Date:   Mon, 9 Sep 2019 19:13:05 +0800
From:   Hsin-Yi Wang <hsinyi@...omium.org>
To:     "michael.kao" <michael.kao@...iatek.com>
Cc:     Zhang Rui <rui.zhang@...el.com>,
        Eduardo Valentin <edubezval@...il.com>,
        Daniel Lezcano <daniel.lezcano@...aro.org>,
        Rob Herring <robh+dt@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        Matthias Brugger <matthias.bgg@...il.com>,
        linux-pm@...r.kernel.org,
        Devicetree List <devicetree@...r.kernel.org>,
        lkml <linux-kernel@...r.kernel.org>,
        "moderated list:ARM/FREESCALE IMX / MXC ARM ARCHITECTURE" 
        <linux-arm-kernel@...ts.infradead.org>,
        linux-mediatek@...ts.infradead.org
Subject: Re: [PATCH v2 7/8] thermal: mediatek: add another get_temp ops for
 thermal sensors

On Fri, May 10, 2019 at 9:27 PM michael.kao <michael.kao@...iatek.com> wrote:
>
> From: Michael Kao <michael.kao@...iatek.com>
>
> 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/
>
> Signed-off-by: Michael Kao <michael.kao@...iatek.com>
> ---
>  drivers/thermal/mtk_thermal.c | 68 ++++++++++++++++++++++++++++++++++++++-----
>  1 file changed, 60 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/thermal/mtk_thermal.c b/drivers/thermal/mtk_thermal.c
> index cb41e46..d5c78b0 100644
> --- a/drivers/thermal/mtk_thermal.c
> +++ b/drivers/thermal/mtk_thermal.c
> @@ -230,6 +230,11 @@ 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;
> @@ -612,7 +617,7 @@ static int mtk_thermal_bank_temperature(struct mtk_thermal_bank *bank)
>                  * not immediately shut down.
>                  */
>                 if (temp > 200000)
> -                       temp = 0;
> +                       temp = -EACCES;
Should we return -EAGAIN here? Otherwise there would be warning:
[    0.344167] thermal thermal_zone5: failed to read out thermal zone (-13)

Since first read is bogus value, I think EAGAIN also makes sense here.
>
>                 if (temp > max)
>                         max = temp;
> @@ -623,7 +628,8 @@ 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;
>
> @@ -636,16 +642,48 @@ static int mtk_read_temp(void *data, int *temperature)
>
>                 mtk_thermal_put_bank(bank);
>         }
> -
>         *temperature = tempmax;
>
>         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  -EACCES;
Same here.
> +
> +       *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)
> @@ -878,6 +916,7 @@ 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)
> @@ -959,11 +998,24 @@ 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 (IS_ERR(tzdev) != -EACCES) {
> +                               ret = PTR_ERR(tzdev);
> +                               goto err_disable_clk_peri_therm;
> +                       }
> +               }
>         }
>
>         return 0;
> --
> 2.6.4
>

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