[v3,1/3] dt-bindings: iio: adc: ti,tsc2046: add vref-supply property

Add property for the voltage reference supply.

Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
---
changes v2
- add Acked-by: Krzysztof Kozlowski
---
 Documentation/devicetree/bindings/iio/adc/ti,tsc2046.yaml | 3 +++
 1 file changed, 3 insertions(+)

Hi Oleksij,

sorry for jumping in, please see below.

On 22-09-01, Oleksij Rempel wrote:
> If VREF pin is attached, we should use external VREF source instead of
> the internal. Otherwise we will get wrong measurements on some of channel
> types.
> 
> Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
> ---
>  drivers/iio/adc/ti-tsc2046.c | 64 +++++++++++++++++++++++++++++++-----
>  1 file changed, 55 insertions(+), 9 deletions(-)
> 
> diff --git a/drivers/iio/adc/ti-tsc2046.c b/drivers/iio/adc/ti-tsc2046.c
> index 0d9436a69cbfb..bbc8b4137b0b1 100644
> --- a/drivers/iio/adc/ti-tsc2046.c
> +++ b/drivers/iio/adc/ti-tsc2046.c
> @@ -8,6 +8,7 @@
>  #include <linux/bitfield.h>
>  #include <linux/delay.h>
>  #include <linux/module.h>
> +#include <linux/regulator/consumer.h>
>  #include <linux/spi/spi.h>
>  
>  #include <asm/unaligned.h>
> @@ -175,6 +176,9 @@ struct tsc2046_adc_priv {
>  	u32 time_per_bit_ns;
>  
>  	struct tsc2046_adc_ch_cfg ch_cfg[TI_TSC2046_MAX_CHAN];
> +	bool use_internal_vref;
> +	unsigned int vref_mv;

We wouldn't need those members if we just enable/disable the regulator
on demand. This would also be more power efficient.

> +	struct regulator *vref_reg;
>  };
>  
>  #define TI_TSC2046_V_CHAN(index, bits, name)			\
> @@ -252,7 +256,9 @@ static u8 tsc2046_adc_get_cmd(struct tsc2046_adc_priv *priv, int ch_idx,
>  	case TI_TSC2046_ADDR_AUX:
>  	case TI_TSC2046_ADDR_VBAT:
>  	case TI_TSC2046_ADDR_TEMP0:
> -		pd |= TI_TSC2046_SER | TI_TSC2046_PD1_VREF_ON;
> +		pd |= TI_TSC2046_SER;
> +		if (priv->use_internal_vref)
> +			pd |= TI_TSC2046_PD1_VREF_ON;

Then this line would become:

+		if (!priv->vref_reg)
+			pd |= TI_TSC2046_PD1_VREF_ON;


>  	}
>  
>  	return TI_TSC2046_START | FIELD_PREP(TI_TSC2046_ADDR, ch_idx) | pd;
> @@ -468,7 +474,7 @@ static int tsc2046_adc_read_raw(struct iio_dev *indio_dev,

This function needs to enable the vref_reg before the switch-case and
disable it afterwards.

>  		 * So, it is better to use external voltage-divider driver
>  		 * instead, which is calculating complete chain.
>  		 */
> -		*val = TI_TSC2046_INT_VREF;
> +		*val = priv->vref_mv;
>  		*val2 = chan->scan_type.realbits;
>  		return IIO_VAL_FRACTIONAL_LOG2;
>  	}
> @@ -781,22 +787,42 @@ static int tsc2046_adc_probe(struct spi_device *spi)
>  	indio_dev->num_channels = dcfg->num_channels;
>  	indio_dev->info = &tsc2046_adc_info;
>  
> +	priv->vref_reg = devm_regulator_get_optional(&spi->dev, "vref");

This line would be enough and we could drop

> +	if (!IS_ERR(priv->vref_reg)) {
> +		ret = regulator_enable(priv->vref_reg);
> +		if (ret)
> +			return ret;
> +
> +		ret = regulator_get_voltage(priv->vref_reg);
> +		if (ret < 0)
> +			goto err_regulator_disable;
> +
> +		priv->vref_mv = ret / 1000;
> +		priv->use_internal_vref = false;
> +	} else {
> +		/* Use internal reference */
> +		priv->vref_mv = TI_TSC2046_INT_VREF;
> +		priv->use_internal_vref = true;
> +	}
> +

this part.

