Re: [PATCH 2/6] thermal/drivers/tsens: Add TSENS enable and calibration support for V2

[Dmitry Baryshkov <dmitry.baryshkov@linaro.org>]

On 10/07/2023 13:37, Praveenkumar I wrote:
> SoCs without RPM have to enable sensors and calibrate from the kernel.
> Though TSENS IP supports 16 sensors, not all are used. So added
> sensors_to_en in tsens data help enable the relevant sensors.
> 
> Added new calibration function for V2 as the tsens.c calib function
> only supports V1.
> 
> Signed-off-by: Praveenkumar I <quic_ipkumar@quicinc.com>
> ---
>   drivers/thermal/qcom/tsens-v2.c | 116 ++++++++++++++++++++++++++++++++
>   drivers/thermal/qcom/tsens.c    |  37 +++++++++-
>   drivers/thermal/qcom/tsens.h    |  56 +++++++++++++++
>   3 files changed, 208 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/thermal/qcom/tsens-v2.c b/drivers/thermal/qcom/tsens-v2.c
> index 29a61d2d6ca3..db48b1d95348 100644
> --- a/drivers/thermal/qcom/tsens-v2.c
> +++ b/drivers/thermal/qcom/tsens-v2.c
> @@ -6,11 +6,20 @@
>   
>   #include <linux/bitops.h>
>   #include <linux/regmap.h>
> +#include <linux/nvmem-consumer.h>
>   #include "tsens.h"
>   
>   /* ----- SROT ------ */
>   #define SROT_HW_VER_OFF	0x0000
>   #define SROT_CTRL_OFF		0x0004
> +#define SROT_MEASURE_PERIOD	0x0008
> +#define SROT_Sn_CONVERSION	0x0060
> +#define V2_SHIFT_DEFAULT	0x0003
> +#define V2_SLOPE_DEFAULT	0x0cd0
> +#define V2_CZERO_DEFAULT	0x016a
> +#define ONE_PT_SLOPE		0x0cd0
> +#define TWO_PT_SHIFTED_GAIN	921600
> +#define ONE_PT_CZERO_CONST	94
>   
>   /* ----- TM ------ */
>   #define TM_INT_EN_OFF			0x0004
> @@ -59,6 +68,16 @@ static const struct reg_field tsens_v2_regfields[MAX_REGFIELDS] = {
>   	/* CTRL_OFF */
>   	[TSENS_EN]     = REG_FIELD(SROT_CTRL_OFF,    0,  0),
>   	[TSENS_SW_RST] = REG_FIELD(SROT_CTRL_OFF,    1,  1),
> +	[SENSOR_EN]    = REG_FIELD(SROT_CTRL_OFF,    3,  18),
> +	[CODE_OR_TEMP] = REG_FIELD(SROT_CTRL_OFF,    21, 21),
> +
> +	/* MAIN_MEASURE_PERIOD */
> +	[MAIN_MEASURE_PERIOD] = REG_FIELD(SROT_MEASURE_PERIOD, 0, 7),
> +
> +	/* Sn Conversion */
> +	REG_FIELD_FOR_EACH_SENSOR16(SHIFT, SROT_Sn_CONVERSION, 23, 24),
> +	REG_FIELD_FOR_EACH_SENSOR16(SLOPE, SROT_Sn_CONVERSION, 10, 22),
> +	REG_FIELD_FOR_EACH_SENSOR16(CZERO, SROT_Sn_CONVERSION, 0, 9),
>   
>   	/* ----- TM ------ */
>   	/* INTERRUPT ENABLE */
> @@ -104,6 +123,103 @@ static const struct reg_field tsens_v2_regfields[MAX_REGFIELDS] = {
>   	[TRDY] = REG_FIELD(TM_TRDY_OFF, 0, 0),
>   };
>   
> +static int tsens_v2_calibration(struct tsens_priv *priv)
> +{
> +	struct device *dev = priv->dev;
> +	u32 mode, base0, base1;
> +	u32 slope, czero;
> +	char name[15];
> +	int i, j, ret;
> +
> +	if (priv->num_sensors > MAX_SENSORS)
> +		return -EINVAL;
> +
> +	ret = nvmem_cell_read_variable_le_u32(priv->dev, "mode", &mode);
> +	if (ret == -ENOENT)
> +		dev_warn(priv->dev, "Calibration data not present in DT\n");
> +	if (ret < 0)
> +		return ret;
> +
> +	dev_dbg(priv->dev, "calibration mode is %d\n", mode);
> +
> +	ret = nvmem_cell_read_variable_le_u32(priv->dev, "base0", &base0);
> +	if (ret < 0)
> +		return ret;
> +
> +	ret = nvmem_cell_read_variable_le_u32(priv->dev, "base1", &base1);
> +	if (ret < 0)
> +		return ret;
> +
> +	/* Read offset values and allocate SHIFT, SLOPE & CZERO regmap for enabled sensors */
> +	for (i = 0; i < priv->num_sensors; i++) {
> +		if (!(priv->sensors_to_en & (0x1 << i)))
> +			continue;
> +
> +		ret = snprintf(name, sizeof(name), "s%d_offset", priv->sensor[i].hw_id);
> +		if (ret < 0)
> +			return ret;
> +
> +		ret = nvmem_cell_read_variable_le_u32(priv->dev, name, &priv->sensor[i].offset);
> +		if (ret)
> +			return ret;
> +
> +		for (j = SHIFT_0; j <= CZERO_0; j++) {
> +			int idx = (i * 3) + j;
> +
> +			priv->rf[idx] = devm_regmap_field_alloc(dev, priv->srot_map,
> +								priv->fields[idx]);
> +			if (IS_ERR(priv->rf[idx]))
> +				return PTR_ERR(priv->rf[idx]);

