Re: [PATCH 12/21] usb: chipidea: msm: Keep device runtime enabled

Peter Chen
2016-06-29T06:53:03Z

On Sun, Jun 26, 2016 at 12:28:29AM -0700, Stephen Boyd wrote:
> Sometimes the usb wrapper device is part of a power domain that
> needs to stay on as long as the device is active. Let's get and
> put the device in driver probe/remove so that we keep the power
> domain powered as long as the device is attached. We can fine
> tune this later to handle wakeup interrupts, etc. for finer grain
> power management later, but this is necessary to make sure we can
> keep accessing the device right now.

Since some of the controllers work abnormal if we enables runtime
pm unconditionally, so I use one system flag CI_HDRC_SUPPORTS_RUNTIME_PM
for it. I can't understand why you can't access device without enable
parent's runtime pm, the controller will not enter runtime suspend
without that flag.

Peter
>
> Cc: Peter Chen <peter.chen@nxp.com>
> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> Signed-off-by: Stephen Boyd <stephen.boyd@linaro.org>
> ---
> drivers/usb/chipidea/ci_hdrc_msm.c | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/drivers/usb/chipidea/ci_hdrc_msm.c b/drivers/usb/chipidea/ci_hdrc_msm.c
> index 520c85e701ef..430856ef1be3 100644
> --- a/drivers/usb/chipidea/ci_hdrc_msm.c
> +++ b/drivers/usb/chipidea/ci_hdrc_msm.c
> @@ -80,6 +80,7 @@ static int ci_hdrc_msm_probe(struct platform_device *pdev)
>
> pm_runtime_no_callbacks(&pdev->dev);
> pm_runtime_enable(&pdev->dev);
> + pm_runtime_get(&pdev->dev);
>
> return 0;
> }
> @@ -88,6 +89,7 @@ static int ci_hdrc_msm_remove(struct platform_device *pdev)
> {
> struct platform_device *plat_ci = platform_get_drvdata(pdev);
>
> + pm_runtime_put(&pdev->dev);
> pm_runtime_disable(&pdev->dev);
> ci_hdrc_remove_device(plat_ci);
>
> --
> 2.9.0.rc2.8.ga28705d
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-usb" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at http://vger.kernel.org/majordomo-info.html

--

Best Regards,
Peter Chen