[PATCH v5 1/3] dt-bindings: iio: adc: ti,tsc2046: add vref-supply property

[PATCH v5 1/3] dt-bindings: iio: adc: ti,tsc2046: add vref-supply property

[Oleksij Rempel]

Add property for the voltage reference supply.

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

diff --git a/Documentation/devicetree/bindings/iio/adc/ti,tsc2046.yaml b/Documentation/devicetree/bindings/iio/adc/ti,tsc2046.yaml
index 601d69971d84a..7faf12b1598b9 100644
--- a/Documentation/devicetree/bindings/iio/adc/ti,tsc2046.yaml
+++ b/Documentation/devicetree/bindings/iio/adc/ti,tsc2046.yaml
@@ -25,6 +25,9 @@ properties:
 
   spi-max-frequency: true
 
+  vref-supply:
+    description: Optional supply of the reference voltage
+
   "#io-channel-cells":
     const: 1
 
-- 
2.30.2

[PATCH v5 2/3] iio: adc: tsc2046: add vref support

[Oleksij Rempel]

If VREF pin is attached, we should use external VREF source instead of
the internal. Otherwise we will get wrong measurements on some of the channel
types.

Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
---
changes v5:
- add "the" before channel
- refactor error handling on regulator registration
- use MILLI instead of 1000
changes v4:
- use vref_reg pointer instead of bool use_internal_vref
- move regulator registration to a separate function
- rework error handling
- add devm_add_action_or_reset
---
 drivers/iio/adc/ti-tsc2046.c | 57 ++++++++++++++++++++++++++++++++++--
 1 file changed, 55 insertions(+), 2 deletions(-)

diff --git a/drivers/iio/adc/ti-tsc2046.c b/drivers/iio/adc/ti-tsc2046.c
index 0d9436a69cbfb..c7601b29b3bef 100644
--- a/drivers/iio/adc/ti-tsc2046.c
+++ b/drivers/iio/adc/ti-tsc2046.c
@@ -8,7 +8,9 @@
 #include <linux/bitfield.h>
 #include <linux/delay.h>
 #include <linux/module.h>
+#include <linux/regulator/consumer.h>
 #include <linux/spi/spi.h>
+#include <linux/units.h>
 
 #include <asm/unaligned.h>
 
@@ -175,6 +177,8 @@ struct tsc2046_adc_priv {
 	u32 time_per_bit_ns;
 
 	struct tsc2046_adc_ch_cfg ch_cfg[TI_TSC2046_MAX_CHAN];
+	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->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,
 		 * 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;
 	}
@@ -740,6 +746,49 @@ static void tsc2046_adc_parse_fwnode(struct tsc2046_adc_priv *priv)
 	}
 }
 
+static void tsc2046_adc_regulator_disable(void *data)
+{
+	struct tsc2046_adc_priv *priv = data;
+
+	regulator_disable(priv->vref_reg);
+}
+
+static int tsc2046_adc_configure_regulator(struct tsc2046_adc_priv *priv)
+{
+	struct device *dev = &priv->spi->dev;
+	int ret;
+
+	priv->vref_reg = devm_regulator_get_optional(dev, "vref");
+	if (IS_ERR(priv->vref_reg)) {
+		/* If regulator exists but can't be get, return an error */
+		if (PTR_ERR(priv->vref_reg) != -ENODEV)
+			return PTR_ERR(priv->vref_reg);
+		priv->vref_reg = NULL;
+	}
+	if (!priv->vref_reg) {
+		/* Use internal reference */
+		priv->vref_mv = TI_TSC2046_INT_VREF;
+		return 0;
+	}
+
+	ret = regulator_enable(priv->vref_reg);
+	if (ret)
+		return ret;
+
+	ret = devm_add_action_or_reset(dev, tsc2046_adc_regulator_disable,
+				       priv);
+	if (ret)
+		return ret;
+
+	ret = regulator_get_voltage(priv->vref_reg);
+	if (ret < 0)
+		return ret;
+
+	priv->vref_mv = ret / MILLI;
+
+	return 0;
+}
+
 static int tsc2046_adc_probe(struct spi_device *spi)
 {
 	const struct tsc2046_adc_dcfg *dcfg;
@@ -781,6 +830,10 @@ static int tsc2046_adc_probe(struct spi_device *spi)
 	indio_dev->num_channels = dcfg->num_channels;
 	indio_dev->info = &tsc2046_adc_info;
 
+	ret = tsc2046_adc_configure_regulator(priv);
+	if (ret)
+		return ret;
+
 	tsc2046_adc_parse_fwnode(priv);
 
 	ret = tsc2046_adc_setup_spi_msg(priv);
-- 
2.30.2

Re: [PATCH v5 2/3] iio: adc: tsc2046: add vref support

[Andy Shevchenko]

On Sat, Sep 3, 2022 at 8:03 AM 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 the channel
> types.

