[PATCH v2] thermal: imx8mm_thermal: wait for a valid measurement

[Peng Fan]

On 10/7/2022 3:30 PM, Marcus Folkesson wrote:
> Check if first measurement is still pending or if temperature is out of
> range.
> Return and try again later if that is the case.
> 
> Fixes: 5eed800a6811 ("thermal: imx8mm: Add support for i.MX8MM thermal monitoring unit")
> Signed-off-by: Marcus Folkesson <marcus.folkesson at gmail.com>

NAK:
Please refer: https://www.nxp.com/docs/en/errata/IMX8MM_0N87W.pdf
ERR051272: TMU: Bit 31 of registers TMU_TSCR/TMU_TRITSR/TMU_TRATSR invalid

Thanks,
Peng.

> ---
> 
> Notes:
>      v2: Also invalidate if temperature > max (125 degrees C)
> 
>   drivers/thermal/imx8mm_thermal.c | 12 +++++++++---
>   1 file changed, 9 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/thermal/imx8mm_thermal.c b/drivers/thermal/imx8mm_thermal.c
> index af666bd9e8d4..e42bf373cebc 100644
> --- a/drivers/thermal/imx8mm_thermal.c
> +++ b/drivers/thermal/imx8mm_thermal.c
> @@ -62,11 +62,17 @@ static int imx8mm_tmu_get_temp(void *data, int *temp)
>   {
>   	struct tmu_sensor *sensor = data;
>   	struct imx8mm_tmu *tmu = sensor->priv;
> -	u32 val;
> +	bool ready;
> +	unsigned long val;
> +
> +	val = readl_relaxed(tmu->base + TRITSR);
> +	ready = test_bit(probe_status_offset(1), &val);
> +	if (!ready)
> +		return -EAGAIN;
>   
> -	val = readl_relaxed(tmu->base + TRITSR) & TRITSR_TEMP0_VAL_MASK;
> +	val = val & TRITSR_TEMP0_VAL_MASK;
>   	*temp = val * 1000;
> -	if (*temp < VER1_TEMP_LOW_LIMIT)
> +	if (*temp < VER1_TEMP_LOW_LIMIT || *temp > VER2_TEMP_HIGH_LIMIT)
>   		return -EAGAIN;
>   
>   	return 0;