diff mbox series

[09/14] iio: adc: rzg2l_adc: Add support for channel 8

Message ID 20241203111314.2420473-10-claudiu.beznea.uj@bp.renesas.com (mailing list archive)
State New
Delegated to: Geert Uytterhoeven
Headers show
Series iio: adc: rzg2l_adc: Add support for RZ/G3S | expand

Commit Message

Claudiu Beznea Dec. 3, 2024, 11:13 a.m. UTC 
From: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>

The ADC on the Renesas RZ/G3S SoC includes an additional channel (channel
8) dedicated to reading temperature values from the Thermal Sensor Unit
(TSU). There is a direct in-SoC connection between the ADC and TSU IPs.

To read the temperature reported by the TSU, a different sampling rate
(compared to channels 0-7) must be configured in the ADM3 register.

The rzg2l_adc driver has been updated to support reading the TSU
temperature.

Signed-off-by: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>
---
 drivers/iio/adc/rzg2l_adc.c | 81 +++++++++++++++++++++++++++----------
 1 file changed, 60 insertions(+), 21 deletions(-)

Comments

Jonathan Cameron Dec. 3, 2024, 8:18 p.m. UTC | #1 
On Tue,  3 Dec 2024 13:13:09 +0200
Claudiu <claudiu.beznea@tuxon.dev> wrote:

> From: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>
> 
> The ADC on the Renesas RZ/G3S SoC includes an additional channel (channel
> 8) dedicated to reading temperature values from the Thermal Sensor Unit
> (TSU). There is a direct in-SoC connection between the ADC and TSU IPs.
> 
> To read the temperature reported by the TSU, a different sampling rate
> (compared to channels 0-7) must be configured in the ADM3 register.
> 
> The rzg2l_adc driver has been updated to support reading the TSU
> temperature.
> 
> Signed-off-by: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>

>  static unsigned int rzg2l_adc_readl(struct rzg2l_adc *adc, u32 reg)
> @@ -161,7 +173,7 @@ static void rzg2l_set_trigger(struct rzg2l_adc *adc)
>  	rzg2l_adc_writel(adc, RZG2L_ADM(1), reg);
>  }
>  
> -static int rzg2l_adc_conversion_setup(struct rzg2l_adc *adc, u8 ch)
> +static int rzg2l_adc_conversion_setup(struct rzg2l_adc *adc, u8 ch, enum iio_chan_type type)
>  {
>  	const struct rzg2l_adc_hw_params *hw_params = adc->hw_params;
>  	u32 reg;
> @@ -177,6 +189,15 @@ static int rzg2l_adc_conversion_setup(struct rzg2l_adc *adc, u8 ch)
>  	reg |= BIT(ch);
>  	rzg2l_adc_writel(adc, RZG2L_ADM(2), reg);
>  
> +	reg = rzg2l_adc_readl(adc, RZG2L_ADM(3));
> +	reg &= ~hw_params->adsmp_mask;
> +	/*
> +	 * type could be IIO_VOLTAGE = 0 or IIO_TEMP = 9. Divide to 8 to get
> +	 * index 0 or 1 depending on the channel type.

That is not particularly nice and potentially a little fragile if we get other device
support in future. Better to match on the type in rzg2l_adc_channels[] possibly wrapped
up in a little utility function bool rzg2l_adc_channels_is_temp(); Then use a
? 1 : 0 to get the offset in default_adsmp[]


> +	 */
> +	reg |= hw_params->default_adsmp[type / 8];
> +	rzg2l_adc_writel(adc, RZG2L_ADM(3), reg);
> +
>  	/*
>  	 * Setup ADINT
>  	 * INTS[31] - Select pulse signal
> @@ -192,7 +213,8 @@ static int rzg2l_adc_conversion_setup(struct rzg2l_adc *adc, u8 ch)
>  	return 0;
>  }
>
>  
> +	case IIO_CHAN_INFO_PROCESSED:
> +		if (chan->type != IIO_TEMP)
> +			return -EINVAL;
> +
> +		mutex_lock(&adc->lock);
> +		ret = rzg2l_adc_conversion(indio_dev, chan->type, adc, ch);
> +		if (!ret) {
> +			/* Convert it to mili Celsius. */
> +			*val = adc->last_val[ch] * 1000;
Prefer you provide a scale of 1000 and report this raw.
> +		}
Also strong preference for error conditions out of line.
As in that other case, guard() makes that easier as yo ucan do
		{

			guard(mutex)(&adc->lock);
			ret = rz....
			if (ret)
				return ret;

