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Date:   Sat, 15 Jul 2023 16:05:37 +0200
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To:     Praveenkumar I <quic_ipkumar@quicinc.com>, amitk@kernel.org,
        thara.gopinath@gmail.com, agross@kernel.org, andersson@kernel.org,
        rafael@kernel.org, daniel.lezcano@linaro.org, rui.zhang@intel.com,
        robh+dt@kernel.org, krzysztof.kozlowski+dt@linaro.org,
        conor+dt@kernel.org, linux-pm@vger.kernel.org,
        linux-arm-msm@vger.kernel.org, devicetree@vger.kernel.org,
        linux-kernel@vger.kernel.org
Cc:     quic_varada@quicinc.com
References: <20230713052732.787853-1-quic_ipkumar@quicinc.com>
 <20230713052732.787853-2-quic_ipkumar@quicinc.com>
From:   Konrad Dybcio <konrad.dybcio@linaro.org>
Subject: Re: [PATCH v3 1/5] thermal/drivers/tsens: Add TSENS enable and
 calibration support for V2
In-Reply-To: <20230713052732.787853-2-quic_ipkumar@quicinc.com>
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Precedence: bulk

On 13.07.2023 07:27, 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 used hw_id
> to 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>
> ---
[...]

>  
>  /* ----- 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
> +#define SENSOR_CONVERSION(n)	(((n) * 4) + SROT_Sn_CONVERSION)
> +#define CONVERSION_SLOPE_SHIFT	10
> +#define CONVERSION_SHIFT_SHIFT	23
Please define bitfields with GENMASK() and use FIELD_PREP/GET() helpers

>  
>  /* ----- TM ------ */
>  #define TM_INT_EN_OFF			0x0004
> @@ -59,6 +71,11 @@ 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),
>  
>  	/* ----- TM ------ */
>  	/* INTERRUPT ENABLE */
> @@ -104,6 +121,130 @@ static const struct reg_field tsens_v2_regfields[MAX_REGFIELDS] = {
>  	[TRDY] = REG_FIELD(TM_TRDY_OFF, 0, 0),
>  };
>  
> +static int tsens_v2_calibrate_sensor(struct device *dev, struct tsens_sensor *sensor,
> +				     struct regmap *map,  u32 mode, u32 base0, u32 base1)
> +{
> +	u32 slope, czero, val;
> +	char name[15];
What's the rationale behind choosing 15 here?

> +	int ret;
> +
[...]

> +static int tsens_v2_calibration(struct tsens_priv *priv)
> +{
> +	struct device *dev = priv->dev;
> +	u32 mode, base0, base1;
> +	int i, 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");
I think bindings don't allow that anyway

> +	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;
> +
> +	/* Calibrate each sensor */
> +	for (i = 0; i < priv->num_sensors; i++) {
> +		ret = tsens_v2_calibrate_sensor(dev, &priv->sensor[i], priv->srot_map,
> +						mode, base0, base1);
> +		if (ret < 0)
> +			return ret;
> +	}
> +
> +	return 0;
> +}
> +
> +static int __init init_tsens_v2_no_rpm(struct tsens_priv *priv)
> +{
> +	int i, ret;
> +	u32 val = 0;
> +	struct device *dev = priv->dev;
Reverse-Christmas-tree, please.

> +
> +	ret = init_common(priv);
> +	if (ret < 0)
> +		return ret;
> +
> +	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]))
> +		return PTR_ERR(priv->rf[CODE_OR_TEMP]);
> +
> +	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]))
> +		return PTR_ERR(priv->rf[MAIN_MEASURE_PERIOD]);
> +
> +	regmap_field_write(priv->rf[TSENS_SW_RST], 0x1);
> +
> +	/* Update measure period to 2ms */
What's the unit? Can we name the 0x1 value?

> +	regmap_field_write(priv->rf[MAIN_MEASURE_PERIOD], 0x1);
> +
> +	/* Enable available sensors */
> +	for (i = 0; i < priv->num_sensors; i++)
> +		val |= 1 << priv->sensor[i].hw_id;
> +
> +	regmap_field_write(priv->rf[SENSOR_EN], val);
> +
> +	/* Real temperature format */
What does that mean?

> +	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);
It would be really nice if you could provide the names of all these
magic values.

Konrad
> +
> +	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..9dc0c2150948 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 && (tsens_version(priv) != VER_2_X_NO_RPM)) {
>  		dev_err(dev, "%s: device not enabled\n", __func__);
>  		ret = -ENODEV;
>  		goto err_put_device;
> diff --git a/drivers/thermal/qcom/tsens.h b/drivers/thermal/qcom/tsens.h
> index 2805de1c6827..b2e8f0f2b466 100644
> --- a/drivers/thermal/qcom/tsens.h
> +++ b/drivers/thermal/qcom/tsens.h
> @@ -35,6 +35,7 @@ enum tsens_ver {
>  	VER_0_1,
>  	VER_1_X,
>  	VER_2_X,
> +	VER_2_X_NO_RPM,
>  };
>  
>  enum tsens_irq_type {
> @@ -168,6 +169,8 @@ enum regfield_ids {
>  	TSENS_SW_RST,
>  	SENSOR_EN,
>  	CODE_OR_TEMP,
> +	/* MEASURE_PERIOD */
> +	MAIN_MEASURE_PERIOD,
>  
>  	/* ----- TM ------ */
>  	/* TRDY */