Mediatek cpufreq driver
>> for intermediate clock source switching. This patch is based on Mediatek
>> clock driver patches[1].
>>
>> [1] http://thread.gmane.org/gmane.linux.kernel/1892436
>>
>> Signed-off-by: pi-cheng.chen <pi-cheng.chen@linaro.org>
>> ---
>> +static long clk_cpumux_determine_rate(struct clk_hw *hw, unsigned long rate,
>> + unsigned long min_rate,
>> + unsigned long max_rate,
>> + unsigned long *best_parent_rate,
>> + struct clk_hw **best_parent_p)
>> +{
>> + struct clk *clk = hw->clk, *parent;
>> + unsigned long parent_rate;
>> + int i;
>> +
>> + for (i = MAINPLL_INDEX; i >= ARMPLL_INDEX; i--) {
>> + parent = clk_get_parent_by_index(clk, i);
>> + if (!parent)
>> + return 0;
>> +
>> + if (i == MAINPLL_INDEX) {
>> + parent_rate = __clk_get_rate(parent);
>> + if (parent_rate == rate)
>> + break;
>> + }
>> +
>> + parent_rate = __clk_round_rate(parent, rate);
>> + }
>> +
>> + *best_parent_rate = parent_rate;
>> + *best_parent_p = __clk_get_hw(parent);
>> + return parent_rate;
>> +}
>
> Why this determine_rate hook? If you want to switch the clock to some
> intermediate parent I would assume you do this explicitly by setting the
> parent and not implicitly by setting a rate.
>
I use determine_rate hook here because I am using generic cpufreq-dt
driver and I want to make clock switching transparent to cpufreq-dt.
I.e. when I am trying to switch the clock from ARMPLL to MAINPLL, I
call clk_set_rate() with the rate of MAINPLL, and determine_rate will
select MAINPLL as the new parent.
>> +int mtk_clk_register_cpumuxes(struct device_node *node,
>> + struct mtk_composite *clks, int num,
>> + struct clk_onecell_data *clk_data)
>> +{
>> + int i;
>> + struct clk *clk;
>> + struct regmap *regmap;
>> +
>> + if (!clk_data)
>> + return -ENOMEM;
>> +
>> + regmap = syscon_node_to_regmap(node);
>> + if (IS_ERR(regmap)) {
>> + pr_err("Cannot find regmap for %s: %ld\n", node->full_name,
>> + PTR_ERR(regmap));
>> + return PTR_ERR(regmap);
>> + }
>> +
>> + for (i = 0; i < num; i++) {
>> + struct mtk_composite *mux = &clks[i];
>> +
>> + clk = mtk_clk_register_cpumux(mux->name, mux->parent_names,
>> + mux->num_parents, regmap,
>> + mux->mux_reg, mux->mux_shift,
>> + mux->mux_width);
>
> Pass 'mux' directly instead of dispatching this struct into the
> individual fields.
> Also, probably better to move this function to
> drivers/clk/mediatek/clk-cpumux.c
Will do it. Thanks for reviewing.
Best Regards,
Pi-Cheng
>
> Sascha
>
> --
> Pengutronix e.K. | |
> Industrial Linux Solutions | http://www.pengutronix.de/ |
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next prev parent reply other threads:[~2015-03-05 2:43 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-03-04 10:49 [PATCH] clk: mediatek: Export CPU mux clocks for CPU frequency control pi-cheng.chen
2015-03-04 11:21 ` Sascha Hauer
2015-03-05 2:43 ` Pi-Cheng Chen [this message]
2015-03-05 7:42 ` Sascha Hauer
2015-03-05 8:58 ` Pi-Cheng Chen
2015-03-05 8:59 ` Viresh Kumar
2015-03-05 9:19 ` Sascha Hauer
2015-03-05 9:39 ` Pi-Cheng Chen
2015-03-05 10:51 ` Sascha Hauer
2015-03-05 11:02 ` Viresh Kumar
2015-03-11 0:13 ` Mike Turquette
2015-03-12 9:21 ` Viresh Kumar
2015-03-12 10:36 ` Russell King - ARM Linux
2015-03-05 11:33 ` Pi-Cheng Chen
2015-03-05 10:23 ` Viresh Kumar
2015-03-05 10:59 ` Sascha Hauer
2015-03-10 23:59 ` Mike Turquette
2015-03-12 9:22 ` Viresh Kumar
2015-03-10 1:53 ` Pi-Cheng Chen
2015-03-10 7:55 ` Sascha Hauer
2015-03-11 7:00 ` Pi-Cheng Chen
2015-07-14 12:47 [PATCH v4] " Daniel Kurtz
2015-07-15 6:38 ` [PATCH] " Pi-Cheng Chen
2015-08-03 11:13 ` Pi-Cheng Chen
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