			*val = ...
			
			return IIO_VAL_INT;
		}

> +		mutex_unlock(&adc->lock);
> +
> +		return ret ? ret : IIO_VAL_INT;
> +
>  	default:
>  		return -EINVAL;
>  	}

>  static const struct iio_info rzg2l_adc_iio_info = {
> @@ -332,11 +368,14 @@ static int rzg2l_adc_parse_properties(struct platform_device *pdev, struct rzg2l
>  		if (channel >= hw_params->num_channels)
>  			return -EINVAL;
>  
> -		chan_array[i].type = IIO_VOLTAGE;
> +		chan_array[i].type = rzg2l_adc_channels[channel].type;
>  		chan_array[i].indexed = 1;
>  		chan_array[i].channel = channel;
> -		chan_array[i].info_mask_separate = BIT(IIO_CHAN_INFO_RAW);
> -		chan_array[i].datasheet_name = rzg2l_adc_channel_name[channel];
> +		if (rzg2l_adc_channels[channel].type == IIO_VOLTAGE)
> +			chan_array[i].info_mask_separate = BIT(IIO_CHAN_INFO_RAW);
> +		else
> +			chan_array[i].info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED);

Make it raw, but I'm curious we have no _SCALE on this device.  Do we really have no idea
of the calibration of these channels?

> +		chan_array[i].datasheet_name = rzg2l_adc_channels[channel].name;
>  		i++;
>  	}
>  
> @@ -386,7 +425,7 @@ static int rzg2l_adc_hw_init(struct device *dev, struct rzg2l_adc *adc)
>  	reg &= ~RZG2L_ADM3_ADCMP_MASK;
>  	reg &= ~hw_params->adsmp_mask;
>  	reg |= FIELD_PREP(RZG2L_ADM3_ADCMP_MASK, hw_params->default_adcmp) |
> -	       hw_params->default_adsmp;
> +	       hw_params->default_adsmp[0];
>  
>  	rzg2l_adc_writel(adc, RZG2L_ADM(3), reg);
>  
> @@ -479,7 +518,7 @@ static int rzg2l_adc_probe(struct platform_device *pdev)
>  static const struct rzg2l_adc_hw_params rzg2l_hw_params = {
>  	.num_channels = 8,
>  	.default_adcmp = 0xe,
> -	.default_adsmp = 0x578,
> +	.default_adsmp = { 0x578 },
>  	.adsmp_mask = GENMASK(15, 0),
>  	.adint_inten_mask = GENMASK(7, 0),
>  	.adivc = true
Claudiu Beznea Dec. 4, 2024, 8:50 a.m. UTC | #2 
Hi, Jonathan,