I think, allocating data structures for 48 regfields, which are written 
just once, to be an overkill.

> +		}
> +	}
> +
> +	/* Based on calib mode, program SHIFT, SLOPE and CZERO for enabled sensors */
> +	switch (mode) {
> +	case TWO_PT_CALIB:
> +		slope = (TWO_PT_SHIFTED_GAIN / (base1 - base0));
> +
> +		for (i = 0; i < priv->num_sensors; i++) {
> +			if (!(priv->sensors_to_en & (0x1 << i)))
> +				continue;
> +
> +			int idx = i * 3;
> +
> +			czero = (base0 + priv->sensor[i].offset - ((base1 - base0) / 3));
> +			regmap_field_write(priv->rf[SHIFT_0 + idx], V2_SHIFT_DEFAULT);
> +			regmap_field_write(priv->rf[SLOPE_0 + idx], slope);
> +			regmap_field_write(priv->rf[CZERO_0 + idx], czero);
> +		}
> +		fallthrough;
> +	case ONE_PT_CALIB2:
> +		for (i = 0; i < priv->num_sensors; i++) {
> +			if (!(priv->sensors_to_en & (0x1 << i)))
> +				continue;
> +
> +			int idx = i * 3;
> +
> +			czero = base0 + priv->sensor[i].offset - ONE_PT_CZERO_CONST;
> +			regmap_field_write(priv->rf[SHIFT_0 + idx], V2_SHIFT_DEFAULT);
> +			regmap_field_write(priv->rf[SLOPE_0 + idx], ONE_PT_SLOPE);
> +			regmap_field_write(priv->rf[CZERO_0 + idx], czero);
> +		}
> +		break;
> +	default:
> +		dev_dbg(priv->dev, "calibrationless mode\n");
> +		for (i = 0; i < priv->num_sensors; i++) {
> +			if (!(priv->sensors_to_en & (0x1 << i)))
> +				continue;
> +
> +			int idx = i * 3;
> +
> +			regmap_field_write(priv->rf[SHIFT_0 + idx], V2_SHIFT_DEFAULT);
> +			regmap_field_write(priv->rf[SLOPE_0 + idx], V2_SLOPE_DEFAULT);
> +			regmap_field_write(priv->rf[CZERO_0 + idx], V2_CZERO_DEFAULT);
> +		}
> +	}

This code iterates over the sensors field several times. Please consider 
extracting a function that handles all setup for a single sensor, then 
calling it in a loop (I should probably do the same for tsens-v0/v1 too).

