25.03.2021 18:02, Dmitry Osipenko пишет:
> 25.03.2021 17:39, Thierry Reding пишет:
>> On Tue, Mar 02, 2021 at 03:25:00PM +0300, Dmitry Osipenko wrote:
>>> Switch all clocks of a power domain to a safe rate which is suitable
>>> for all possible voltages in order to ensure that hardware constraints
>>> aren't violated when power domain state toggles.
>>>
>>> Tested-by: Peter Geis <pgwipeout@xxxxxxxxx> # Ouya T30
>>> Tested-by: Nicolas Chauvet <kwizart@xxxxxxxxx> # PAZ00 T20 and TK1 T124
>>> Tested-by: Matt Merhar <mattmerhar@xxxxxxxxxxxxxx> # Ouya T30
>>> Signed-off-by: Dmitry Osipenko <digetx@xxxxxxxxx>
>>> ---
>>> drivers/soc/tegra/pmc.c | 92 ++++++++++++++++++++++++++++++++++++++++-
>>> 1 file changed, 90 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/drivers/soc/tegra/pmc.c b/drivers/soc/tegra/pmc.c
>>> index f970b615ee27..a87645fac735 100644
>>> --- a/drivers/soc/tegra/pmc.c
>>> +++ b/drivers/soc/tegra/pmc.c
>>> @@ -237,6 +237,7 @@ struct tegra_powergate {
>>> unsigned int id;
>>> struct clk **clks;
>>> unsigned int num_clks;
>>> + unsigned long *clk_rates;
>>> struct reset_control *reset;
>>> };
>>>
>>> @@ -641,6 +642,57 @@ static int __tegra_powergate_remove_clamping(struct tegra_pmc *pmc,
>>> return 0;
>>> }
>>>
>>> +static int tegra_powergate_prepare_clocks(struct tegra_powergate *pg)
>>> +{
>>> + unsigned long safe_rate = 100 * 1000 * 1000;
>>
>> This seems a bit arbitrary. Where did you come up with that value?
>>
>> I'm going to apply this to see how it fares in our testing.
>
> This value is chosen based on the OPP table voltages and frequencies.
>
> Maybe you could add this clarifying comment to the code(?):
>
> "There is no hardware unit on any of Tegra SoCs which requires higher
> voltages for the rates above 100MHz."
I meant below, of course :)
