From: thierry.reding@gmail.com (Thierry Reding)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH v2 14/16] cpufreq: Add cpufreq driver for Tegra124
Date: Wed, 23 Jul 2014 15:51:28 +0200 [thread overview]
Message-ID: <20140723135127.GB14263@ulmo.nvidia.com> (raw)
In-Reply-To: <CAKohponfKzuK+TnQvWcvaT8hRX8XZJWXWGMQw138DCwP=qcx+A@mail.gmail.com>
On Wed, Jul 23, 2014 at 01:55:57PM +0530, Viresh Kumar wrote:
> On 23 July 2014 12:54, Thierry Reding <thierry.reding@gmail.com> wrote:
> > ARM_TEGRA_CPUFREQ is still optional, so the select only applies when the
> > Tegra cpufreq driver is enabled. This is mostly just out of convenience,
> > though. The Tegra cpufreq driver uses the generic CPU0 cpufreq driver so
> > a select will automatically pull in the necessary dependency. With a
>
> Not necessarily. cpufreq-cpu0 can have few unmet dependency. And so
> there are chances that tegra driver is compiled but cpufreq-cpu0 isn't as
> we didn't mention it as a *hard* dependency.
>
> And so at boot, there wouldn't be any cpufreq support even when tegra's
> cpufreq driver is available.
>
> Though, menuconfig may give some warnings no such situations.
>
> > "depends on" the Tegra cpufreq driver only becomes available after
> > you've selected GENERIC_CPUFREQ_CPU0, which is somewhat unintuitive.
> >
> > To illustrate with an example: as a user, I want to enable CPU frequency
> > scaling on Tegra. So I use menuconfig to navigate to the "CPU Frequency
> > scaling" menu (enable it if not available yet) and look for an entry
> > that says "Tegra". But I can't find it because it's hidden due to the
> > lack of GENERIC_CPUFREQ_CPU0. That the Tegra CPU frequency driver uses a
> > generic driver is an implementation detail that users shouldn't have to
> > be aware of.
>
> Don't know, the guy compiling out stuff should be knowledgeable enough to
> have a look why tegra cpufreq entry isn't shown in menu. As, probably the
> above problem I mentioned looks to be of more significance than this one,
> atleast to me :)
>
> And, another thing to mention is that CONFIG_TEGRA_CPUFREQ is valid
> for earlier platforms as well and so a select/depends wouldn't be valid for
> earlier platforms. We probably need another Kconfig entry here.
Yes, sounds like a new Kconfig entry for this specific driver would be a
better approach and should remove all the above concerns.
Thierry
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next prev parent reply other threads:[~2014-07-23 13:51 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-07-21 15:38 [PATCH v2 00/16] Tegra124 CL-DVFS / DFLL clocksource, plus cpufreq Tuomas Tynkkynen
2014-07-21 15:38 ` [PATCH v2 01/16] regmap: Add regmap_get_device Tuomas Tynkkynen
2014-07-25 17:34 ` Mark Brown
2014-07-25 17:43 ` Mark Brown
2014-07-21 15:38 ` [PATCH v2 02/16] regulator: Add helpers for low-level register access Tuomas Tynkkynen
2014-07-25 17:48 ` Mark Brown
2014-07-21 15:38 ` [PATCH v2 03/16] clk: tegra: Add binding for the Tegra124 DFLL clocksource Tuomas Tynkkynen
2014-07-21 15:38 ` [PATCH v2 04/16] clk: tegra: Add library for the DFLL clock source (open-loop mode) Tuomas Tynkkynen
2014-08-18 6:05 ` Vince Hsu
2014-07-21 15:38 ` [PATCH v2 05/16] clk: tegra: Add closed loop support for the DFLL Tuomas Tynkkynen
2014-08-18 6:08 ` Vince Hsu
2014-07-21 15:38 ` [PATCH v2 06/16] clk: tegra: Add functions for parsing CVB tables Tuomas Tynkkynen
2014-07-21 15:38 ` [PATCH v2 07/16] clk: tegra: Add DFLL DVCO reset control for Tegra124 Tuomas Tynkkynen
2014-07-21 15:38 ` [PATCH v2 08/16] clk: tegra: Add Tegra124 DFLL clocksource platform driver Tuomas Tynkkynen
2014-08-12 10:37 ` Vince Hsu
2014-07-21 15:38 ` [PATCH v2 09/16] clk: tegra: Save/restore CCLKG_BURST_POLICY on suspend Tuomas Tynkkynen
2014-07-21 15:38 ` [PATCH v2 10/16] clk: tegra: Add the DFLL as a possible parent of the cclk_g clock Tuomas Tynkkynen
2014-07-21 15:38 ` [PATCH v2 11/16] ARM: tegra: Add the DFLL to Tegra124 device tree Tuomas Tynkkynen
2014-07-21 15:38 ` [PATCH v2 12/16] ARM: tegra: Enable the DFLL on the Jetson TK1 Tuomas Tynkkynen
2014-07-21 15:38 ` [PATCH v2 13/16] cpufreq: tegra124: Add device tree bindings Tuomas Tynkkynen
2014-07-21 15:39 ` [PATCH v2 14/16] cpufreq: Add cpufreq driver for Tegra124 Tuomas Tynkkynen
2014-07-22 0:49 ` Rafael J. Wysocki
2014-07-23 4:44 ` Viresh Kumar
2014-07-23 6:54 ` Thierry Reding
2014-07-23 6:58 ` Viresh Kumar
2014-07-23 7:24 ` Thierry Reding
2014-07-23 8:25 ` Viresh Kumar
2014-07-23 13:51 ` Thierry Reding [this message]
2014-07-23 11:57 ` Tuomas Tynkkynen
2014-07-23 16:50 ` Viresh Kumar
2014-07-23 19:17 ` Tuomas Tynkkynen
2014-07-24 0:13 ` Viresh Kumar
2014-07-24 9:10 ` Thierry Reding
2014-07-23 7:09 ` Thierry Reding
2014-07-23 12:35 ` Tuomas Tynkkynen
2014-07-23 13:59 ` Thierry Reding
2014-07-23 7:21 ` pramod gurav
2014-07-21 15:39 ` [PATCH v2 15/16] ARM: tegra: Add entries for cpufreq on Tegra124 Tuomas Tynkkynen
2014-07-21 15:39 ` [PATCH v2 16/16] ARM: tegra: Update defconfig for tegra124-cpufreq Tuomas Tynkkynen
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