Re: [PATCH v5 3/4] thermal: qoriq: workaround unexpected temperature readings from tmu

[Frank Li <Frank.li@nxp.com>]

On Tue, Apr 21, 2026 at 03:42:24PM +0800, Jacky Bai wrote:
> Invalid temperature measurements may be observed across the temperature
> range specified in the device data sheet. The invalid temperature can
> be read from any remote site and from any capture or report registers.
> The invalid change in temperature can be positive or negative and the
> resulting temperature can be outside the calibrated range, in which
> case the TSR[ORL] or TSR[ORH] bit will be set.
>
> Workaround:
> Use the raising/falling edge threshold to filter out the invalid temp.
> Check the TIDR register to make sure no jump happens When reading the temp.
>
> i.MX93 ERR052243:
> (https://www.nxp.com/webapp/Download?colCode=IMX93_2P87F&appType=license)
>
> Signed-off-by: Jacky Bai <ping.bai@nxp.com>
> ---
>  - v5 changes:
>   - replace the check errata macro with inline function
>
>  - v4 changes:
>   - include bitfield.h to fix compilation errors for RISC-V
>   - use macro define for temp rate related setting
>
>  - v3 changes:
>   - refine the code with FIELD_PREP macro
>   - add errata doc url link and refine the commit log
>
>  - v2 changes:
>   - no
> ---
>  drivers/thermal/qoriq_thermal.c | 49 ++++++++++++++++++++++++++++++++++++++++-
>  1 file changed, 48 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/thermal/qoriq_thermal.c b/drivers/thermal/qoriq_thermal.c
> index 297a855311f3d6a8d527794abe17ac86c47bf152..57c712b9b359d713f2ff4926eb890a0641aa96bd 100644
> --- a/drivers/thermal/qoriq_thermal.c
> +++ b/drivers/thermal/qoriq_thermal.c
> @@ -3,6 +3,7 @@
>  // Copyright 2016 Freescale Semiconductor, Inc.
>  // Copyright 2025 NXP
>
> +#include <linux/bitfield.h>
>  #include <linux/clk.h>
>  #include <linux/err.h>
>  #include <linux/io.h>
> @@ -30,6 +31,9 @@
>  #define TMU_VER1		0x1
>  #define TMU_VER2		0x2
>
> +/* errata ID info define */
> +#define TMU_ERR052243	BIT(0)
> +
>  #define REGS_TMR	0x000	/* Mode Register */
>  #define TMR_DISABLE	0x0
>  #define TMR_ME		0x80000000
> @@ -45,6 +49,15 @@
>  #define REGS_TIER	0x020	/* Interrupt Enable Register */
>  #define TIER_DISABLE	0x0
>
> +#define REGS_TIDR	0x24
> +#define TEMP_RATE_IRQ_MASK	GENMASK(25, 24)
> +#define TMRTRCTR	0x70
> +#define TMRTRCTR_EN	BIT(31)
> +#define TMRTRCTR_TEMP_MASK	GENMASK(7, 0)
> +#define TMFTRCTR	0x74
> +#define TMFTRCTR_EN	BIT(31)
> +#define TMFTRCTR_TEMP_MASK	GENMASK(7, 0)
> +#define TEMP_RATE_THR_LVL	0x7
>
>  #define REGS_TTCFGR	0x080	/* Temperature Configuration Register */
>  #define REGS_TSCFGR	0x084	/* Sensor Configuration Register */
> @@ -77,6 +90,7 @@ struct qoriq_sensor {
>
>  struct tmu_drvdata {
>  	u32 teumr0;
> +	u32 tmu_errata;
>  };
>
>  struct qoriq_tmu_data {
> @@ -88,6 +102,12 @@ struct qoriq_tmu_data {
>  	const struct tmu_drvdata *drvdata;
>  };
>
> +static inline bool qoriq_tmu_has_errata(const struct tmu_drvdata *drvdata,
> +					u32 flag)
> +{
> +	return drvdata->tmu_errata & flag;
> +}
> +
>  static struct qoriq_tmu_data *qoriq_sensor_to_data(struct qoriq_sensor *s)
>  {
>  	return container_of(s, struct qoriq_tmu_data, sensor[s->id]);
> @@ -97,7 +117,7 @@ static int tmu_get_temp(struct thermal_zone_device *tz, int *temp)
>  {
>  	struct qoriq_sensor *qsensor = thermal_zone_device_priv(tz);
>  	struct qoriq_tmu_data *qdata = qoriq_sensor_to_data(qsensor);
> -	u32 val;
> +	u32 val, tidr;
>  	/*
>  	 * REGS_TRITSR(id) has the following layout:
>  	 *
> @@ -122,6 +142,15 @@ static int tmu_get_temp(struct thermal_zone_device *tz, int *temp)
>  	if (!(val & TMR_ME))
>  		return -EAGAIN;
>
> +	/* ERR052243: If a raising or falling edge happens, try later */
> +	if (qoriq_tmu_has_errata(qdata->drvdata, TMU_ERR052243)) {
> +		regmap_read(qdata->regmap, REGS_TIDR, &tidr);
> +		if (tidr & TEMP_RATE_IRQ_MASK) {
> +			regmap_write(qdata->regmap, REGS_TIDR, TEMP_RATE_IRQ_MASK);
> +			return -EAGAIN;
> +		}
> +	}
> +
>  	if (regmap_read_poll_timeout(qdata->regmap,
>  				     REGS_TRITSR(qsensor->id),
>  				     val,
> @@ -130,6 +159,15 @@ static int tmu_get_temp(struct thermal_zone_device *tz, int *temp)
>  				     10 * USEC_PER_MSEC))
>  		return -ENODATA;
>
> +	/*ERR052243: If a raising or falling edge happens, try later */
> +	if (qoriq_tmu_has_errata(qdata->drvdata, TMU_ERR052243)) {
> +		regmap_read(qdata->regmap, REGS_TIDR, &tidr);
> +		if (tidr & TEMP_RATE_IRQ_MASK) {
> +			regmap_write(qdata->regmap, REGS_TIDR, TEMP_RATE_IRQ_MASK);
> +			return -EAGAIN;
> +		}
> +	}
> +

