Re: [PATCH v2] ALSA: hda/tegra: enable clock during probe

Takashi Iwai
2019-01-30T16:40:48Z

On Wed, 30 Jan 2019 13:45:49 +0100,
Jon Hunter wrote:
>
>
> On 25/01/2019 11:06, Sameer Pujar wrote:
> > If CONFIG_PM is disabled or runtime PM calls are forbidden, the clocks
> > will not be ON. This could cause issue during probe, where hda init
> > setup is done. This patch enables clocks unconditionally during probe.
> >
> > Along with above, follwoing changes are done.
> > * enable runtime PM before exiting from probe work. This helps to avoid
> > usage of pm_runtime_get_sync/pm_runtime_put() in probe work.
> > * hda_tegra_disable_clocks() is moved out of CONFIG_PM_SLEEP check.
> > * runtime PM callbacks moved out of CONFIG_PM check
> >
> > Signed-off-by: Sameer Pujar <spujar@nvidia.com>
> > Reviewed-by: Ravindra Lokhande <rlokhande@nvidia.com>
> > Reviewed-by: Jon Hunter <jonathanh@nvidia.com>
> > ---
> > sound/pci/hda/hda_tegra.c | 26 +++++++++++++++++---------
> > 1 file changed, 17 insertions(+), 9 deletions(-)
> >
> > diff --git a/sound/pci/hda/hda_tegra.c b/sound/pci/hda/hda_tegra.c
> > index c8d18dc..ba6175f 100644
> > --- a/sound/pci/hda/hda_tegra.c
> > +++ b/sound/pci/hda/hda_tegra.c
> > @@ -219,7 +219,6 @@ static int hda_tegra_enable_clocks(struct hda_tegra *data)
> > return rc;
> > }
> >
> > -#ifdef CONFIG_PM_SLEEP
> > static void hda_tegra_disable_clocks(struct hda_tegra *data)
> > {
> > clk_disable_unprepare(data->hda2hdmi_clk);
> > @@ -227,6 +226,7 @@ static void hda_tegra_disable_clocks(struct hda_tegra *data)
> > clk_disable_unprepare(data->hda_clk);
> > }
> >
> > +#ifdef CONFIG_PM_SLEEP
> > /*
> > * power management
> > */
> > @@ -257,7 +257,6 @@ static int hda_tegra_resume(struct device *dev)
> > }
> > #endif /* CONFIG_PM_SLEEP */
> >
> > -#ifdef CONFIG_PM
> > static int hda_tegra_runtime_suspend(struct device *dev)
> > {
> > struct snd_card *card = dev_get_drvdata(dev);
> > @@ -283,7 +282,7 @@ static int hda_tegra_runtime_resume(struct device *dev)
> > int rc;
> >
> > rc = hda_tegra_enable_clocks(hda);
> > - if (rc != 0)
> > + if (rc)
> > return rc;
> > if (chip && chip->running) {
> > hda_tegra_init(hda);
> > @@ -292,7 +291,6 @@ static int hda_tegra_runtime_resume(struct device *dev)
> >
> > return 0;
> > }
> > -#endif /* CONFIG_PM */
> >
> > static const struct dev_pm_ops hda_tegra_pm = {
> > SET_SYSTEM_SLEEP_PM_OPS(hda_tegra_suspend, hda_tegra_resume)
> > @@ -551,9 +549,9 @@ static int hda_tegra_probe(struct platform_device *pdev)
> >
> > dev_set_drvdata(&pdev->dev, card);
> >
> > - pm_runtime_enable(hda->dev);
> > - if (!azx_has_pm_runtime(chip))
> > - pm_runtime_forbid(hda->dev);
> > + err = hda_tegra_enable_clocks(hda);
> > + if (err)
> > + goto out_free;
>
> We also need to think about power-domains here. Enabling the clocks
> might not be enough as the appropriate power-domain needs to be enabled.
> For 64-bit Tegra runtime-pm will handle the power-domains (assuming they
> are populated in device-tree). So I still think it is better we call
> pm_runtime_get_sync() at some point rather than just replying on
> enabling the clocks.

If I understand correctly the code, the pm domain is already activated
at calling driver's probe callback.

thanks,

Takashi