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From: "Jonathan Neuschäfer" <j.neuschaefer@gmx.net>
To: Alexandre Belloni <alexandre.belloni@bootlin.com>
Cc: "Jonathan Neuschäfer" <j.neuschaefer@gmx.net>,
	linux-kernel@vger.kernel.org, "Lee Jones" <lee.jones@linaro.org>,
	"Rob Herring" <robh+dt@kernel.org>,
	"Thierry Reding" <thierry.reding@gmail.com>,
	"Uwe Kleine-König" <u.kleine-koenig@pengutronix.de>,
	"Alessandro Zummo" <a.zummo@towertech.it>,
	"Shawn Guo" <shawnguo@kernel.org>,
	"Sascha Hauer" <s.hauer@pengutronix.de>,
	"Pengutronix Kernel Team" <kernel@pengutronix.de>,
	"Fabio Estevam" <festevam@gmail.com>,
	"NXP Linux Team" <linux-imx@nxp.com>,
	"Sam Ravnborg" <sam@ravnborg.org>,
	"Linus Walleij" <linus.walleij@linaro.org>,
	"Heiko Stuebner" <heiko.stuebner@theobroma-systems.com>,
	"Stephan Gerhold" <stephan@gerhold.net>,
	"Lubomir Rintel" <lkundrak@v3.sk>,
	"Mark Brown" <broonie@kernel.org>, allen <allen.chen@ite.com.tw>,
	"Mauro Carvalho Chehab" <mchehab+huawei@kernel.org>,
	"David S. Miller" <davem@davemloft.net>,
	devicetree@vger.kernel.org, linux-pwm@vger.kernel.org,
	linux-rtc@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
	"Heiko Stuebner" <heiko@sntech.de>,
	"Josua Mayer" <josua.mayer@jm0.eu>,
	"Andreas Kemnade" <andreas@kemnade.info>,
	"Arnd Bergmann" <arnd@arndb.de>,
	"Daniel Palmer" <daniel@0x0f.com>,
	"Andy Shevchenko" <andy.shevchenko@gmail.com>
Subject: Re: [PATCH v4 5/7] rtc: New driver for RTC in Netronix embedded controller
Date: Mon, 23 Nov 2020 22:31:05 +0100	[thread overview]
Message-ID: <20201123213105.GC456020@latitude> (raw)
In-Reply-To: <20201122231054.GH348979@piout.net>

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On Mon, Nov 23, 2020 at 12:10:54AM +0100, Alexandre Belloni wrote:
> Hi,
> 
> On 22/11/2020 23:27:37+0100, Jonathan Neuschäfer wrote:
> > With this driver, mainline Linux can keep its time and date in sync with
> > the vendor kernel.
> > 
> > Advanced functionality like alarm and automatic power-on is not yet
> > supported.
> > 
> > Signed-off-by: Jonathan Neuschäfer <j.neuschaefer@gmx.net>
> Acked-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
> 
> However, two comments below:
> 
> > +static int ntxec_set_time(struct device *dev, struct rtc_time *tm)
> > +{
> > +	struct ntxec_rtc *rtc = dev_get_drvdata(dev);
> > +	int res = 0;
> > +
> > +	/*
> > +	 * To avoid time overflows while we're writing the full date/time,
> > +	 * set the seconds field to zero before doing anything else. For the
> > +	 * next 59 seconds (plus however long it takes until the RTC's next
> > +	 * update of the second field), the seconds field will not overflow
> > +	 * into the other fields.
> > +	 */
> > +	res = regmap_write(rtc->ec->regmap, NTXEC_REG_WRITE_SECOND, ntxec_reg8(0));
> > +	if (res)
> > +		return res;
> > +
> > +	res = regmap_write(rtc->ec->regmap, NTXEC_REG_WRITE_YEAR, ntxec_reg8(tm->tm_year - 100));
> > +	if (res)
> > +		return res;
> > +
> > +	res = regmap_write(rtc->ec->regmap, NTXEC_REG_WRITE_MONTH, ntxec_reg8(tm->tm_mon + 1));
> > +	if (res)
> > +		return res;
> > +
> > +	res = regmap_write(rtc->ec->regmap, NTXEC_REG_WRITE_DAY, ntxec_reg8(tm->tm_mday));
> > +	if (res)
> > +		return res;
> > +
> > +	res = regmap_write(rtc->ec->regmap, NTXEC_REG_WRITE_HOUR, ntxec_reg8(tm->tm_hour));
> > +	if (res)
> > +		return res;
> > +
> > +	res = regmap_write(rtc->ec->regmap, NTXEC_REG_WRITE_MINUTE, ntxec_reg8(tm->tm_min));
> > +	if (res)
> > +		return res;
> > +
> > +	return regmap_write(rtc->ec->regmap, NTXEC_REG_WRITE_SECOND, ntxec_reg8(tm->tm_sec));
> 
> Couldn't you do a regmap_block_write or a regmap_multi_reg_write which
> would be more efficient as they would be locking the regmap only once.

I can't find regmap_block_write anywhere, but regmap_multi_reg_write
looks like a good approach to simplify the code here.


[...]
> Note that this won't compile after
> https://git.kernel.org/pub/scm/linux/kernel/git/abelloni/linux.git/commit/?id=fdcfd854333be5b30377dc5daa9cd0fa1643a979
> 
> We can solve that with immutable branches though.

Thanks for the heads-up. Please let me know if/when there is any action
that I need to take here.


Jonathan

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  reply	other threads:[~2020-11-23 21:32 UTC|newest]

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-11-22 22:27 [PATCH v4 0/7] Netronix embedded controller driver for Kobo and Tolino ebook readers Jonathan Neuschäfer
2020-11-22 22:27 ` [PATCH v4 1/7] dt-bindings: Add vendor prefix for Netronix, Inc Jonathan Neuschäfer
2020-11-22 22:27 ` [PATCH v4 2/7] dt-bindings: mfd: Add binding for Netronix embedded controller Jonathan Neuschäfer
2020-11-22 22:27 ` [PATCH v4 3/7] mfd: Add base driver " Jonathan Neuschäfer
2020-12-02 13:05   ` Lee Jones
2020-12-02 13:06     ` Lee Jones
2020-12-02 14:00     ` Jonathan Neuschäfer
2020-12-02 15:09       ` Lee Jones
2020-12-02 17:11         ` Jonathan Neuschäfer
2020-11-22 22:27 ` [PATCH v4 4/7] pwm: ntxec: Add driver for PWM function in Netronix EC Jonathan Neuschäfer
2020-11-24  8:20   ` Uwe Kleine-König
2020-11-26 23:19     ` Jonathan Neuschäfer
2020-11-27  7:11       ` Uwe Kleine-König
2020-11-27 11:08         ` Thierry Reding
2020-11-27 14:23           ` Uwe Kleine-König
2020-11-29 17:59             ` Jonathan Neuschäfer
2020-11-29 17:48         ` Jonathan Neuschäfer
2020-11-22 22:27 ` [PATCH v4 5/7] rtc: New driver for RTC in Netronix embedded controller Jonathan Neuschäfer
2020-11-22 23:10   ` Alexandre Belloni
2020-11-23 21:31     ` Jonathan Neuschäfer [this message]
2020-11-23 21:34       ` Mark Brown
2020-11-23 21:38       ` Alexandre Belloni
2020-11-22 22:27 ` [PATCH v4 6/7] MAINTAINERS: Add entry for " Jonathan Neuschäfer
2020-11-23  0:09 ` [PATCH v4 7/7] ARM: dts: imx50-kobo-aura: Add " Jonathan Neuschäfer

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