On 03.12.2024 22:18, Jonathan Cameron wrote:
> On Tue,  3 Dec 2024 13:13:09 +0200
> Claudiu <claudiu.beznea@tuxon.dev> wrote:
> 
>> From: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>
>>
>> The ADC on the Renesas RZ/G3S SoC includes an additional channel (channel
>> 8) dedicated to reading temperature values from the Thermal Sensor Unit
>> (TSU). There is a direct in-SoC connection between the ADC and TSU IPs.
>>
>> To read the temperature reported by the TSU, a different sampling rate
>> (compared to channels 0-7) must be configured in the ADM3 register.
>>
>> The rzg2l_adc driver has been updated to support reading the TSU
>> temperature.
>>
>> Signed-off-by: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>
> 
>>  static unsigned int rzg2l_adc_readl(struct rzg2l_adc *adc, u32 reg)
>> @@ -161,7 +173,7 @@ static void rzg2l_set_trigger(struct rzg2l_adc *adc)
>>  	rzg2l_adc_writel(adc, RZG2L_ADM(1), reg);
>>  }
>>  
>> -static int rzg2l_adc_conversion_setup(struct rzg2l_adc *adc, u8 ch)
>> +static int rzg2l_adc_conversion_setup(struct rzg2l_adc *adc, u8 ch, enum iio_chan_type type)
>>  {
>>  	const struct rzg2l_adc_hw_params *hw_params = adc->hw_params;
>>  	u32 reg;
>> @@ -177,6 +189,15 @@ static int rzg2l_adc_conversion_setup(struct rzg2l_adc *adc, u8 ch)
>>  	reg |= BIT(ch);
>>  	rzg2l_adc_writel(adc, RZG2L_ADM(2), reg);
>>  
>> +	reg = rzg2l_adc_readl(adc, RZG2L_ADM(3));
>> +	reg &= ~hw_params->adsmp_mask;
>> +	/*
>> +	 * type could be IIO_VOLTAGE = 0 or IIO_TEMP = 9. Divide to 8 to get
>> +	 * index 0 or 1 depending on the channel type.
> 
> That is not particularly nice and potentially a little fragile if we get other device
> support in future. Better to match on the type in rzg2l_adc_channels[] possibly wrapped
> up in a little utility function bool rzg2l_adc_channels_is_temp(); Then use a
> ? 1 : 0 to get the offset in default_adsmp[]

I though about this, too, but considered we should not go beyond 1 as the
rzg2l_adc_conversion_setup() is currently call in places where the channel
type is only IIO_VOLTAGE and IIO_TEMP, just saying...

I'll switch to the approach you propose in the next version.

> 
> 
>> +	 */
>> +	reg |= hw_params->default_adsmp[type / 8];
>> +	rzg2l_adc_writel(adc, RZG2L_ADM(3), reg);
>> +
>>  	/*
>>  	 * Setup ADINT
>>  	 * INTS[31] - Select pulse signal
>> @@ -192,7 +213,8 @@ static int rzg2l_adc_conversion_setup(struct rzg2l_adc *adc, u8 ch)
>>  	return 0;
>>  }
>>
>>  
>> +	case IIO_CHAN_INFO_PROCESSED:
>> +		if (chan->type != IIO_TEMP)
>> +			return -EINVAL;
>> +
>> +		mutex_lock(&adc->lock);
>> +		ret = rzg2l_adc_conversion(indio_dev, chan->type, adc, ch);
>> +		if (!ret) {
>> +			/* Convert it to mili Celsius. */
>> +			*val = adc->last_val[ch] * 1000;
> Prefer you provide a scale of 1000 and report this raw.

I'll look to this.

>> +		}
> Also strong preference for error conditions out of line.
> As in that other case, guard() makes that easier as yo ucan do
> 		{
> 
> 			guard(mutex)(&adc->lock);
> 			ret = rz....
> 			if (ret)
> 				return ret;
> 
> 			*val = ...
> 			
> 			return IIO_VAL_INT;
> 		}


I agree, looks cleaner with guard().

> 
>> +		mutex_unlock(&adc->lock);
>> +
>> +		return ret ? ret : IIO_VAL_INT;
>> +
>>  	default:
>>  		return -EINVAL;
>>  	}
> 
>>  static const struct iio_info rzg2l_adc_iio_info = {
>> @@ -332,11 +368,14 @@ static int rzg2l_adc_parse_properties(struct platform_device *pdev, struct rzg2l
>>  		if (channel >= hw_params->num_channels)
>>  			return -EINVAL;
>>  
>> -		chan_array[i].type = IIO_VOLTAGE;
>> +		chan_array[i].type = rzg2l_adc_channels[channel].type;
>>  		chan_array[i].indexed = 1;
>>  		chan_array[i].channel = channel;
>> -		chan_array[i].info_mask_separate = BIT(IIO_CHAN_INFO_RAW);
>> -		chan_array[i].datasheet_name = rzg2l_adc_channel_name[channel];
>> +		if (rzg2l_adc_channels[channel].type == IIO_VOLTAGE)
>> +			chan_array[i].info_mask_separate = BIT(IIO_CHAN_INFO_RAW);
>> +		else
>> +			chan_array[i].info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED);
> 
> Make it raw, but I'm curious we have no _SCALE on this device.  Do we really have no idea
> of the calibration of these channels?

