Messages in this thread | | | Date | Tue, 24 Apr 2018 11:48:06 +0900 | From | Chanwoo Choi <> | Subject | Re: [PATCH 1/3] PM / devfreq: Actually support providing freq_table |
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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@linaro.org> > --- > > 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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