From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757320Ab2DDWXu (ORCPT ); Wed, 4 Apr 2012 18:23:50 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:43784 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753868Ab2DDWXt (ORCPT ); Wed, 4 Apr 2012 18:23:49 -0400 Date: Wed, 4 Apr 2012 15:23:47 -0700 From: Andrew Morton To: rtc-linux@googlegroups.com Cc: Alexander Stein , Alessandro Zummo , linux-kernel@vger.kernel.org Subject: Re: [rtc-linux] [PATCH 1/2 RFC] rtc: Add ioctl to get/clear battery low voltage status Message-Id: <20120404152347.2982ec50.akpm@linux-foundation.org> In-Reply-To: <1329236025-31323-1-git-send-email-alexander.stein@systec-electronic.com> References: <1329236025-31323-1-git-send-email-alexander.stein@systec-electronic.com> X-Mailer: Sylpheed 3.0.2 (GTK+ 2.20.1; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 14 Feb 2012 17:13:44 +0100 Alexander Stein wrote: > Currently there is no generic way to get the RTC battery status within > an application. So add an ioctl to read the status bit. > The idea is that the bit is set once a low voltage is detected. It stays > there until it is reset using the RTC_VL_CLR ioctl. > > Signed-off-by: Alexander Stein > --- > include/linux/rtc.h | 3 +++ > 1 files changed, 3 insertions(+), 0 deletions(-) > > diff --git a/include/linux/rtc.h b/include/linux/rtc.h > index 93f4d03..1a6ec5f 100644 > --- a/include/linux/rtc.h > +++ b/include/linux/rtc.h > @@ -91,6 +91,9 @@ struct rtc_pll_info { > #define RTC_PLL_GET _IOR('p', 0x11, struct rtc_pll_info) /* Get PLL correction */ > #define RTC_PLL_SET _IOW('p', 0x12, struct rtc_pll_info) /* Set PLL correction */ > > +#define RTC_VL_READ _IOR('p', 0x13, int) /* Voltage low detector */ > +#define RTC_VL_CLR _IO('p', 0x14) /* Clear voltage low information */ > + > /* interrupt flags */ > #define RTC_IRQF 0x80 /* Any of the following is active */ > #define RTC_PF 0x40 /* Periodic interrupt */ Looks good to me, but I'd like to hear from other RTC driver maintainers, please. Which other devices provide support for reading the batttery status, and is the proposed interface suitable for their drivers?