On 四, 2016-08-18 at 11:39 -0700, Eric Anholt wrote:
> Eric Anholt <eric@xxxxxxxxxx> writes:
>
> >
> > kernel@xxxxxxxxxxxxxxxx writes:
> >
> > >
> > > From: Martin Sperl <kernel@xxxxxxxxxxxxxxxx>
> > >
> > > Add basic thermal driver for bcm2835 SOC.
> > >
> > > This driver currently relies on the firmware setting up the
> > > tsense HW block and does not set it up itself.
> > >
> > > Signed-off-by: Martin Sperl <kernel@xxxxxxxxxxxxxxxx>
> > >
> > > ChangeLog:
> > > V1 -> V2: added specific settings depending on compatiblity
> > > added trip point based on register
> > > setting up ctrl-register if HW is not enabled by firmware
> > > as per recommendation of Eric (untested)
> > > check that clock frequency is in range
> > > (1.9 - 5MHz - as per comment in clk-bcm2835.c)
> > > ---
> > >
> > > diff --git a/drivers/thermal/bcm/Makefile
> > > b/drivers/thermal/bcm/Makefile
> > > new file mode 100644
> > > index 0000000..13456d2
> > > --- /dev/null
> > > +++ b/drivers/thermal/bcm/Makefile
> > > @@ -0,0 +1 @@
> > > +obj-$(CONFIG_BCM2835_THERMAL) :=
> > > bcm2835_thermal.o
> > > diff --git a/drivers/thermal/bcm/bcm2835_thermal.c
> > > b/drivers/thermal/bcm/bcm2835_thermal.c
> > > new file mode 100644
> > > index 0000000..73138cb
> > > --- /dev/null
> > > +++ b/drivers/thermal/bcm/bcm2835_thermal.c
> > >
> > > +static const struct of_device_id
> > > bcm2835_thermal_of_match_table[];
> > > +static int bcm2835_thermal_probe(struct platform_device *pdev)
> > > +{
> > >
> > > + /* enable clock and check rate */
> > > + clk_prepare_enable(data->clk);
> > > + rate = clk_get_rate(data->clk);
> > > + if ((rate < 1920000) || (rate > 5000000)) {
> > > + dev_warn(&pdev->dev,
> > > + "Clock %pCn is running at %pCr Hz,
> > > which is outside the recommended range of 1.9 to 5.0 MHz\n",
> > > + data->clk, data->clk);
> > > + }
> > > +
> > > + /* register it */
> > > + tz = thermal_zone_device_register("bcm2835_thermal",
> > > + 1, 0, data,
> > > + &bcm2835_thermal_ops,
> > > + NULL, 0, 0);
> > I notice that the polling_delay is set to 0, but we're not using
> > interrupts to trigger the trip. Is it valid to expose a trip
> > without a
> > polling_delay or interrupts? Should passive_delay be set as well?
> >
> > This is up to the thermal maintainers. As far as I'm concerned,
> > it's:
> >
> > Acked-by: Eric Anholt <eric@xxxxxxxxxx>
> >
> > One it lands I'll pull the defconfig and DT bits.
> Ping on this question to thermal maintainers. I'd still love to see
> this driver land.
hmmm, how is this driver supposed to work?
With this patch set, I think the only benefit is that we can get the
temperature and trip point information via thermal sysfs interface, but
kernel thermal control is a no-op here, right?
thanks,
rui
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