The above two code blocks are the same. Use helper function to avoid
duplicat code. And why need check twice?

	ret = qoriq_tmu_err052243()
	if (ret)
		return ret;

Frank

>  	if (qdata->ver == TMU_VER1) {
>  		*temp = (val & GENMASK(7, 0)) * MILLIDEGREE_PER_DEGREE;
>  	} else {
> @@ -247,6 +285,14 @@ static void qoriq_tmu_init_device(struct qoriq_tmu_data *data)
>  		regmap_write(data->regmap, REGS_V2_TEUMR(0), teumr0_val);
>  	}
>
> +	/* ERR052243: Set the raising & falling edge monitor */
> +	if (qoriq_tmu_has_errata(data->drvdata, TMU_ERR052243)) {
> +		regmap_write(data->regmap, TMRTRCTR, TMRTRCTR_EN |
> +			     FIELD_PREP(TMRTRCTR_TEMP_MASK, TEMP_RATE_THR_LVL));
> +		regmap_write(data->regmap, TMFTRCTR, TMFTRCTR_EN |
> +			     FIELD_PREP(TMFTRCTR_TEMP_MASK, TEMP_RATE_THR_LVL));
> +
> +	}
>  	/* Disable monitoring */
>  	regmap_write(data->regmap, REGS_TMR, TMR_DISABLE);
>  }
> @@ -400,6 +446,7 @@ static const struct tmu_drvdata imx8mq_tmu_data = {
>
>  static const struct tmu_drvdata imx93_data = {
>  	.teumr0 = TEUMR0_V21,
> +	.tmu_errata = TMU_ERR052243,
>  };
>
>  static const struct of_device_id qoriq_tmu_match[] = {
>
> --
> 2.34.1
>