[PATCH v4 0/2] iio: dac: update ltc2632 device driver

[PATCH v4 0/2] iio: dac: update ltc2632 device driver

[Silvan Murer]

Changes in v4:
	- fix patch format issues
Change in v3:
	- remove extra spaces and tab
Changes in v2:
	- Add 'optional properties' documentation
	- Return an error when a regulator is specified
	- Use internal reference when no regulator is specified
	- Use iio_device_register instead of devm_iio_device_register

[PATCH v4 1/2] iio: dac: fix missing of_match_table assignment in the LTC 2632 device

[Silvan Murer]

Signed-off-by: Silvan Murer <silvan.murer@gmail.com>
Reviewed-by: Lars-Peter Clausen <lars@metafoo.de>
---
 drivers/iio/dac/ltc2632.c | 19 ++++++++++---------
 1 file changed, 10 insertions(+), 9 deletions(-)

diff --git a/drivers/iio/dac/ltc2632.c b/drivers/iio/dac/ltc2632.c
index ac5e05f..d322b78 100644
--- a/drivers/iio/dac/ltc2632.c
+++ b/drivers/iio/dac/ltc2632.c
@@ -276,15 +276,6 @@ static const struct spi_device_id ltc2632_id[] = {
 };
 MODULE_DEVICE_TABLE(spi, ltc2632_id);
 
-static struct spi_driver ltc2632_driver = {
-	.driver		= {
-		.name	= "ltc2632",
-	},
-	.probe		= ltc2632_probe,
-	.id_table	= ltc2632_id,
-};
-module_spi_driver(ltc2632_driver);
-
 static const struct of_device_id ltc2632_of_match[] = {
 	{
 		.compatible = "lltc,ltc2632-l12",
@@ -309,6 +300,16 @@ static const struct of_device_id ltc2632_of_match[] = {
 };
 MODULE_DEVICE_TABLE(of, ltc2632_of_match);
 
+static struct spi_driver ltc2632_driver = {
+	.driver		= {
+		.name	= "ltc2632",
+		.of_match_table = of_match_ptr(ltc2632_of_match),
+	},
+	.probe		= ltc2632_probe,
+	.id_table	= ltc2632_id,
+};
+module_spi_driver(ltc2632_driver);
+
 MODULE_AUTHOR("Maxime Roussin-Belanger <maxime.roussinbelanger@gmail.com>");
 MODULE_DESCRIPTION("LTC2632 DAC SPI driver");
 MODULE_LICENSE("GPL v2");
-- 
2.7.4

[PATCH v4 2/2] iio: dac: Add support for external reference voltage through the regulator framework.

[Silvan Murer]

Signed-off-by: Silvan Murer <silvan.murer@gmail.com>
Reviewed-by: Lars-Peter Clausen <lars@metafoo.de>
---
 .../devicetree/bindings/iio/dac/ltc2632.txt        | 14 +++++
 drivers/iio/dac/ltc2632.c                          | 70 +++++++++++++++++++---
 2 files changed, 75 insertions(+), 9 deletions(-)

diff --git a/Documentation/devicetree/bindings/iio/dac/ltc2632.txt b/Documentation/devicetree/bindings/iio/dac/ltc2632.txt
index eb911e5..e0d5fea 100644
--- a/Documentation/devicetree/bindings/iio/dac/ltc2632.txt
+++ b/Documentation/devicetree/bindings/iio/dac/ltc2632.txt
@@ -12,12 +12,26 @@ Required properties:
 Property rules described in Documentation/devicetree/bindings/spi/spi-bus.txt
 apply. In particular, "reg" and "spi-max-frequency" properties must be given.
 
+Optional properties:
+	- vref-supply: Phandle to the external reference voltage supply. This should
+	  only be set if there is an external reference voltage connected to the VREF
+	  pin. If the property is not set the internal reference is used.
+
 Example:
 
+	vref: regulator-vref {
+		compatible = "regulator-fixed";
+		regulator-name = "vref-ltc2632";
+		regulator-min-microvolt = <1250000>;
+		regulator-max-microvolt = <1250000>;
+		regulator-always-on;
+	};
+
 	spi_master {
 		dac: ltc2632@0 {
 			compatible = "lltc,ltc2632-l12";
 			reg = <0>; /* CS0 */
 			spi-max-frequency = <1000000>;
+			vref-supply = <&vref>; /* optional */
 		};
 	};
diff --git a/drivers/iio/dac/ltc2632.c b/drivers/iio/dac/ltc2632.c
index d322b78..9551156 100644
--- a/drivers/iio/dac/ltc2632.c
+++ b/drivers/iio/dac/ltc2632.c
@@ -2,6 +2,7 @@
  * LTC2632 Digital to analog convertors spi driver
  *
  * Copyright 2017 Maxime Roussin-B�langer
+ * expanded by Silvan Murer <silvan.murer@gmail.com>
  *
  * Licensed under the GPL-2.
  */
@@ -10,6 +11,7 @@
 #include <linux/spi/spi.h>
 #include <linux/module.h>
 #include <linux/iio/iio.h>
+#include <linux/regulator/consumer.h>
 
