[PATCH V2] PM / Domains: Add pm_genpd_lookup() API to lookup domain by firmware node

[Rafael J. Wysocki]

On Friday, November 28, 2014 11:38:35 AM Ulf Hansson wrote:
> In a step to move away from using genpd's name based APIs, such as the
> pm_genpd_add_subdomain_names(), provide an API to lookup an already
> initialized generic PM domain by its firmware node.
> 
> This API would typically be a called from SOC specific code, to fetch a
> handle to the domain. Especially convenient to configure subdomains and
> when the hierarchy of the domains are described in DT.
> 
> Do note, before pm_genpd_init() is invoked to initialize a generic PM
> domain, it's the callers responsibility to assign the new ->fwnode
> pointer in the struct generic_pm_domain, to enable pm_genpd_lookup() to
> find the domain.
> 
> Signed-off-by: Ulf Hansson <ulf.hansson at linaro.org>

I have no problems with that, but do you have a user for it?

> ---
> 
> Changes in v2:
> 	Change from using struct device_node to struct fwnode_handle.
> 	Updated commit header accordingly.
> 
> ---
>  drivers/base/power/domain.c | 27 +++++++++++++++++++++++++++
>  include/linux/pm_domain.h   |  4 ++++
>  2 files changed, 31 insertions(+)
> 
> diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c
> index 735c473..2d881d5 100644
> --- a/drivers/base/power/domain.c
> +++ b/drivers/base/power/domain.c
> @@ -75,6 +75,33 @@ struct generic_pm_domain *dev_to_genpd(struct device *dev)
>  	return pd_to_genpd(dev->pm_domain);
>  }
>  
> +/**
> + * pm_genpd_lookup - Fetch a generic PM domain object by firmware node.
> + * @node: Firmware node to a corresponding genpd.
> + *
> + * Returns a valid pointer to struct generic_pm_domain on success or ERR_PTR()
> + * on failure.
> + */
> +struct generic_pm_domain *pm_genpd_lookup(struct fwnode_handle *node)
> +{
> +	struct generic_pm_domain *genpd = ERR_PTR(-ENOENT), *gpd;
> +
> +	if (IS_ERR_OR_NULL(node))
> +		return ERR_PTR(-EINVAL);
> +
> +	mutex_lock(&gpd_list_lock);
> +	list_for_each_entry(gpd, &gpd_list, gpd_list_node) {
> +		if (gpd->fwnode == node) {
> +			genpd = gpd;
> +			break;
> +		}
> +	}
> +	mutex_unlock(&gpd_list_lock);
> +
> +	return genpd;
> +}
> +EXPORT_SYMBOL_GPL(pm_genpd_lookup);
> +
>  static int genpd_stop_dev(struct generic_pm_domain *genpd, struct device *dev)
>  {
>  	return GENPD_DEV_TIMED_CALLBACK(genpd, int, stop, dev,
> diff --git a/include/linux/pm_domain.h b/include/linux/pm_domain.h
> index 8cbd32e..aa01050 100644
> --- a/include/linux/pm_domain.h
> +++ b/include/linux/pm_domain.h
> @@ -43,6 +43,8 @@ struct gpd_cpuidle_data {
>  	struct cpuidle_state *idle_state;
>  };
>  
> +struct fwnode_handle;
> +
>  struct generic_pm_domain {
>  	struct dev_pm_domain domain;	/* PM domain operations */
>  	struct list_head gpd_list_node;	/* Node in the global PM domains list */
> @@ -53,6 +55,7 @@ struct generic_pm_domain {
>  	struct dev_power_governor *gov;
>  	struct work_struct power_off_work;
>  	const char *name;
> +	struct fwnode_handle *fwnode;	/* Firware node for the PM domain */
>  	unsigned int in_progress;	/* Number of devices being suspended now */
>  	atomic_t sd_count;	/* Number of subdomains with power "on" */
>  	enum gpd_status status;	/* Current state of the domain */
> @@ -126,6 +129,7 @@ static inline struct generic_pm_domain_data *dev_gpd_data(struct device *dev)
>  }
>  
>  extern struct generic_pm_domain *dev_to_genpd(struct device *dev);
> +extern struct generic_pm_domain *pm_genpd_lookup(struct fwnode_handle *node);
>  extern int __pm_genpd_add_device(struct generic_pm_domain *genpd,
>  				 struct device *dev,
>  				 struct gpd_timing_data *td);
> 

-- 
I speak only for myself.
Rafael J. Wysocki, Intel Open Source Technology Center.