[PATCH v2] iio: dac: mcp4725: Add basic support for MCP4726

[PATCH v2] iio: dac: mcp4725: Add basic support for MCP4726

[Akinobu Mita]

MCP4726 is a single channel 12-bit DAC.  We can support MCP4726 with
a little changes to mcp4725 driver.  In power-down mode, they have
different selection of VOUT pull-down registers.

MCP4726 also has features:
 - Output gain options: 1x, 2x
 - Voltage reference selection: VDD, VREF (Unbuffered or Buffered)

But these are not supported in this change. (1x gain, VDD is selected)

datasheet: http://ww1.microchip.com/downloads/en/DeviceDoc/22272C.pdf

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Cc: Jonathan Cameron <jic23@kernel.org>
Cc: Hartmut Knaack <knaack.h@gmx.de>
Cc: Lars-Peter Clausen <lars@metafoo.de>
Cc: Peter Meerwald <pmeerw@pmeerw.net>
Cc: linux-iio@vger.kernel.org
---
* v2
- add two modes to Documentation/ABI/testing/sysfs-bus-iio
  (suggested by Peter Meerwald-Stadler)

 Documentation/ABI/testing/sysfs-bus-iio |  2 +
 drivers/iio/dac/Kconfig                 |  4 +-
 drivers/iio/dac/mcp4725.c               | 87 +++++++++++++++++++++++++--------
 3 files changed, 71 insertions(+), 22 deletions(-)

diff --git a/Documentation/ABI/testing/sysfs-bus-iio b/Documentation/ABI/testing/sysfs-bus-iio
index 0439c2a..8fadd27 100644
--- a/Documentation/ABI/testing/sysfs-bus-iio
+++ b/Documentation/ABI/testing/sysfs-bus-iio
@@ -497,7 +497,9 @@ Description:
 		6kohm_to_gnd: connected to ground via a 6kOhm resistor,
 		20kohm_to_gnd: connected to ground via a 20kOhm resistor,
 		100kohm_to_gnd: connected to ground via an 100kOhm resistor,
+		125kohm_to_gnd: connected to ground via an 125kOhm resistor,
 		500kohm_to_gnd: connected to ground via a 500kOhm resistor,
+		640kohm_to_gnd: connected to ground via a 640kOhm resistor,
 		three_state: left floating.
 		For a list of available output power down options read
 		outX_powerdown_mode_available. If Y is not present the
diff --git a/drivers/iio/dac/Kconfig b/drivers/iio/dac/Kconfig
index e701e28..5263c51 100644
--- a/drivers/iio/dac/Kconfig
+++ b/drivers/iio/dac/Kconfig
@@ -176,11 +176,11 @@ config MAX5821
 	  10 bits DAC.
 
 config MCP4725
-	tristate "MCP4725 DAC driver"
+	tristate "MCP4725/6 DAC driver"
 	depends on I2C
 	---help---
 	  Say Y here if you want to build a driver for the Microchip
-	  MCP 4725 12-bit digital-to-analog converter (DAC) with I2C
+	  MCP 4725/6 12-bit digital-to-analog converter (DAC) with I2C
 	  interface.
 
 	  To compile this driver as a module, choose M here: the module
diff --git a/drivers/iio/dac/mcp4725.c b/drivers/iio/dac/mcp4725.c
index 43d1458..fb4b336 100644
--- a/drivers/iio/dac/mcp4725.c
+++ b/drivers/iio/dac/mcp4725.c
@@ -1,5 +1,5 @@
 /*
- * mcp4725.c - Support for Microchip MCP4725
+ * mcp4725.c - Support for Microchip MCP4725/6
  *
  * Copyright (C) 2012 Peter Meerwald <pmeerw@pmeerw.net>
  *
@@ -134,6 +134,12 @@ static const char * const mcp4725_powerdown_modes[] = {
 	"500kohm_to_gnd"
 };
 
+static const char * const mcp4726_powerdown_modes[] = {
+	"1kohm_to_gnd",
+	"125kohm_to_gnd",
+	"640kohm_to_gnd"
+};
+
 static int mcp4725_get_powerdown_mode(struct iio_dev *indio_dev,
 	const struct iio_chan_spec *chan)
 {
@@ -182,11 +188,24 @@ static ssize_t mcp4725_write_powerdown(struct iio_dev *indio_dev,
 	return len;
 }
 