>  	tsc2046_adc_parse_fwnode(priv);
>  
>  	ret = tsc2046_adc_setup_spi_msg(priv);
>  	if (ret)
> -		return ret;
> +		goto err_regulator_disable;
>  
>  	mutex_init(&priv->slock);
>  
>  	ret = devm_request_irq(dev, spi->irq, &tsc2046_adc_irq,
>  			       IRQF_NO_AUTOEN, indio_dev->name, indio_dev);
>  	if (ret)
> -		return ret;
> +		goto err_regulator_disable;
>  
>  	trig = devm_iio_trigger_alloc(dev, "touchscreen-%s", indio_dev->name);
> -	if (!trig)
> -		return -ENOMEM;
> +	if (!trig) {
> +		ret = -ENOMEM;
> +		goto err_regulator_disable;
> +	}
>  
>  	priv->trig = trig;
>  	iio_trigger_set_drvdata(trig, indio_dev);
> @@ -811,20 +837,39 @@ static int tsc2046_adc_probe(struct spi_device *spi)
>  	ret = devm_iio_trigger_register(dev, trig);
>  	if (ret) {
>  		dev_err(dev, "failed to register trigger\n");
> -		return ret;
> +		goto err_regulator_disable;
>  	}
>  
>  	ret = devm_iio_triggered_buffer_setup(dev, indio_dev, NULL,
>  					      &tsc2046_adc_trigger_handler, NULL);
>  	if (ret) {
>  		dev_err(dev, "Failed to setup triggered buffer\n");
> -		return ret;
> +		goto err_regulator_disable;
>  	}
>  
>  	/* set default trigger */
>  	indio_dev->trig = iio_trigger_get(priv->trig);
>  
> -	return devm_iio_device_register(dev, indio_dev);
> +	ret = devm_iio_device_register(dev, indio_dev);
> +	if (ret)
> +		goto err_regulator_disable;
> +
> +	return 0;
> +
> +err_regulator_disable:
> +	if (!IS_ERR(priv->vref_reg))
> +		regulator_disable(priv->vref_reg);
> +
> +	return ret;

As well as the whole new error handling and

> +}
> +
> +static void tsc2046_adc_remove(struct spi_device *spi)
> +{
> +	struct iio_dev *indio_dev = spi_get_drvdata(spi);
> +	struct tsc2046_adc_priv *priv = iio_priv(indio_dev);
> +
> +	if (!IS_ERR(priv->vref_reg))
> +		regulator_disable(priv->vref_reg);
>  }

the remove callback.

Regards,
  Marco

>  static const struct of_device_id ads7950_of_table[] = {
> @@ -839,6 +884,7 @@ static struct spi_driver tsc2046_adc_driver = {
>  		.of_match_table = ads7950_of_table,
>  	},
>  	.probe = tsc2046_adc_probe,
> +	.remove = tsc2046_adc_remove,
>  };
>  module_spi_driver(tsc2046_adc_driver);
>  
> -- 
> 2.30.2
> 
> 
>

Hi Marco,

On Thu, Sep 01, 2022 at 10:24:25AM +0200, Marco Felsch wrote:
> Hi Oleksij,
> 
> sorry for jumping in, please see below.
> 
> On 22-09-01, Oleksij Rempel wrote:
> > If VREF pin is attached, we should use external VREF source instead of
> > the internal. Otherwise we will get wrong measurements on some of channel
> > types.
> > 
> > Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
> > ---
> >  drivers/iio/adc/ti-tsc2046.c | 64 +++++++++++++++++++++++++++++++-----
> >  1 file changed, 55 insertions(+), 9 deletions(-)
> > 
> > diff --git a/drivers/iio/adc/ti-tsc2046.c b/drivers/iio/adc/ti-tsc2046.c
> > index 0d9436a69cbfb..bbc8b4137b0b1 100644
> > --- a/drivers/iio/adc/ti-tsc2046.c
> > +++ b/drivers/iio/adc/ti-tsc2046.c
> > @@ -8,6 +8,7 @@
> >  #include <linux/bitfield.h>
> >  #include <linux/delay.h>
> >  #include <linux/module.h>
> > +#include <linux/regulator/consumer.h>
> >  #include <linux/spi/spi.h>
> >  
> >  #include <asm/unaligned.h>
> > @@ -175,6 +176,9 @@ struct tsc2046_adc_priv {
> >  	u32 time_per_bit_ns;
> >  
> >  	struct tsc2046_adc_ch_cfg ch_cfg[TI_TSC2046_MAX_CHAN];
> > +	bool use_internal_vref;
> > +	unsigned int vref_mv;
> 
> We wouldn't need those members if we just enable/disable the regulator
> on demand. This would also be more power efficient.

