From mboxrd@z Thu Jan 1 00:00:00 1970 From: Chanwoo Choi Subject: Re: [PATCH v3 3/8] PM / devfreq: Show the available min/max frequency through sysfs node Date: Fri, 13 Oct 2017 15:47:25 +0900 Message-ID: <59E0617D.10309@samsung.com> References: <1507691364-3899-1-git-send-email-cw00.choi@samsung.com> <1507691364-3899-4-git-send-email-cw00.choi@samsung.com> <20171011111532epcms1p3036bcc7be2cc00057fe478fc868ba71d@epcms1p3> <59DEEAA5.3050905@samsung.com> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 8BIT Return-path: Received: from mailout2.samsung.com ([203.254.224.25]:13631 "EHLO mailout2.samsung.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751414AbdJMGr1 (ORCPT ); Fri, 13 Oct 2017 02:47:27 -0400 In-reply-to: <59DEEAA5.3050905@samsung.com> Sender: linux-pm-owner@vger.kernel.org List-Id: linux-pm@vger.kernel.org To: "myungjoo.ham@samsung.com" Cc: cwchoi00@gmail.com, Kyungmin Park , "rafael.j.wysocki@intel.com" , Inki Dae , "linux-kernel@vger.kernel.org" , "linux-pm@vger.kernel.org" Hi, On 2017년 10월 12일 13:08, Chanwoo Choi wrote: > On 2017년 10월 11일 21:57, Chanwoo Choi wrote: >> On Wed, Oct 11, 2017 at 8:15 PM, MyungJoo Ham wrote: >>>> The existing {min|max}_freq sysfs nodes don't consider whether min/max_freq >>>> are available or not. Those sysfs nodes show just the stored value >>>> in the struct devfreq. >>>> >>>> The devfreq uses the OPP interface and then dev_pm_opp_{disable|add}() >>>> might change the state of the device's supported frequency. This patch >>>> shows the available minimum and maximum frequency through sysfs node. >>>> >>>> Signed-off-by: Chanwoo Choi >>>> --- >>>> drivers/devfreq/devfreq.c | 18 ++++++++++++++++-- >>>> 1 file changed, 16 insertions(+), 2 deletions(-) >>>> >>>> diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c >>>> index 2ce1fd0a1324..799a0cf75d39 100644 >>>> --- a/drivers/devfreq/devfreq.c >>>> +++ b/drivers/devfreq/devfreq.c >>>> @@ -1128,7 +1128,14 @@ static ssize_t min_freq_store(struct device *dev, struct device_attribute *attr, >>>> static ssize_t min_freq_show(struct device *dev, struct device_attribute *attr, >>>> char *buf) >>>> { >>>> - return sprintf(buf, "%lu\n", to_devfreq(dev)->min_freq); >>>> + struct devfreq *df = to_devfreq(dev); >>>> + unsigned long min_freq = to_devfreq(dev)->min_freq; >>>> + unsigned long available_min_freq = find_available_min_freq(df); >>>> + >>>> + if (available_min_freq != 0 && min_freq < available_min_freq) >>> >>> nitpick: >>> >>> If available_min_freq == 0, >>> it can't be min_freq < available_min_freq anyway; >>> it's unsigned. >> >> If the dev_pm_opp_find_*() return the error in the find_available_min_freq(), >> avaiable_min_freq is zero. So, if available_min_freq is zero, >> min_freq_show doesn't need to compare 'min_freq < available_min_freq'. >> >> In result, if 'available_min_freq' is zero, min_freq_show() only considers >> the 'min_freq' variable. > > I'll modify this patch as following: How about that? > > + if (available_min_freq == 0) > + goto out; > + else if (min_freq < available_min_freq) > + min_freq = available_min_freq; > + > +out: > + return sprintf(buf, "%lu\n", min_freq); > Please ignore this approach because I'll use the new 'scaling_min/max_freq' variables on v4. > >>> >>>> + min_freq = available_min_freq; >>>> + >>>> + return sprintf(buf, "%lu\n", min_freq); >>>> } >>>> >>>> static ssize_t max_freq_store(struct device *dev, struct device_attribute *attr, >>>> @@ -1162,7 +1169,14 @@ static ssize_t max_freq_store(struct device *dev, struct device_attribute *attr, >>>> static ssize_t max_freq_show(struct device *dev, struct device_attribute *attr, >>>> char *buf) >>>> { >>>> - return sprintf(buf, "%lu\n", to_devfreq(dev)->max_freq); >>>> + struct devfreq *df = to_devfreq(dev); >>>> + unsigned long max_freq = to_devfreq(dev)->max_freq; >>>> + unsigned long available_max_freq = find_available_max_freq(df); >>>> + >>>> + if (available_max_freq != 0 && max_freq > available_max_freq) >>>> + max_freq = available_max_freq; >>> >>> similar here. >> >> ditto. >> >>> >>>> + >>>> + return sprintf(buf, "%lu\n", max_freq); >>>> } >>>> static DEVICE_ATTR_RW(max_freq); >> >> > > -- Best Regards, Chanwoo Choi Samsung Electronics