Messages in this thread Patch in this message | | | Date | Wed, 22 Feb 2006 14:15:54 -0800 | From | Andrew Morton <> | Subject | Re: [PATCH 01/11] RTC subsystem, class |
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Alessandro Zummo <a.zummo@towertech.it> wrote: > > This patch adds the basic RTC subsytem infrastructure > to the kernel. > > rtc/class.c - registration facilities for RTC drivers > rtc/interface.c - kernel/rtc interface functions > rtc/utils.c - misc rtc-related utility functions > rtc/hctosys.c - snippet of code that copies hw clock to sw clock > at bootup, if configured to do so.
Couple of questions.
a) Is all this code 100% compatible with existing kernel interfaces? No userspace-visible breakage? Right down the all the same -EFOO return codes for all the same errors?
b) Will the kernel compile and run at each stage of your patch series? I hit a nasty no-compile half an hour through a git-bisect session yesterday and it's still smarting.
Code looks nice and clean.
> + if (idr_pre_get(&rtc_idr, GFP_KERNEL) == 0) { > + err = -ENOMEM; > + goto exit; > + } > + > + > + mutex_lock(&idr_lock); > + err = idr_get_new(&rtc_idr, NULL, &id); > + mutex_unlock(&idr_lock);
Oh the IDR API does suck. Not your fault though.
> + if ((rtc = kzalloc(sizeof(struct rtc_device), GFP_KERNEL)) == NULL) {
You do a lot of
if ((lhs = rhs) == something)
But preferred kernel style is
lhs = rhs; if (lhs == something)
Generally, kernel style is to keep things as utterly simple as they can be.
+config RTC_CLASS > + tristate "RTC class" > + depends on EXPERIMENTAL > + default y > + help > + Generic RTC class support. If you say yes here, you will > + be allowed to plug one or more RTCs to your system. You will > + probably want to enable one of more of the interfaces below. > + > + This driver can also be built as a module. If so, the module > + will be called rtc-class. > + > +config RTC_HCTOSYS > + bool "Set system time from RTC on startup" > + depends on RTC_CLASS = y > + default y > + help > + If you say yes here, the system time will be set using > + the value read from the specified RTC device. This is useful > + in order to avoid unnecessary fschk runs. > + > +config RTC_HCTOSYS_DEVICE > + string "The RTC to read the time from" > + depends on RTC_HCTOSYS = y > + default "rtc0" > + help > + The RTC device that will be used as the source for > + the system time, usually rtc0.
hm. Doesn't the above disable RTC_HCTOSYS and RTC_HCTOSYS_DEVICE if RTC_CLASS=m?
> --- /dev/null 1970-01-01 00:00:00.000000000 +0000 > +++ linux-rtc/drivers/rtc/interface.c 2006-02-15 04:13:37.000000000 +0100 > @@ -0,0 +1,274 @@ > +/* > + * RTC subsystem, interface functions > + * > + * Copyright (C) 2005 Tower Technologies > + * Author: Alessandro Zummo <a.zummo@towertech.it> > + * > + * based on arch/arm/common/rtctime.c > + * > + * This program is free software; you can redistribute it and/or modify > + * it under the terms of the GNU General Public License as published by > + * the Free Software Foundation; version 2 of the License. > +*/ > + > +#include <linux/rtc.h> > + > +extern struct class *rtc_class; Please always put extern declarations in a header file.
> +} > +EXPORT_SYMBOL(rtc_set_alarm); > + > +void rtc_update_irq(struct class_device *class_dev, > + unsigned long num, unsigned long events) > +{ > + struct rtc_device *rtc = to_rtc_device(class_dev); > + > + spin_lock(&rtc->irq_lock); > + rtc->irq_data = (rtc->irq_data + (num << 8)) | events; > + spin_unlock(&rtc->irq_lock); > + > + spin_lock(&rtc->irq_task_lock); > + if (rtc->irq_task) > + rtc->irq_task->func(rtc->irq_task->private_data); > + spin_unlock(&rtc->irq_task_lock); > + > + wake_up_interruptible(&rtc->irq_queue); > + kill_fasync(&rtc->async_queue, SIGIO, POLL_IN); > +} > +EXPORT_SYMBOL(rtc_update_irq);
I don't know what this does.
Please document all non-static functions. Preferably with kernel-doc format. Feel free to document static functions too..
> +int rtc_irq_set_freq(struct class_device *class_dev, struct rtc_task *task, int freq) > +{ > + int err = 0, tmp = 0; > + unsigned long flags; > + struct rtc_device *rtc = to_rtc_device(class_dev); > + > + /* allowed range is 2-8192 */ > + if (freq < 2 || freq > 8192) > + return -EINVAL; > + > +/* if ((freq > rtc_max_user_freq) && (!capable(CAP_SYS_RESOURCE))) > + return -EACCES; > +*/
What happened to rtc_max_user_freq?
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