Not really.
- it is reference voltage. There is no load.
- usually no one care to add extra switch to disable reference voltage
  on a controller which should be enabled all the time any way.
- we add more CPU cycles on every access to enable/disable things, which are
  usually never have dedicated regulator.

> > +	struct regulator *vref_reg;
> >  };
> >  
> >  #define TI_TSC2046_V_CHAN(index, bits, name)			\
> > @@ -252,7 +256,9 @@ static u8 tsc2046_adc_get_cmd(struct tsc2046_adc_priv *priv, int ch_idx,
> >  	case TI_TSC2046_ADDR_AUX:
> >  	case TI_TSC2046_ADDR_VBAT:
> >  	case TI_TSC2046_ADDR_TEMP0:
> > -		pd |= TI_TSC2046_SER | TI_TSC2046_PD1_VREF_ON;
> > +		pd |= TI_TSC2046_SER;
> > +		if (priv->use_internal_vref)
> > +			pd |= TI_TSC2046_PD1_VREF_ON;
> 
> Then this line would become:

ack. I agree here.

> +		if (!priv->vref_reg)
> +			pd |= TI_TSC2046_PD1_VREF_ON;
> 
> 
> >  	}
> >  
> >  	return TI_TSC2046_START | FIELD_PREP(TI_TSC2046_ADDR, ch_idx) | pd;
> > @@ -468,7 +474,7 @@ static int tsc2046_adc_read_raw(struct iio_dev *indio_dev,
> 
> This function needs to enable the vref_reg before the switch-case and
> disable it afterwards.

it will not enable power supply of this controller. There is no need to
do this.

> >  		 * So, it is better to use external voltage-divider driver
> >  		 * instead, which is calculating complete chain.
> >  		 */
> > -		*val = TI_TSC2046_INT_VREF;
> > +		*val = priv->vref_mv;
> >  		*val2 = chan->scan_type.realbits;
> >  		return IIO_VAL_FRACTIONAL_LOG2;
> >  	}
> > @@ -781,22 +787,42 @@ static int tsc2046_adc_probe(struct spi_device *spi)
> >  	indio_dev->num_channels = dcfg->num_channels;
> >  	indio_dev->info = &tsc2046_adc_info;
> >  
> > +	priv->vref_reg = devm_regulator_get_optional(&spi->dev, "vref");
> 
> This line would be enough and we could drop
> 
> > +	if (!IS_ERR(priv->vref_reg)) {
> > +		ret = regulator_enable(priv->vref_reg);
> > +		if (ret)
> > +			return ret;
> > +
> > +		ret = regulator_get_voltage(priv->vref_reg);
> > +		if (ret < 0)
> > +			goto err_regulator_disable;
> > +
> > +		priv->vref_mv = ret / 1000;
> > +		priv->use_internal_vref = false;
> > +	} else {
> > +		/* Use internal reference */
> > +		priv->vref_mv = TI_TSC2046_INT_VREF;
> > +		priv->use_internal_vref = true;
> > +	}
> > +
> 
> this part.

In this case we will not get any power saving, but instead we will need
to run enable/disable + regulator_get_voltage + extra calculation
without any advantage.