 #define LTC2632_DAC_CHANNELS                    2
 
@@ -28,7 +30,7 @@
 /**
  * struct ltc2632_chip_info - chip specific information
  * @channels:		channel spec for the DAC
- * @vref_mv:		reference voltage
+ * @vref_mv:		internal reference voltage
  */
 struct ltc2632_chip_info {
 	const struct iio_chan_spec *channels;
@@ -39,10 +41,14 @@ struct ltc2632_chip_info {
  * struct ltc2632_state - driver instance specific data
  * @spi_dev:			pointer to the spi_device struct
  * @powerdown_cache_mask	used to show current channel powerdown state
+ * @vref_mv			used reference voltage (internal or external)
+ * @vref_reg		regulator for the reference voltage
  */
 struct ltc2632_state {
 	struct spi_device *spi_dev;
 	unsigned int powerdown_cache_mask;
+	int vref_mv;
+	struct regulator *vref_reg;
 };
 
 enum ltc2632_supported_device_ids {
@@ -90,7 +96,7 @@ static int ltc2632_read_raw(struct iio_dev *indio_dev,
 
 	switch (m) {
 	case IIO_CHAN_INFO_SCALE:
-		*val = chip_info->vref_mv;
+		*val = st->vref_mv;
 		*val2 = chan->scan_type.realbits;
 		return IIO_VAL_FRACTIONAL_LOG2;
 	}
@@ -247,6 +253,45 @@ static int ltc2632_probe(struct spi_device *spi)
 	chip_info = (struct ltc2632_chip_info *)
 			spi_get_device_id(spi)->driver_data;
 
+	st->vref_reg = devm_regulator_get_optional(&spi->dev, "vref");
+	if (PTR_ERR(st->vref_reg) == -ENODEV) {
+		/* use internal reference voltage */
+		st->vref_reg = NULL;
+		st->vref_mv = chip_info->vref_mv;
+
+		ret = ltc2632_spi_write(spi, LTC2632_CMD_INTERNAL_REFER,
+				0, 0, 0);
+		if (ret) {
+			dev_err(&spi->dev,
+				"Set internal reference command failed, %d\n",
+				ret);
+			return ret;
+		}
+	} else if (IS_ERR(st->vref_reg)) {
+		dev_err(&spi->dev,
+				"Error getting voltage reference regulator\n");
+		return PTR_ERR(st->vref_reg);
+	} else {
+		/* use external reference voltage */
+		ret = regulator_enable(st->vref_reg);
+		if (ret) {
+			dev_err(&spi->dev,
+				"enable reference regulator failed, %d\n",
+				ret);
+			return ret;
+		}
+		st->vref_mv = regulator_get_voltage(st->vref_reg) / 1000;
+
+		ret = ltc2632_spi_write(spi, LTC2632_CMD_EXTERNAL_REFER,
+				0, 0, 0);
+		if (ret) {
+			dev_err(&spi->dev,
+				"Set external reference command failed, %d\n",
+				ret);
+			return ret;
+		}
+	}
+
 	indio_dev->dev.parent = &spi->dev;
 	indio_dev->name = dev_of_node(&spi->dev) ? dev_of_node(&spi->dev)->name
 						 : spi_get_device_id(spi)->name;
@@ -255,14 +300,20 @@ static int ltc2632_probe(struct spi_device *spi)
 	indio_dev->channels = chip_info->channels;
 	indio_dev->num_channels = LTC2632_DAC_CHANNELS;
 
-	ret = ltc2632_spi_write(spi, LTC2632_CMD_INTERNAL_REFER, 0, 0, 0);
-	if (ret) {
-		dev_err(&spi->dev,
-			"Set internal reference command failed, %d\n", ret);
-		return ret;
-	}
+	return iio_device_register(indio_dev);
+}
+
+static int ltc2632_remove(struct spi_device *spi)
+{
+	struct iio_dev *indio_dev = spi_get_drvdata(spi);
+	struct ltc2632_state *st = iio_priv(indio_dev);
+
+	iio_device_unregister(indio_dev);
+
+	if (st->vref_reg)
+		regulator_disable(st->vref_reg);
 
