Re: [PATCH v5 4/5] thermal/drivers/sun8i: Add support for A523 THS0/1 controllers

[Mikhail Kalashnikov <iuncuim@gmail.com>]

On 7/21/26 23:23, Chen-Yu Tsai wrote:
> On Sun, Jul 5, 2026 at 1:15 AM Mikhail Kalashnikov <iuncuim@gmail.com> wrote:
>>
>> The A523 processor has two temperature controllers, THS0 and THS1.
>> THS0 has only one temperature sensor, which is located in the DRAM
>> controller. THS1 does have 3 sensors:
>> ths1_0 - "big" cores
>> ths1_1 - "little" cores
>> ths1_2 - gpu
>>
>> The datasheet mentions a fourth sensor in the NPU, but lacks any registers
>> for operation other than calibration registers. The vendor code reads the
>> value from ths1_2, but uses separate calibration data, so we get two
>> different values from real one.
> 
> Are you sure? The calibration data is written to the sensor register.
> 
> The BSP simply reads the sensor data from the GPU sensor, and passes it
> off as the value for the NPU sensor. No extra calculation involving the
> calibration data is done.
> 
Yes, I think you're right. And as Juan pointed out, my current
implementation doesn't match the BSP, since:

#define SUN55IW3_GPU_SENSOR_ID (2)
#define SUN55IW3_NPU_SENSOR_ID (3)
...
/* use NPU sensor data instead of GPU */
if (id == SUN55IW3_GPU_SENSOR_ID) {
     id = SUN55IW3_NPU_SENSOR_ID;
     ...
}

In other words, in the BSP driver, the NPU sensor is used for the GPU. 
However, based on the A523 user manual—which describes registers for
only three sensors, I had argued the opposite. The user manual for the
T527 includes a description of a fourth sensor.

Thus, it seems that all four sensors are working, but the purpose of
this workaround in the BSP remains unclear to me.