The calibration data is stored on the TSU (Thermal Sensor Unit) hardware
block. From the TSU driver (not yet published) we read the temperature
through the ADC channel and apply the calibration data on the value
returned by ADC (this is how HW manual suggests). This is the current
(internal) struct thermal_zone_device_ops::get_temp() API of the TSU driver
(it will be published later, after some clarifications with hardware team
on SoC specific aspects):

// ..

#define TSU_READ_STEPS		8
#define MCELSIUS(temp)		(temp * MILLIDEGREE_PER_DEGREE)

// ...

struct rzg3s_thermal_priv {
	void __iomem *base;
	struct device *dev;
	struct thermal_zone_device *tz;
	struct reset_control *rstc;
	struct iio_channel *channel;
	u16 calib0;
	u16 calib1;
};

// ...

static int rzg3s_thermal_get_temp(struct thermal_zone_device *tz, int *temp)
{
	struct rzg3s_thermal_priv *priv = thermal_zone_device_priv(tz);
	struct device *dev = priv->dev;
	u32 ts_code_ave = 0;
	int ret, val;

	ret = pm_runtime_resume_and_get(dev);
	if (ret)
		return ret;

	for (u8 i = 0; i < TSU_READ_STEPS; i++) {
		ret = iio_read_channel_processed(priv->channel, &val);
		if (ret < 0)
			goto rpm_put;
		
		ts_code_ave += val;
		/*
		 * According to HW manual (section 40.4.4 Procedure for
		 * Measuring the Temperature) we need to wait here at
		 * leat 3us.
		 */
		usleep_range(5, 10);
	}

	ret = 0;
	ts_code_ave = DIV_ROUND_CLOSEST(ts_code_ave, TSU_READ_STEPS);

	/*
	 * According to HW manual (section 40.4.4 Procedure for Measuring
	 * the Temperature) the formula mentioned in the hardware manual is
	 * as follows;
	 *
	 * Tj = (ts_code_ave - priv->calib0) * (165 / (priv->calib0 -
	 * priv->calib1)) - 40
	 *
	 * As the temperature retrieved from the IIO channel is in
	 * milicelsius convert all members of the equation to milicelsius.
	 * It has been chose like this to avoid loosing precisions by
	 * converting IIO reported temperature to celsius.
	 */
	*temp = DIV_ROUND_CLOSEST_ULL(((u64)(ts_code_ave -
		MCELSIUS(priv->calib1)) * MCELSIUS(165)),
		MCELSIUS((priv->calib0 - priv->calib1))) - MCELSIUS(40);

	/* Round it up to 0.5 degrees Celsius. */
	*temp = roundup(*temp, 500);

rpm_put:
	pm_runtime_mark_last_busy(dev);
	pm_runtime_put_autosuspend(dev);

	return ret;
}


> 
>> +		chan_array[i].datasheet_name = rzg2l_adc_channels[channel].name;
>>  		i++;
>>  	}
>>  
>> @@ -386,7 +425,7 @@ static int rzg2l_adc_hw_init(struct device *dev, struct rzg2l_adc *adc)
>>  	reg &= ~RZG2L_ADM3_ADCMP_MASK;
>>  	reg &= ~hw_params->adsmp_mask;
>>  	reg |= FIELD_PREP(RZG2L_ADM3_ADCMP_MASK, hw_params->default_adcmp) |
>> -	       hw_params->default_adsmp;
>> +	       hw_params->default_adsmp[0];
>>  
>>  	rzg2l_adc_writel(adc, RZG2L_ADM(3), reg);
>>  
>> @@ -479,7 +518,7 @@ static int rzg2l_adc_probe(struct platform_device *pdev)
>>  static const struct rzg2l_adc_hw_params rzg2l_hw_params = {
>>  	.num_channels = 8,
>>  	.default_adcmp = 0xe,
>> -	.default_adsmp = 0x578,
>> +	.default_adsmp = { 0x578 },
>>  	.adsmp_mask = GENMASK(15, 0),
>>  	.adint_inten_mask = GENMASK(7, 0),
>>  	.adivc = true
>
diff mbox series

