From mboxrd@z Thu Jan 1 00:00:00 1970 From: Nicolas Ferre Subject: Re: [PATCH v6 7/9] rtc: at91sam9: use clk API instead of relying on AT91_SLOW_CLOCK Date: Tue, 23 Sep 2014 10:21:27 +0200 Message-ID: <54212D87.4060908@atmel.com> References: <1411400563-570-1-git-send-email-boris.brezillon@free-electrons.com> <1411400563-570-8-git-send-email-boris.brezillon@free-electrons.com> Mime-Version: 1.0 Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1411400563-570-8-git-send-email-boris.brezillon-wi1+55ScJUtKEb57/3fJTNBPR1lH4CV8@public.gmane.org> Sender: devicetree-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Boris BREZILLON , Jean-Christophe Plagniol-Villard , Alexandre Belloni , Andrew Victor , Alessandro Zummo , rtc-linux-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org, Samuel Ortiz , Lee Jones , Johan Hovold Cc: Rob Herring , Pawel Moll , Mark Rutland , Ian Campbell , Kumar Gala , devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: devicetree@vger.kernel.org On 22/09/2014 17:42, Boris BREZILLON : > The RTT block is using the slow clock which is accessible through the clk > API. > Use the clk API to retrieve, enable and get the slow clk rate instead of > the AT91_SLOW_CLOCK macro (which hardcodes the slow clk rate). > Doing this allows us to reference the clk thus preventing the CCF from > disabling it during the "disable unused" phase. > > Signed-off-by: Boris BREZILLON > Acked-by: Alexandre Belloni Acked-by: Nicolas Ferre > --- > drivers/rtc/rtc-at91sam9.c | 28 ++++++++++++++++++++++++---- > 1 file changed, 24 insertions(+), 4 deletions(-) > > diff --git a/drivers/rtc/rtc-at91sam9.c b/drivers/rtc/rtc-at91sam9.c > index 902cd01..d20e118 100644 > --- a/drivers/rtc/rtc-at91sam9.c > +++ b/drivers/rtc/rtc-at91sam9.c > @@ -23,6 +23,7 @@ > #include > #include > #include > +#include > > /* > * This driver uses two configurable hardware resources that live in the > @@ -61,8 +62,6 @@ > #define AT91_RTT_ALMS (1 << 0) /* Real-time Alarm Status */ > #define AT91_RTT_RTTINC (1 << 1) /* Real-time Timer Increment */ > > -#define AT91_SLOW_CLOCK 32768 > - > /* > * We store ALARM_DISABLED in ALMV to record that no alarm is set. > * It's also the reset value for that field. > @@ -77,6 +76,7 @@ struct sam9_rtc { > struct regmap *gpbr; > unsigned int gpbr_offset; > int irq; > + struct clk *sclk; > }; > > #define rtt_readl(rtc, field) \ > @@ -328,6 +328,7 @@ static int at91_rtc_probe(struct platform_device *pdev) > struct sam9_rtc *rtc; > int ret, irq; > u32 mr; > + unsigned int sclk_rate; > > irq = platform_get_irq(pdev, 0); > if (irq < 0) { > @@ -385,11 +386,27 @@ static int at91_rtc_probe(struct platform_device *pdev) > return -ENOMEM; > } > > + rtc->sclk = devm_clk_get(&pdev->dev, NULL); > + if (IS_ERR(rtc->sclk)) > + return PTR_ERR(rtc->sclk); > + > + sclk_rate = clk_get_rate(rtc->sclk); > + if (!sclk_rate || sclk_rate > AT91_RTT_RTTRST) { > + dev_err(&pdev->dev, "Invalid slow clock rate"); > + return -EINVAL; > + } > + > + ret = clk_prepare_enable(rtc->sclk); > + if (ret) { > + dev_err(&pdev->dev, "Could not enable slow clock"); > + return ret; > + } > + > mr = rtt_readl(rtc, MR); > > /* unless RTT is counting at 1 Hz, re-initialize it */ > - if ((mr & AT91_RTT_RTPRES) != AT91_SLOW_CLOCK) { > - mr = AT91_RTT_RTTRST | (AT91_SLOW_CLOCK & AT91_RTT_RTPRES); > + if ((mr & AT91_RTT_RTPRES) != sclk_rate) { > + mr = AT91_RTT_RTTRST | (sclk_rate & AT91_RTT_RTPRES); > gpbr_writel(rtc, 0); > } > > @@ -434,6 +451,9 @@ static int at91_rtc_remove(struct platform_device *pdev) > /* disable all interrupts */ > rtt_writel(rtc, MR, mr & ~(AT91_RTT_ALMIEN | AT91_RTT_RTTINCIEN)); > > + if (!IS_ERR(rtc->sclk)) > + clk_disable_unprepare(rtc->sclk); > + > return 0; > } > > -- Nicolas Ferre -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html