linux-kernel - Re: [PATCH v2 9/9] rtc: Add support for the MediaTek MT6358 RTC

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Message-ID: <20190402140627.GC22216@piout.net>
Date:   Tue, 2 Apr 2019 16:06:27 +0200
From:   Alexandre Belloni <alexandre.belloni@...tlin.com>
To:     Yingjoe Chen <yingjoe.chen@...iatek.com>
Cc:     Hsin-Hsiung Wang <hsin-hsiung.wang@...iatek.com>,
        Lee Jones <lee.jones@...aro.org>,
        Rob Herring <robh+dt@...nel.org>,
        Matthias Brugger <matthias.bgg@...il.com>,
        Mark Brown <broonie@...nel.org>,
        Eddie Huang <eddie.huang@...iatek.com>,
        linux-rtc@...r.kernel.org, devicetree@...r.kernel.org,
        srv_heupstream@...iatek.com,
        Alessandro Zummo <a.zummo@...ertech.it>,
        Marc Zyngier <marc.zyngier@....com>,
        Ran Bi <ran.bi@...iatek.com>,
        Sean Wang <sean.wang@...iatek.com>,
        linux-kernel@...r.kernel.org, Liam Girdwood <lgirdwood@...il.com>,
        linux-mediatek@...ts.infradead.org,
        Mark Rutland <mark.rutland@....com>,
        linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH v2 9/9] rtc: Add support for the MediaTek MT6358 RTC

On 21/03/2019 17:51:26+0800, Yingjoe Chen wrote:
> 
> Hi,
> 
> 
> Should use 'rtc: mt6397: ' as prefix for this patch.
> 
> 
> On Mon, 2019-03-11 at 11:46 +0800, Hsin-Hsiung Wang wrote:
> > From: Ran Bi <ran.bi@...iatek.com>
> > 
> > This add support for the MediaTek MT6358 RTC. MT6397 mfd will pass
> > RTC_WRTGR address offset to RTC driver.
> > 
> > Signed-off-by: Ran Bi <ran.bi@...iatek.com>
> > ---
> >  drivers/rtc/rtc-mt6397.c | 16 ++++++++++++++--
> >  1 file changed, 14 insertions(+), 2 deletions(-)
> > 
> > diff --git a/drivers/rtc/rtc-mt6397.c b/drivers/rtc/rtc-mt6397.c
> > index f85f1fc..c8a0090 100644
> > --- a/drivers/rtc/rtc-mt6397.c
> > +++ b/drivers/rtc/rtc-mt6397.c
> > @@ -27,7 +27,7 @@
> >  #define RTC_BBPU		0x0000
> >  #define RTC_BBPU_CBUSY		BIT(6)
> >  
> > -#define RTC_WRTGR		0x003c
> > +#define RTC_WRTGR_DEFAULT	0x003c
> >  
> >  #define RTC_IRQ_STA		0x0002
> >  #define RTC_IRQ_STA_AL		BIT(0)
> > @@ -78,6 +78,7 @@ struct mt6397_rtc {
> >  	struct regmap		*regmap;
> >  	int			irq;
> >  	u32			addr_base;
> > +	u32			wrtgr_offset;
> >  };
> >  
> >  static int mtk_rtc_write_trigger(struct mt6397_rtc *rtc)
> > @@ -86,7 +87,8 @@ static int mtk_rtc_write_trigger(struct mt6397_rtc *rtc)
> >  	int ret;
> >  	u32 data;
> >  
> > -	ret = regmap_write(rtc->regmap, rtc->addr_base + RTC_WRTGR, 1);
> > +	ret = regmap_write(rtc->regmap,
> > +			   rtc->addr_base + rtc->wrtgr_offset, 1);
> >  	if (ret < 0)
> >  		return ret;
> >  
> > @@ -341,6 +343,15 @@ static int mtk_rtc_probe(struct platform_device *pdev)
> >  	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> >  	rtc->addr_base = res->start;
> >  
> > +	res = platform_get_resource(pdev, IORESOURCE_REG, 0);
> > +	if (res) {
> > +		rtc->wrtgr_offset = res->start;
> > +		dev_info(&pdev->dev, "register offset:%d\n", rtc->wrtgr_offset);
> > +	} else {
> > +		rtc->wrtgr_offset = RTC_WRTGR_DEFAULT;
> > +		dev_err(&pdev->dev, "Failed to get register offset\n");
> > +	}
> > +
> 
> Since this will be passed by MFD, do we still need to keep the DEFAULT?
> Any case this platform_get_resource will failed?
> 
> It's too bad HW changed this offset, but I'm not sure about passing this
> information from MFD. We have 1 register that have different offset now,
> and might have others for future chips, adding each one by
> IORESOURCE_IRQ doesn't looks like a good solution. Keeping this
> information in RTC driver only also looks better.
> 

I agree, this would be better.


-- 
Alexandre Belloni, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com