[PATCH] imx: thermal: use CPU temperature grade info for thresholds

[Tim Harvey]

On Thu, Apr 30, 2015 at 9:02 AM, Tim Harvey <tharvey at gateworks.com> wrote:
> The IMX6Q/IMX6DL SoC's have a 2-bit temperature grade stored in OTP. Instead
> of assuming 85C for passive cooling threshold and 105C for critical use
> the thermal grade for these configurations. For IMX6SX which does not have
> a temperature grade in OTP (according to the ref manual) assume 105C critical.
> We will default the user-settable passive threshold to crit - 20C.
>
> Cc: Anson Huang <b20788 at freescale.com>
> Cc: Fabio Estevam <fabio.estevam at freescale.com>
> Cc: Shawn Guo <shawn.guo at linaro.org>
> Signed-off-by: Tim Harvey <tharvey at gateworks.com>
> ---
>  drivers/thermal/imx_thermal.c | 64 +++++++++++++++++++++++++++++++++----------
>  1 file changed, 49 insertions(+), 15 deletions(-)
>
> diff --git a/drivers/thermal/imx_thermal.c b/drivers/thermal/imx_thermal.c
> index 2ccbc07..c6a4eed 100644
> --- a/drivers/thermal/imx_thermal.c
> +++ b/drivers/thermal/imx_thermal.c
> @@ -55,6 +55,7 @@
>  #define TEMPSENSE2_PANIC_VALUE_SHIFT   16
>  #define TEMPSENSE2_PANIC_VALUE_MASK    0xfff0000
>
> +#define OCOTP_MEM0                     0x0480
>  #define OCOTP_ANA1                     0x04e0
>
>  /* The driver supports 1 passive trip point and 1 critical trip point */
> @@ -64,12 +65,6 @@ enum imx_thermal_trip {
>         IMX_TRIP_NUM,
>  };
>
> -/*
> - * It defines the temperature in millicelsius for passive trip point
> - * that will trigger cooling action when crossed.
> - */
> -#define IMX_TEMP_PASSIVE               85000
> -
>  #define IMX_POLLING_DELAY              2000 /* millisecond */
>  #define IMX_PASSIVE_DELAY              1000
>
> @@ -106,6 +101,7 @@ struct imx_thermal_data {
>         int irq;
>         struct clk *thermal_clk;
>         const struct thermal_soc_data *socdata;
> +       const char *temp_grade;
>  };
>
>  static void imx_set_panic_temp(struct imx_thermal_data *data,
> @@ -289,7 +285,8 @@ static int imx_set_trip_temp(struct thermal_zone_device *tz, int trip,
>         if (trip == IMX_TRIP_CRITICAL)
>                 return -EPERM;
>
> -       if (temp > IMX_TEMP_PASSIVE)
> +       /* do not allow passive to be set higher than critical - 20C */
> +       if (temp > (data->temp_critical - (1000 * 20)))
>                 return -EINVAL;
>
>         data->temp_passive = temp;
> @@ -404,17 +401,50 @@ static int imx_get_sensor_data(struct platform_device *pdev)
>         data->c1 = temp64;
>         data->c2 = n1 * data->c1 + 1000 * t1;
>
> -       /*
> -        * Set the default passive cooling trip point,
> -        * can be changed from userspace.
> -        */
> -       data->temp_passive = IMX_TEMP_PASSIVE;
> +       /* Assume Extended Commercial temperature grade limits (105C max) */
> +       data->temp_grade = "unknown";
> +       data->temp_critical = 105000;
> +
> +       /* For IMX6Q use OTP for thermal grade */
> +       if (data->socdata->version == TEMPMON_IMX6Q) {
> +               ret = regmap_read(map, OCOTP_MEM0, &val);
> +               if (ret) {
> +                       dev_err(&pdev->dev, "failed to read temp grade: %d\n",
> +                               ret);
> +                       return ret;
> +               }
> +
> +               if (val == 0 || val == ~0) {
> +                       dev_err(&pdev->dev, "invalid temp grade data\n");
> +                       return -EINVAL;
> +               }
> +
> +               /* The maximum die temp is specified by the Temperature Grade */
> +               switch ((val >> 6) & 0x3) {
> +               case 0: /* Commercial (0 to 95C) */
> +                       data->temp_grade = "Commercial";
> +                       data->temp_critical = 95000;
> +                       break;
> +               case 1: /* Extended Commercial (-20 to 105C) */
> +                       data->temp_grade = "Extended Commercial";
> +                       data->temp_critical = 105000;
> +                       break;
> +               case 2: /* Industrial (-40 to 105C) */
> +                       data->temp_grade = "Industrial";
> +                       data->temp_critical = 105000;
> +                       break;
> +               case 3: /* Automotive (-40 to 125C) */
> +                       data->temp_grade = "Automotive";
> +                       data->temp_critical = 125000;
> +                       break;
> +               }
> +       }
>
>         /*
> -        * The maximum die temperature set to 20 C higher than
> -        * IMX_TEMP_PASSIVE.
> +        * Set the default passive cooling trip point to critical - 20C
> +        * (can be changed from userspace)
>          */
> -       data->temp_critical = 1000 * 20 + data->temp_passive;
> +       data->temp_passive = data->temp_critical - (1000 * 20);
>
>         return 0;
>  }
> @@ -559,6 +589,10 @@ static int imx_thermal_probe(struct platform_device *pdev)
>                 return ret;
>         }
>
> +       dev_info(&pdev->dev, "%s CPU temperature grade - "
> +                "thresholds: crit:%ldC passive:%ldC\n", data->temp_grade,
> +                data->temp_critical / 1000, data->temp_passive / 1000);
> +
>         /* Enable measurements at ~ 10 Hz */
>         regmap_write(map, TEMPSENSE1 + REG_CLR, TEMPSENSE1_MEASURE_FREQ);
>         measure_freq = DIV_ROUND_UP(32768, 10); /* 10 Hz */
> --
> 1.9.1
>

Any feedback on this?

After using it a bit, I personally feel like the passive temp should
be changed to max-5C instead of max-20C.

Tim