Re: [PATCH] thermal: rockchip: fix handling of invalid readings

[Caesar Wang]

å 2015å08æ10æ 15:59, Dmitry Torokhov åé:
> Hi Caesar,
>
> On Sun, Aug 9, 2015 at 11:30 PM, Caesar Wang <wxt@xxxxxxxxxxxxxx> wrote:
> > Dear Dmitry,
> >
> > Thanks your patch.
> >
> > The code looks like fine,but I don't think the TS-ADC will work on rk3288
> > SoC.
> What do you mean? It seems to work when I ran it...

Making a mistake.:-(

> > å 2015å08æ08æ 04:59, Dmitry Torokhov åé:
> > > We attempted to signal invalid code by returning -EAGAIN from
> > > rk_tsadcv2_code_to_temp(), unfortunately the return value was stuffed
> > > directly into the temperature pointer, potentially confusing upper
> > > layers with temperature of -EINVAL.
> > >
> > > Let's split temperature from error/success indicator to avoid such
> > > confusion.
> > >
> > > Also change the way we scan the temperature table to start with the 2nd
> > > element so that we do not need to worry that we may reference out of
> > > bounds element while doing binary search and keep checking that we end
> > > up with 'mid' equal to 0 (since we are looking for the temperature that
> > > would fall into interval between the 'mid' and 'mid - 1') .
> > >
> > > Signed-off-by: Dmitry Torokhov <dtor@xxxxxxxxxxxx>
> > > ---
> > >    drivers/thermal/rockchip_thermal.c | 28 +++++++++++++---------------
> > >    1 file changed, 13 insertions(+), 15 deletions(-)
> > >
> > > diff --git a/drivers/thermal/rockchip_thermal.c
> > > b/drivers/thermal/rockchip_thermal.c
> > > index c89ffb2..93ee307 100644
> > > --- a/drivers/thermal/rockchip_thermal.c
> > > +++ b/drivers/thermal/rockchip_thermal.c
> > > @@ -124,7 +124,7 @@ struct rockchip_thermal_data {
> > >    #define TSADCV2_AUTO_PERIOD_HT_TIME           50  /* msec */
> > >      struct tsadc_table {
> > > -       unsigned long code;
> > > +       u32 code;
> > >          long temp;
> > >    };
> > >    @@ -164,7 +164,6 @@ static const struct tsadc_table v2_code_table[] = {
> > >          {3452, 115000},
> > >          {3437, 120000},
> > >          {3421, 125000},
> > > -       {0, 125000},
> > >    };
> > >      static u32 rk_tsadcv2_temp_to_code(long temp)
> > > @@ -191,19 +190,21 @@ static u32 rk_tsadcv2_temp_to_code(long temp)
> > >          return 0;
> > >    }
> > >    -static int rk_tsadcv2_code_to_temp(u32 code)
> > > +static int rk_tsadcv2_code_to_temp(u32 code, int *temp)

It's wired that can't git-am this patch.

I search the Eduardo'branch[0] for rockchip-thermal.c driver. The 
function is "static long rk_tsadcv2_code_to_temp(u32 code)"

Maybe i'm missing something, I verified this patch on my board but this 
fixed.

So you can free add it:
Tested-by: Caesar Wang <wxt@xxxxxxxxxxxxxx>

[0]:
url = 
git://git.kernel.org/pub/scm/linux/kernel/git/evalenti/linux-soc-thermal.git



---
Thanks,
Caesar



> > >    {
> > > -       unsigned int low = 0;
> > > +       unsigned int low = 1;
> > >          unsigned int high = ARRAY_SIZE(v2_code_table) - 1;
> > >          unsigned int mid = (low + high) / 2;
> > >          unsigned int num;
> > >          unsigned long denom;
> > >    -     /* Invalid code, return -EAGAIN */
> > > -       if (code > TSADCV2_DATA_MASK)
> > > -               return -EAGAIN;
> > > +       BUILD_BUG_ON(ARRAY_SIZE(v2_code_table) < 2);
> > >    -     while (low <= high && mid) {
> > > +       code &= TSADCV2_DATA_MASK;
> > > +       if (code < v2_code_table[high].code)
> > > +               return -EAGAIN;         /* Incorrect reading */
> > > +
> > > +       while (low <= high) {
> > >                  if (code >= v2_code_table[mid].code &&
> > >                      code < v2_code_table[mid - 1].code)
> > >                          break;
> > > @@ -223,7 +224,9 @@ static int rk_tsadcv2_code_to_temp(u32 code)
> > >          num = v2_code_table[mid].temp - v2_code_table[mid - 1].temp;
> > >          num *= v2_code_table[mid - 1].code - code;
> > >          denom = v2_code_table[mid - 1].code - v2_code_table[mid].code;
> > > -       return v2_code_table[mid - 1].temp + (num / denom);
> > > +       *temp = v2_code_table[mid - 1].temp + (num / denom);
> > > +
> > > +       return 0;
> > >    }
> > >      /**
> > > @@ -281,14 +284,9 @@ static int rk_tsadcv2_get_temp(int chn, void __iomem
> > > *regs, int *temp)
> > >    {
> > >          u32 val;
> > >    -     /* the A/D value of the channel last conversion need some time */
> > >          val = readl_relaxed(regs + TSADCV2_DATA(chn));
> > > -       if (val == 0)
> > > -               return -EAGAIN;
> > > -
> >
> > if we reserve the above code, that will get the ADC value.
> But if we pass  0 into rk_tsadcv2_code_to_temp() it will trigger:
>
> > > +       if (code < v2_code_table[high].code)
> > > +               return -EAGAIN;         /* Incorrect reading */
> and still return -EAGAIN, as it was. There is no behavior change as
> far as I can see.
Yup, that's ok for me.

> > > -       *temp = rk_tsadcv2_code_to_temp(val);
> > >    -     return 0;
> > > +       return rk_tsadcv2_code_to_temp(val, temp);
> > >    }
> > >      static void rk_tsadcv2_tshut_temp(int chn, void __iomem *regs, long
> > > temp)
> Thanks,
> Dmitry


--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/