> 
> >  	tsc2046_adc_parse_fwnode(priv);
> >  
> >  	ret = tsc2046_adc_setup_spi_msg(priv);
> >  	if (ret)
> > -		return ret;
> > +		goto err_regulator_disable;
> >  
> >  	mutex_init(&priv->slock);
> >  
> >  	ret = devm_request_irq(dev, spi->irq, &tsc2046_adc_irq,
> >  			       IRQF_NO_AUTOEN, indio_dev->name, indio_dev);
> >  	if (ret)
> > -		return ret;
> > +		goto err_regulator_disable;
> >  
> >  	trig = devm_iio_trigger_alloc(dev, "touchscreen-%s", indio_dev->name);
> > -	if (!trig)
> > -		return -ENOMEM;
> > +	if (!trig) {
> > +		ret = -ENOMEM;
> > +		goto err_regulator_disable;
> > +	}
> >  
> >  	priv->trig = trig;
> >  	iio_trigger_set_drvdata(trig, indio_dev);
> > @@ -811,20 +837,39 @@ static int tsc2046_adc_probe(struct spi_device *spi)
> >  	ret = devm_iio_trigger_register(dev, trig);
> >  	if (ret) {
> >  		dev_err(dev, "failed to register trigger\n");
> > -		return ret;
> > +		goto err_regulator_disable;
> >  	}
> >  
> >  	ret = devm_iio_triggered_buffer_setup(dev, indio_dev, NULL,
> >  					      &tsc2046_adc_trigger_handler, NULL);
> >  	if (ret) {
> >  		dev_err(dev, "Failed to setup triggered buffer\n");
> > -		return ret;
> > +		goto err_regulator_disable;
> >  	}
> >  
> >  	/* set default trigger */
> >  	indio_dev->trig = iio_trigger_get(priv->trig);
> >  
> > -	return devm_iio_device_register(dev, indio_dev);
> > +	ret = devm_iio_device_register(dev, indio_dev);
> > +	if (ret)
> > +		goto err_regulator_disable;
> > +
> > +	return 0;
> > +
> > +err_regulator_disable:
> > +	if (!IS_ERR(priv->vref_reg))
> > +		regulator_disable(priv->vref_reg);
> > +
> > +	return ret;
> 
> As well as the whole new error handling and
> 
> > +}
> > +
> > +static void tsc2046_adc_remove(struct spi_device *spi)
> > +{
> > +	struct iio_dev *indio_dev = spi_get_drvdata(spi);
> > +	struct tsc2046_adc_priv *priv = iio_priv(indio_dev);
> > +
> > +	if (!IS_ERR(priv->vref_reg))
> > +		regulator_disable(priv->vref_reg);
> >  }
> 
> the remove callback.

no.

On Thu, 1 Sep 2022 06:11:45 +0200
Oleksij Rempel <o.rempel@pengutronix.de> wrote:

> If VREF pin is attached, we should use external VREF source instead of
> the internal. Otherwise we will get wrong measurements on some of channel
> types.
> 
> Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
Hi Oleksij,

I'm not sure why I didn't review this patch in v1...

Anyhow, some comments below.

Jonathan

> ---
>  drivers/iio/adc/ti-tsc2046.c | 64 +++++++++++++++++++++++++++++++-----
>  1 file changed, 55 insertions(+), 9 deletions(-)
> 
> diff --git a/drivers/iio/adc/ti-tsc2046.c b/drivers/iio/adc/ti-tsc2046.c
> index 0d9436a69cbfb..bbc8b4137b0b1 100644
> --- a/drivers/iio/adc/ti-tsc2046.c
> +++ b/drivers/iio/adc/ti-tsc2046.c
> @@ -8,6 +8,7 @@
>  #include <linux/bitfield.h>
>  #include <linux/delay.h>
>  #include <linux/module.h>
> +#include <linux/regulator/consumer.h>
>  #include <linux/spi/spi.h>
>  
>  #include <asm/unaligned.h>
> @@ -175,6 +176,9 @@ struct tsc2046_adc_priv {
>  	u32 time_per_bit_ns;
>  
>  	struct tsc2046_adc_ch_cfg ch_cfg[TI_TSC2046_MAX_CHAN];
> +	bool use_internal_vref;
> +	unsigned int vref_mv;
> +	struct regulator *vref_reg;
>  };
>  
>  #define TI_TSC2046_V_CHAN(index, bits, name)			\
> @@ -252,7 +256,9 @@ static u8 tsc2046_adc_get_cmd(struct tsc2046_adc_priv *priv, int ch_idx,
>  	case TI_TSC2046_ADDR_AUX:
>  	case TI_TSC2046_ADDR_VBAT:
>  	case TI_TSC2046_ADDR_TEMP0:
> -		pd |= TI_TSC2046_SER | TI_TSC2046_PD1_VREF_ON;
> +		pd |= TI_TSC2046_SER;
> +		if (priv->use_internal_vref)
> +			pd |= TI_TSC2046_PD1_VREF_ON;
>  	}
>  
>  	return TI_TSC2046_START | FIELD_PREP(TI_TSC2046_ADDR, ch_idx) | pd;
> @@ -468,7 +474,7 @@ static int tsc2046_adc_read_raw(struct iio_dev *indio_dev,
>  		 * So, it is better to use external voltage-divider driver
>  		 * instead, which is calculating complete chain.
>  		 */
> -		*val = TI_TSC2046_INT_VREF;
> +		*val = priv->vref_mv;
>  		*val2 = chan->scan_type.realbits;
>  		return IIO_VAL_FRACTIONAL_LOG2;
>  	}
> @@ -781,22 +787,42 @@ static int tsc2046_adc_probe(struct spi_device *spi)
>  	indio_dev->num_channels = dcfg->num_channels;
>  	indio_dev->info = &tsc2046_adc_info;
>  
> +	priv->vref_reg = devm_regulator_get_optional(&spi->dev, "vref");
> +	if (!IS_ERR(priv->vref_reg)) {
> +		ret = regulator_enable(priv->vref_reg);
> +		if (ret)
> +			return ret;
> +
> +		ret = regulator_get_voltage(priv->vref_reg);
> +		if (ret < 0)
> +			goto err_regulator_disable;

