From patchwork Mon Mar 4 14:05:43 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Steffen Trumtrar X-Patchwork-Id: 2213021 Return-Path: X-Original-To: patchwork-linux-arm@patchwork.kernel.org Delivered-To: patchwork-process-083081@patchwork2.kernel.org Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) by patchwork2.kernel.org (Postfix) with ESMTP id DC58ADF2F2 for ; Mon, 4 Mar 2013 14:13:17 +0000 (UTC) Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1UCW5o-0002tQ-6F; Mon, 04 Mar 2013 14:10:16 +0000 Received: from metis.ext.pengutronix.de ([2001:6f8:1178:4:290:27ff:fe1d:cc33]) by merlin.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1UCW2W-0000xE-B6 for linux-arm-kernel@lists.infradead.org; Mon, 04 Mar 2013 14:06:53 +0000 Received: from dude.hi.pengutronix.de ([2001:6f8:1178:2:21e:67ff:fe11:9c5c]) by metis.ext.pengutronix.de with esmtp (Exim 4.72) (envelope-from ) id 1UCW1j-0004Yf-Ak; Mon, 04 Mar 2013 15:06:03 +0100 Received: from str by dude.hi.pengutronix.de with local (Exim 4.80) (envelope-from ) id 1UCW1h-0002Ja-9K; Mon, 04 Mar 2013 15:06:01 +0100 From: Steffen Trumtrar To: rtc-linux@googlegroups.com, devicetree-discuss@lists.ozlabs.org Subject: [PATCH 4/9] MXS/i.MX28: there is more than one way to clock the RTC Date: Mon, 4 Mar 2013 15:05:43 +0100 Message-Id: <1362405948-12992-5-git-send-email-s.trumtrar@pengutronix.de> X-Mailer: git-send-email 1.7.10.4 In-Reply-To: <1362405948-12992-1-git-send-email-s.trumtrar@pengutronix.de> References: <1362405948-12992-1-git-send-email-s.trumtrar@pengutronix.de> X-SA-Exim-Connect-IP: 2001:6f8:1178:2:21e:67ff:fe11:9c5c X-SA-Exim-Mail-From: str@pengutronix.de X-SA-Exim-Scanned: No (on metis.ext.pengutronix.de); SAEximRunCond expanded to false X-PTX-Original-Recipient: linux-arm-kernel@lists.infradead.org X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20130304_090652_690695_76E6BBA6 X-CRM114-Status: GOOD ( 21.39 ) X-Spam-Score: -2.5 (--) X-Spam-Report: SpamAssassin version 3.3.2 on merlin.infradead.org summary: Content analysis details: (-2.5 points) pts rule name description ---- ---------------------- -------------------------------------------------- -0.6 RP_MATCHES_RCVD Envelope sender domain matches handover relay domain -1.9 BAYES_00 BODY: Bayes spam probability is 0 to 1% [score: 0.0000] Cc: Alessandro Zummo , Shawn Guo , kernel@pengutronix.de, Steffen Trumtrar , linux-arm-kernel@lists.infradead.org X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org 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"; }; 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"); + 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,