-	return devm_iio_device_register(&spi->dev, indio_dev);
+	return 0;
 }
 
 static const struct spi_device_id ltc2632_id[] = {
@@ -306,6 +357,7 @@ static struct spi_driver ltc2632_driver = {
 		.of_match_table = of_match_ptr(ltc2632_of_match),
 	},
 	.probe		= ltc2632_probe,
+	.remove		= ltc2632_remove,
 	.id_table	= ltc2632_id,
 };
 module_spi_driver(ltc2632_driver);
-- 
2.7.4

[PATCH v4 2/2] iio: dac: Add support for external reference voltage through the regulator framework.

[Silvan Murer]

[-- Warning: decoded text below may be mangled, UTF-8 assumed --]
[-- Attachment #1: Type: text/plain; charset=UTF-8, Size: 5391 bytes --]

Signed-off-by: Silvan Murer <silvan.murer@gmail.com>
Reviewed-by: Lars-Peter Clausen <lars@metafoo.de>
---
 .../devicetree/bindings/iio/dac/ltc2632.txt        | 14 +++++
 drivers/iio/dac/ltc2632.c                          | 70 +++++++++++++++++++---
 2 files changed, 75 insertions(+), 9 deletions(-)

diff --git a/Documentation/devicetree/bindings/iio/dac/ltc2632.txt b/Documentation/devicetree/bindings/iio/dac/ltc2632.txt
index eb911e5..e0d5fea 100644
--- a/Documentation/devicetree/bindings/iio/dac/ltc2632.txt
+++ b/Documentation/devicetree/bindings/iio/dac/ltc2632.txt
@@ -12,12 +12,26 @@ Required properties:
 Property rules described in Documentation/devicetree/bindings/spi/spi-bus.txt
 apply. In particular, "reg" and "spi-max-frequency" properties must be given.
 
+Optional properties:
+	- vref-supply: Phandle to the external reference voltage supply. This should
+	  only be set if there is an external reference voltage connected to the VREF
+	  pin. If the property is not set the internal reference is used.
+
 Example:
 
+	vref: regulator-vref {
+		compatible = "regulator-fixed";
+		regulator-name = "vref-ltc2632";
+		regulator-min-microvolt = <1250000>;
+		regulator-max-microvolt = <1250000>;
+		regulator-always-on;
+	};
+
 	spi_master {
 		dac: ltc2632@0 {
 			compatible = "lltc,ltc2632-l12";
 			reg = <0>; /* CS0 */
 			spi-max-frequency = <1000000>;
+			vref-supply = <&vref>; /* optional */
 		};
 	};
diff --git a/drivers/iio/dac/ltc2632.c b/drivers/iio/dac/ltc2632.c
index d322b78..9551156 100644
--- a/drivers/iio/dac/ltc2632.c
+++ b/drivers/iio/dac/ltc2632.c
@@ -2,6 +2,7 @@
  * LTC2632 Digital to analog convertors spi driver
  *
  * Copyright 2017 Maxime Roussin-Bélanger
+ * expanded by Silvan Murer <silvan.murer@gmail.com>
  *
  * Licensed under the GPL-2.
  */
@@ -10,6 +11,7 @@
 #include <linux/spi/spi.h>
 #include <linux/module.h>
 #include <linux/iio/iio.h>
+#include <linux/regulator/consumer.h>
 
 #define LTC2632_DAC_CHANNELS                    2
 
@@ -28,7 +30,7 @@
 /**
  * struct ltc2632_chip_info - chip specific information
  * @channels:		channel spec for the DAC
- * @vref_mv:		reference voltage
+ * @vref_mv:		internal reference voltage
  */
 struct ltc2632_chip_info {
 	const struct iio_chan_spec *channels;
@@ -39,10 +41,14 @@ struct ltc2632_chip_info {
  * struct ltc2632_state - driver instance specific data
  * @spi_dev:			pointer to the spi_device struct
  * @powerdown_cache_mask	used to show current channel powerdown state
+ * @vref_mv			used reference voltage (internal or external)
+ * @vref_reg		regulator for the reference voltage
  */
 struct ltc2632_state {
 	struct spi_device *spi_dev;
 	unsigned int powerdown_cache_mask;
+	int vref_mv;
+	struct regulator *vref_reg;
 };
 
 enum ltc2632_supported_device_ids {
@@ -90,7 +96,7 @@ static int ltc2632_read_raw(struct iio_dev *indio_dev,
 
 	switch (m) {
 	case IIO_CHAN_INFO_SCALE:
-		*val = chip_info->vref_mv;
+		*val = st->vref_mv;
 		*val2 = chan->scan_type.realbits;
 		return IIO_VAL_FRACTIONAL_LOG2;
 	}
@@ -247,6 +253,45 @@ static int ltc2632_probe(struct spi_device *spi)
 	chip_info = (struct ltc2632_chip_info *)
 			spi_get_device_id(spi)->driver_data;
 