-static const struct iio_enum mcp4725_powerdown_mode_enum = {
-	.items = mcp4725_powerdown_modes,
-	.num_items = ARRAY_SIZE(mcp4725_powerdown_modes),
-	.get = mcp4725_get_powerdown_mode,
-	.set = mcp4725_set_powerdown_mode,
+enum {
+	MCP4725,
+	MCP4726,
+};
+
+static const struct iio_enum mcp472x_powerdown_mode_enum[] = {
+	[MCP4725] = {
+		.items = mcp4725_powerdown_modes,
+		.num_items = ARRAY_SIZE(mcp4725_powerdown_modes),
+		.get = mcp4725_get_powerdown_mode,
+		.set = mcp4725_set_powerdown_mode,
+	},
+	[MCP4726] = {
+		.items = mcp4726_powerdown_modes,
+		.num_items = ARRAY_SIZE(mcp4726_powerdown_modes),
+		.get = mcp4725_get_powerdown_mode,
+		.set = mcp4725_set_powerdown_mode,
+	},
 };
 
 static const struct iio_chan_spec_ext_info mcp4725_ext_info[] = {
@@ -196,19 +215,46 @@ static const struct iio_chan_spec_ext_info mcp4725_ext_info[] = {
 		.write = mcp4725_write_powerdown,
 		.shared = IIO_SEPARATE,
 	},
-	IIO_ENUM("powerdown_mode", IIO_SEPARATE, &mcp4725_powerdown_mode_enum),
-	IIO_ENUM_AVAILABLE("powerdown_mode", &mcp4725_powerdown_mode_enum),
+	IIO_ENUM("powerdown_mode", IIO_SEPARATE,
+			&mcp472x_powerdown_mode_enum[MCP4725]),
+	IIO_ENUM_AVAILABLE("powerdown_mode",
+			&mcp472x_powerdown_mode_enum[MCP4725]),
+	{ },
+};
+
+static const struct iio_chan_spec_ext_info mcp4726_ext_info[] = {
+	{
+		.name = "powerdown",
+		.read = mcp4725_read_powerdown,
+		.write = mcp4725_write_powerdown,
+		.shared = IIO_SEPARATE,
+	},
+	IIO_ENUM("powerdown_mode", IIO_SEPARATE,
+			&mcp472x_powerdown_mode_enum[MCP4726]),
+	IIO_ENUM_AVAILABLE("powerdown_mode",
+			&mcp472x_powerdown_mode_enum[MCP4726]),
 	{ },
 };
 
-static const struct iio_chan_spec mcp4725_channel = {
-	.type		= IIO_VOLTAGE,
-	.indexed	= 1,
-	.output		= 1,
-	.channel	= 0,
-	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
-	.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
-	.ext_info	= mcp4725_ext_info,
+static const struct iio_chan_spec mcp472x_channel[] = {
+	[MCP4725] = {
+		.type		= IIO_VOLTAGE,
+		.indexed	= 1,
+		.output		= 1,
+		.channel	= 0,
+		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
+		.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
+		.ext_info	= mcp4725_ext_info,
+	},
+	[MCP4726] = {
+		.type		= IIO_VOLTAGE,
+		.indexed	= 1,
+		.output		= 1,
+		.channel	= 0,
+		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
+		.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
+		.ext_info	= mcp4726_ext_info,
+	},
 };
 
 static int mcp4725_set_value(struct iio_dev *indio_dev, int val)
@@ -301,7 +347,7 @@ static int mcp4725_probe(struct i2c_client *client,
 
 	indio_dev->dev.parent = &client->dev;
 	indio_dev->info = &mcp4725_info;
-	indio_dev->channels = &mcp4725_channel;
+	indio_dev->channels = &mcp472x_channel[id->driver_data];
 	indio_dev->num_channels = 1;
 	indio_dev->modes = INDIO_DIRECT_MODE;
 
@@ -315,7 +361,7 @@ static int mcp4725_probe(struct i2c_client *client,
 	}
 	pd = (inbuf[0] >> 1) & 0x3;
 	data->powerdown = pd > 0 ? true : false;
-	data->powerdown_mode = pd ? pd-1 : 2; /* 500kohm_to_gnd */
+	data->powerdown_mode = pd ? pd - 1 : 2; /* largest register to gnd */
 	data->dac_value = (inbuf[1] << 4) | (inbuf[2] >> 4);
 
 	return iio_device_register(indio_dev);
@@ -328,7 +374,8 @@ static int mcp4725_remove(struct i2c_client *client)
 }
 
 static const struct i2c_device_id mcp4725_id[] = {
-	{ "mcp4725", 0 },
+	{ "mcp4725", MCP4725 },
+	{ "mcp4726", MCP4726 },
 	{ }
 };
 MODULE_DEVICE_TABLE(i2c, mcp4725_id);
@@ -345,5 +392,5 @@ static struct i2c_driver mcp4725_driver = {
 module_i2c_driver(mcp4725_driver);
 