> +
> +	return 0;
> +}
> +
>   static const struct tsens_ops ops_generic_v2 = {
>   	.init		= init_common,
>   	.get_temp	= get_temp_tsens_valid,
> diff --git a/drivers/thermal/qcom/tsens.c b/drivers/thermal/qcom/tsens.c
> index 98c356acfe98..169690355dad 100644
> --- a/drivers/thermal/qcom/tsens.c
> +++ b/drivers/thermal/qcom/tsens.c
> @@ -974,7 +974,7 @@ int __init init_common(struct tsens_priv *priv)
>   	ret = regmap_field_read(priv->rf[TSENS_EN], &enabled);
>   	if (ret)
>   		goto err_put_device;
> -	if (!enabled) {
> +	if (!enabled && !priv->sensors_to_en) {
>   		dev_err(dev, "%s: device not enabled\n", __func__);
>   		ret = -ENODEV;
>   		goto err_put_device;
> @@ -1006,6 +1006,40 @@ int __init init_common(struct tsens_priv *priv)
>   		goto err_put_device;
>   	}
>   
> +	/* Do TSENS initialization if required */
> +	if (priv->sensors_to_en) {

Maybe it would be better to explicitly add VER_2_X_NO_RPM and check it here?

> +		priv->rf[CODE_OR_TEMP] = devm_regmap_field_alloc(dev, priv->srot_map,
> +								 priv->fields[CODE_OR_TEMP]);
> +		if (IS_ERR(priv->rf[CODE_OR_TEMP])) {
> +			ret = PTR_ERR(priv->rf[CODE_OR_TEMP]);
> +			goto err_put_device;
> +		}
> +
> +		priv->rf[MAIN_MEASURE_PERIOD] =
> +			devm_regmap_field_alloc(dev, priv->srot_map,
> +						priv->fields[MAIN_MEASURE_PERIOD]);
> +		if (IS_ERR(priv->rf[MAIN_MEASURE_PERIOD])) {
> +			ret = PTR_ERR(priv->rf[MAIN_MEASURE_PERIOD]);
> +			goto err_put_device;
> +		}
> +
> +		regmap_field_write(priv->rf[TSENS_SW_RST], 0x1);
> +
> +		/* Update measure period to 2ms */
> +		regmap_field_write(priv->rf[MAIN_MEASURE_PERIOD], 0x1);
> +
> +		/* Enable available sensors */
> +		regmap_field_write(priv->rf[SENSOR_EN], priv->sensors_to_en);
> +
> +		/* Real temperature format */
> +		regmap_field_write(priv->rf[CODE_OR_TEMP], 0x1);
> +
> +		regmap_field_write(priv->rf[TSENS_SW_RST], 0x0);
> +
> +		/* Enable TSENS */
> +		regmap_field_write(priv->rf[TSENS_EN], 0x1);
> +	}
> +
>   	/* This loop might need changes if enum regfield_ids is reordered */
>   	for (j = LAST_TEMP_0; j <= UP_THRESH_15; j += 16) {
>   		for (i = 0; i < priv->feat->max_sensors; i++) {
> @@ -1282,6 +1316,7 @@ static int tsens_probe(struct platform_device *pdev)
>   
>   	priv->dev = dev;
>   	priv->num_sensors = num_sensors;
> +	priv->sensors_to_en = data->sensors_to_en;
>   	priv->ops = data->ops;
>   	for (i = 0;  i < priv->num_sensors; i++) {
>   		if (data->hw_ids)
> diff --git a/drivers/thermal/qcom/tsens.h b/drivers/thermal/qcom/tsens.h