>>
>> Signed-off-by: Mikhail Kalashnikov <iuncuim@gmail.com>
>> Reviewed-by: Chen-Yu Tsai <wens@kernel.org>
>> ---
>>   drivers/thermal/sun8i_thermal.c | 133 ++++++++++++++++++++++++++++++++
>>   1 file changed, 133 insertions(+)
>>
>> diff --git a/drivers/thermal/sun8i_thermal.c b/drivers/thermal/sun8i_thermal.c
>> index 3bdd62aa8..f48ed9eae 100644
>> --- a/drivers/thermal/sun8i_thermal.c
>> +++ b/drivers/thermal/sun8i_thermal.c
>> @@ -59,6 +59,12 @@
>>   #define SUN50I_H6_THS_PC_TEMP_PERIOD(x)                ((GENMASK(19, 0) & (x)) << 12)
>>   #define SUN50I_H6_THS_DATA_IRQ_STS(x)          BIT(x)
>>
>> +#define SUN55I_A523_DELIMITER                  0x7c8
>> +#define SUN55I_A523_OFFSET_ABOVE               2736
>> +#define SUN55I_A523_OFFSET_BELOW               2825
>> +#define SUN55I_A523_SCALE_ABOVE                        74
>> +#define SUN55I_A523_SCALE_BELOW                        65
>> +
>>   struct tsensor {
>>          struct ths_device               *tmdev;
>>          struct thermal_zone_device      *tzd;
>> @@ -114,6 +120,15 @@ static int sun50i_h5_calc_temp(struct ths_device *tmdev,
>>                  return -1590 * reg / 10 + 276000;
>>   }
>>
>> +static int sun55i_a523_calc_temp(struct ths_device *tmdev,
>> +                                int id, int reg)
>> +{
>> +       if (reg >= SUN55I_A523_DELIMITER)
>> +               return SUN55I_A523_SCALE_ABOVE * (SUN55I_A523_OFFSET_ABOVE - reg);
>> +       else
>> +               return SUN55I_A523_SCALE_BELOW * (SUN55I_A523_OFFSET_BELOW - reg);
>> +}
>> +
>>   static int sun8i_ths_get_temp(struct thermal_zone_device *tz, int *temp)
>>   {
>>          struct tsensor *s = thermal_zone_device_priv(tz);
>> @@ -299,6 +314,97 @@ static int sun50i_h6_ths_calibrate(struct ths_device *tmdev,
>>          return 0;
>>   }
>>
>> +/*
>> + * The A523 nvmem calibration values. The ths1_3 is not used as it
>> + * doesn't have its own sensor and doesn't have any internal switch.
>> + * Instead, the value from the ths1_2 sensor is used, which gives the
>> + * illusion of an independent sensor for NPU and GPU when using
>> + * different calibration values.
>> + *
>> + * efuse layout 0x38-0x3F (caldata[0..3]):
>> + *     caldata[0]      caldata[1]      caldata[2]      caldata[3]
>> + * 0               16      24      32  36          48          60 64
>> + * +---------------+---------------+---------------+---------------+
>> + * |               |       |   temp    |  ths1_0   |  ths1_1   |   +
>> + * +---------------+---------------+---------------+---------------+
>> + *
>> + * efuse layout 0x44-0x4B (caldata[4..7]):
>> + *     caldata[4]      caldata[5]      caldata[6]      caldata[7]
>> + * 0           12  16      24      32  36          48             64
>> + * +---------------+---------------+---------------+---------------+
>> + * |  ths1_2   |  ths1_3   |    ths0   |           |               +
>> + * +---------------+---------------+---------------+---------------+
>> + */
>> +static int sun55i_a523_ths_calibrate(struct ths_device *tmdev,
>> +                                    u16 *caldata, int callen)
>> +{
>> +       struct device *dev = tmdev->dev;
>> +       int i, ft_temp;
>> +
>> +       if (!caldata[0])
>> +               return -EINVAL;
>> +
>> +       ft_temp = (((caldata[2] << 8) | (caldata[1] >> 8)) & FT_TEMP_MASK) * 100;
>> +
>> +       for (i = 0; i < tmdev->chip->sensor_num; i++) {
>> +               int sensor_reg, sensor_temp, cdata, offset;
>> +               /*
>> +                * Chips ths0 and ths1 have common parameters for value
>> +                * calibration. To separate them we can use the number of
>> +                * temperature sensors on each chip.
>> +                * For ths0 this value is 1.
>> +                */
>> +               if (tmdev->chip->sensor_num == 1) {
>> +                       sensor_reg = ((caldata[5] >> 8) | (caldata[6] << 8)) & TEMP_CALIB_MASK;
>> +               } else {
>> +                       switch (i) {
>> +                       case 0:
>> +                               sensor_reg = (caldata[2] >> 4) & TEMP_CALIB_MASK;
>> +                               break;
>> +                       case 1:
>> +                               sensor_reg = caldata[3] & TEMP_CALIB_MASK;
>> +                               break;
>> +                       case 2:
>> +                               sensor_reg = caldata[4] & TEMP_CALIB_MASK;
>> +                               break;
>> +                       default:
>> +                               sensor_reg = 0;
>> +                               break;
>> +                       }
>> +               }
>> +
>> +               sensor_temp = tmdev->chip->calc_temp(tmdev, i, sensor_reg);
>> +
>> +               /*
>> +                * Calibration data is CALIBRATE_DEFAULT - (calculated
>> +                * temperature from sensor reading at factory temperature
>> +                * minus actual factory temperature) * X (scale from
>> +                * temperature to register values)
>> +                */
>> +               cdata = CALIBRATE_DEFAULT -
>> +                       ((sensor_temp - ft_temp) / SUN55I_A523_SCALE_ABOVE);
> 
> The BSP version works out to:
> 
>      cdata = CALIBRATE_DEFAULT -
>              (sensor_temp - ft_temp - 5000) / SU55I_A523_SCALE_BELOW
> 
> Any particular reason why it's different?

In the early versions, I didn't use 'define' for constants, but later
added them based on the logic of the value read from the register: a
value below the threshold is 'BELOW', and a value above is 'ABOVE'. The
BSP driver uses a name for the temperature, but the temperature
decreases as the value read from the register increases; therefore, the
formula uses SCALE constants with different names but identical values.

In the next version, I’ll align them with the BSP values and add a 
comment explaining that the constants refer to the final temperature 
value, not the value read from the register.