+	st->vref_reg = devm_regulator_get_optional(&spi->dev, "vref");
+	if (PTR_ERR(st->vref_reg) == -ENODEV) {
+		/* use internal reference voltage */
+		st->vref_reg = NULL;
+		st->vref_mv = chip_info->vref_mv;
+
+		ret = ltc2632_spi_write(spi, LTC2632_CMD_INTERNAL_REFER,
+				0, 0, 0);
+		if (ret) {
+			dev_err(&spi->dev,
+				"Set internal reference command failed, %d\n",
+				ret);
+			return ret;
+		}
+	} else if (IS_ERR(st->vref_reg)) {
+		dev_err(&spi->dev,
+				"Error getting voltage reference regulator\n");
+		return PTR_ERR(st->vref_reg);
+	} else {
+		/* use external reference voltage */
+		ret = regulator_enable(st->vref_reg);
+		if (ret) {
+			dev_err(&spi->dev,
+				"enable reference regulator failed, %d\n",
+				ret);
+			return ret;
+		}
+		st->vref_mv = regulator_get_voltage(st->vref_reg) / 1000;
+
+		ret = ltc2632_spi_write(spi, LTC2632_CMD_EXTERNAL_REFER,
+				0, 0, 0);
+		if (ret) {
+			dev_err(&spi->dev,
+				"Set external reference command failed, %d\n",
+				ret);
+			return ret;
+		}
+	}
+
 	indio_dev->dev.parent = &spi->dev;
 	indio_dev->name = dev_of_node(&spi->dev) ? dev_of_node(&spi->dev)->name
 						 : spi_get_device_id(spi)->name;
@@ -255,14 +300,20 @@ static int ltc2632_probe(struct spi_device *spi)
 	indio_dev->channels = chip_info->channels;
 	indio_dev->num_channels = LTC2632_DAC_CHANNELS;
 
-	ret = ltc2632_spi_write(spi, LTC2632_CMD_INTERNAL_REFER, 0, 0, 0);
-	if (ret) {
-		dev_err(&spi->dev,
-			"Set internal reference command failed, %d\n", ret);
-		return ret;
-	}
+	return iio_device_register(indio_dev);
+}
+
+static int ltc2632_remove(struct spi_device *spi)
+{
+	struct iio_dev *indio_dev = spi_get_drvdata(spi);
+	struct ltc2632_state *st = iio_priv(indio_dev);
+
+	iio_device_unregister(indio_dev);
+
+	if (st->vref_reg)
+		regulator_disable(st->vref_reg);
 
-	return devm_iio_device_register(&spi->dev, indio_dev);
+	return 0;
 }
 
 static const struct spi_device_id ltc2632_id[] = {
@@ -306,6 +357,7 @@ static struct spi_driver ltc2632_driver = {
 		.of_match_table = of_match_ptr(ltc2632_of_match),
 	},
 	.probe		= ltc2632_probe,
+	.remove		= ltc2632_remove,
 	.id_table	= ltc2632_id,
 };
 module_spi_driver(ltc2632_driver);
-- 
2.7.4

Re: [PATCH v4 1/2] iio: dac: fix missing of_match_table assignment in the LTC 2632 device

[Jonathan Cameron]

On Mon, 21 May 2018 14:21:27 +0200
Silvan Murer <silvan.murer@gmail.com> wrote:

> Signed-off-by: Silvan Murer <silvan.murer@gmail.com>
> Reviewed-by: Lars-Peter Clausen <lars@metafoo.de>

Applied to the togreg branch of iio.git and pushed out as testing for
the autobuilders to play with it.