Whilst regulators voltages of references rarely change at runtime
they are allowed to, so it is logically better to query the
voltage at the point of use. Requests for scale should be
rare (unless there is a consumer that keeps querying this?)
so the slightly overhead there
shouldn't matter.

> +
> +		priv->vref_mv = ret / 1000;
> +		priv->use_internal_vref = false;
> +	} else {
> +		/* Use internal reference */
> +		priv->vref_mv = TI_TSC2046_INT_VREF;
> +		priv->use_internal_vref = true;
> +	}
> +
>  	tsc2046_adc_parse_fwnode(priv);
>  
>  	ret = tsc2046_adc_setup_spi_msg(priv);
>  	if (ret)
> -		return ret;
> +		goto err_regulator_disable;
>  
>  	mutex_init(&priv->slock);
>  
>  	ret = devm_request_irq(dev, spi->irq, &tsc2046_adc_irq,
>  			       IRQF_NO_AUTOEN, indio_dev->name, indio_dev);
>  	if (ret)
> -		return ret;
> +		goto err_regulator_disable;
>  
>  	trig = devm_iio_trigger_alloc(dev, "touchscreen-%s", indio_dev->name);
> -	if (!trig)
> -		return -ENOMEM;
> +	if (!trig) {
> +		ret = -ENOMEM;
> +		goto err_regulator_disable;
> +	}
>  
>  	priv->trig = trig;
>  	iio_trigger_set_drvdata(trig, indio_dev);
> @@ -811,20 +837,39 @@ static int tsc2046_adc_probe(struct spi_device *spi)
>  	ret = devm_iio_trigger_register(dev, trig);
>  	if (ret) {
>  		dev_err(dev, "failed to register trigger\n");
> -		return ret;
> +		goto err_regulator_disable;

Please don't mix devm and non devm calls. It makes it much harder to reason about
the correctness of ordering.
Use devm_add_action_or_reset() to register a callback to disable the
vref regulator.

Alternative is back out the devm_ based registration of everything after
the regulator enable.
>  	}
>  
>  	ret = devm_iio_triggered_buffer_setup(dev, indio_dev, NULL,
>  					      &tsc2046_adc_trigger_handler, NULL);
>  	if (ret) {
>  		dev_err(dev, "Failed to setup triggered buffer\n");
> -		return ret;
> +		goto err_regulator_disable;
>  	}
>  
>  	/* set default trigger */
>  	indio_dev->trig = iio_trigger_get(priv->trig);
>  
> -	return devm_iio_device_register(dev, indio_dev);
> +	ret = devm_iio_device_register(dev, indio_dev);
> +	if (ret)
> +		goto err_regulator_disable;
> +
> +	return 0;
> +
> +err_regulator_disable:
> +	if (!IS_ERR(priv->vref_reg))
> +		regulator_disable(priv->vref_reg);
> +
> +	return ret;
> +}
> +
> +static void tsc2046_adc_remove(struct spi_device *spi)
> +{
> +	struct iio_dev *indio_dev = spi_get_drvdata(spi);
> +	struct tsc2046_adc_priv *priv = iio_priv(indio_dev);
> +
> +	if (!IS_ERR(priv->vref_reg))
> +		regulator_disable(priv->vref_reg);

