Re: [PATCH 2/2] thermal: qcom: Add support for Qualcomm MBG thermal monitoring

[Konrad Dybcio]

On 6/1/26 1:01 PM, Sachin Gupta wrote:
> From: Satya Priya Kakitapalli <quic_skakitap@xxxxxxxxxxx>
> 
> Add driver for the Qualcomm MBG thermal monitoring device. It monitors
> the die temperature, and when there is a level 1 upper threshold
> violation, it receives an interrupt over spmi. The driver reads
> the fault status register and notifies thermal accordingly.
> 
> Signed-off-by: Satya Priya Kakitapalli <quic_skakitap@xxxxxxxxxxx>
> Co-developed-by: Sachin Gupta <sachin.gupta@xxxxxxxxxxxxxxxx>
> Signed-off-by: Sachin Gupta <sachin.gupta@xxxxxxxxxxxxxxxx>
> ---

[...]

> +static const struct mbg_map_table map_table[] = {
> +	/* minT	vtemp0	tc */

The struct is defined 2 lines above, the reader can tell the names
of the fields
> +	{ -60000, 4337, 1967 },
> +	{ -40000, 4731, 1964 },
> +	{ -20000, 5124, 1957 },
> +	{ 0,      5515, 1949 },
> +	{ 20000,  5905, 1940 },
> +	{ 40000,  6293, 1930 },
> +	{ 60000,  6679, 1921 },
> +	{ 80000,  7064, 1910 },
> +	{ 100000, 7446, 1896 },
> +	{ 120000, 7825, 1878 },
> +	{ 140000, 8201, 1859 },
> +};

Please add a comment stating this map is not PMIC-specific

[...]

> +	/* The HW has a limitation that the trip set must be above 25C */
> +	if (temp > MBG_MIN_TRIP_TEMP && temp < MBG_MAX_SUPPORTED_TEMP) {
> +		ret = regmap_set_bits(chip->map, chip->base + MBG_TEMP_MON2_MISC_CFG,
> +				      MON2_UP_THRESH_EN);
> +		if (ret < 0)
> +			return ret;
> +
> +		ret = regmap_write(chip->map, chip->base + MON2_LVL1_UP_THRESH,
> +				   temp_to_vtemp_mv(temp));
> +		if (ret < 0)
> +			return ret;
> +	} else {
> +		dev_dbg(chip->dev, "Set trip b/w 25C and 160C\n");

Should this be an error print, returning an error condition?

> +		ret = regmap_clear_bits(chip->map, chip->base + MBG_TEMP_MON2_MISC_CFG,
> +					MON2_UP_THRESH_EN);
> +		return ret;
> +	}
> +
> +	/*
> +	 * Configure the last_temp one degree higher, to ensure the
> +	 * violated temp is returned to thermal framework when it reads
> +	 * temperature for the first time after the violation happens.
> +	 * This is needed to account for the inaccuracy in the conversion
> +	 * formula used which leads to the thermal framework setting back
> +	 * the same thresholds in case the temperature it reads does not
> +	 * show violation.
> +	 */
> +	chip->last_temp = temp + MBG_TEMP_CONSTANT;

Will this work fine if the user tries to set the max temp supported
by the hardware (i.e. is there headroom for max+1)?

> +
> +	return ret;
> +}
> +
> +static const struct thermal_zone_device_ops mbg_tm_ops = {
> +	.get_temp = mbg_tm_get_temp,
> +	.set_trips = mbg_tm_set_trip_temp,
> +};
> +
> +static irqreturn_t mbg_tm_isr(int irq, void *data)
> +{
> +	struct mbg_tm_chip *chip = data;
> +	int ret, val;
> +
> +	scoped_guard(mutex, &chip->lock) {
> +		ret = regmap_read(chip->map, chip->base + MBG_TEMP_MON2_FAULT_STATUS, &val);
> +		if (ret < 0)
> +			return IRQ_HANDLED;
> +	}
> +
> +	if (FIELD_GET(MON_FAULT_STATUS_MASK, val) & MON_FAULT_LVL1_UPR) {
> +		chip->last_thres_crossed = true;
> +		dev_dbg(chip->dev, "Notifying Thermal, fault status=%d\n", val);
> +		thermal_zone_device_update(chip->tz_dev, THERMAL_TRIP_VIOLATED);

Should the assignment and this call also be guarded by the mutex?

Konrad