Patch

diff --git a/drivers/iio/adc/rzg2l_adc.c b/drivers/iio/adc/rzg2l_adc.c
index aff41152ebf8..f938b0f9a795 100644
--- a/drivers/iio/adc/rzg2l_adc.c
+++ b/drivers/iio/adc/rzg2l_adc.c
@@ -55,7 +55,8 @@ 
 
 /**
  * struct rzg2l_adc_hw_params - ADC hardware specific parameters
- * @default_adsmp: default ADC sampling period (see ADM3 register)
+ * @default_adsmp: default ADC sampling period (see ADM3 register); index 0 is
+ * used for voltage channels, index 1 is used for temperature channel
  * @adsmp_mask: ADC sampling period mask (see ADM3 register)
  * @adint_inten_mask: conversion end interrupt mask (see ADINT register)
  * @default_adcmp: default ADC cmp (see ADM3 register)
@@ -63,7 +64,7 @@ 
  * @adivc: specifies if ADVIC register is available
  */
 struct rzg2l_adc_hw_params {
-	u16 default_adsmp;
+	u16 default_adsmp[2];
 	u16 adsmp_mask;
 	u16 adint_inten_mask;
 	u8 default_adcmp;
@@ -87,15 +88,26 @@  struct rzg2l_adc {
 	struct mutex lock;
 };
 
-static const char * const rzg2l_adc_channel_name[] = {
-	"adc0",
-	"adc1",
-	"adc2",
-	"adc3",
-	"adc4",
-	"adc5",
-	"adc6",
-	"adc7",
+/**
+ * struct rzg2l_adc_channel - ADC channel descriptor
+ * @name: ADC channel name
+ * @type: ADC channel type
+ */
+struct rzg2l_adc_channel {
+	const char * const name;
+	enum iio_chan_type type;
+};
+
+static const struct rzg2l_adc_channel rzg2l_adc_channels[] = {
+	{ "adc0", IIO_VOLTAGE },
+	{ "adc1", IIO_VOLTAGE },
+	{ "adc2", IIO_VOLTAGE },
+	{ "adc3", IIO_VOLTAGE },
+	{ "adc4", IIO_VOLTAGE },
+	{ "adc5", IIO_VOLTAGE },
+	{ "adc6", IIO_VOLTAGE },
+	{ "adc7", IIO_VOLTAGE },
+	{ "adc8", IIO_TEMP },
 };
 
 static unsigned int rzg2l_adc_readl(struct rzg2l_adc *adc, u32 reg)
@@ -161,7 +173,7 @@  static void rzg2l_set_trigger(struct rzg2l_adc *adc)
 	rzg2l_adc_writel(adc, RZG2L_ADM(1), reg);
 }
 
-static int rzg2l_adc_conversion_setup(struct rzg2l_adc *adc, u8 ch)
+static int rzg2l_adc_conversion_setup(struct rzg2l_adc *adc, u8 ch, enum iio_chan_type type)
 {
 	const struct rzg2l_adc_hw_params *hw_params = adc->hw_params;
 	u32 reg;
@@ -177,6 +189,15 @@  static int rzg2l_adc_conversion_setup(struct rzg2l_adc *adc, u8 ch)
 	reg |= BIT(ch);
 	rzg2l_adc_writel(adc, RZG2L_ADM(2), reg);
 
+	reg = rzg2l_adc_readl(adc, RZG2L_ADM(3));
+	reg &= ~hw_params->adsmp_mask;
+	/*
+	 * type could be IIO_VOLTAGE = 0 or IIO_TEMP = 9. Divide to 8 to get
+	 * index 0 or 1 depending on the channel type.
+	 */
+	reg |= hw_params->default_adsmp[type / 8];
+	rzg2l_adc_writel(adc, RZG2L_ADM(3), reg);
+
 	/*
 	 * Setup ADINT
 	 * INTS[31] - Select pulse signal
@@ -192,7 +213,8 @@  static int rzg2l_adc_conversion_setup(struct rzg2l_adc *adc, u8 ch)
 	return 0;
 }
 
