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: Thu, 12 Oct 2017 13:08:05 +0900 Message-ID: <59DEEAA5.3050905@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> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 8BIT Return-path: Received: from mailout4.samsung.com ([203.254.224.34]:45529 "EHLO mailout4.samsung.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750722AbdJLEII (ORCPT ); Thu, 12 Oct 2017 00:08:08 -0400 In-reply-to: Sender: linux-pm-owner@vger.kernel.org List-Id: linux-pm@vger.kernel.org To: cwchoi00@gmail.com, "myungjoo.ham@samsung.com" Cc: Kyungmin Park , "rafael.j.wysocki@intel.com" , Inki Dae , "linux-kernel@vger.kernel.org" , "linux-pm@vger.kernel.org" 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); >> >>> + 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