On Sunday, May 13, 2018 07:54:02 PM Krzysztof Kozlowski wrote:
> Thermal core tries to read temperature during sensor registering in
> thermal_zone_of_sensor_register().  In that time Exynos TMU driver and
> hardware are not yet initialized.  Commit 0eb875d88aaa ("thermal:
> exynos: Reading temperature makes sense only when TMU is turned on")
> added a boolean flag to prevent reading bogus temperature in such
> case but it exposed warning message during boot:
>       [    3.864913] thermal thermal_zone0: failed to read out thermal zone 
> (-22)
> 
> Return EAGAIN in such case to skip omitting such message because it
> might mislead user.

Hi Krzysztof,

I've fixed this in generic way a month ago:

        https://lkml.org/lkml/2018/4/10/376

(there has been not much feedback on it yet)

However since my patchset is not v4.17 material:

> Signed-off-by: Krzysztof Kozlowski <k...@kernel.org>

Acked-by: Bartlomiej Zolnierkiewicz <b.zolnier...@samsung.com>

Eduardo, please queue it for v4.17 if possible, thanks.

> ---
>  drivers/thermal/samsung/exynos_tmu.c | 8 +++++++-
>  1 file changed, 7 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/thermal/samsung/exynos_tmu.c 
> b/drivers/thermal/samsung/exynos_tmu.c
> index 3b20309789e3..c24969d740d1 100644
> --- a/drivers/thermal/samsung/exynos_tmu.c
> +++ b/drivers/thermal/samsung/exynos_tmu.c
> @@ -666,8 +666,14 @@ static int exynos_get_temp(void *p, int *temp)
>       struct exynos_tmu_data *data = p;
>       int value, ret = 0;
>  
> -     if (!data || !data->tmu_read || !data->enabled)
> +     if (!data || !data->tmu_read)
>               return -EINVAL;
> +     else if (!data->enabled)
> +             /*
> +              * Called too early, probably
> +              * from thermal_zone_of_sensor_register().
> +              */
> +             return -EAGAIN;
>  
>       mutex_lock(&data->lock);
>       clk_enable(data->clk);

Best regards,
--
Bartlomiej Zolnierkiewicz
Samsung R&D Institute Poland
Samsung Electronics

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