>  }
>  
>  static const struct of_device_id ads7950_of_table[] = {
> @@ -839,6 +884,7 @@ static struct spi_driver tsc2046_adc_driver = {
>  		.of_match_table = ads7950_of_table,
>  	},
>  	.probe = tsc2046_adc_probe,
> +	.remove = tsc2046_adc_remove,
>  };
>  module_spi_driver(tsc2046_adc_driver);
>

On Thu, Sep 01, 2022 at 12:45:49PM +0100, Jonathan Cameron wrote:
> On Thu, 1 Sep 2022 06:11:45 +0200
> Oleksij Rempel <o.rempel@pengutronix.de> wrote:
> 
> > If VREF pin is attached, we should use external VREF source instead of
> > the internal. Otherwise we will get wrong measurements on some of channel
> > types.
> > 
> > Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
> Hi Oleksij,
> 
> I'm not sure why I didn't review this patch in v1...
> 
> Anyhow, some comments below.
> 
> Jonathan
> 
> > ---
> >  drivers/iio/adc/ti-tsc2046.c | 64 +++++++++++++++++++++++++++++++-----
> >  1 file changed, 55 insertions(+), 9 deletions(-)
> > 
> > diff --git a/drivers/iio/adc/ti-tsc2046.c b/drivers/iio/adc/ti-tsc2046.c
> > index 0d9436a69cbfb..bbc8b4137b0b1 100644
> > --- a/drivers/iio/adc/ti-tsc2046.c
> > +++ b/drivers/iio/adc/ti-tsc2046.c
> > @@ -8,6 +8,7 @@
> >  #include <linux/bitfield.h>
> >  #include <linux/delay.h>
> >  #include <linux/module.h>
> > +#include <linux/regulator/consumer.h>
> >  #include <linux/spi/spi.h>
> >  
> >  #include <asm/unaligned.h>
> > @@ -175,6 +176,9 @@ struct tsc2046_adc_priv {
> >  	u32 time_per_bit_ns;
> >  
> >  	struct tsc2046_adc_ch_cfg ch_cfg[TI_TSC2046_MAX_CHAN];
> > +	bool use_internal_vref;
> > +	unsigned int vref_mv;
> > +	struct regulator *vref_reg;
> >  };
> >  
> >  #define TI_TSC2046_V_CHAN(index, bits, name)			\
> > @@ -252,7 +256,9 @@ static u8 tsc2046_adc_get_cmd(struct tsc2046_adc_priv *priv, int ch_idx,
> >  	case TI_TSC2046_ADDR_AUX:
> >  	case TI_TSC2046_ADDR_VBAT:
> >  	case TI_TSC2046_ADDR_TEMP0:
> > -		pd |= TI_TSC2046_SER | TI_TSC2046_PD1_VREF_ON;
> > +		pd |= TI_TSC2046_SER;
> > +		if (priv->use_internal_vref)
> > +			pd |= TI_TSC2046_PD1_VREF_ON;
> >  	}
> >  
> >  	return TI_TSC2046_START | FIELD_PREP(TI_TSC2046_ADDR, ch_idx) | pd;
> > @@ -468,7 +474,7 @@ static int tsc2046_adc_read_raw(struct iio_dev *indio_dev,
> >  		 * So, it is better to use external voltage-divider driver
> >  		 * instead, which is calculating complete chain.
> >  		 */
> > -		*val = TI_TSC2046_INT_VREF;
> > +		*val = priv->vref_mv;
> >  		*val2 = chan->scan_type.realbits;
> >  		return IIO_VAL_FRACTIONAL_LOG2;
> >  	}
> > @@ -781,22 +787,42 @@ static int tsc2046_adc_probe(struct spi_device *spi)
> >  	indio_dev->num_channels = dcfg->num_channels;
> >  	indio_dev->info = &tsc2046_adc_info;
> >  
> > +	priv->vref_reg = devm_regulator_get_optional(&spi->dev, "vref");
> > +	if (!IS_ERR(priv->vref_reg)) {
> > +		ret = regulator_enable(priv->vref_reg);
> > +		if (ret)
> > +			return ret;
> > +
> > +		ret = regulator_get_voltage(priv->vref_reg);
> > +		if (ret < 0)
> > +			goto err_regulator_disable;
> 
> Whilst regulators voltages of references rarely change at runtime
> they are allowed to, so it is logically better to query the
> voltage at the point of use. Requests for scale should be
> rare (unless there is a consumer that keeps querying this?)
> so the slightly overhead there
> shouldn't matter.

