RE: [PATCH v2 2/3] thermal: exynos_tmu: Support new hardware and update TMU interface

[손신 <shin.son@samsung.com>]

Hello Henrik Grimler,

> -----Original Message-----
> From: Henrik Grimler [mailto:henrik@grimler.se]
> Sent: Thursday, September 4, 2025 5:38 PM
> To: Shin Son <shin.son@samsung.com>
> Cc: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>; Krzysztof Kozlowski
> <krzk@kernel.org>; Rafael J . Wysocki <rafael@kernel.org>; Daniel Lezcano
> <daniel.lezcano@linaro.org>; Zhang Rui <rui.zhang@intel.com>; Lukasz Luba
> <lukasz.luba@arm.com>; Rob Herring <robh@kernel.org>; Conor Dooley
> <conor+dt@kernel.org>; Alim Akhtar <alim.akhtar@samsung.com>; linux-
> pm@vger.kernel.org; linux-samsung-soc@vger.kernel.org;
> devicetree@vger.kernel.org; linux-arm-kernel@lists.infradead.org; linux-
> kernel@vger.kernel.org
> Subject: Re: [PATCH v2 2/3] thermal: exynos_tmu: Support new hardware and
> update TMU interface
> 
> Hi Shin,
> 
> On Wed, Sep 03, 2025 at 04:36:33PM +0900, Shin Son wrote:
> > The Exynos tmu driver's private data structure has been extended to
> > support the exynosautov920 hardware, which requires per-sensor
> > interrupt enablement and dual-zone handling:
> >
> > - Add 'slope_comp' : compensation parameter below 25 degrees.
> > - Add 'calib_temp' : stores the fused calibaration temperature.
> > - Add 'tz_count' : reflects the new 1:2 hardware-to-thermal-zone ratio.
> > - Add 'valid_sensor_bitmap' : bitmap to enable interrupts
> > 			      for each valid sensor.
> > - Rename 'tzd' -> 'tzd_array' to register multiple thermal zones.
> >
> > Since splitting this patch causes runtime errors during temperature
> > emulation or problems where the read temperature feature fails to
> > retrieve values, I have submitted it as a single commit. To add
> > support for the exynosautov920 to the exisiting TMU interface, the
> > following changes are included:
> >
> > 1. Branch 'code_to_temp' and 'temp_to_code' for exynosautov920 SoC
> variant.
> > 2. Loop over 'tz_count' in critical-point setup.
> > 3. Introduce 'update_con_reg' for exynosautov920 control-register
> updates.
> > 4. Add exynosautov920-specific branch in 'exynos_tmu_update_temp'
> function.
> > 5. Skip high & low temperature threshold setup in exynosautov920.
> > 6. Enable interrupts via bitmap in 'exynosautov920_tmu_set_crit_temp'.
> > 7. Initialize all new members during 'exynosautov920_tmu_initialize'.
> > 8. Clear IRQs by iterating the bitamp in exynosautov920.
> > 9. Register each zone with 'devm_thermal_of_zone_register()'
> >    based on 'tz_count'.
> >
> > Signed-off-by: Shin Son <shin.son@samsung.com>
> > ---
> >  drivers/thermal/samsung/exynos_tmu.c | 340
> > ++++++++++++++++++++++++---
> >  1 file changed, 303 insertions(+), 37 deletions(-)
> >
> > diff --git a/drivers/thermal/samsung/exynos_tmu.c
> > b/drivers/thermal/samsung/exynos_tmu.c
> > index 47a99b3c5395..60d5ab33c593 100644
> > --- a/drivers/thermal/samsung/exynos_tmu.c
> > +++ b/drivers/thermal/samsung/exynos_tmu.c
> 
> [ ... ]
> 
> > +#define EXYNOSAUTOV920_TMU_REG_THRESHOLD(p)	(((p)) * 0x50 +
0x00D0)
> > +#define EXYNOSAUTOV920_TMU_REG_INTEN(p)		(((p)) * 0x50 +
> 0x00F0)
> > +#define EXYNOSAUTOV920_TMU_REG_INT_PEND(p)	(((p)) * 0x50 + 0x00F8)
> > +
> > +#define EXYNOSAUTOV920_CURRENT_TEMP_P1_P0	0x084
> > +#define EXYNOSAUTOV920_TMU_REG_EMUL_CON		0x0B0
> > +
> > +#define EXYNOSAUTOV920_TMU_REG_CONTROL		0x50
> > +#define EXYNOSAUTOV920_TMU_REG_CONTROL1		0x54
> > +#define EXYNOSAUTOV920_TMU_REG_AVG_CONTROL	0x58
> > +#define EXYNOSAUTOV920_TMU_SAMPLING_INTERVAL	0x70
> > +#define EXYNOSAUTOV920_TMU_REG_COUNTER_VALUE0	0x74
> > +#define EXYNOSAUTOV920_TMU_REG_COUNTER_VALUE1	0x78
> > +
> > +#define EXYNOSAUTOV920_TMU_THERM_TRIP_EN_SHIFT	12
> 
> There already is a EXYNOS_TMU_THERM_TRIP_EN_SHIFT constant with the same
> value. Is there some fundamental difference between
> EXYNOSAUTOV920_TMU_THERM_TRIP_EN_SHIFT and EXYNOS_TMU_THERM_TRIP_EN_SHIFT?
> 
> > +#define EXYNOSAUTOV920_TMU_T_BUF_VREF_SEL_SHIFT		8
> > +#define EXYNOSAUTOV920_TMU_T_BUF_VREF_SEL_MASK		0x1f
> > +#define EXYNOSAUTOV920_TMU_T_BUF_SLOPE_SEL_SHIFT	3
> > +#define EXYNOSAUTOV920_TMU_T_BUF_SLOPE_SEL_MASK		0xf
> > +#define EXYNOSAUTOV920_TMU_NUM_PROBE_MASK		0xf
> > +#define EXYNOSAUTOV920_TMU_NUM_PROBE_SHIFT		16
> > +#define EXYNOSAUTOV920_TMU_LPI_MODE_MASK		1
> > +#define EXYNOSAUTOV920_TMU_LPI_MODE_SHIFT		10
