linux-kernel - Re: [PATCH v8 05/21] clk: tegra: pll: Save and restore pll context

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Date:   Fri, 9 Aug 2019 10:39:11 -0700
From:   Sowjanya Komatineni <skomatineni@...dia.com>
To:     Dmitry Osipenko <digetx@...il.com>, <thierry.reding@...il.com>,
        <jonathanh@...dia.com>, <tglx@...utronix.de>,
        <jason@...edaemon.net>, <marc.zyngier@....com>,
        <linus.walleij@...aro.org>, <stefan@...er.ch>,
        <mark.rutland@....com>
CC:     <pdeschrijver@...dia.com>, <pgaikwad@...dia.com>,
        <sboyd@...nel.org>, <linux-clk@...r.kernel.org>,
        <linux-gpio@...r.kernel.org>, <jckuo@...dia.com>,
        <josephl@...dia.com>, <talho@...dia.com>,
        <linux-tegra@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        <mperttunen@...dia.com>, <spatra@...dia.com>, <robh+dt@...nel.org>,
        <devicetree@...r.kernel.org>, <rjw@...ysocki.net>,
        <viresh.kumar@...aro.org>, <linux-pm@...r.kernel.org>
Subject: Re: [PATCH v8 05/21] clk: tegra: pll: Save and restore pll context


On 8/9/19 4:33 AM, Dmitry Osipenko wrote:
> 09.08.2019 2:46, Sowjanya Komatineni пишет:
>> This patch implements save and restore of PLL context.
>>
>> During system suspend, core power goes off and looses the settings
>> of the Tegra CAR controller registers.
>>
>> So during suspend entry pll context is stored and on resume it is
>> restored back along with its state.
>>
>> Acked-by: Thierry Reding <treding@...dia.com>
>> Signed-off-by: Sowjanya Komatineni <skomatineni@...dia.com>
>> ---
>>   drivers/clk/tegra/clk-pll.c | 88 ++++++++++++++++++++++++++++-----------------
>>   drivers/clk/tegra/clk.h     |  2 ++
>>   2 files changed, 58 insertions(+), 32 deletions(-)
>>
>> diff --git a/drivers/clk/tegra/clk-pll.c b/drivers/clk/tegra/clk-pll.c
>> index 1583f5fc992f..e52add2bbdbb 100644
>> --- a/drivers/clk/tegra/clk-pll.c
>> +++ b/drivers/clk/tegra/clk-pll.c
>> @@ -1008,6 +1008,28 @@ static unsigned long clk_plle_recalc_rate(struct clk_hw *hw,
>>   	return rate;
>>   }
>>   
>> +static void tegra_clk_pll_restore_context(struct clk_hw *hw)
>> +{
>> +	struct tegra_clk_pll *pll = to_clk_pll(hw);
>> +	struct clk_hw *parent = clk_hw_get_parent(hw);
>> +	unsigned long parent_rate = clk_hw_get_rate(parent);
>> +	unsigned long rate = clk_hw_get_rate(hw);
>> +	u32 val;
>> +
>> +	if (clk_pll_is_enabled(hw))
>> +		return;
>> +
>> +	if (pll->params->set_defaults)
>> +		pll->params->set_defaults(pll);
>> +
>> +	clk_pll_set_rate(hw, rate, parent_rate);
>> +
>> +	if (!__clk_get_enable_count(hw->clk))
> What about orphaned clocks? Is enable_count > 0 for them?
There are no orphaned pll clocks.
>> +		clk_pll_disable(hw);
>> +	else
>> +		clk_pll_enable(hw);
>> +}
> [snip]