From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.free-electrons.com (down.free-electrons.com. [37.187.137.238]) by gmr-mx.google.com with ESMTP id e130si767366wme.2.2016.02.04.14.08.05 for ; Thu, 04 Feb 2016 14:08:05 -0800 (PST) Date: Thu, 4 Feb 2016 23:07:54 +0100 From: Alexandre Belloni To: Joshua Clayton Cc: Alessandro Zummo , rtc-linux@googlegroups.com, linux-kernel@vger.kernel.org Subject: [rtc-linux] Re: [PATCH v3 1/3] rtc: Add functions to set and read rtc offset Message-ID: <20160204220754.GB4782@piout.net> References: <20160202104111.GU20165@piout.net> <1454519804-13770-1-git-send-email-stillcompiling@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 In-Reply-To: <1454519804-13770-1-git-send-email-stillcompiling@gmail.com> Reply-To: rtc-linux@googlegroups.com List-ID: List-Post: , List-Help: , List-Archive: , List-Unsubscribe: , Hi, On 03/02/2016 at 09:16:42 -0800, Joshua Clayton wrote : > diff --git a/drivers/rtc/interface.c b/drivers/rtc/interface.c > index 5836751..c064eb9 100644 > --- a/drivers/rtc/interface.c > +++ b/drivers/rtc/interface.c > @@ -939,4 +939,61 @@ void rtc_timer_cancel(struct rtc_device *rtc, struct rtc_timer *timer) > mutex_unlock(&rtc->ops_lock); > } > > +/** > + * rtc_read_offset - Read the amount of rtc offset in parts per billion > + * @ rtc: rtc device to be used > + * @ offset: the offset in parts per billion > + * > + * see below for details. > + * > + * Kernel interface to read rtc clock offset > + * Returns 0 on success, or a negative number on error. > + * If the rtc offset is not setable (or not implemented), return 0 and put > + * 0 in the offset value; > + */ > +int rtc_read_offset(struct rtc_device *rtc, long *offset) > +{ > + int ret = 0; > + > + if (!rtc->ops) > + return -ENODEV; > + > + if (!rtc->ops->set_offset) { > + *offset = 0; > + return 0; > + } > + I should have been clearer but this is not necessary anymore since the sysfs interface will not always be present but you should probably test rtc->ops->read_offset instead. > + mutex_lock(&rtc->ops_lock); > + ret = rtc->ops->read_offset(rtc->dev.parent, offset); > + mutex_unlock(&rtc->ops_lock); > + return ret; > +} > > +/** > + * rtc_set_offset - Adjusts the duration of the average second > + * @ rtc: rtc device to be used > + * @ offset: the offset in parts per billion > + * > + * Some rtc's allow an adjustment to the average duration of a second > + * to compensate for differences in the actual clock rate due to temperature, > + * the crystal, capacitor, etc. > + * > + * Kernel interface to adjust an rtc clock offset. > + * Return 0 on success, or a negative number on error. > + * If the rtc offset is not setable (or not implemented), return -EINVAL > + */ > +int rtc_set_offset(struct rtc_device *rtc, long offset) > +{ > + int ret = 0; > + > + if (!rtc->ops) > + return -ENODEV; > + > + if (!rtc->ops->set_offset) > + return -EINVAL; > + > + mutex_lock(&rtc->ops_lock); > + ret = rtc->ops->set_offset(rtc->dev.parent, offset); > + mutex_unlock(&rtc->ops_lock); > + return ret; > +} > diff --git a/include/linux/rtc.h b/include/linux/rtc.h > index 3359f04..b693ada 100644 > --- a/include/linux/rtc.h > +++ b/include/linux/rtc.h > @@ -89,6 +89,8 @@ struct rtc_class_ops { > int (*set_mmss)(struct device *, unsigned long secs); > int (*read_callback)(struct device *, int data); > int (*alarm_irq_enable)(struct device *, unsigned int enabled); > + int (*read_offset)(struct device *, long *offset); > + int (*set_offset)(struct device *, long offset); > }; > > #define RTC_DEVICE_NAME_SIZE 20 > @@ -208,6 +210,8 @@ void rtc_timer_init(struct rtc_timer *timer, void (*f)(void *p), void *data); > int rtc_timer_start(struct rtc_device *rtc, struct rtc_timer *timer, > ktime_t expires, ktime_t period); > void rtc_timer_cancel(struct rtc_device *rtc, struct rtc_timer *timer); > +int rtc_read_offset(struct rtc_device *rtc, long *offset); > +int rtc_set_offset(struct rtc_device *rtc, long offset); > void rtc_timer_do_work(struct work_struct *work); > > static inline bool is_leap_year(unsigned int year) > -- > 2.5.0 > -- Alexandre Belloni, Free Electrons Embedded Linux, Kernel and Android engineering http://free-electrons.com -- -- You received this message because you are subscribed to "rtc-linux". Membership options at http://groups.google.com/group/rtc-linux . Please read http://groups.google.com/group/rtc-linux/web/checklist before submitting a driver. --- You received this message because you are subscribed to the Google Groups "rtc-linux" group. To unsubscribe from this group and stop receiving emails from it, send an email to rtc-linux+unsubscribe@googlegroups.com. For more options, visit https://groups.google.com/d/optout.