Re: [PATCH v3 3/5] clk: add support for clocks provided by SCP(System Control Processor)

From: Stephen Boyd <sboyd@codeaurora.org>
To: Sudeep Holla <sudeep.holla@arm.com>
Cc: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"linux-pm@vger.kernel.org" <linux-pm@vger.kernel.org>,
	"linux-clk@vger.kernel.org" <linux-clk@vger.kernel.org>,
	"linux-arm-kernel@lists.infradead.org" 
	<linux-arm-kernel@lists.infradead.org>,
	Liviu Dudau <Liviu.Dudau@arm.com>,
	Lorenzo Pieralisi <Lorenzo.Pieralisi@arm.com>,
	"Jon Medhurst (Tixy)" <tixy@linaro.org>,
	Arnd Bergmann <arnd@arndb.de>, Kevin Hilman <khilman@kernel.org>,
	Olof Johansson <olof@lixom.net>,
	Mike Turquette <mturquette@linaro.org>
Subject: Re: [PATCH v3 3/5] clk: add support for clocks provided by SCP(System Control Processor)
Date: Fri, 5 Jun 2015 18:12:25 -0700	[thread overview]
Message-ID: <20150606011225.GF29237@codeaurora.org> (raw)
In-Reply-To: <5571D7F5.1030405@arm.com>

On 06/05, Sudeep Holla wrote:
> 
> 
> On 05/06/15 10:36, Sudeep Holla wrote:
> >
> >
> >On 04/06/15 21:20, Stephen Boyd wrote:
> >>On 05/27, Sudeep Holla wrote:
> 
> [...]
> 
> >>>+
> >>>+static unsigned long scpi_clk_recalc_rate(struct clk_hw *hw,
> >>>+					  unsigned long parent_rate)
> >>>+{
> >>>+	struct scpi_clk *clk = to_scpi_clk(hw);
> >>>+
> >>>+	return scpi_ops->clk_get_val(clk->id);
> >>>+}
> >>>+
> >>>+static long scpi_clk_round_rate(struct clk_hw *hw, unsigned long rate,
> >>>+				unsigned long *parent_rate)
> >>>+{
> >>>+	struct scpi_clk *clk = to_scpi_clk(hw);
> >>>+
> >>>+	if (WARN_ON(clk->rate_min && rate < clk->rate_min))
> >>>+		rate = clk->rate_min;
> >>>+	if (WARN_ON(clk->rate_max && rate > clk->rate_max))
> >>>+		rate = clk->rate_max;
> >>>+
> >>>+	return rate;
> >>>+}
> >>
> >>Hm.. this seems really generic. It might be better to support a
> >>way to tell the framework to limit the min/max rate that's
> >>accepted for a clk. That could be done later though.
> >>
> >
> >True, framework have some boundary checks in place. I will check if
> >I can use it with minimum changes to the core. If not, we can take this
> >up later as you suggested.
> >
> 
> I found that the framework already provides clk_set_rate_range for this
> purpose. Sorry for missing this earlier(seems like that's added quite
> recently in v4.0). I think I still need to retain round_rate as the core
> framework insists.

Sure, or use determine_rate if you want to limit the min/max from
the clk provider itself.

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