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Subject: Re: [v4,6/7] thermal: mediatek: add another get_temp ops for thermal
 sensors
To:     Michael Kao <michael.kao@mediatek.com>,
        Matthias Brugger <matthias.bgg@gmail.com>,
        Zhang Rui <rui.zhang@intel.com>,
        Eduardo Valentin <edubezval@gmail.com>,
        Rob Herring <robh+dt@kernel.org>,
        Mark Rutland <mark.rutland@arm.com>, hsinyi@chromium.org,
        linux-pm@vger.kernel.org, srv_heupstream@mediatek.com
Cc:     devicetree@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-arm-kernel@lists.infradead.org,
        linux-mediatek@lists.infradead.org
References: <20200323121537.22697-1-michael.kao@mediatek.com>
 <20200323121537.22697-7-michael.kao@mediatek.com>
From:   Daniel Lezcano <daniel.lezcano@linaro.org>
Message-ID: <fa43c55b-96c2-30c8-eb7e-983177dad13d@linaro.org>
Date:   Fri, 22 May 2020 17:32:04 +0200
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On 23/03/2020 13:15, Michael Kao wrote:
> Provide thermal zone to read thermal sensor
> in the SoC. We can read all the thermal sensors
> value in the SoC by the node /sys/class/thermal/
> 
> In mtk_thermal_bank_temperature, return -EAGAIN instead of -EACCESS
> on the first read of sensor that often are bogus values.
> This can avoid following warning on boot:
> 
>   thermal thermal_zone6: failed to read out thermal zone (-13)

What the source problem of the sensor returning bogus values?


> Signed-off-by: Michael Kao <michael.kao@mediatek.com>
> Signed-off-by: Hsin-Yi Wang <hsinyi@chromium.org>
> ---
>  drivers/thermal/mtk_thermal.c | 74 +++++++++++++++++++++++++++++++----
>  1 file changed, 67 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/thermal/mtk_thermal.c b/drivers/thermal/mtk_thermal.c
> index 6b7ef1993d7e..9eaca432920e 100644
> --- a/drivers/thermal/mtk_thermal.c
> +++ b/drivers/thermal/mtk_thermal.c
> @@ -225,6 +225,11 @@ enum {
>  
>  struct mtk_thermal;
>  
> +struct mtk_thermal_zone {
> +	struct mtk_thermal *mt;
> +	int id;
> +};
> +
>  struct thermal_bank_cfg {
>  	unsigned int num_sensors;
>  	const int *sensors;
> @@ -607,7 +612,7 @@ static int mtk_thermal_bank_temperature(struct mtk_thermal_bank *bank)
>  		 * not immediately shut down.
>  		 */
>  		if (temp > 200000)
> -			temp = 0;
> +			temp = -EAGAIN;
>  
>  		if (temp > max)
>  			max = temp;
> @@ -618,7 +623,8 @@ static int mtk_thermal_bank_temperature(struct mtk_thermal_bank *bank)
>  
>  static int mtk_read_temp(void *data, int *temperature)
>  {
> -	struct mtk_thermal *mt = data;
> +	struct mtk_thermal_zone *tz = data;
> +	struct mtk_thermal *mt = tz->mt;
>  	int i;
>  	int tempmax = INT_MIN;
>  
> @@ -637,10 +643,44 @@ static int mtk_read_temp(void *data, int *temperature)
>  	return 0;
>  }
>  
> +static int mtk_read_sensor_temp(void *data, int *temperature)
> +{
> +	struct mtk_thermal_zone *tz = data;
> +	struct mtk_thermal *mt = tz->mt;
> +	const struct mtk_thermal_data *conf = mt->conf;
> +	int id = tz->id - 1;
> +	int temp = INT_MIN;
> +	u32 raw;
> +
> +	if (id < 0)
> +		return  -EACCES;
> +
> +	raw = readl(mt->thermal_base + conf->msr[id]);
> +
> +	temp = raw_to_mcelsius(mt, id, raw);
> +
> +	/*
> +	 * The first read of a sensor often contains very high bogus
> +	 * temperature value. Filter these out so that the system does
> +	 * not immediately shut down.
> +	 */
> +
> +	if (temp > 200000)
> +		return  -EAGAIN;
> +
> +	*temperature = temp;
> +
> +	return 0;
> +}
> +
>  static const struct thermal_zone_of_device_ops mtk_thermal_ops = {
>  	.get_temp = mtk_read_temp,
>  };
>  
> +static const struct thermal_zone_of_device_ops mtk_thermal_sensor_ops = {
> +	.get_temp = mtk_read_sensor_temp,
> +};
> +
>  static void mtk_thermal_init_bank(struct mtk_thermal *mt, int num,
>  				  u32 apmixed_phys_base, u32 auxadc_phys_base,
>  				  int ctrl_id)
> @@ -873,6 +913,7 @@ static int mtk_thermal_probe(struct platform_device *pdev)
>  	struct resource *res;
>  	u64 auxadc_phys_base, apmixed_phys_base;
>  	struct thermal_zone_device *tzdev;
> +	struct mtk_thermal_zone *tz;
>  
>  	mt = devm_kzalloc(&pdev->dev, sizeof(*mt), GFP_KERNEL);
>  	if (!mt)
> @@ -954,11 +995,30 @@ static int mtk_thermal_probe(struct platform_device *pdev)
>  
>  	platform_set_drvdata(pdev, mt);
>  
> -	tzdev = devm_thermal_zone_of_sensor_register(&pdev->dev, 0, mt,
> -						     &mtk_thermal_ops);
> -	if (IS_ERR(tzdev)) {
> -		ret = PTR_ERR(tzdev);
> -		goto err_disable_clk_peri_therm;
> +	for (i = 0; i < mt->conf->num_sensors + 1; i++) {
> +		tz = kmalloc(sizeof(*tz), GFP_KERNEL);
> +		if (!tz)
> +			return -ENOMEM;
> +
> +		tz->mt = mt;
> +		tz->id = i;
> +
> +		tzdev = devm_thermal_zone_of_sensor_register(&pdev->dev, i,
> +							     tz, (i == 0) ?
> +				&mtk_thermal_ops : &mtk_thermal_sensor_ops);
> +
> +		if (IS_ERR(tzdev)) {
> +			if (PTR_ERR(tzdev) == -ENODEV) {
> +				dev_warn(&pdev->dev,
> +					 "sensor %d not registered in thermal zone in dt\n",
> +					 i);
> +				continue;
> +			}
> +			if (PTR_ERR(tzdev) == -EACCES) {
> +				ret = PTR_ERR(tzdev);
> +				goto err_disable_clk_peri_therm;
> +			}
> +		}
>  	}
>  
>  	return 0;
> 


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