Thanks,

Jonathan

> ---
>  drivers/iio/dac/ltc2632.c | 19 ++++++++++---------
>  1 file changed, 10 insertions(+), 9 deletions(-)
> 
> diff --git a/drivers/iio/dac/ltc2632.c b/drivers/iio/dac/ltc2632.c
> index ac5e05f..d322b78 100644
> --- a/drivers/iio/dac/ltc2632.c
> +++ b/drivers/iio/dac/ltc2632.c
> @@ -276,15 +276,6 @@ static const struct spi_device_id ltc2632_id[] = {
>  };
>  MODULE_DEVICE_TABLE(spi, ltc2632_id);
>  
> -static struct spi_driver ltc2632_driver = {
> -	.driver		= {
> -		.name	= "ltc2632",
> -	},
> -	.probe		= ltc2632_probe,
> -	.id_table	= ltc2632_id,
> -};
> -module_spi_driver(ltc2632_driver);
> -
>  static const struct of_device_id ltc2632_of_match[] = {
>  	{
>  		.compatible = "lltc,ltc2632-l12",
> @@ -309,6 +300,16 @@ static const struct of_device_id ltc2632_of_match[] = {
>  };
>  MODULE_DEVICE_TABLE(of, ltc2632_of_match);
>  
> +static struct spi_driver ltc2632_driver = {
> +	.driver		= {
> +		.name	= "ltc2632",
> +		.of_match_table = of_match_ptr(ltc2632_of_match),
> +	},
> +	.probe		= ltc2632_probe,
> +	.id_table	= ltc2632_id,
> +};
> +module_spi_driver(ltc2632_driver);
> +
>  MODULE_AUTHOR("Maxime Roussin-Belanger <maxime.roussinbelanger@gmail.com>");
>  MODULE_DESCRIPTION("LTC2632 DAC SPI driver");
>  MODULE_LICENSE("GPL v2");

Re: [PATCH v4 2/2] iio: dac: Add support for external reference voltage through the regulator framework.

[Jonathan Cameron]

On Mon, 21 May 2018 14:21:28 +0200
Silvan Murer <silvan.murer@gmail.com> wrote:

> Signed-off-by: Silvan Murer <silvan.murer@gmail.com>
> Reviewed-by: Lars-Peter Clausen <lars@metafoo.de>

Applied to the togreg branch of iio.git and pushed out as testing
for the autobuilders to play with it.