-static int rzg2l_adc_conversion(struct iio_dev *indio_dev, struct rzg2l_adc *adc, u8 ch)
+static int rzg2l_adc_conversion(struct iio_dev *indio_dev, enum iio_chan_type type,
+				struct rzg2l_adc *adc, u8 ch)
 {
 	const struct rzg2l_adc_hw_params *hw_params = adc->hw_params;
 	struct device *dev = indio_dev->dev.parent;
@@ -202,7 +224,7 @@  static int rzg2l_adc_conversion(struct iio_dev *indio_dev, struct rzg2l_adc *adc
 	if (ret)
 		return ret;
 
-	ret = rzg2l_adc_conversion_setup(adc, ch);
+	ret = rzg2l_adc_conversion_setup(adc, ch, type);
 	if (ret)
 		goto rpm_put;
 
@@ -238,13 +260,27 @@  static int rzg2l_adc_read_raw(struct iio_dev *indio_dev,
 			return -EINVAL;
 
 		mutex_lock(&adc->lock);
-		ret = rzg2l_adc_conversion(indio_dev, adc, ch);
+		ret = rzg2l_adc_conversion(indio_dev, chan->type, adc, ch);
 		if (!ret)
 			*val = adc->last_val[ch];
 		mutex_unlock(&adc->lock);
 
 		return ret ? ret : IIO_VAL_INT;
 
+	case IIO_CHAN_INFO_PROCESSED:
+		if (chan->type != IIO_TEMP)
+			return -EINVAL;
+
+		mutex_lock(&adc->lock);
+		ret = rzg2l_adc_conversion(indio_dev, chan->type, adc, ch);
+		if (!ret) {
+			/* Convert it to mili Celsius. */
+			*val = adc->last_val[ch] * 1000;
+		}
+		mutex_unlock(&adc->lock);
+
+		return ret ? ret : IIO_VAL_INT;
+
 	default:
 		return -EINVAL;
 	}
@@ -254,7 +290,7 @@  static int rzg2l_adc_read_label(struct iio_dev *iio_dev,
 				const struct iio_chan_spec *chan,
 				char *label)
 {
-	return sysfs_emit(label, "%s\n", rzg2l_adc_channel_name[chan->channel]);
+	return sysfs_emit(label, "%s\n", rzg2l_adc_channels[chan->channel].name);
 }
 
 static const struct iio_info rzg2l_adc_iio_info = {
@@ -332,11 +368,14 @@  static int rzg2l_adc_parse_properties(struct platform_device *pdev, struct rzg2l
 		if (channel >= hw_params->num_channels)
 			return -EINVAL;
 
-		chan_array[i].type = IIO_VOLTAGE;
+		chan_array[i].type = rzg2l_adc_channels[channel].type;
 		chan_array[i].indexed = 1;
 		chan_array[i].channel = channel;
-		chan_array[i].info_mask_separate = BIT(IIO_CHAN_INFO_RAW);
-		chan_array[i].datasheet_name = rzg2l_adc_channel_name[channel];
+		if (rzg2l_adc_channels[channel].type == IIO_VOLTAGE)
+			chan_array[i].info_mask_separate = BIT(IIO_CHAN_INFO_RAW);
+		else
+			chan_array[i].info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED);
+		chan_array[i].datasheet_name = rzg2l_adc_channels[channel].name;
 		i++;
 	}
 
@@ -386,7 +425,7 @@  static int rzg2l_adc_hw_init(struct device *dev, struct rzg2l_adc *adc)
 	reg &= ~RZG2L_ADM3_ADCMP_MASK;
 	reg &= ~hw_params->adsmp_mask;
 	reg |= FIELD_PREP(RZG2L_ADM3_ADCMP_MASK, hw_params->default_adcmp) |
-	       hw_params->default_adsmp;
+	       hw_params->default_adsmp[0];
 
 	rzg2l_adc_writel(adc, RZG2L_ADM(3), reg);
 
@@ -479,7 +518,7 @@  static int rzg2l_adc_probe(struct platform_device *pdev)
 static const struct rzg2l_adc_hw_params rzg2l_hw_params = {
 	.num_channels = 8,
 	.default_adcmp = 0xe,
-	.default_adsmp = 0x578,
+	.default_adsmp = { 0x578 },
 	.adsmp_mask = GENMASK(15, 0),
 	.adint_inten_mask = GENMASK(7, 0),
 	.adivc = true