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

> Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
> ---
> changes v5:
> - add "the" before channel
> - refactor error handling on regulator registration
> - use MILLI instead of 1000
> changes v4:
> - use vref_reg pointer instead of bool use_internal_vref
> - move regulator registration to a separate function
> - rework error handling
> - add devm_add_action_or_reset
> ---
>  drivers/iio/adc/ti-tsc2046.c | 57 ++++++++++++++++++++++++++++++++++--
>  1 file changed, 55 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/iio/adc/ti-tsc2046.c b/drivers/iio/adc/ti-tsc2046.c
> index 0d9436a69cbfb..c7601b29b3bef 100644
> --- a/drivers/iio/adc/ti-tsc2046.c
> +++ b/drivers/iio/adc/ti-tsc2046.c
> @@ -8,7 +8,9 @@
>  #include <linux/bitfield.h>
>  #include <linux/delay.h>
>  #include <linux/module.h>
> +#include <linux/regulator/consumer.h>
>  #include <linux/spi/spi.h>
> +#include <linux/units.h>
>
>  #include <asm/unaligned.h>
>
> @@ -175,6 +177,8 @@ struct tsc2046_adc_priv {
>         u32 time_per_bit_ns;
>
>         struct tsc2046_adc_ch_cfg ch_cfg[TI_TSC2046_MAX_CHAN];
> +       unsigned int vref_mv;
> +       struct regulator *vref_reg;

I would put pointer first since it will make sizeof(priv) 4 bytes less
on some architectures due to padding elimination.

>  };
>
>  #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->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,
>                  * 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;
>         }
> @@ -740,6 +746,49 @@ static void tsc2046_adc_parse_fwnode(struct tsc2046_adc_priv *priv)
>         }
>  }
>
> +static void tsc2046_adc_regulator_disable(void *data)
> +{
> +       struct tsc2046_adc_priv *priv = data;
> +
> +       regulator_disable(priv->vref_reg);
> +}
> +
> +static int tsc2046_adc_configure_regulator(struct tsc2046_adc_priv *priv)
> +{
> +       struct device *dev = &priv->spi->dev;
> +       int ret;
> +
> +       priv->vref_reg = devm_regulator_get_optional(dev, "vref");
> +       if (IS_ERR(priv->vref_reg)) {
> +               /* If regulator exists but can't be get, return an error */
> +               if (PTR_ERR(priv->vref_reg) != -ENODEV)
> +                       return PTR_ERR(priv->vref_reg);
> +               priv->vref_reg = NULL;
> +       }
> +       if (!priv->vref_reg) {
> +               /* Use internal reference */
> +               priv->vref_mv = TI_TSC2046_INT_VREF;
> +               return 0;
> +       }
> +
> +       ret = regulator_enable(priv->vref_reg);
> +       if (ret)
> +               return ret;
> +
> +       ret = devm_add_action_or_reset(dev, tsc2046_adc_regulator_disable,
> +                                      priv);
> +       if (ret)
> +               return ret;
> +
> +       ret = regulator_get_voltage(priv->vref_reg);
> +       if (ret < 0)
> +               return ret;
> +
> +       priv->vref_mv = ret / MILLI;
> +
> +       return 0;
> +}
> +
>  static int tsc2046_adc_probe(struct spi_device *spi)
>  {
>         const struct tsc2046_adc_dcfg *dcfg;
> @@ -781,6 +830,10 @@ static int tsc2046_adc_probe(struct spi_device *spi)
>         indio_dev->num_channels = dcfg->num_channels;
>         indio_dev->info = &tsc2046_adc_info;
>
> +       ret = tsc2046_adc_configure_regulator(priv);
> +       if (ret)
> +               return ret;
> +
>         tsc2046_adc_parse_fwnode(priv);
>
>         ret = tsc2046_adc_setup_spi_msg(priv);
> --
> 2.30.2
>


-- 
With Best Regards,
Andy Shevchenko

[PATCH v5 3/3] iio: adc: tsc2046: silent spi_device_id warning

[Oleksij Rempel]

Add spi_device_id to silent following kernel runtime warning:
"SPI driver tsc2046 has no spi_device_id for ti,tsc2046e-adc".

Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
---
changes v4:
- add Reviewed-by: Andy Shevchenko
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 c7601b29b3bef..c023163f71464 100644
--- a/drivers/iio/adc/ti-tsc2046.c
+++ b/drivers/iio/adc/ti-tsc2046.c
@@ -805,6 +805,11 @@ 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;
 
@@ -886,11 +891,18 @@ 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,
 };
 module_spi_driver(tsc2046_adc_driver);
-- 
2.30.2