Thanks,

Jonathan

> ---
>  .../devicetree/bindings/iio/dac/ltc2632.txt        | 14 +++++
>  drivers/iio/dac/ltc2632.c                          | 70 +++++++++++++++++++---
>  2 files changed, 75 insertions(+), 9 deletions(-)
> 
> diff --git a/Documentation/devicetree/bindings/iio/dac/ltc2632.txt b/Documentation/devicetree/bindings/iio/dac/ltc2632.txt
> index eb911e5..e0d5fea 100644
> --- a/Documentation/devicetree/bindings/iio/dac/ltc2632.txt
> +++ b/Documentation/devicetree/bindings/iio/dac/ltc2632.txt
> @@ -12,12 +12,26 @@ Required properties:
>  Property rules described in Documentation/devicetree/bindings/spi/spi-bus.txt
>  apply. In particular, "reg" and "spi-max-frequency" properties must be given.
>  
> +Optional properties:
> +	- vref-supply: Phandle to the external reference voltage supply. This should
> +	  only be set if there is an external reference voltage connected to the VREF
> +	  pin. If the property is not set the internal reference is used.
> +
>  Example:
>  
> +	vref: regulator-vref {
> +		compatible = "regulator-fixed";
> +		regulator-name = "vref-ltc2632";
> +		regulator-min-microvolt = <1250000>;
> +		regulator-max-microvolt = <1250000>;
> +		regulator-always-on;
> +	};
> +
>  	spi_master {
>  		dac: ltc2632@0 {
>  			compatible = "lltc,ltc2632-l12";
>  			reg = <0>; /* CS0 */
>  			spi-max-frequency = <1000000>;
> +			vref-supply = <&vref>; /* optional */
>  		};
>  	};
> diff --git a/drivers/iio/dac/ltc2632.c b/drivers/iio/dac/ltc2632.c
> index d322b78..9551156 100644
> --- a/drivers/iio/dac/ltc2632.c
> +++ b/drivers/iio/dac/ltc2632.c
> @@ -2,6 +2,7 @@
>   * LTC2632 Digital to analog convertors spi driver
>   *
>   * Copyright 2017 Maxime Roussin-B_langer
> + * expanded by Silvan Murer <silvan.murer@gmail.com>
>   *
>   * Licensed under the GPL-2.
>   */
> @@ -10,6 +11,7 @@
>  #include <linux/spi/spi.h>
>  #include <linux/module.h>
>  #include <linux/iio/iio.h>
> +#include <linux/regulator/consumer.h>
>  
>  #define LTC2632_DAC_CHANNELS                    2
>  
> @@ -28,7 +30,7 @@
>  /**
>   * struct ltc2632_chip_info - chip specific information
>   * @channels:		channel spec for the DAC
> - * @vref_mv:		reference voltage
> + * @vref_mv:		internal reference voltage
>   */
>  struct ltc2632_chip_info {
>  	const struct iio_chan_spec *channels;
> @@ -39,10 +41,14 @@ struct ltc2632_chip_info {
>   * struct ltc2632_state - driver instance specific data
>   * @spi_dev:			pointer to the spi_device struct
>   * @powerdown_cache_mask	used to show current channel powerdown state
> + * @vref_mv			used reference voltage (internal or external)
> + * @vref_reg		regulator for the reference voltage
>   */
>  struct ltc2632_state {
>  	struct spi_device *spi_dev;
>  	unsigned int powerdown_cache_mask;
> +	int vref_mv;
> +	struct regulator *vref_reg;
>  };
>  
>  enum ltc2632_supported_device_ids {
> @@ -90,7 +96,7 @@ static int ltc2632_read_raw(struct iio_dev *indio_dev,
>  
>  	switch (m) {
>  	case IIO_CHAN_INFO_SCALE:
> -		*val = chip_info->vref_mv;
> +		*val = st->vref_mv;
>  		*val2 = chan->scan_type.realbits;
>  		return IIO_VAL_FRACTIONAL_LOG2;
>  	}
> @@ -247,6 +253,45 @@ static int ltc2632_probe(struct spi_device *spi)
>  	chip_info = (struct ltc2632_chip_info *)
>  			spi_get_device_id(spi)->driver_data;
>  
> +	st->vref_reg = devm_regulator_get_optional(&spi->dev, "vref");
> +	if (PTR_ERR(st->vref_reg) == -ENODEV) {
> +		/* use internal reference voltage */
> +		st->vref_reg = NULL;
> +		st->vref_mv = chip_info->vref_mv;
> +
> +		ret = ltc2632_spi_write(spi, LTC2632_CMD_INTERNAL_REFER,
> +				0, 0, 0);
> +		if (ret) {
> +			dev_err(&spi->dev,
> +				"Set internal reference command failed, %d\n",
> +				ret);
> +			return ret;
> +		}
> +	} else if (IS_ERR(st->vref_reg)) {
> +		dev_err(&spi->dev,
> +				"Error getting voltage reference regulator\n");
> +		return PTR_ERR(st->vref_reg);
> +	} else {
> +		/* use external reference voltage */
> +		ret = regulator_enable(st->vref_reg);
> +		if (ret) {
> +			dev_err(&spi->dev,
> +				"enable reference regulator failed, %d\n",
> +				ret);
> +			return ret;
> +		}
> +		st->vref_mv = regulator_get_voltage(st->vref_reg) / 1000;
> +
> +		ret = ltc2632_spi_write(spi, LTC2632_CMD_EXTERNAL_REFER,
> +				0, 0, 0);
> +		if (ret) {
> +			dev_err(&spi->dev,
> +				"Set external reference command failed, %d\n",
> +				ret);
> +			return ret;
> +		}
> +	}
> +
>  	indio_dev->dev.parent = &spi->dev;
>  	indio_dev->name = dev_of_node(&spi->dev) ? dev_of_node(&spi->dev)->name
>  						 : spi_get_device_id(spi)->name;
> @@ -255,14 +300,20 @@ static int ltc2632_probe(struct spi_device *spi)
>  	indio_dev->channels = chip_info->channels;
>  	indio_dev->num_channels = LTC2632_DAC_CHANNELS;
>  
> -	ret = ltc2632_spi_write(spi, LTC2632_CMD_INTERNAL_REFER, 0, 0, 0);
> -	if (ret) {
> -		dev_err(&spi->dev,
> -			"Set internal reference command failed, %d\n", ret);
> -		return ret;
> -	}
> +	return iio_device_register(indio_dev);
> +}
> +
> +static int ltc2632_remove(struct spi_device *spi)
> +{
> +	struct iio_dev *indio_dev = spi_get_drvdata(spi);
> +	struct ltc2632_state *st = iio_priv(indio_dev);
> +
> +	iio_device_unregister(indio_dev);
> +
> +	if (st->vref_reg)
> +		regulator_disable(st->vref_reg);
>  
> -	return devm_iio_device_register(&spi->dev, indio_dev);
> +	return 0;
>  }
>  
>  static const struct spi_device_id ltc2632_id[] = {
> @@ -306,6 +357,7 @@ static struct spi_driver ltc2632_driver = {
>  		.of_match_table = of_match_ptr(ltc2632_of_match),
>  	},
>  	.probe		= ltc2632_probe,
> +	.remove		= ltc2632_remove,
>  	.id_table	= ltc2632_id,
>  };
>  module_spi_driver(ltc2632_driver);

Re: [PATCH v4 2/2] iio: dac: Add support for external reference voltage through the regulator framework.

