Re: [PATCH V5 02/18] pinctrl: tegra: Add suspend and resume support

Dmitry Osipenko
2019-06-29T16:28:13Z

29.06.2019 18:58, Dmitry Osipenko пишет:
> 29.06.2019 18:46, Dmitry Osipenko пишет:
>> 28.06.2019 5:12, Sowjanya Komatineni пишет:
>>> This patch adds support for Tegra pinctrl driver suspend and resume.
>>>
>>> During suspend, context of all pinctrl registers are stored and
>>> on resume they are all restored to have all the pinmux and pad
>>> configuration for normal operation.
>>>
>>> Acked-by: Thierry Reding <treding@nvidia.com>
>>> Signed-off-by: Sowjanya Komatineni <skomatineni@nvidia.com>
>>> ---
>>> drivers/pinctrl/tegra/pinctrl-tegra.c | 52 ++++++++++++++++++++++++++++++++
>>> drivers/pinctrl/tegra/pinctrl-tegra.h | 3 ++
>>> drivers/pinctrl/tegra/pinctrl-tegra210.c | 1 +
>>> 3 files changed, 56 insertions(+)
>>>
>>> diff --git a/drivers/pinctrl/tegra/pinctrl-tegra.c b/drivers/pinctrl/tegra/pinctrl-tegra.c
>>> index 34596b246578..e7c0a1011cba 100644
>>> --- a/drivers/pinctrl/tegra/pinctrl-tegra.c
>>> +++ b/drivers/pinctrl/tegra/pinctrl-tegra.c
>>> @@ -621,6 +621,43 @@ static void tegra_pinctrl_clear_parked_bits(struct tegra_pmx *pmx)
>>> }
>>> }
>>>
>>> +static int tegra_pinctrl_suspend(struct device *dev)
>>> +{
>>> + struct tegra_pmx *pmx = dev_get_drvdata(dev);
>>> + u32 *backup_regs = pmx->backup_regs;
>>> + u32 *regs;
>>> + unsigned int i, j;
>>> +
>>> + for (i = 0; i < pmx->nbanks; i++) {
>>> + regs = pmx->regs[i];
>>> + for (j = 0; j < pmx->reg_bank_size[i] / 4; j++)
>>> + *backup_regs++ = readl(regs++);
>>> + }
>>> +
>>> + return pinctrl_force_sleep(pmx->pctl);
>>> +}
>>> +
>>> +static int tegra_pinctrl_resume(struct device *dev)
>>> +{
>>> + struct tegra_pmx *pmx = dev_get_drvdata(dev);
>>> + u32 *backup_regs = pmx->backup_regs;
>>> + u32 *regs;
>>> + unsigned int i, j;
>>> +
>>> + for (i = 0; i < pmx->nbanks; i++) {
>>> + regs = pmx->regs[i];
>>> + for (j = 0; j < pmx->reg_bank_size[i] / 4; j++)
>>> + writel(*backup_regs++, regs++);
>>> + }
>>> +
>>> + return 0;
>>> +}
>>> +
>>> +const struct dev_pm_ops tegra_pinctrl_pm = {
>>> + .suspend = &tegra_pinctrl_suspend,
>>> + .resume = &tegra_pinctrl_resume
>>> +};
>>
>> Hm, so this are the generic platform-driver suspend-resume OPS here, which is very
>> nice! But.. shouldn't pinctrl be resumed before the CLK driver (which is syscore_ops
>> in this version of the series)? .. Given that "clock" function may need to be
>> selected for some of the pins.
>>
>
> Oh, also what about GPIO-pinctrl suspend resume ordering .. is it okay that pinctrl
> will be resumed after GPIO? Shouldn't a proper pin-muxing be selected at first?
>
> This also looks to me very unsafe in a context of older Tegras which are initializing
> the static muxing very early during of the boot, otherwise things won't work well for
> the drivers.
>

Although, scratch what I wrote about older Tegras. We are probing pinctl driver very
early, hence it should suspend last and resume first. Should be okay.