Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752331Ab1BUX6F (ORCPT ); Mon, 21 Feb 2011 18:58:05 -0500 Received: from e3.ny.us.ibm.com ([32.97.182.143]:43789 "EHLO e3.ny.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751250Ab1BUXzz (ORCPT ); Mon, 21 Feb 2011 18:55:55 -0500 From: John Stultz To: LKML Cc: John Stultz , Thomas Gleixner , Alessandro Zummo , Marcelo Roberto Jimenez , rtc-linux@googlegroups.com Subject: [PATCH 10/10] RTC: Fix up rtc.txt documentation to reflect changes to generic rtc layer Date: Mon, 21 Feb 2011 15:55:38 -0800 Message-Id: <1298332538-31216-11-git-send-email-john.stultz@linaro.org> X-Mailer: git-send-email 1.7.3.2.146.gca209 In-Reply-To: <1298332538-31216-1-git-send-email-john.stultz@linaro.org> References: <1298332538-31216-1-git-send-email-john.stultz@linaro.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3472 Lines: 73 Now that the genric RTC layer handles much of the RTC functionality, the rtc.txt documentation needs to be updated to remove outdated information. CC: Thomas Gleixner CC: Alessandro Zummo CC: Marcelo Roberto Jimenez CC: rtc-linux@googlegroups.com Signed-off-by: John Stultz --- Documentation/rtc.txt | 29 ++++++++++------------------- 1 files changed, 10 insertions(+), 19 deletions(-) diff --git a/Documentation/rtc.txt b/Documentation/rtc.txt index 9104c10..2501604 100644 --- a/Documentation/rtc.txt +++ b/Documentation/rtc.txt @@ -178,38 +178,29 @@ RTC class framework, but can't be supported by the older driver. setting the longer alarm time and enabling its IRQ using a single request (using the same model as EFI firmware). - * RTC_UIE_ON, RTC_UIE_OFF ... if the RTC offers IRQs, it probably - also offers update IRQs whenever the "seconds" counter changes. - If needed, the RTC framework can emulate this mechanism. + * RTC_UIE_ON, RTC_UIE_OFF ... if the RTC offers IRQs, the RTC framework + will emulate this mechanism. - * RTC_PIE_ON, RTC_PIE_OFF, RTC_IRQP_SET, RTC_IRQP_READ ... another - feature often accessible with an IRQ line is a periodic IRQ, issued - at settable frequencies (usually 2^N Hz). + * RTC_PIE_ON, RTC_PIE_OFF, RTC_IRQP_SET, RTC_IRQP_READ ... these icotls + are emulated via a kernel hrtimer. In many cases, the RTC alarm can be a system wake event, used to force Linux out of a low power sleep state (or hibernation) back to a fully operational state. For example, a system could enter a deep power saving state until it's time to execute some scheduled tasks. -Note that many of these ioctls need not actually be implemented by your -driver. The common rtc-dev interface handles many of these nicely if your -driver returns ENOIOCTLCMD. Some common examples: +Note that many of these ioctls are handled by the common rtc-dev interface. +Some common examples: * RTC_RD_TIME, RTC_SET_TIME: the read_time/set_time functions will be called with appropriate values. - * RTC_ALM_SET, RTC_ALM_READ, RTC_WKALM_SET, RTC_WKALM_RD: the - set_alarm/read_alarm functions will be called. + * RTC_ALM_SET, RTC_ALM_READ, RTC_WKALM_SET, RTC_WKALM_RD: gets or sets + the alarm rtc_timer. May call the set_alarm driver function. - * RTC_IRQP_SET, RTC_IRQP_READ: the irq_set_freq function will be called - to set the frequency while the framework will handle the read for you - since the frequency is stored in the irq_freq member of the rtc_device - structure. Your driver needs to initialize the irq_freq member during - init. Make sure you check the requested frequency is in range of your - hardware in the irq_set_freq function. If it isn't, return -EINVAL. If - you cannot actually change the frequency, do not define irq_set_freq. + * RTC_IRQP_SET, RTC_IRQP_READ: These are emulated by the generic code. - * RTC_PIE_ON, RTC_PIE_OFF: the irq_set_state function will be called. + * RTC_PIE_ON, RTC_PIE_OFF: These are also emulated by the generic code. If all else fails, check out the rtc-test.c driver! -- 1.7.3.2.146.gca209 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/