linux-kernel - Re: [PATCH 2/3] hwmon: Driver for OMAP3 temperature sensor

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Date:	Sat, 27 Dec 2014 23:35:16 +0100
From:	Pavel Machek <pavel@....cz>
To:	Sebastian Reichel <sre@...nel.org>
Cc:	Pali Rohar <pali.rohar@...il.com>, Jean Delvare <jdelvare@...e.de>,
	Guenter Roeck <linux@...ck-us.net>,
	Tony Lindgren <tony@...mide.com>,
	Benoît Cousson <bcousson@...libre.com>,
	linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
	linux-omap@...r.kernel.org, lm-sensors@...sensors.org,
	devicetree@...r.kernel.org, Rob Herring <robh+dt@...nel.org>,
	Pawel Moll <pawel.moll@....com>,
	Mark Rutland <mark.rutland@....com>,
	Ian Campbell <ijc+devicetree@...lion.org.uk>,
	Kumar Gala <galak@...eaurora.org>
Subject: Re: [PATCH 2/3] hwmon: Driver for OMAP3 temperature sensor

On Sat 2014-12-27 20:58:25, Pavel Machek wrote:
> On Fri 2014-12-26 13:34:53, Sebastian Reichel wrote:
> > OMAP34xx and OMAP36xx processors contain a register in the syscon area,
> > which can be used to determine the SoCs temperature. This patch provides
> > a DT based driver for the temperature sensor based on an older driver
> > written by Peter De Schrijver for the Nokia N900 and N9.
> > 
> > Signed-off-by: Sebastian Reichel <sre@...nel.org>
> > ---
> >  drivers/hwmon/Kconfig      |   8 ++
> >  drivers/hwmon/Makefile     |   1 +
> >  drivers/hwmon/omap3-temp.c | 307 +++++++++++++++++++++++++++++++++++++++++++++
> >  3 files changed, 316 insertions(+)
> >  create mode 100644 drivers/hwmon/omap3-temp.c
> 
> When it hangs, it loops here:
> 
> do {
> regmap_read(data->syscon, SYSCON_TEMP_REG,&temp_sensor_reg);
> if ((temp_sensor_reg & eocz_mask) == level)
>    return true;
> printk("=");
> }
> while (ktime_us_delta(expire, ktime_get()) > 0);

And this fixes the hang, and makes level handling more readable.

Fix the timeout code, now it actually works. Driver still fails after
a while.

Signed-off-by: Pavel Machek <pavel@....cz>

diff --git a/drivers/hwmon/omap3-temp.c b/drivers/hwmon/omap3-temp.c
index 8a69604..1b8c768 100644
--- a/drivers/hwmon/omap3-temp.c
+++ b/drivers/hwmon/omap3-temp.c
@@ -130,9 +130,7 @@ static inline bool wait_for_eocz(struct omap3_temp_data *data,
 	ktime_t timeout, expire;
 	u32 temp_sensor_reg, eocz_mask;
 
 	eocz_mask = BIT(data->hwdata->eocz_bit);
-	level &= 1;
-	level *= eocz_mask;
 
 	expire = ktime_add_ns(ktime_get(), max_delay);
 	timeout = ktime_set(0, min_delay);
@@ -140,9 +141,9 @@ static inline bool wait_for_eocz(struct omap3_temp_data *data,
 	schedule_hrtimeout(&timeout, HRTIMER_MODE_REL);
 	do {
 		regmap_read(data->syscon, SYSCON_TEMP_REG, &temp_sensor_reg);
-		if ((temp_sensor_reg & eocz_mask) == level)
+		if (!!(temp_sensor_reg & eocz_mask) == level)
 			return true;
-	} while (ktime_us_delta(expire, ktime_get()) > 0);
+	} while (ktime_after(expire, ktime_get()));
 
 	return false;
 }

-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
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