From mboxrd@z Thu Jan 1 00:00:00 1970 From: Steffen Trumtrar Subject: Re: [PATCH 4/9] MXS/i.MX28: there is more than one way to clock the RTC Date: Thu, 7 Mar 2013 09:19:08 +0100 Message-ID: <20130307081908.GB3571@pengutronix.de> References: <1362405948-12992-1-git-send-email-s.trumtrar@pengutronix.de> <1362405948-12992-5-git-send-email-s.trumtrar@pengutronix.de> <20130307064824.GD5372@S2101-09.ap.freescale.net> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: <20130307064824.GD5372-rvtDTF3kK1ictlrPMvKcciBecyulp+rMXqFh9Ls21Oc@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: devicetree-discuss-bounces+gldd-devicetree-discuss=m.gmane.org-uLR06cmDAlY/bJ5BZ2RsiQ@public.gmane.org Sender: "devicetree-discuss" To: Shawn Guo Cc: Alessandro Zummo , rtc-linux-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org, devicetree-discuss-uLR06cmDAlY/bJ5BZ2RsiQ@public.gmane.org, Juergen Beisert , kernel-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org, linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org List-Id: devicetree@vger.kernel.org Hi Shawn! On Thu, Mar 07, 2013 at 02:48:26PM +0800, Shawn Guo wrote: > On Mon, Mar 04, 2013 at 03:05:43PM +0100, Steffen Trumtrar wrote: > > From: Juergen Beisert > > > > Reflect the possibilities via device tree and configure the RTC correctly > > > > Signed-off-by: Juergen Beisert > > Signed-off-by: Steffen Trumtrar > > --- > > arch/arm/boot/dts/imx28.dtsi | 2 ++ > > drivers/rtc/rtc-stmp3xxx.c | 76 ++++++++++++++++++++++++++++++++++++++++++ > > 2 files changed, 78 insertions(+) > > > > diff --git a/arch/arm/boot/dts/imx28.dtsi b/arch/arm/boot/dts/imx28.dtsi > > index dcd0844..d89af79 100644 > > --- a/arch/arm/boot/dts/imx28.dtsi > > +++ b/arch/arm/boot/dts/imx28.dtsi > > @@ -818,6 +818,8 @@ > > compatible = "fsl,imx28-rtc", "fsl,stmp3xxx-rtc"; > > reg = <0x80056000 0x2000>; > > interrupts = <29>; > > + clocks = <&clks 65>, <&clks 40> ; > > + clock-names = "32k", "24m"; > > The changes should be in some mxs/arch patch. > > > }; > > > > i2c0: i2c@80058000 { > > diff --git a/drivers/rtc/rtc-stmp3xxx.c b/drivers/rtc/rtc-stmp3xxx.c > > index 7311292..fb4b823 100644 > > --- a/drivers/rtc/rtc-stmp3xxx.c > > +++ b/drivers/rtc/rtc-stmp3xxx.c > > @@ -21,6 +21,7 @@ > > #include > > #include > > #include > > +#include > > #include > > #include > > #include > > @@ -176,11 +177,55 @@ static irqreturn_t stmp3xxx_rtc_interrupt(int irq, void *dev_id) > > return IRQ_NONE; > > } > > > > +/* > > + * To keep the energy consumption low, keep only > > + * the really used oscillator running when the power is down > > + */ > > +static void stmp3xxx_alarm_keep_oscillator(const struct stmp3xxx_rtc_data *rtc_data) > > +{ > > + switch (rtc_data->clk_src) { > > + case MXS_OSC_24M: > > + /* keep the 24 MHz oscillator running even in power down */ > > + writel(STMP3XXX_RTC_PERSISTENT0_XTAL32_FREQ | /* 24 MHz / 750 */ > > + STMP3XXX_RTC_PERSISTENT0_XTAL24MHZ_PWRUP, > > + rtc_data->io + STMP3XXX_RTC_PERSISTENT0_SET); > > + writel(STMP3XXX_RTC_PERSISTENT0_XTAL32KHZ_PWRUP | > > + STMP3XXX_RTC_PERSISTENT0_CLOCKSOURCE, > > + rtc_data->io + STMP3XXX_RTC_PERSISTENT0_CLR); > > + break; > > + case MXS_OSC_32K: > > + /* keep the 32 kHz oscillator running