Regarding SUN55IW3_CAL_COM 5000 — when I first looked at the driver
code, it seemed to me that this was the value intended for ft_deviation,
but now that I’ve double-checked, the version of the calibration formula
with SUN55IW3_CAL_COM and without ft_deviation gives the same result as
the version without SUN55IW3_CAL_COM but with ft_deviation=5000.

But if you'd rather I match BSP literally (5000 in the calibration
numerator, ft_deviation = 0), I can do that instead.
> 
>> +               if (cdata & ~TEMP_CALIB_MASK) {
>> +                       /*
>> +                        * Calibration value more than 12-bit, but calibration
>> +                        * register is 12-bit. In this case, ths hardware can
>> +                        * still work without calibration, although the data
>> +                        * won't be so accurate.
>> +                        */
>> +                       dev_warn(dev, "sensor%d is not calibrated.\n", i);
>> +                       continue;
>> +               }
>> +
>> +               offset = (i % 2) * 16;
>> +               regmap_update_bits(tmdev->regmap,
>> +                                  SUN50I_H6_THS_TEMP_CALIB + (i / 2 * 4),
>> +                                  TEMP_CALIB_MASK << offset,
>> +                                  cdata << offset);
>> +       }
>> +
>> +       return 0;
>> +}
>> +
>>   static int sun8i_ths_calibrate(struct ths_device *tmdev)
>>   {
>>          struct nvmem_cell *calcell = NULL;
>> @@ -717,6 +823,31 @@ static const struct ths_thermal_chip sun50i_h616_ths = {
>>          .calc_temp = sun8i_ths_calc_temp,
>>   };
>>
>> +/* The A523 has a shared reset line for both chips */
>> +static const struct ths_thermal_chip sun55i_a523_ths0 = {
>> +       .sensor_num = 1,
>> +       .has_bus_clk_reset = true,
>> +       .has_mod_clk = true,
>> +       .ft_deviation = 5000,
> 
> In the BSP this is 0.

> 
>> +       .temp_data_base = SUN50I_H6_THS_TEMP_DATA,
>> +       .calibrate = sun55i_a523_ths_calibrate,
>> +       .init = sun50i_h6_thermal_init,
>> +       .irq_ack = sun50i_h6_irq_ack,
>> +       .calc_temp = sun55i_a523_calc_temp,
>> +};
>> +
>> +static const struct ths_thermal_chip sun55i_a523_ths1 = {
>> +       .sensor_num = 3,
>> +       .has_bus_clk_reset = true,
>> +       .has_mod_clk = true,
>> +       .ft_deviation = 5000,
> 
> In the BSP this is 0.
> 
> 
> ChenYu
> 
>> +       .temp_data_base = SUN50I_H6_THS_TEMP_DATA,
>> +       .calibrate = sun55i_a523_ths_calibrate,
>> +       .init = sun50i_h6_thermal_init,
>> +       .irq_ack = sun50i_h6_irq_ack,
>> +       .calc_temp = sun55i_a523_calc_temp,
>> +};
>> +
>>   static const struct of_device_id of_ths_match[] = {
>>          { .compatible = "allwinner,sun8i-a83t-ths", .data = &sun8i_a83t_ths },
>>          { .compatible = "allwinner,sun8i-h3-ths", .data = &sun8i_h3_ths },
>> @@ -727,6 +858,8 @@ static const struct of_device_id of_ths_match[] = {
>>          { .compatible = "allwinner,sun50i-h6-ths", .data = &sun50i_h6_ths },
>>          { .compatible = "allwinner,sun20i-d1-ths", .data = &sun20i_d1_ths },
>>          { .compatible = "allwinner,sun50i-h616-ths", .data = &sun50i_h616_ths },
>> +       { .compatible = "allwinner,sun55i-a523-ths0", .data = &sun55i_a523_ths0 },
>> +       { .compatible = "allwinner,sun55i-a523-ths1", .data = &sun55i_a523_ths1 },
>>          { /* sentinel */ },
>>   };
>>   MODULE_DEVICE_TABLE(of, of_ths_match);
>> --
>> 2.55.0
>>