linux-kernel - Re: [PATCH v1] rtc: snvs: add poweroff function

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Date:	Fri, 26 Sep 2014 10:21:12 +0800
From:	Robin Gong <b38343@...escale.com>
To:	Shawn Guo <shawn.guo@...escale.com>
CC:	<robh+dt@...nel.org>, <pawel.moll@....com>, <mark.rutland@....com>,
	<ijc+devicetree@...lion.org.uk>, <galak@...eaurora.org>,
	<a.zummo@...ertech.it>, <grant.likely@...aro.org>,
	<kernel@...gutronix.de>, <LW@...O-electronics.de>,
	<linux-arm-kernel@...ts.infradead.org>,
	<devicetree@...r.kernel.org>, <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v1] rtc: snvs: add poweroff function

On Fri, Sep 26, 2014 at 09:24:11AM +0800, Shawn Guo wrote:
> On Thu, Sep 25, 2014 at 10:13:53AM +0800, Robin Gong wrote:
> > On i.mx6 chips, PMIC_ON_REQ can be pulled by snvs LPCR. That can be
> > used poweroff system if PMIC_ON_REQ connected with external PMIC or
> > power control circuit.Power up again if PMIC_ON_REQ pulled high.
> > 
> > Signed-off-by: Robin Gong <b38343@...escale.com>
> 
> I'm not sure it's a good idea to plug poweroff support into RTC driver.
> If RTC driver is built out, poweroff function is gone too.
> 
> Shawn
>
Yes, that's true since there is no real SNVS driver, only snvs-rtc and
snvs-caam driver. I'll pick up the patch about the driver which located
in drivers/power/reset.
> > ---
> >  Documentation/devicetree/bindings/crypto/fsl-sec4.txt |  4 ++++
> >  drivers/rtc/rtc-snvs.c                                | 18 ++++++++++++++++++
> >  2 files changed, 22 insertions(+)
> > 
> > diff --git a/Documentation/devicetree/bindings/crypto/fsl-sec4.txt b/Documentation/devicetree/bindings/crypto/fsl-sec4.txt
> > index e402277..00d67f2 100644
> > --- a/Documentation/devicetree/bindings/crypto/fsl-sec4.txt
> > +++ b/Documentation/devicetree/bindings/crypto/fsl-sec4.txt
> > @@ -363,11 +363,15 @@ Secure Non-Volatile Storage (SNVS) Low Power (LP) RTC Node
> >        Value type: <prop-encoded-array>
> >        Definition: A standard property.  Specifies the physical
> >            address and length of the SNVS LP configuration registers.
> > +  - fsl,poweroff
> > +      Usage: opertional, recommend if PMIC_ON_REQ connected with external
> > +	PMIC or power control circuit.
> >  
> >  EXAMPLE
> >  	sec_mon_rtc_lp@...000 {
> >  		compatible = "fsl,sec-v4.0-mon-rtc-lp";
> >  		reg = <0x34 0x58>;
> > +		fsl,poweroff;
> >  	};
> >  
> >  =====================================================================
> > diff --git a/drivers/rtc/rtc-snvs.c b/drivers/rtc/rtc-snvs.c
> > index fa384fe..ef32541 100644
> > --- a/drivers/rtc/rtc-snvs.c
> > +++ b/drivers/rtc/rtc-snvs.c
> > @@ -29,6 +29,8 @@
> >  #define SNVS_LPCR_SRTC_ENV	(1 << 0)
> >  #define SNVS_LPCR_LPTA_EN	(1 << 1)
> >  #define SNVS_LPCR_LPWUI_EN	(1 << 3)
> > +#define SNVS_LPCR_DP		(1 << 5)
> > +#define SNVS_LPCR_TOP		(1 << 6)
> >  #define SNVS_LPSR_LPTA		(1 << 0)
> >  
> >  #define SNVS_LPPGDR_INIT	0x41736166
> > @@ -41,6 +43,8 @@ struct snvs_rtc_data {
> >  	spinlock_t lock;
> >  };
> >  
> > +static void __iomem *snvs_base;
> > +
> >  static u32 rtc_read_lp_counter(void __iomem *ioaddr)
> >  {
> >  	u64 read1, read2;
> > @@ -241,8 +245,17 @@ static irqreturn_t snvs_rtc_irq_handler(int irq, void *dev_id)
> >  	return events ? IRQ_HANDLED : IRQ_NONE;
> >  }
> >  
> > +static void snvs_poweroff(void)
> > +{
> > +	u32 value;
> > +
> > +	value = readl(snvs_base + SNVS_LPCR);
> > +	writel(value | SNVS_LPCR_DP | SNVS_LPCR_TOP, snvs_base + SNVS_LPCR);
> > +}
> > +
> >  static int snvs_rtc_probe(struct platform_device *pdev)
> >  {
> > +	struct device_node *np = pdev->dev.of_node;
> >  	struct snvs_rtc_data *data;
> >  	struct resource *res;
> >  	int ret;
> > @@ -260,6 +273,11 @@ static int snvs_rtc_probe(struct platform_device *pdev)
> >  	if (data->irq < 0)
> >  		return data->irq;
> >  
> > +	if (np && of_get_property(np, "fsl,poweroff", NULL)) {
> > +		snvs_base = data->ioaddr;
> > +		pm_power_off = snvs_poweroff;
> > +	}
> > +
> >  	platform_set_drvdata(pdev, data);
> >  
> >  	spin_lock_init(&data->lock);
> > -- 
> > 1.9.1
> > 
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