even in power down */ > > + writel(STMP3XXX_RTC_PERSISTENT0_XTAL32_FREQ | /* 32 kHz */ > > + STMP3XXX_RTC_PERSISTENT0_XTAL32KHZ_PWRUP | > > + STMP3XXX_RTC_PERSISTENT0_CLOCKSOURCE, > > + rtc_data->io + STMP3XXX_RTC_PERSISTENT0_SET); > > + writel(STMP3XXX_RTC_PERSISTENT0_XTAL24MHZ_PWRUP, > > + rtc_data->io + STMP3XXX_RTC_PERSISTENT0_CLR); > > + break; > > + case MXS_OSC_32K768: > > + /* keep the 32 kHz oscillator running even in power down */ > > + writel(STMP3XXX_RTC_PERSISTENT0_XTAL32KHZ_PWRUP | > > + STMP3XXX_RTC_PERSISTENT0_CLOCKSOURCE, > > + rtc_data->io + STMP3XXX_RTC_PERSISTENT0_SET); > > + writel(STMP3XXX_RTC_PERSISTENT0_XTAL32_FREQ | /* 32.768 kHz */ > > + STMP3XXX_RTC_PERSISTENT0_XTAL24MHZ_PWRUP, > > + rtc_data->io + STMP3XXX_RTC_PERSISTENT0_CLR); > > + break; > > + case MXS_UNKNOWN: > > + default: > > + break; > > + } > > +} > > + > > static int stmp3xxx_alarm_irq_enable(struct device *dev, unsigned int enabled) > > { > > struct stmp3xxx_rtc_data *rtc_data = dev_get_drvdata(dev); > > > > + stmp3xxx_alarm_keep_oscillator(rtc_data); > > + > > if (enabled) { > > + writel(STMP3XXX_RTC_PERSISTENT0_ALARM_WAKE, /* to be able to sleep */ > > + rtc_data->io + STMP3XXX_RTC_PERSISTENT0_CLR); > > writel(STMP3XXX_RTC_PERSISTENT0_ALARM_EN | > > STMP3XXX_RTC_PERSISTENT0_ALARM_WAKE_EN, > > rtc_data->io + STMP3XXX_RTC_PERSISTENT0_SET); > > @@ -248,6 +293,8 @@ static int stmp3xxx_rtc_probe(struct platform_device *pdev) > > { > > struct stmp3xxx_rtc_data *rtc_data; > > struct resource *r; > > + struct clk *clk; > > + unsigned long rate; > > int err; > > > > rtc_data = kzalloc(sizeof *rtc_data, GFP_KERNEL); > > @@ -280,6 +327,35 @@ static int stmp3xxx_rtc_probe(struct platform_device *pdev) > > platform_set_drvdata(pdev, rtc_data); > > > > mxs_reset_block(rtc_data->io); > > + > > + /* > > + * configure the RTC to provide the correct time > > + */ > > + clk = clk_get(&pdev->dev, "32k"); > > devm_clk_get > > Shawn > > > + if (IS_ERR(clk)) { > > + /* just a fall back */ > > + dev_warn(&pdev->dev, "RTC's input clock undefined\n"); > > + rtc_data->clk_src = MXS_OSC_24M; > > + } else { > > + rate = clk_get_rate(clk); > > + if (rate == 0) { > > + /* no dedicated external crystal */ > > + rtc_data->clk_src = MXS_OSC_24M; > > + dev_info(&pdev->dev, "Using 24 MHz as RTC's clock\n"); > > + } else if (rate == 32000) { > > + rtc_data->clk_src = MXS_OSC_32K; > > + dev_info(&pdev->dev, "Using 32.0 kHz as RTC's clock\n"); > > + } else if (rate == 32768) { > > + rtc_data->clk_src = MXS_OSC_32K768; > > + dev_info(&pdev->dev, "Using 32.768 kHz as RTC's clock\n"); > > + } else > > + dev_warn(&pdev->dev, > > + "Cannot init the RTC's clock source\n"); > > + } > > + > > + /* basically configure the RTC's input clock */ > > + stmp3xxx_alarm_keep_oscillator(rtc_data); > > + > > writel(STMP3XXX_RTC_PERSISTENT0_ALARM_EN | > > STMP3XXX_RTC_PERSISTENT0_ALARM_WAKE_EN | > > STMP3XXX_RTC_PERSISTENT0_ALARM_WAKE, > > -- > > 1.7.10.4 > > > > I can agree to all your comments to this patch and the others in this series and will take care of all of them. Thanks, Steffen -- Pengutronix e.K. | | Industrial Linux Solutions | http://www.pengutronix.de/ | Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |