Re: [PATCH v1] cpufreq: tegra20: Fix imbalanced clock enable count

From: Dmitry Osipenko
Date: Wed May 23 2018 - 05:50:56 EST


On 23.05.2018 08:58, Viresh Kumar wrote:
> On 23-05-18, 00:14, Dmitry Osipenko wrote:
>> Tegra20-cpufreq driver missed enabling the CPU clocks. This results in a
>> clock-enable refcount disbalance on PLL_P <-> PLL_X reparent, causing
>> PLL_X to get disabled while it shouldn't. Fix this by enabling the clocks
>> on the driver probe.
>>
>> Signed-off-by: Dmitry Osipenko <digetx@xxxxxxxxx>
>> ---
>>
>> CPUFreq maintainers,
>>
>> Please take into account that this patch is made on top of my recent
>> series of patches [0] "Clean up Tegra20 cpufreq driver" that was fully
>> reviewed, but seems not applied yet. Let me know if you prefer to re-spin
>> the [0], including this patch into the series.
>>
>> [0] https://patchwork.ozlabs.org/project/linux-tegra/list/?series=45321
>
> This is already picked by Rafael and is sitting in pm/bleeding-edge
> branch. Should get merged into linux-next in a day or two.
>
>> drivers/cpufreq/tegra20-cpufreq.c | 16 +++++++++++++++-
>> 1 file changed, 15 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/cpufreq/tegra20-cpufreq.c b/drivers/cpufreq/tegra20-cpufreq.c
>> index 05f57dcd5215..ca5229265b60 100644
>> --- a/drivers/cpufreq/tegra20-cpufreq.c
>> +++ b/drivers/cpufreq/tegra20-cpufreq.c
>> @@ -176,6 +176,14 @@ static int tegra20_cpufreq_probe(struct platform_device *pdev)
>> goto put_pll_x;
>> }
>>
>> + err = clk_prepare_enable(cpufreq->pll_x_clk);
>> + if (err)
>> + goto put_pll_p;
>> +
>> + err = clk_prepare_enable(cpufreq->pll_p_clk);
>> + if (err)
>> + goto disable_pll_x;
>> +
>> cpufreq->dev = &pdev->dev;
>> cpufreq->driver.get = cpufreq_generic_get;
>> cpufreq->driver.attr = cpufreq_generic_attr;
>> @@ -192,12 +200,16 @@ static int tegra20_cpufreq_probe(struct platform_device *pdev)
>>
>> err = cpufreq_register_driver(&cpufreq->driver);
>> if (err)
>> - goto put_pll_p;
>> + goto disable_pll_p;
>>
>> platform_set_drvdata(pdev, cpufreq);
>>
>> return 0;
>>
>> +disable_pll_p:
>> + clk_disable_unprepare(cpufreq->pll_p_clk);
>> +disable_pll_x:
>> + clk_disable_unprepare(cpufreq->pll_x_clk);
>> put_pll_p:
>> clk_put(cpufreq->pll_p_clk);
>> put_pll_x:
>> @@ -214,6 +226,8 @@ static int tegra20_cpufreq_remove(struct platform_device *pdev)
>>
>> cpufreq_unregister_driver(&cpufreq->driver);
>>
>> + clk_disable_unprepare(cpufreq->pll_p_clk);
>> + clk_disable_unprepare(cpufreq->pll_x_clk);
>> clk_put(cpufreq->pll_p_clk);
>> clk_put(cpufreq->pll_x_clk);
>> clk_put(cpufreq->cpu_clk);
>
> Acked-by: Viresh Kumar <viresh.kumar@xxxxxxxxxx>
>

Please hold on this patch, seems I interpreted the cpufreq driver logic
incorrectly and it is probably fine as it is. I'll re-check later today.