Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753248AbbDGDaW (ORCPT ); Mon, 6 Apr 2015 23:30:22 -0400 Received: from comal.ext.ti.com ([198.47.26.152]:42983 "EHLO comal.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753062AbbDGDaT (ORCPT ); Mon, 6 Apr 2015 23:30:19 -0400 Message-ID: <55234F25.5060708@ti.com> Date: Tue, 7 Apr 2015 08:59:41 +0530 From: Keerthy User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.5.0 MIME-Version: 1.0 To: Andrew Morton , CC: Keerthy , , , Subject: Re: [rtc-linux] [PATCH] rtc: OMAP: Add external 32k clock feature References: <1425375722-13412-1-git-send-email-j-keerthy@ti.com> <20150324155916.cfd1b7ab442271466160283f@linux-foundation.org> In-Reply-To: <20150324155916.cfd1b7ab442271466160283f@linux-foundation.org> Content-Type: text/plain; charset="windows-1252"; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1785 Lines: 53 Hi Andrew, Apologies for replying late. On Wednesday 25 March 2015 04:29 AM, Andrew Morton wrote: > On Tue, 3 Mar 2015 15:12:02 +0530 Keerthy wrote: > >> Add external 32k clock feature. The internal clock will be gated during suspend. >> Hence make use of the external 32k clock so that rtc is functional accross >> suspend/resume. >> >> ... >> >> @@ -446,6 +449,7 @@ static const struct omap_rtc_device_type omap_rtc_default_type = { >> >> static const struct omap_rtc_device_type omap_rtc_am3352_type = { >> .has_32kclk_en = true, >> + .has_osc_ext_32k = true, >> .has_kicker = true, >> .has_irqwakeen = true, >> .has_pmic_mode = true, >> @@ -543,7 +547,16 @@ static int __init omap_rtc_probe(struct platform_device *pdev) >> if (rtc->type->has_32kclk_en) { >> reg = rtc_read(rtc, OMAP_RTC_OSC_REG); >> rtc_writel(rtc, OMAP_RTC_OSC_REG, >> - reg | OMAP_RTC_OSC_32KCLK_EN); >> + reg | OMAP_RTC_OSC_32KCLK_EN); >> + } >> + >> + /* Enable External clock as the source */ >> + >> + if (rtc->type->has_osc_ext_32k) { >> + rtc_writel(rtc, OMAP_RTC_OSC_REG, >> + (OMAP_RTC_OSC_EXT_32K | >> + rtc_read(rtc, OMAP_RTC_OSC_REG)) & >> + (~OMAP_RTC_OSC_OSC32K_GZ)); >> } > > How do we know that all systems have this external clock and that it > works OK? > AM335 and AM43X have the external clock feature which we choose using RTC_OSC_REG. I verified it works OK by seeing the RTC seconds ticking even after switching the source to the external 32k Clock. Regards, Keerthy -- 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/