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

Jon Hunter
2019-01-30T12:45:49Z

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.

Cheers
Jon

--
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