Re: [RFC PATCH 1/8] PM / Domains: Add new helper functions for device-tree

From: Jon Hunter <jonathanh@nvidia.com>
To: "Rafael J. Wysocki" <rjw@rjwysocki.net>,
	Kevin Hilman <khilman@kernel.org>,
	Ulf Hansson <ulf.hansson@linaro.org>
Cc: Krzysztof Kozlowski <k.kozlowski@samsung.com>,
	linux-pm@vger.kernel.org, Alexander Aring <alex.aring@gmail.com>,
	Eric Anholt <eric@anholt.net>,
	Thierry Reding <thierry.reding@gmail.com>,
	Kukjin Kim <kgene@kernel.org>,
	linux-tegra@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org
Subject: Re: [RFC PATCH 1/8] PM / Domains: Add new helper functions for device-tree
Date: Wed, 22 Jun 2016 12:00:22 +0100	[thread overview]
Message-ID: <576A6FC6.4000307@nvidia.com> (raw)
In-Reply-To: <1457090634-14785-2-git-send-email-jonathanh@nvidia.com>

On 04/03/16 11:23, Jon Hunter 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@nvidia.com>
> ---
>  drivers/base/power/domain.c | 44 ++++++++++++++++++++++++++++++++++++++++++++
>  include/linux/pm_domain.h   | 16 ++++++++++++++++
>  2 files changed, 60 insertions(+)
> 
> diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c
> index 5bdb42bf40f4..b24893499454 100644
> --- a/drivers/base/power/domain.c
> +++ b/drivers/base/power/domain.c
> @@ -1706,6 +1706,50 @@ 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);
> +}
> +
> +/**
> + * 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);
> +}
> +
> +/**
>   * 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 49cd8890b873..2b6ee670b231 100644
> --- a/include/linux/pm_domain.h
> +++ b/include/linux/pm_domain.h
> @@ -210,6 +210,10 @@ 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 */
> @@ -229,6 +233,18 @@ 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_pm_genpd_add_device(struct of_phandle_args *args,
> +					 struct device *dev)

This should be of_genpd_add_device. Will fix.

Jon

-- 
nvpublic