Date: Thu, 23 Aug 2012 07:21:19 +0000 (GMT)
From: MyungJoo Ham <myungjoo.ham@samsung.com>
Subject: Re: [PATCH 1/2] PM: devfreq: add freq table and available_freqs
To: "XiaoguangChen<chenxg"@marvell.com
Cc: linux-kernel@vger.kernel.org
Reply-to: myungjoo.ham@samsung.com
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> Devfreq framework don't have a frequency table, add it
> for easy use.
> 
> Signed-off-by: Xiaoguang Chen <chenxg@marvell.com>

As we are going to have transition statistics (similar with trans_table
and time_in_state of CPUfreq), we are going to have a data structure
that your suggested code may use.

Could you please rephrase your code to be based on Jonghwa's patch?
"devfreq: Add sysfs node for representing frequency transition information."

Cheers!
MyungJoo

> ---
>  drivers/devfreq/devfreq.c |   26 ++++++++++++++++++++++++++
>  include/linux/devfreq.h   |   12 ++++++++++++
>  2 files changed, 38 insertions(+), 0 deletions(-)
> 
> diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
> index 70c31d4..2144200 100644
> --- a/drivers/devfreq/devfreq.c
> +++ b/drivers/devfreq/devfreq.c
> @@ -460,6 +460,17 @@ int devfreq_remove_device(struct devfreq *devfreq)
>  	return 0;
>  }
>  
> +/*
> + * devfreq_set_freq_table()- Set frequency table for devfreq
> + * @devfreq	The devfreq instance
> + * @table	The frequency table that device supports
> + */
> +void devfreq_set_freq_table(struct devfreq *devfreq,
> +			    struct devfreq_frequency_table *table)
> +{
> +	devfreq->freq_table = table;
> +}
> +
>  static ssize_t show_governor(struct device *dev,
>  			     struct device_attribute *attr, char *buf)
>  {
> @@ -472,6 +483,20 @@ static ssize_t show_freq(struct device *dev,
>  	return sprintf(buf, "%lu\n", to_devfreq(dev)->previous_freq);
>  }
>  
> +static ssize_t show_avail_freq(struct device *dev,
> +			       struct device_attribute *attr, char *buf)
> +{
> +	int len = 0, i;
> +	struct devfreq *devfreq = to_devfreq(dev);
> +	if (devfreq->freq_table)
> +		for (i = 0; devfreq->freq_table[i].frequency != DEVFREQ_TABLE_END; i++)
> +			len += sprintf(buf + len, "%lu\n",
> +				       devfreq->freq_table[i].frequency);
> +	if (len == 0)
> +		len += sprintf(buf + len, "No frequency table is provided\n");
> +	return len;
> +}
> +
>  static ssize_t show_polling_interval(struct device *dev,
>  				     struct device_attribute *attr, char *buf)
>  {
> @@ -595,6 +620,7 @@ static struct device_attribute devfreq_attrs[] = {
>  	       store_polling_interval),
>  	__ATTR(min_freq, S_IRUGO | S_IWUSR, show_min_freq, store_min_freq),
>  	__ATTR(max_freq, S_IRUGO | S_IWUSR, show_max_freq, store_max_freq),
> +	__ATTR(available_freqs, S_IRUGO, show_avail_freq, NULL),
>  	{ },
>  };
>  
> diff --git a/include/linux/devfreq.h b/include/linux/devfreq.h
> index 281c72a..e5e4036 100644
> --- a/include/linux/devfreq.h
> +++ b/include/linux/devfreq.h
> @@ -52,6 +52,14 @@ struct devfreq_dev_status {
>   */
>  #define DEVFREQ_FLAG_LEAST_UPPER_BOUND		0x1
>  
> +#define DEVFREQ_ENTRY_INVALID (~0)
> +#define DEVFREQ_TABLE_END     (~1)
> +
> +struct devfreq_frequency_table {
> +	unsigned int index;
> +	unsigned long frequency;
> +};
> +
>  /**
>   * struct devfreq_dev_profile - Devfreq's user device profile
>   * @initial_freq	The operating frequency when devfreq_add_device() is
> @@ -130,6 +138,7 @@ struct devfreq_governor {
>   *			"devfreq_monitor" executions to reevaluate
>   *			frequency/voltage of the device. Set by
>   *			profile's polling_ms interval.
> + * @freq_table	The frequency table that device supports
>   * @data	Private data of the governor. The devfreq framework does not
>   *		touch this.
>   * @being_removed	a flag to mark that this object is being removed in
> @@ -157,6 +166,7 @@ struct devfreq {
>  	unsigned long polling_jiffies;
>  	unsigned long previous_freq;
>  	unsigned int next_polling;
> +	struct devfreq_frequency_table *freq_table;
>  
>  	void *data; /* private data for governors */
>  
> @@ -180,6 +190,8 @@ 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 void devfreq_set_freq_table(struct devfreq *devfreq,
> +				   struct devfreq_frequency_table *table);
>  
>  #ifdef CONFIG_DEVFREQ_GOV_POWERSAVE
>  extern const struct devfreq_governor devfreq_powersave;
> -- 
> 1.7.0.4
> 
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