Subject: Re: [PATCH 8/8] PM / devfreq: Move opp notifier registration to core

From: Chanwoo Choi <[email-masked]>
Date: Tue, 1 Oct 2019 06:49:27 +0900

On 19. 9. 18. 오전 9:18, Leonard Crestez wrote:
> An opp notifier can be registered by devfreq in order to respond to OPPs
> being enabled or disabled at runtime (for example by thermal). This is
> currently handled explicitly by drivers.
> 
> Move notifier handling to devfreq_add_device because this shouldn't be
> hardware-specific.
> 
> Handling this inside the core also takes less code.
> 
> Signed-off-by: Leonard Crestez <[email-masked]>
> ---
>  drivers/devfreq/devfreq.c    | 84 +++---------------------------------
>  drivers/devfreq/exynos-bus.c |  7 ---
>  drivers/devfreq/rk3399_dmc.c |  6 ---
>  include/linux/devfreq.h      |  8 ----
>  4 files changed, 6 insertions(+), 99 deletions(-)
> 
> diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
> index 7977bad93949..b9177430ae8f 100644
> --- a/drivers/devfreq/devfreq.c
> +++ b/drivers/devfreq/devfreq.c
> @@ -663,10 +663,11 @@ static void devfreq_dev_release(struct device *dev)
>  
>  	mutex_lock(&devfreq_list_lock);
>  	list_del(&devfreq->node);
>  	mutex_unlock(&devfreq_list_lock);
>  
> +	dev_pm_opp_unregister_notifier(devfreq->dev.parent, &devfreq->nb);
>  	dev_pm_qos_remove_notifier(devfreq->dev.parent, &devfreq->nb_max,
>  			DEV_PM_QOS_MAX_FREQUENCY);
>  	dev_pm_qos_remove_notifier(devfreq->dev.parent, &devfreq->nb_min,
>  			DEV_PM_QOS_MIN_FREQUENCY);
>  
> @@ -728,11 +729,10 @@ struct devfreq *devfreq_add_device(struct device *dev,
>  	devfreq->profile = profile;
>  	strncpy(devfreq->governor_name, governor_name, DEVFREQ_NAME_LEN);
>  	devfreq->previous_freq = profile->initial_freq;
>  	devfreq->last_status.current_frequency = profile->initial_freq;
>  	devfreq->data = data;
> -	devfreq->nb.notifier_call = devfreq_notifier_call;
>  
>  	if (!devfreq->profile->max_state && !devfreq->profile->freq_table) {
>  		err = set_freq_table(devfreq);
>  		if (err < 0)
>  			goto err_dev;
> @@ -810,10 +810,15 @@ struct devfreq *devfreq_add_device(struct device *dev,
>  	err = dev_pm_qos_add_notifier(devfreq->dev.parent, &devfreq->nb_max,
>  				      DEV_PM_QOS_MAX_FREQUENCY);
>  	if (err)
>  		goto err_devfreq;
>  
> +	devfreq->nb.notifier_call = devfreq_notifier_call;
> +	err = dev_pm_opp_register_notifier(devfreq->dev.parent, &devfreq->nb);
> +	if (err)
> +		goto err_devfreq;
> +
>  	mutex_lock(&devfreq_list_lock);
>  
>  	governor = try_then_request_governor(devfreq->governor_name);
>  	if (IS_ERR(governor)) {
>  		dev_err(dev, "%s: Unable to find governor for the device\n",
> @@ -1624,87 +1629,10 @@ struct dev_pm_opp *devfreq_recommended_opp(struct device *dev,
>  
>  	return opp;
>  }
>  EXPORT_SYMBOL(devfreq_recommended_opp);
>  
> -/**
> - * devfreq_register_opp_notifier() - Helper function to get devfreq notified
> - *				     for any changes in the OPP availability
> - *				     changes
> - * @dev:	The devfreq user device. (parent of devfreq)
> - * @devfreq:	The devfreq object.
> - */
> -int devfreq_register_opp_notifier(struct device *dev, struct devfreq *devfreq)
> -{
> -	return dev_pm_opp_register_notifier(dev, &devfreq->nb);
> -}
> -EXPORT_SYMBOL(devfreq_register_opp_notifier);
> -
> -/**
> - * devfreq_unregister_opp_notifier() - Helper function to stop getting devfreq
> - *				       notified for any changes in the OPP
> - *				       availability changes anymore.
> - * @dev:	The devfreq user device. (parent of devfreq)
> - * @devfreq:	The devfreq object.
> - *
> - * At exit() callback of devfreq_dev_profile, this must be included if
> - * devfreq_recommended_opp is used.
> - */
> -int devfreq_unregister_opp_notifier(struct device *dev, struct devfreq *devfreq)
> -{
> -	return dev_pm_opp_unregister_notifier(dev, &devfreq->nb);
> -}
> -EXPORT_SYMBOL(devfreq_unregister_opp_notifier);
> -
> -static void devm_devfreq_opp_release(struct device *dev, void *res)
> -{
> -	devfreq_unregister_opp_notifier(dev, *(struct devfreq **)res);
> -}
> -
> -/**
> - * devm_devfreq_register_opp_notifier() - Resource-managed
> - *					  devfreq_register_opp_notifier()
> - * @dev:	The devfreq user device. (parent of devfreq)
> - * @devfreq:	The devfreq object.
> - */
> -int devm_devfreq_register_opp_notifier(struct device *dev,
> -				       struct devfreq *devfreq)
