Re: [PATCH] devfreq_cooling: pass a pointer to devfreq in the power model callbacks

From: Javi Merino
Date: Mon Jun 20 2016 - 13:43:53 EST


Eduardo, Rui,

On Fri, Jun 03, 2016 at 10:25:31AM +0100, Javi Merino wrote:
> When the devfreq cooling device was designed, it was an oversight not to
> pass a pointer to the struct devfreq as the first parameters of the
> callbacks. The design patterns of the kernel suggest it for a good
> reason.
>
> By passing a pointer to struct devfreq, the driver can register one
> function that works with multiple devices. With the current
> implementation, a driver that can work with multiple devices has to
> create multiple copies of the same function with different parameters so
> that each devfreq_cooling_device can use the appropriate one. By
> passing a pointer to struct devfreq, the driver can identify which
> device it's referring to.
>
> Cc: Zhang Rui <rui.zhang@xxxxxxxxx>
> Cc: Eduardo Valentin <edubezval@xxxxxxxxx>
> Reviewed-by: Punit Agrawal <punit.agrawal@xxxxxxx>
> Signed-off-by: Javi Merino <javi.merino@xxxxxxx>
> ---
> drivers/thermal/devfreq_cooling.c | 5 +++--
> include/linux/devfreq_cooling.h | 6 ++++--
> 2 files changed, 7 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/thermal/devfreq_cooling.c b/drivers/thermal/devfreq_cooling.c
> index 01f0015f80dc..c549d83a0c7d 100644
> --- a/drivers/thermal/devfreq_cooling.c
> +++ b/drivers/thermal/devfreq_cooling.c
> @@ -238,7 +238,7 @@ get_static_power(struct devfreq_cooling_device *dfc, unsigned long freq)
> return 0;
> }
>
> - return dfc->power_ops->get_static_power(voltage);
> + return dfc->power_ops->get_static_power(df, voltage);
> }
>
> /**
> @@ -262,7 +262,8 @@ get_dynamic_power(struct devfreq_cooling_device *dfc, unsigned long freq,
> struct devfreq_cooling_power *dfc_power = dfc->power_ops;
>
> if (dfc_power->get_dynamic_power)
> - return dfc_power->get_dynamic_power(freq, voltage);
> + return dfc_power->get_dynamic_power(dfc->devfreq, freq,
> + voltage);
>
> freq_mhz = freq / 1000000;
> power = (u64)dfc_power->dyn_power_coeff * freq_mhz * voltage * voltage;
> diff --git a/include/linux/devfreq_cooling.h b/include/linux/devfreq_cooling.h
> index 7adf6cc4b305..959714e93e5b 100644
> --- a/include/linux/devfreq_cooling.h
> +++ b/include/linux/devfreq_cooling.h
> @@ -37,8 +37,10 @@
> * @dyn_power_coeff * frequency * voltage^2
> */
> struct devfreq_cooling_power {
> - unsigned long (*get_static_power)(unsigned long voltage);
> - unsigned long (*get_dynamic_power)(unsigned long freq,
> + unsigned long (*get_static_power)(struct devfreq *devfreq,
> + unsigned long voltage);
> + unsigned long (*get_dynamic_power)(struct devfreq *devfreq,
> + unsigned long freq,
> unsigned long voltage);
> unsigned long dyn_power_coeff;
> };

If there are no objections, can you pick this for the next merge
window?

Thanks,
Javi