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SubjectRe: [PATCH 2/3] hwmon: Driver for OMAP3 temperature sensor
On Sun, Dec 28, 2014 at 12:24:47AM -0800, Guenter Roeck wrote:
> On Sat, Dec 27, 2014 at 11:35:16PM +0100, Pavel Machek wrote:
> > 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@kernel.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@ucw.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()));
> >
> Does this have to be a hard loop, without sleep ? I am a bit concerned that it
> may loop for more than a ms.
>
> Other than that, I assume we'll see an updated version with the coding style
> issues and hang-up problems fixed.

I will send a v2 patchset with Pavels change requests. It may take a
few days though, since I'm currently at a conference (31C3).

-- Sebastian
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