Re: [PATCH V4 1/1] soc: qcom: smp2p: Add wakeup capability to SMP2P IRQ

[Stephen Boyd <swboyd@chromium.org>]

Quoting Deepak Kumar Singh (2021-09-18 12:02:15)
> diff --git a/drivers/soc/qcom/smp2p.c b/drivers/soc/qcom/smp2p.c
> index 2df4883..60ad632 100644
> --- a/drivers/soc/qcom/smp2p.c
> +++ b/drivers/soc/qcom/smp2p.c
> @@ -14,6 +14,7 @@
>  #include <linux/mfd/syscon.h>
>  #include <linux/module.h>
>  #include <linux/platform_device.h>
> +#include <linux/pm_wakeirq.h>
>  #include <linux/regmap.h>
>  #include <linux/soc/qcom/smem.h>
>  #include <linux/soc/qcom/smem_state.h>
> @@ -538,9 +539,26 @@ static int qcom_smp2p_probe(struct platform_device *pdev)
>                 goto unwind_interfaces;
>         }
>
> +       /*
> +        * Treat smp2p interrupt as wakeup source, but keep it disabled
> +        * by default. User space can decide enabling it depending on its
> +        * use cases. For example if remoteproc crashes and device wants
> +        * to handle it immediatedly (e.g. to not miss phone calls) it can
> +        * enable wakeup source from user space, while other devices which
> +        * do not have proper autosleep feature may want to handle it with
> +        * other wakeup events (e.g. Power button) instead waking up immediately.
> +        */
> +       device_set_wakeup_capable(&pdev->dev, true);
> +
> +       ret = dev_pm_set_wake_irq(&pdev->dev, irq);
> +       if (ret)
> +               goto set_wake_irq_fail;
>
>         return 0;
>
> +set_wake_irq_fail:
> +       dev_pm_clear_wake_irq(&pdev->dev);
> +
>  unwind_interfaces:
>         list_for_each_entry(entry, &smp2p->inbound, node)
>                 irq_domain_remove(entry->domain);
> @@ -565,6 +583,9 @@ static int qcom_smp2p_remove(struct platform_device *pdev)
>         struct qcom_smp2p *smp2p = platform_get_drvdata(pdev);
>         struct smp2p_entry *entry;
>
> +       dev_pm_clear_wake_irq(&pdev->dev);
> +       device_init_wakeup(&pdev->dev, false);

Is this device_init_wakeup() call necessary? It looks like we can get
away without it and then once this driver probes the device will have
the wakeup capability set on it. Future binding/unbinding of the driver
will keep working.