The voltage scale is related to actual adc measurements. If it variates,
we will have different scale of challenges.

> > +
> > +		priv->vref_mv = ret / 1000;
> > +		priv->use_internal_vref = false;
> > +	} else {
> > +		/* Use internal reference */
> > +		priv->vref_mv = TI_TSC2046_INT_VREF;
> > +		priv->use_internal_vref = true;
> > +	}
> > +
> >  	tsc2046_adc_parse_fwnode(priv);
> >  
> >  	ret = tsc2046_adc_setup_spi_msg(priv);
> >  	if (ret)
> > -		return ret;
> > +		goto err_regulator_disable;
> >  
> >  	mutex_init(&priv->slock);
> >  
> >  	ret = devm_request_irq(dev, spi->irq, &tsc2046_adc_irq,
> >  			       IRQF_NO_AUTOEN, indio_dev->name, indio_dev);
> >  	if (ret)
> > -		return ret;
> > +		goto err_regulator_disable;
> >  
> >  	trig = devm_iio_trigger_alloc(dev, "touchscreen-%s", indio_dev->name);
> > -	if (!trig)
> > -		return -ENOMEM;
> > +	if (!trig) {
> > +		ret = -ENOMEM;
> > +		goto err_regulator_disable;
> > +	}
> >  
> >  	priv->trig = trig;
> >  	iio_trigger_set_drvdata(trig, indio_dev);
> > @@ -811,20 +837,39 @@ static int tsc2046_adc_probe(struct spi_device *spi)
> >  	ret = devm_iio_trigger_register(dev, trig);
> >  	if (ret) {
> >  		dev_err(dev, "failed to register trigger\n");
> > -		return ret;
> > +		goto err_regulator_disable;
> 
> Please don't mix devm and non devm calls. It makes it much harder to reason about
> the correctness of ordering.
> Use devm_add_action_or_reset() to register a callback to disable the
> vref regulator.
> 
> Alternative is back out the devm_ based registration of everything after
> the regulator enable.

ok.

Regards,
Oleksij

On Thu, Sep 1, 2022 at 7:12 AM Oleksij Rempel <o.rempel@pengutronix.de> wrote:
>
> Add spi_device_id to silent following kernel runtime warning:
> "SPI driver tsc2046 has no spi_device_id for ti,tsc2046e-adc".

Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>

> Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
> ---
> changes v3:
> - add missing point
> - remove unneeded blank line
> - assignment id at the definition line
> changes v2:
> - attach actual driver_data
> - use spi_get_device_id fallback
> ---
>  drivers/iio/adc/ti-tsc2046.c | 12 ++++++++++++
>  1 file changed, 12 insertions(+)
>
> diff --git a/drivers/iio/adc/ti-tsc2046.c b/drivers/iio/adc/ti-tsc2046.c
> index bbc8b4137b0b1..d5d799972fefd 100644
> --- a/drivers/iio/adc/ti-tsc2046.c
> +++ b/drivers/iio/adc/ti-tsc2046.c
> @@ -762,6 +762,11 @@ static int tsc2046_adc_probe(struct spi_device *spi)
>         }
>
>         dcfg = device_get_match_data(dev);
> +       if (!dcfg) {
> +               const struct spi_device_id *id = spi_get_device_id(spi);
> +
> +               dcfg = (const struct tsc2046_adc_dcfg *)id->driver_data;
> +       }
>         if (!dcfg)
>                 return -EINVAL;
>
> @@ -878,11 +883,18 @@ static const struct of_device_id ads7950_of_table[] = {
>  };
>  MODULE_DEVICE_TABLE(of, ads7950_of_table);
>
> +static const struct spi_device_id tsc2046_adc_spi_ids[] = {
> +       { "tsc2046e-adc", (unsigned long)&tsc2046_adc_dcfg_tsc2046e },
> +       { }
> +};
> +MODULE_DEVICE_TABLE(spi, tsc2046_adc_spi_ids);
> +
>  static struct spi_driver tsc2046_adc_driver = {
>         .driver = {
>                 .name = "tsc2046",
>                 .of_match_table = ads7950_of_table,
>         },
> +       .id_table = tsc2046_adc_spi_ids,
>         .probe = tsc2046_adc_probe,
>         .remove = tsc2046_adc_remove,
>  };
> --
> 2.30.2
>