> -{
> -	struct devfreq **ptr;
> -	int ret;
> -
> -	ptr = devres_alloc(devm_devfreq_opp_release, sizeof(*ptr), GFP_KERNEL);
> -	if (!ptr)
> -		return -ENOMEM;
> -
> -	ret = devfreq_register_opp_notifier(dev, devfreq);
> -	if (ret) {
> -		devres_free(ptr);
> -		return ret;
> -	}
> -
> -	*ptr = devfreq;
> -	devres_add(dev, ptr);
> -
> -	return 0;
> -}
> -EXPORT_SYMBOL(devm_devfreq_register_opp_notifier);
> -
> -/**
> - * devm_devfreq_unregister_opp_notifier() - Resource-managed
> - *					    devfreq_unregister_opp_notifier()
> - * @dev:	The devfreq user device. (parent of devfreq)
> - * @devfreq:	The devfreq object.
> - */
> -void devm_devfreq_unregister_opp_notifier(struct device *dev,
> -					 struct devfreq *devfreq)
> -{
> -	WARN_ON(devres_release(dev, devm_devfreq_opp_release,
> -			       devm_devfreq_dev_match, devfreq));
> -}
> -EXPORT_SYMBOL(devm_devfreq_unregister_opp_notifier);
> -
>  /**
>   * devfreq_register_notifier() - Register a driver with devfreq
>   * @devfreq:	The devfreq object.
>   * @nb:		The notifier block to register.
>   * @list:	DEVFREQ_TRANSITION_NOTIFIER.
> diff --git a/drivers/devfreq/exynos-bus.c b/drivers/devfreq/exynos-bus.c
> index c832673273a2..29f422469960 100644
> --- a/drivers/devfreq/exynos-bus.c
> +++ b/drivers/devfreq/exynos-bus.c
> @@ -356,17 +356,10 @@ static int exynos_bus_probe(struct platform_device *pdev)
>  		dev_err(dev, "failed to add devfreq device\n");
>  		ret = PTR_ERR(bus->devfreq);
>  		goto err;
>  	}
>  
> -	/* Register opp_notifier to catch the change of OPP  */
> -	ret = devm_devfreq_register_opp_notifier(dev, bus->devfreq);
> -	if (ret < 0) {
> -		dev_err(dev, "failed to register opp notifier\n");
> -		goto err;
> -	}
> -
>  	/*
>  	 * Enable devfreq-event to get raw data which is used to determine
>  	 * current bus load.
>  	 */
>  	ret = exynos_bus_enable_edev(bus);
> diff --git a/drivers/devfreq/rk3399_dmc.c b/drivers/devfreq/rk3399_dmc.c
> index 2e65d7279d79..f660d2031e8a 100644
> --- a/drivers/devfreq/rk3399_dmc.c
> +++ b/drivers/devfreq/rk3399_dmc.c
> @@ -454,12 +454,10 @@ static int rk3399_dmcfreq_probe(struct platform_device *pdev)
>  	if (IS_ERR(data->devfreq)) {
>  		ret = PTR_ERR(data->devfreq);
>  		goto err_free_opp;
>  	}
>  
> -	devm_devfreq_register_opp_notifier(dev, data->devfreq);
> -
>  	data->dev = dev;
>  	platform_set_drvdata(pdev, data);
>  
>  	return 0;
>  
> @@ -470,14 +468,10 @@ static int rk3399_dmcfreq_probe(struct platform_device *pdev)
>  
>  static int rk3399_dmcfreq_remove(struct platform_device *pdev)
>  {
>  	struct rk3399_dmcfreq *dmcfreq = dev_get_drvdata(&pdev->dev);
>  
> -	/*
> -	 * Before remove the opp table we need to unregister the opp notifier.
> -	 */
> -	devm_devfreq_unregister_opp_notifier(dmcfreq->dev, dmcfreq->devfreq);
>  	dev_pm_opp_of_remove_table(dmcfreq->dev);
>  
>  	return 0;
>  }
>  
> diff --git a/include/linux/devfreq.h b/include/linux/devfreq.h
> index 4b5cc80abbe3..bf6ebfbc1e8a 100644
> --- a/include/linux/devfreq.h
> +++ b/include/linux/devfreq.h
> @@ -220,18 +220,10 @@ extern void devfreq_resume(void);
>  extern int update_devfreq(struct devfreq *devfreq);
>  
>  /* Helper functions for devfreq user device driver with OPP. */
>  extern struct dev_pm_opp *devfreq_recommended_opp(struct device *dev,
>  					   unsigned long *freq, u32 flags);
> -extern int devfreq_register_opp_notifier(struct device *dev,
> -					 struct devfreq *devfreq);
> -extern int devfreq_unregister_opp_notifier(struct device *dev,
> -					   struct devfreq *devfreq);
> -extern int devm_devfreq_register_opp_notifier(struct device *dev,
> -					      struct devfreq *devfreq);
> -extern void devm_devfreq_unregister_opp_notifier(struct device *dev,
> -						struct devfreq *devfreq);
>  extern int devfreq_register_notifier(struct devfreq *devfreq,
>  					struct notifier_block *nb,
>  					unsigned int list);
>  extern int devfreq_unregister_notifier(struct devfreq *devfreq,
>  					struct notifier_block *nb,
> 

It looks good to me.
But, this patch don't remove the inline functions in devfreq.h.
- devfreq_register_opp_notifier
- devfreq_unregister_opp_notifier
- devm_devfreq_register_opp_notifier
- devm_devfreq_unregister_opp_notifier

-- 
Best Regards,
Chanwoo Choi
Samsung Electronics

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