Re: [PATCH v3 2/2] cpufreq: tegra: Re-model Tegra cpufreq driver

From: bilhuang
Date: Tue Dec 17 2013 - 05:52:41 EST


On 12/17/2013 02:54 PM, Viresh Kumar wrote:
On 5 December 2013 13:14, Bill Huang <bilhuang@xxxxxxxxxx> wrote:
Re-model Tegra cpufreq driver to support all Tegra series of SoCs.

* Make tegra-cpufreq.c a generic Tegra cpufreq driver.
* Move Tegra20 specific codes into tegra20-cpufreq.c.
* Bind Tegra cpufreq dirver with a fake device so defer probe would work
when we're going to get regulator in the driver to support voltage
scaling (DVFS).

I strongly feel we must reuse cpufreq-cpu0 driver here after adding a
clk/regulator driver for tegra to support all that.

Tegra20 DVFS is a little bit complicated due to the fact that we can't scale VDD_CPU directly, there are constraints or relationship to other power rails so I don't think it is a good idea to use generic cpufreq-cpu0 driver if we're going to support voltage scaling.

@Stephen: If you want we can keep all that tegra specific stuff
(clk/regulator) in
tegra-cpufreq.c, but we can easily use cpufreq-cpu0 driver without much
complications..

I have tried it earlier, got some comments and then got busy in other stuff..
https://lkml.org/lkml/2013/8/7/364

static int tegra_cpu_exit(struct cpufreq_policy *policy)
{
- clk_disable_unprepare(cpu_clk);
- clk_disable_unprepare(emc_clk);
+ cpufreq_frequency_table_cpuinfo(policy, tegra_data->freq_table);

Btw, why do you need this here?

Actually the latest version is v4 which is quite different against v3.
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