Re: [PATCH 01/10] PM / Domains: Add new helper functions for device-tree

From: Ulf Hansson <ulf.hansson-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>
To: Jon Hunter <jonathanh-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>
Cc: "Rafael J. Wysocki" <rjw-LthD3rsA81gm4RdzfppkhA@public.gmane.org>,
	Kevin Hilman <khilman-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>,
	Thierry Reding
	<thierry.reding-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>,
	Kukjin Kim <kgene-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>,
	Krzysztof Kozlowski
	<k.kozlowski-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org>,
	Alexander Aring
	<alex.aring-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>,
	Eric Anholt <eric-WhKQ6XTQaPysTnJN9+BGXg@public.gmane.org>,
	"linux-pm-u79uwXL29TY76Z2rM5mHXA@public.gmane.org"
	<linux-pm-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>,
	"linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org"
	<linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org>,
	"linux-tegra-u79uwXL29TY76Z2rM5mHXA@public.gmane.org"
	<linux-tegra-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>
Subject: Re: [PATCH 01/10] PM / Domains: Add new helper functions for device-tree
Date: Thu, 8 Sep 2016 13:34:42 +0200	[thread overview]
Message-ID: <CAPDyKFovdk4WzZXbXv2kygD+FTRMKOwYcEgkJDxRPyXbtNfEHA@mail.gmail.com> (raw)
In-Reply-To: <1471340976-5379-2-git-send-email-jonathanh-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>

On 16 August 2016 at 11:49, Jon Hunter <jonathanh-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org> wrote:
> Ideally, if we are returning a reference to a PM domain via a call to
> of_genpd_get_from_provider(), then we should keep track of such
> references via a reference count. The reference count could then be used
> to determine if a PM domain can be safely removed. Alternatively, it is
> possible to avoid such external references by providing APIs to access
> the PM domain and hence, eliminate any calls to
> of_genpd_get_from_provider().
>
> Add new helper functions for adding a device and a subdomain to a PM
> domain when using device-tree, so that external calls to
> of_genpd_get_from_provider() can be removed.
>
> Signed-off-by: Jon Hunter <jonathanh-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>

Acked-by: Ulf Hansson <ulf.hansson-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>

Kind regards
Uffe

> ---
>  drivers/base/power/domain.c | 46 +++++++++++++++++++++++++++++++++++++++++++++
>  include/linux/pm_domain.h   | 16 ++++++++++++++++
>  2 files changed, 62 insertions(+)
>
> diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c
> index a1f2aff33997..43c2a959a7bf 100644
> --- a/drivers/base/power/domain.c
> +++ b/drivers/base/power/domain.c
> @@ -1502,6 +1502,52 @@ struct generic_pm_domain *of_genpd_get_from_provider(
>  EXPORT_SYMBOL_GPL(of_genpd_get_from_provider);
>
>  /**
> + * of_genpd_add_device() - Add a device to an I/O PM domain
> + * @genpdspec: OF phandle args to use for look-up PM domain
> + * @dev: Device to be added.
> + *
> + * Looks-up an I/O PM domain based upon phandle args provided and adds
> + * the device to the PM domain. Returns a negative error code on failure.
> + */
> +int of_genpd_add_device(struct of_phandle_args *genpdspec, struct device *dev)
> +{
> +       struct generic_pm_domain *genpd;
> +
> +       genpd = of_genpd_get_from_provider(genpdspec);
> +       if (IS_ERR(genpd))
> +               return PTR_ERR(genpd);
> +
> +       return pm_genpd_add_device(genpd, dev);
> +}
> +EXPORT_SYMBOL_GPL(of_genpd_add_device);
> +
> +/**
> + * of_genpd_add_subdomain - Add a subdomain to an I/O PM domain.
> + * @parent_spec: OF phandle args to use for parent PM domain look-up
> + * @subdomain_spec: OF phandle args to use for subdomain look-up
> + *
> + * Looks-up a parent PM domain and subdomain based upon phandle args
> + * provided and adds the subdomain to the parent PM domain. Returns a
> + * negative error code on failure.
> + */
> +int of_genpd_add_subdomain(struct of_phandle_args *parent_spec,
> +                          struct of_phandle_args *subdomain_spec)
> +{
> +       struct generic_pm_domain *parent, *subdomain;
> +
> +       parent = of_genpd_get_from_provider(parent_spec);
> +       if (IS_ERR(parent))
> +               return PTR_ERR(parent);
> +
> +       subdomain = of_genpd_get_from_provider(subdomain_spec);
> +       if (IS_ERR(subdomain))
> +               return PTR_ERR(subdomain);
> +
> +       return pm_genpd_add_subdomain(parent, subdomain);
> +}
> +EXPORT_SYMBOL_GPL(of_genpd_add_subdomain);
> +
> +/**
>   * genpd_dev_pm_detach - Detach a device from its PM domain.
>   * @dev: Device to detach.
>   * @power_off: Currently not used
> diff --git a/include/linux/pm_domain.h b/include/linux/pm_domain.h
> index 31fec858088c..e1964a242389 100644
> --- a/include/linux/pm_domain.h
> +++ b/include/linux/pm_domain.h
> @@ -208,6 +208,10 @@ struct generic_pm_domain *__of_genpd_xlate_simple(
>  struct generic_pm_domain *__of_genpd_xlate_onecell(
>                                         struct of_phandle_args *genpdspec,
>                                         void *data);
> +extern int of_genpd_add_device(struct of_phandle_args *args,
> +                              struct device *dev);
> +extern int of_genpd_add_subdomain(struct of_phandle_args *parent,
> +                                 struct of_phandle_args *new_subdomain);
>
>  int genpd_dev_pm_attach(struct device *dev);
>  #else /* !CONFIG_PM_GENERIC_DOMAINS_OF */
> @@ -227,6 +231,18 @@ static inline struct generic_pm_domain *of_genpd_get_from_provider(
>  #define __of_genpd_xlate_simple                NULL
>  #define __of_genpd_xlate_onecell       NULL
>
> +static inline int of_genpd_add_device(struct of_phandle_args *args,
> +                                     struct device *dev)
> +{
> +       return -ENODEV;
> +}
> +
> +static inline int of_genpd_add_subdomain(struct of_phandle_args *parent,
> +                                        struct of_phandle_args *new_subdomain)
> +{
> +       return -ENODEV;
> +}
> +
>  static inline int genpd_dev_pm_attach(struct device *dev)
>  {
>         return -ENODEV;
> --
> 2.1.4
>