> Devfreq returns governor predicted frequency as current
> frequency via sysfs interface. But device may not support
> all frequencies that governor predicts. As per the design
> its driver responsibility to maintain current frequency
> at which device is operating. So add a callback in device
> profile to fix this.
>
> Signed-off-by: Rajagopal Venkat <rajagopal.ven...@linaro.org>
We still need to support "intended frequency".
The "cur_freq" node is to show the intended frequency.
As told before, you need to make additional API and ABI for the
"actual frequency".
Cheers!
MyungJoo
> ---
> drivers/devfreq/devfreq.c | 14 ++++++++++++--
> include/linux/devfreq.h | 6 +++---
> 2 files changed, 15 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
> index 375b5aa1..798e8ca 100644
> --- a/drivers/devfreq/devfreq.c
> +++ b/drivers/devfreq/devfreq.c
> @@ -176,7 +176,6 @@ struct devfreq *devfreq_add_device(struct device *dev,
> devfreq->dev.release = devfreq_dev_release;
> devfreq->profile = profile;
> devfreq->governor = governor;
> - devfreq->previous_freq = profile->initial_freq;
> devfreq->governor_data = data;
> devfreq->nb.notifier_call = devfreq_notifier_call;
> devfreq->min_freq = profile->min_freq;
> @@ -272,7 +271,18 @@ static ssize_t show_governor(struct device *dev,
> static ssize_t show_freq(struct device *dev,
> struct device_attribute *attr, char *buf)
> {
> - return sprintf(buf, "%lu\n", to_devfreq(dev)->previous_freq);
> + int ret;
> + unsigned long freq;
> + struct devfreq *devfreq = to_devfreq(dev);
> +
> + if (devfreq->profile->get_cur_freq) {
> + ret = devfreq->profile->get_cur_freq(devfreq->dev.parent,
> + &freq);
> + if (!ret)
> + return sprintf(buf, "%lu\n", freq);
> + }
> +
> + return sprintf(buf, "<unknown>");
> }
>
> static ssize_t store_min_freq(struct device *dev, struct device_attribute
> *attr,
> diff --git a/include/linux/devfreq.h b/include/linux/devfreq.h
> index 7c6517f..43f111f 100644
> --- a/include/linux/devfreq.h
> +++ b/include/linux/devfreq.h
> @@ -76,6 +76,8 @@ struct devfreq_dev_status {
> * explained above with "DEVFREQ_FLAG_*" macros.
> * @get_dev_status The device should provide the current performance
> * status to devfreq, which is used by governors.
> + * @get_cur_freq The device should provide the current frequency
> + * at which it is operating.
> * @exit An optional callback that is called when devfreq
> * is removing the devfreq object due to error or
> * from devfreq_remove_device() call. If the user
> @@ -91,6 +93,7 @@ struct devfreq_dev_profile {
> int (*target)(struct device *dev, unsigned long *freq, u32 flags);
> int (*get_dev_status)(struct device *dev,
> struct devfreq_dev_status *stat);
> + int (*get_cur_freq)(struct device *dev, unsigned long *freq);
> void (*exit)(struct device *dev);
> };
>
> @@ -119,7 +122,6 @@ struct devfreq_governor {
> * @nb notifier block used to notify devfreq object that it
> should
> * reevaluate operable frequencies. Devfreq users may use
> * devfreq.nb to the corresponding register notifier call chain.
> - * @previous_freq previously configured frequency value.
> * @governor_data Private data of the governor. The devfreq framework
> * does not touch this.
> * @min_freq Limit minimum frequency requested by user (0: none)
> @@ -142,8 +144,6 @@ struct devfreq {
> const struct devfreq_governor *governor;
> struct notifier_block nb;
>
> - unsigned long previous_freq;
> -
> void *governor_data; /* private data for governors */
>
> unsigned long min_freq;
> --
> 1.7.11.3
>
>
>
>
>
>
>
>
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