> > +
> > +#define EXYNOSAUTOV920_TMU_AVG_CON_UPDATE		0x0008011A
> > +#define EXYNOSAUTOV920_TMU_COUNTER_VALUE0_UPDATE	0x030003C0
> > +#define EXYNOSAUTOV920_TMU_COUNTER_VALUE1_UPDATE	0x03C0004D
> 
> If I am not mistaken lowercase letters is preferred in defines. The file
> already has a mix, but let's not make it worse. Please change to
> 0x03c0004d and so on in constants above.
> 
> >  #define MCELSIUS	1000
> >
> > +#define EXYNOS_DEFAULT_TZ_COUNT		1
> > +#define EXYNOS_MAX_TZ_COUNT		2
> > +
> >  enum soc_type {
> >  	SOC_ARCH_EXYNOS3250 = 1,
> >  	SOC_ARCH_EXYNOS4210,
> > @@ -133,6 +179,7 @@ enum soc_type {
> >  	SOC_ARCH_EXYNOS5420_TRIMINFO,
> >  	SOC_ARCH_EXYNOS5433,
> >  	SOC_ARCH_EXYNOS7,
> > +	SOC_ARCH_EXYNOSAUTOV920,
> >  };
> >
> >  /**
> > @@ -150,6 +197,8 @@ enum soc_type {
> >   * @efuse_value: SoC defined fuse value
> >   * @min_efuse_value: minimum valid trimming data
> >   * @max_efuse_value: maximum valid trimming data
> > + * @slope_comp: allocated value of the slope compensation.
> > + * @calib_temp: calibration temperature of the TMU.
> >   * @temp_error1: fused value of the first point trim.
> >   * @temp_error2: fused value of the second point trim.
> >   * @gain: gain of amplifier in the positive-TC generator block @@
> > -157,7 +206,9 @@ enum soc_type {
> >   * @reference_voltage: reference voltage of amplifier
> >   *	in the positive-TC generator block
> >   *	0 < reference_voltage <= 31
> > - * @tzd: pointer to thermal_zone_device structure
> > + * @tz_count: The allocated number of the thermal zone
> > + * @tzd_array: pointer array of thermal_zone_device structure
> > + * @valid_sensor_bitmap: The enabled sensor of the TMU device
> >   * @enabled: current status of TMU device
> >   * @tmu_set_low_temp: SoC specific method to set trip (falling
> threshold)
> >   * @tmu_set_high_temp: SoC specific method to set trip (rising
> > threshold) @@ -181,10 +232,14 @@ struct exynos_tmu_data {
> >  	u32 efuse_value;
> >  	u32 min_efuse_value;
> >  	u32 max_efuse_value;
> > +	u16 slope_comp;
> > +	u16 calib_temp;
> >  	u16 temp_error1, temp_error2;
> >  	u8 gain;
> >  	u8 reference_voltage;
> > -	struct thermal_zone_device *tzd;
> > +	u8 tz_count;
> > +	unsigned long valid_sensor_bitmap;
> > +	struct thermal_zone_device *tzd_array[EXYNOS_MAX_TZ_COUNT];
> >  	bool enabled;
> >
> >  	void (*tmu_set_low_temp)(struct exynos_tmu_data *data, u8 temp); @@
> > -208,10 +263,25 @@ static int temp_to_code(struct exynos_tmu_data *data,
> u8 temp)
> >  	if (data->cal_type == TYPE_ONE_POINT_TRIMMING)
> >  		return temp + data->temp_error1 - EXYNOS_FIRST_POINT_TRIM;
> >
> > -	return (temp - EXYNOS_FIRST_POINT_TRIM) *
> > -		(data->temp_error2 - data->temp_error1) /
> > -		(EXYNOS_SECOND_POINT_TRIM - EXYNOS_FIRST_POINT_TRIM) +
> > -		data->temp_error1;
> > +	if (data->soc == SOC_ARCH_EXYNOSAUTOV920) {
> > +		if ((temp - EXYNOS_FIRST_POINT_TRIM) >= 0) {
> > +			return (temp - EXYNOS_FIRST_POINT_TRIM) *
> > +				(data->temp_error2 - data->temp_error1) /
> > +				(data->calib_temp -
EXYNOS_FIRST_POINT_TRIM) +
> > +				data->temp_error1;
> > +		} else {
> > +			return ((temp - EXYNOS_FIRST_POINT_TRIM) *
> > +				(data->temp_error2 - data->temp_error1) /
> > +				(data->calib_temp -
EXYNOS_FIRST_POINT_TRIM) *
> > +				((57 + data->slope_comp) * 1000 / 65)) /
1000 +
> > +				data->temp_error1;
> > +		}
> > +	} else {
> > +		return (temp - EXYNOS_FIRST_POINT_TRIM) *
> > +			(data->temp_error2 - data->temp_error1) /
> > +			(EXYNOS_SECOND_POINT_TRIM -
EXYNOS_FIRST_POINT_TRIM) +
> > +			data->temp_error1;
> 
> This is essentially the same as the first return in the
> SOC_ARCH_EXYNOSAUTOV920 path. How about putting EXYNOS_SECOND_POINT_TRIM
> in the calib_temp field for the non autov920 SoCs, then we can simplify
> temp_to_code and code_to_temp to something more readable like:
> 
> static int temp_to_code(struct exynos_tmu_data *data, u8 temp) {
> 	if (data->cal_type == TYPE_ONE_POINT_TRIMMING)
> 		return temp + data->temp_error1 - EXYNOS_FIRST_POINT_TRIM;
> 
> 	int coeff = (data->temp_error2 - data->temp_error1) /
> 			(data->calib_temp - EXYNOS_FIRST_POINT_TRIM);
> 
> 	if (data->soc == SOC_ARCH_EXYNOSAUTOV920 &&
> 	    temp < EXYNOS_FIRST_POINT_TRIM)
> 		coeff *= (57 + data->slope_comp) * 1000 / 65)) / 1000;
> 
> 	return (temp - EXYNOS_FIRST_POINT_TRIM) * coeff + data-
> >temp_error1; }
> 

