From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <rtc-linux+bncBD66BCOYSQBBBLE6RWUQKGQEO6QRZ3Q@googlegroups.com>
Received: from comal.ext.ti.com (comal.ext.ti.com. [198.47.26.152])
        by gmr-mx.google.com with ESMTPS id t6si557383igz.3.2015.04.06.20.29.48
        for <rtc-linux@googlegroups.com>
        (version=TLSv1 cipher=RC4-SHA bits=128/128);
        Mon, 06 Apr 2015 20:29:48 -0700 (PDT)
Message-ID: <55234F25.5060708@ti.com>
Date: Tue, 7 Apr 2015 08:59:41 +0530
From: Keerthy <a0393675@ti.com>
MIME-Version: 1.0
To: Andrew Morton <akpm@linux-foundation.org>, <rtc-linux@googlegroups.com>
CC: Keerthy <j-keerthy@ti.com>, <a.zummo@towertech.it>,
        <linux-kernel@vger.kernel.org>, <linux-omap@vger.kernel.org>
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=UTF-8; format=flowed
Reply-To: rtc-linux@googlegroups.com
List-ID: <rtc-linux.googlegroups.com>
List-Post: <http://groups.google.com/group/rtc-linux/post>, <mailto:rtc-linux@googlegroups.com>
List-Help: <http://groups.google.com/support/>, <mailto:rtc-linux+help@googlegroups.com>
List-Archive: <http://groups.google.com/group/rtc-linux
Sender: rtc-linux@googlegroups.com
List-Subscribe: <http://groups.google.com/group/rtc-linux/subscribe>, <mailto:rtc-linux+subscribe@googlegroups.com>
List-Unsubscribe: <mailto:googlegroups-manage+712029733259+unsubscribe@googlegroups.com>,
 <http://groups.google.com/group/rtc-linux/subscribe>

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 <j-keerthy@ti.com> 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

-- 
-- 
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.