[Silvan Murer]

Thank you Jonathan

On Die, 2018-05-22 at 18:25 +0100, Jonathan Cameron wrote:
> On Mon, 21 May 2018 14:21:28 +0200
> Silvan Murer <silvan.murer@gmail.com> wrote:
> 
> > 
> > Signed-off-by: Silvan Murer <silvan.murer@gmail.com>
> > Reviewed-by: Lars-Peter Clausen <lars@metafoo.de>
> Applied to the togreg branch of iio.git and pushed out as testing
> for the autobuilders to play with it.
> 
> Thanks,
> 
> Jonathan
> 
> > 
> > ---
> >  .../devicetree/bindings/iio/dac/ltc2632.txt        | 14 +++++
> >  drivers/iio/dac/ltc2632.c                          | 70
> > +++++++++++++++++++---
> >  2 files changed, 75 insertions(+), 9 deletions(-)
> > 
> > diff --git a/Documentation/devicetree/bindings/iio/dac/ltc2632.txt
> > b/Documentation/devicetree/bindings/iio/dac/ltc2632.txt
> > index eb911e5..e0d5fea 100644
> > --- a/Documentation/devicetree/bindings/iio/dac/ltc2632.txt
> > +++ b/Documentation/devicetree/bindings/iio/dac/ltc2632.txt
> > @@ -12,12 +12,26 @@ Required properties:
> >  Property rules described in
> > Documentation/devicetree/bindings/spi/spi-bus.txt
> >  apply. In particular, "reg" and "spi-max-frequency" properties
> > must be given.
> >  
> > +Optional properties:
> > +	- vref-supply: Phandle to the external reference voltage
> > supply. This should
> > +	  only be set if there is an external reference voltage
> > connected to the VREF
> > +	  pin. If the property is not set the internal reference
> > is used.
> > +
> >  Example:
> >  
> > +	vref: regulator-vref {
> > +		compatible = "regulator-fixed";
> > +		regulator-name = "vref-ltc2632";
> > +		regulator-min-microvolt = <1250000>;
> > +		regulator-max-microvolt = <1250000>;
> > +		regulator-always-on;
> > +	};
> > +
> >  	spi_master {
> >  		dac: ltc2632@0 {
> >  			compatible = "lltc,ltc2632-l12";
> >  			reg = <0>; /* CS0 */
> >  			spi-max-frequency = <1000000>;
> > +			vref-supply = <&vref>; /* optional */
> >  		};
> >  	};
> > diff --git a/drivers/iio/dac/ltc2632.c b/drivers/iio/dac/ltc2632.c
> > index d322b78..9551156 100644
> > --- a/drivers/iio/dac/ltc2632.c
> > +++ b/drivers/iio/dac/ltc2632.c
> > @@ -2,6 +2,7 @@
> >   * LTC2632 Digital to analog convertors spi driver
> >   *
> >   * Copyright 2017 Maxime Roussin-B_langer
> > + * expanded by Silvan Murer <silvan.murer@gmail.com>
> >   *
> >   * Licensed under the GPL-2.
> >   */
> > @@ -10,6 +11,7 @@
> >  #include <linux/spi/spi.h>
> >  #include <linux/module.h>
> >  #include <linux/iio/iio.h>
> > +#include <linux/regulator/consumer.h>
> >  
> >  #define LTC2632_DAC_CHANNELS                    2
> >  
> > @@ -28,7 +30,7 @@
> >  /**
> >   * struct ltc2632_chip_info - chip specific information
> >   * @channels:		channel spec for the DAC
> > - * @vref_mv:		reference voltage
> > + * @vref_mv:		internal reference voltage
> >   */
> >  struct ltc2632_chip_info {
> >  	const struct iio_chan_spec *channels;
> > @@ -39,10 +41,14 @@ struct ltc2632_chip_info {
> >   * struct ltc2632_state - driver instance specific data
> >   * @spi_dev:			pointer to the spi_device
> > struct
> >   * @powerdown_cache_mask	used to show current channel
> > powerdown state
> > + * @vref_mv			used reference voltage
> > (internal or external)
> > + * @vref_reg		regulator for the reference voltage