> index 2805de1c6827..f8897bc8944e 100644
> --- a/drivers/thermal/qcom/tsens.h
> +++ b/drivers/thermal/qcom/tsens.h
> @@ -168,6 +168,58 @@ enum regfield_ids {
>   	TSENS_SW_RST,
>   	SENSOR_EN,
>   	CODE_OR_TEMP,
> +	/* MEASURE_PERIOD */
> +	MAIN_MEASURE_PERIOD,
> +
> +	/* Sn_CONVERSION */
> +	SHIFT_0,
> +	SLOPE_0,
> +	CZERO_0,
> +	SHIFT_1,
> +	SLOPE_1,
> +	CZERO_1,
> +	SHIFT_2,
> +	SLOPE_2,
> +	CZERO_2,
> +	SHIFT_3,
> +	SLOPE_3,
> +	CZERO_3,
> +	SHIFT_4,
> +	SLOPE_4,
> +	CZERO_4,
> +	SHIFT_5,
> +	SLOPE_5,
> +	CZERO_5,
> +	SHIFT_6,
> +	SLOPE_6,
> +	CZERO_6,
> +	SHIFT_7,
> +	SLOPE_7,
> +	CZERO_7,
> +	SHIFT_8,
> +	SLOPE_8,
> +	CZERO_8,
> +	SHIFT_9,
> +	SLOPE_9,
> +	CZERO_9,
> +	SHIFT_10,
> +	SLOPE_10,
> +	CZERO_10,
> +	SHIFT_11,
> +	SLOPE_11,
> +	CZERO_11,
> +	SHIFT_12,
> +	SLOPE_12,
> +	CZERO_12,
> +	SHIFT_13,
> +	SLOPE_13,
> +	CZERO_13,
> +	SHIFT_14,
> +	SLOPE_14,
> +	CZERO_14,
> +	SHIFT_15,
> +	SLOPE_15,
> +	CZERO_15,
>   
>   	/* ----- TM ------ */
>   	/* TRDY */
> @@ -524,6 +576,7 @@ struct tsens_features {
>   /**
>    * struct tsens_plat_data - tsens compile-time platform data
>    * @num_sensors: Number of sensors supported by platform
> + * @sensors_to_en: Sensors to be enabled. Each bit represent a sensor
>    * @ops: operations the tsens instance supports
>    * @hw_ids: Subset of sensors ids supported by platform, if not the first n
>    * @feat: features of the IP
> @@ -531,6 +584,7 @@ struct tsens_features {
>    */
>   struct tsens_plat_data {
>   	const u32		num_sensors;
> +	const u16		sensors_to_en;

There is already a similar field, hw_ids. Can it be used instead?

>   	const struct tsens_ops	*ops;
>   	unsigned int		*hw_ids;
>   	struct tsens_features	*feat;
> @@ -551,6 +605,7 @@ struct tsens_context {
>    * struct tsens_priv - private data for each instance of the tsens IP
>    * @dev: pointer to struct device
>    * @num_sensors: number of sensors enabled on this device
> + * @sensors_to_en: sensors to be enabled. Each bit represents a sensor
>    * @tm_map: pointer to TM register address space
>    * @srot_map: pointer to SROT register address space
>    * @tm_offset: deal with old device trees that don't address TM and SROT
> @@ -569,6 +624,7 @@ struct tsens_context {
>   struct tsens_priv {
>   	struct device			*dev;
>   	u32				num_sensors;
> +	u16				sensors_to_en;
>   	struct regmap			*tm_map;
>   	struct regmap			*srot_map;
>   	u32				tm_offset;

-- 
With best wishes
Dmitry