Thanks for your advice. I will reflect it and revise the code accordingly.

> >  }
> >
> >  /*
> > @@ -223,10 +293,25 @@ static int code_to_temp(struct exynos_tmu_data
> *data, u16 temp_code)
> >  	if (data->cal_type == TYPE_ONE_POINT_TRIMMING)
> >  		return temp_code - data->temp_error1 +
> EXYNOS_FIRST_POINT_TRIM;
> >
> > -	return (temp_code - data->temp_error1) *
> > -		(EXYNOS_SECOND_POINT_TRIM - EXYNOS_FIRST_POINT_TRIM) /
> > -		(data->temp_error2 - data->temp_error1) +
> > -		EXYNOS_FIRST_POINT_TRIM;
> > +	if (data->soc == SOC_ARCH_EXYNOSAUTOV920) {
> > +		if ((temp_code - data->temp_error1) >= 0) {
> > +			return (temp_code - data->temp_error1) *
> > +				(data->calib_temp -
EXYNOS_FIRST_POINT_TRIM) /
> > +				(data->temp_error2 - data->temp_error1) +
> > +				EXYNOS_FIRST_POINT_TRIM;
> > +		} else {
> > +			return ((temp_code - data->temp_error1) *
> > +				(data->calib_temp -
EXYNOS_FIRST_POINT_TRIM) /
> > +				(data->temp_error2 - data->temp_error1) *
> > +				(65 * 1000 / (57 + data->slope_comp))) /
1000 +
> > +				EXYNOS_FIRST_POINT_TRIM;
> > +		}
> > +	} else {
> > +		return (temp_code - data->temp_error1) *
> > +			(EXYNOS_SECOND_POINT_TRIM -
EXYNOS_FIRST_POINT_TRIM) /
> > +			(data->temp_error2 - data->temp_error1) +
> > +			EXYNOS_FIRST_POINT_TRIM;
> > +	}
> 
> Similar suggestion as for temp_to_code applies here as well.
> 
> Best regards,
> Henrik Grimler

Thanks,
Best regards
Shin son