Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751615AbaKMFdQ (ORCPT ); Thu, 13 Nov 2014 00:33:16 -0500 Received: from mail-pa0-f50.google.com ([209.85.220.50]:61325 "EHLO mail-pa0-f50.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750837AbaKMFdP (ORCPT ); Thu, 13 Nov 2014 00:33:15 -0500 Message-ID: <54644295.2050003@gmail.com> Date: Thu, 13 Nov 2014 11:03:09 +0530 From: Sanchayan Maity User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.2.0 MIME-Version: 1.0 To: Shawn Guo CC: Stefan Agner , rtc-linux@googlegroups.com, linux@arm.linux.org.uk, kernel@pengutronix.de, b35083@freescale.com, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [[PATCHv2] 3/3] drivers/rtc/rtc-snvs: Add clock support References: <30e496ce2d6521e608df3b68b73b3e05caa1daef.1415364391.git.maitysanchayan@gmail.com> <7807253ec0fd349b5bb1489e0d3b1347@agner.ch> <546320D3.2030501@gmail.com> <20141112104735.GK2704@dragon> In-Reply-To: <20141112104735.GK2704@dragon> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wednesday 12 November 2014 04:17 PM, Shawn Guo wrote: > On Wed, Nov 12, 2014 at 02:26:51PM +0530, Sanchayan Maity wrote: >> On Wednesday 12 November 2014 02:57 AM, Stefan Agner wrote: >>> On 2014-11-07 14:04, Sanchayan Maity wrote: >>>> This patch adds clock enable and disable support for >>>> the SNVS peripheral, which is required for using the >>>> RTC within the SNVS block. >>> >>> What happens if the device tree node is there while this patch is not >>> applied? I guess the driver would load, but since the clocks of the >>> peripheral are not enabled the first register access would lead to bus >>> error or similar. If this is the case, this would break bisectability. >>> You should move the device tree patch to the end. >>> >> >> If the DT node was present with this patch not applied, the driver would >> still crash with a bus error, since the clocks for SNVS are not explicitly >> enabled anywhere else. I had not thought about any problems which might >> occur later with git bisect. Will move this to the end with v3. > > Since changes on rtc-snvs.c will need to go through RTC subsystem tree, > that means I cannot apply DTS changes until the driver patch gets > mainlined and appears on my tree. > > Shawn Shawn So the approach in this patch is OK and acceptable? Since the DT changes cannot be applied by you, till this goes through the RTC subsystem tree, gets mainlined and appears on your tree, I will send out this patch by itself then and send the DT changes later once this gets mainlined? I did not CC Alessandro Zummo, the maintainer of RTC subsystem by mistake. Once you ACK/OK this i will send out this patch in isolation then or just CC Alessandro Zummo. - Sanchayan > >> >> Thanks. >> >> Regards, >> Sanchayan. >> >>> Other than that >>> Acked-by: Stefan Agner >>> >>> -- >>> Stefan >>> >>>> >>>> Signed-off-by: Sanchayan Maity >>>> --- >>>> drivers/rtc/rtc-snvs.c | 34 ++++++++++++++++++++++++++++++++-- >>>> 1 file changed, 32 insertions(+), 2 deletions(-) >>>> >>>> diff --git a/drivers/rtc/rtc-snvs.c b/drivers/rtc/rtc-snvs.c >>>> index fa384fe..d4a6512 100644 >>>> --- a/drivers/rtc/rtc-snvs.c >>>> +++ b/drivers/rtc/rtc-snvs.c >>>> @@ -17,6 +17,7 @@ >>>> #include >>>> #include >>>> #include >>>> +#include >>>> >>>> /* These register offsets are relative to LP (Low Power) range */ >>>> #define SNVS_LPCR 0x04 >>>> @@ -39,6 +40,7 @@ struct snvs_rtc_data { >>>> void __iomem *ioaddr; >>>> int irq; >>>> spinlock_t lock; >>>> + struct clk *clk; >>>> }; >>>> >>>> static u32 rtc_read_lp_counter(void __iomem *ioaddr) >>>> @@ -260,6 +262,18 @@ static int snvs_rtc_probe(struct platform_device *pdev) >>>> if (data->irq < 0) >>>> return data->irq; >>>> >>>> + data->clk = devm_clk_get(&pdev->dev, "snvs-rtc"); >>>> + if (IS_ERR(data->clk)) { >>>> + data->clk = NULL; >>>> + } else { >>>> + ret = clk_prepare_enable(data->clk); >>>> + if (ret) { >>>> + dev_err(&pdev->dev, >>>> + "Could not prepare or enable the snvs clock\n"); >>>> + return ret; >>>> + } >>>> + } >>>> + >>>> platform_set_drvdata(pdev, data); >>>> >>>> spin_lock_init(&data->lock); >>>> @@ -280,7 +294,7 @@ static int snvs_rtc_probe(struct platform_device *pdev) >>>> if (ret) { >>>> dev_err(&pdev->dev, "failed to request irq %d: %d\n", >>>> data->irq, ret); >>>> - return ret; >>>> + goto error_rtc_device_register; >>>> } >>>> >>>> data->rtc = devm_rtc_device_register(&pdev->dev, pdev->name, >>>> @@ -288,10 +302,16 @@ static int snvs_rtc_probe(struct platform_device *pdev) >>>> if (IS_ERR(data->rtc)) { >>>> ret = PTR_ERR(data->rtc); >>>> dev_err(&pdev->dev, "failed to register rtc: %d\n", ret); >>>> - return ret; >>>> + goto error_rtc_device_register; >>>> } >>>> >>>> return 0; >>>> + >>>> +error_rtc_device_register: >>>> + if (data->clk) >>>> + clk_disable_unprepare(data->clk); >>>> + >>>> + return ret; >>>> } >>>> >>>> #ifdef CONFIG_PM_SLEEP >>>> @@ -302,16 +322,26 @@ static int snvs_rtc_suspend(struct device *dev) >>>> if (device_may_wakeup(dev)) >>>> enable_irq_wake(data->irq); >>>> >>>> + if (data->clk) >>>> + clk_disable_unprepare(data->clk); >>>> + >>>> return 0; >>>> } >>>> >>>> static int snvs_rtc_resume(struct device *dev) >>>> { >>>> struct snvs_rtc_data *data = dev_get_drvdata(dev); >>>> + int ret; >>>> >>>> if (device_may_wakeup(dev)) >>>> disable_irq_wake(data->irq); >>>> >>>> + if (data->clk) { >>>> + ret = clk_prepare_enable(data->clk); >>>> + if (ret) >>>> + return ret; >>>> + } >>>> + >>>> return 0; >>>> } >>>> #endif >>> -- 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/