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

Dmitry Osipenko
2019-06-29T15:58:43Z

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.