Hi,
On 2018년 04월 24일 09:20, Bjorn Andersson wrote:
> The code in devfreq_add_device() handles the case where a freq_table is
> passed by the client, but then requests min and max frequences from
> the, in this case absent, opp tables.
>
> Read the min and max frequencies from the frequency table, which has
> been built from the opp table if one exists, instead of querying the
> opp table.
>
> Signed-off-by: Bjorn Andersson <bjorn.andersson@xxxxxxxxxx>
> ---
>
> An alternative approach is to clarify in the devfreq code that it's not
> possible to pass a freq_table and then in patch 3 create an opp table for the
> device in runtime; although the error handling of this becomes non-trivial.
>
> Transitioning the UFSHCD to use opp tables directly is hindered by the fact
> that the Qualcomm UFS hardware has two different clocks that needs to be
> running at different rates, so we would need a way to describe the two rates in
> the opp table. (And would force us to change the DT binding)
>
> drivers/devfreq/devfreq.c | 22 ++++------------------
> 1 file changed, 4 insertions(+), 18 deletions(-)
>
> diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
> index fe2af6aa88fc..086ced50a13d 100644
> --- a/drivers/devfreq/devfreq.c
> +++ b/drivers/devfreq/devfreq.c
> @@ -74,30 +74,16 @@ static struct devfreq *find_device_devfreq(struct device *dev)
>
> static unsigned long find_available_min_freq(struct devfreq *devfreq)
> {
> - struct dev_pm_opp *opp;
> - unsigned long min_freq = 0;
> -
> - opp = dev_pm_opp_find_freq_ceil(devfreq->dev.parent, &min_freq);
> - if (IS_ERR(opp))
> - min_freq = 0;
> - else
> - dev_pm_opp_put(opp);
> + struct devfreq_dev_profile *profile = devfreq->profile;
>
> - return min_freq;
> + return profile->freq_table[0];
It is wrong. The thermal framework support the devfreq-cooling device
which uses the dev_pm_opp_enable/disable().
In order to find the correct available min frequency,
the devfreq have to use the OPP function instead of using the first entry
of the freq_table array.
> }
>
> static unsigned long find_available_max_freq(struct devfreq *devfreq)
> {
> - struct dev_pm_opp *opp;
> - unsigned long max_freq = ULONG_MAX;
> -
> - opp = dev_pm_opp_find_freq_floor(devfreq->dev.parent, &max_freq);
> - if (IS_ERR(opp))
> - max_freq = 0;
> - else
> - dev_pm_opp_put(opp);
> + struct devfreq_dev_profile *profile = devfreq->profile;
>
> - return max_freq;
> + return profile->freq_table[profile->max_state - 1];
> }
ditto.
>
> /**
>
--
Best Regards,
Chanwoo Choi
Samsung Electronics
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