> >   */
> >  struct ltc2632_state {
> >  	struct spi_device *spi_dev;
> >  	unsigned int powerdown_cache_mask;
> > +	int vref_mv;
> > +	struct regulator *vref_reg;
> >  };
> >  
> >  enum ltc2632_supported_device_ids {
> > @@ -90,7 +96,7 @@ static int ltc2632_read_raw(struct iio_dev
> > *indio_dev,
> >  
> >  	switch (m) {
> >  	case IIO_CHAN_INFO_SCALE:
> > -		*val = chip_info->vref_mv;
> > +		*val = st->vref_mv;
> >  		*val2 = chan->scan_type.realbits;
> >  		return IIO_VAL_FRACTIONAL_LOG2;
> >  	}
> > @@ -247,6 +253,45 @@ static int ltc2632_probe(struct spi_device
> > *spi)
> >  	chip_info = (struct ltc2632_chip_info *)
> >  			spi_get_device_id(spi)->driver_data;
> >  
> > +	st->vref_reg = devm_regulator_get_optional(&spi->dev,
> > "vref");
> > +	if (PTR_ERR(st->vref_reg) == -ENODEV) {
> > +		/* use internal reference voltage */
> > +		st->vref_reg = NULL;
> > +		st->vref_mv = chip_info->vref_mv;
> > +
> > +		ret = ltc2632_spi_write(spi,
> > LTC2632_CMD_INTERNAL_REFER,
> > +				0, 0, 0);
> > +		if (ret) {
> > +			dev_err(&spi->dev,
> > +				"Set internal reference command
> > failed, %d\n",
> > +				ret);
> > +			return ret;
> > +		}
> > +	} else if (IS_ERR(st->vref_reg)) {
> > +		dev_err(&spi->dev,
> > +				"Error getting voltage reference
> > regulator\n");
> > +		return PTR_ERR(st->vref_reg);
> > +	} else {
> > +		/* use external reference voltage */
> > +		ret = regulator_enable(st->vref_reg);
> > +		if (ret) {
> > +			dev_err(&spi->dev,
> > +				"enable reference regulator
> > failed, %d\n",
> > +				ret);
> > +			return ret;
> > +		}
> > +		st->vref_mv = regulator_get_voltage(st->vref_reg)
> > / 1000;
> > +
> > +		ret = ltc2632_spi_write(spi,
> > LTC2632_CMD_EXTERNAL_REFER,
> > +				0, 0, 0);
> > +		if (ret) {
> > +			dev_err(&spi->dev,
> > +				"Set external reference command
> > failed, %d\n",
> > +				ret);
> > +			return ret;
> > +		}
> > +	}
> > +
> >  	indio_dev->dev.parent = &spi->dev;
> >  	indio_dev->name = dev_of_node(&spi->dev) ?
> > dev_of_node(&spi->dev)->name
> >  						 :
> > spi_get_device_id(spi)->name;
> > @@ -255,14 +300,20 @@ static int ltc2632_probe(struct spi_device
> > *spi)
> >  	indio_dev->channels = chip_info->channels;
> >  	indio_dev->num_channels = LTC2632_DAC_CHANNELS;
> >  
> > -	ret = ltc2632_spi_write(spi, LTC2632_CMD_INTERNAL_REFER,
> > 0, 0, 0);
> > -	if (ret) {
> > -		dev_err(&spi->dev,
> > -			"Set internal reference command failed,
> > %d\n", ret);
> > -		return ret;
> > -	}
> > +	return iio_device_register(indio_dev);
> > +}
> > +
> > +static int ltc2632_remove(struct spi_device *spi)
> > +{
> > +	struct iio_dev *indio_dev = spi_get_drvdata(spi);
> > +	struct ltc2632_state *st = iio_priv(indio_dev);
> > +
> > +	iio_device_unregister(indio_dev);
> > +
> > +	if (st->vref_reg)
> > +		regulator_disable(st->vref_reg);
> >  
> > -	return devm_iio_device_register(&spi->dev, indio_dev);
> > +	return 0;
> >  }
> >  
> >  static const struct spi_device_id ltc2632_id[] = {
> > @@ -306,6 +357,7 @@ static struct spi_driver ltc2632_driver = {
> >  		.of_match_table = of_match_ptr(ltc2632_of_match),
> >  	},
> >  	.probe		= ltc2632_probe,
> > +	.remove		= ltc2632_remove,
> >  	.id_table	= ltc2632_id,
> >  };
> >  module_spi_driver(ltc2632_driver);