 MODULE_AUTHOR("Peter Meerwald <pmeerw@pmeerw.net>");
-MODULE_DESCRIPTION("MCP4725 12-bit DAC");
+MODULE_DESCRIPTION("MCP4725/6 12-bit DAC");
 MODULE_LICENSE("GPL");
-- 
1.9.1

Re: [PATCH v2] iio: dac: mcp4725: Add basic support for MCP4726

[Jonathan Cameron]

On 26/12/15 12:17, Akinobu Mita wrote:
> MCP4726 is a single channel 12-bit DAC.  We can support MCP4726 with
> a little changes to mcp4725 driver.  In power-down mode, they have
> different selection of VOUT pull-down registers.
> 
> MCP4726 also has features:
>  - Output gain options: 1x, 2x
>  - Voltage reference selection: VDD, VREF (Unbuffered or Buffered)
> 
> But these are not supported in this change. (1x gain, VDD is selected)
> 
> datasheet: http://ww1.microchip.com/downloads/en/DeviceDoc/22272C.pdf
> 
> Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
> Cc: Jonathan Cameron <jic23@kernel.org>
> Cc: Hartmut Knaack <knaack.h@gmx.de>
> Cc: Lars-Peter Clausen <lars@metafoo.de>
> Cc: Peter Meerwald <pmeerw@pmeerw.net>
> Cc: linux-iio@vger.kernel.org
Looks good to me

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

This branch won't be going anywhere for a week or so, hence I'm happy to
add reviewed-by/acked-by if anyone wants to add them.

Jonathan
> ---
> * v2
> - add two modes to Documentation/ABI/testing/sysfs-bus-iio
>   (suggested by Peter Meerwald-Stadler)
> 
>  Documentation/ABI/testing/sysfs-bus-iio |  2 +
>  drivers/iio/dac/Kconfig                 |  4 +-
>  drivers/iio/dac/mcp4725.c               | 87 +++++++++++++++++++++++++--------
>  3 files changed, 71 insertions(+), 22 deletions(-)
> 
> diff --git a/Documentation/ABI/testing/sysfs-bus-iio b/Documentation/ABI/testing/sysfs-bus-iio
> index 0439c2a..8fadd27 100644
> --- a/Documentation/ABI/testing/sysfs-bus-iio
> +++ b/Documentation/ABI/testing/sysfs-bus-iio
> @@ -497,7 +497,9 @@ Description:
>  		6kohm_to_gnd: connected to ground via a 6kOhm resistor,
>  		20kohm_to_gnd: connected to ground via a 20kOhm resistor,
>  		100kohm_to_gnd: connected to ground via an 100kOhm resistor,
> +		125kohm_to_gnd: connected to ground via an 125kOhm resistor,
>  		500kohm_to_gnd: connected to ground via a 500kOhm resistor,
> +		640kohm_to_gnd: connected to ground via a 640kOhm resistor,
>  		three_state: left floating.
>  		For a list of available output power down options read
>  		outX_powerdown_mode_available. If Y is not present the
> diff --git a/drivers/iio/dac/Kconfig b/drivers/iio/dac/Kconfig
> index e701e28..5263c51 100644
> --- a/drivers/iio/dac/Kconfig
> +++ b/drivers/iio/dac/Kconfig
> @@ -176,11 +176,11 @@ config MAX5821
>  	  10 bits DAC.
>  
>  config MCP4725
> -	tristate "MCP4725 DAC driver"
> +	tristate "MCP4725/6 DAC driver"
>  	depends on I2C
>  	---help---
>  	  Say Y here if you want to build a driver for the Microchip
> -	  MCP 4725 12-bit digital-to-analog converter (DAC) with I2C
> +	  MCP 4725/6 12-bit digital-to-analog converter (DAC) with I2C
>  	  interface.
>  
>  	  To compile this driver as a module, choose M here: the module
> diff --git a/drivers/iio/dac/mcp4725.c b/drivers/iio/dac/mcp4725.c
> index 43d1458..fb4b336 100644
> --- a/drivers/iio/dac/mcp4725.c
> +++ b/drivers/iio/dac/mcp4725.c
> @@ -1,5 +1,5 @@
>  /*
> - * mcp4725.c - Support for Microchip MCP4725
> + * mcp4725.c - Support for Microchip MCP4725/6
>   *
>   * Copyright (C) 2012 Peter Meerwald <pmeerw@pmeerw.net>
>   *
> @@ -134,6 +134,12 @@ static const char * const mcp4725_powerdown_modes[] = {
>  	"500kohm_to_gnd"
>  };
>  
> +static const char * const mcp4726_powerdown_modes[] = {
> +	"1kohm_to_gnd",
> +	"125kohm_to_gnd",
> +	"640kohm_to_gnd"
> +};
> +
>  static int mcp4725_get_powerdown_mode(struct iio_dev *indio_dev,
>  	const struct iio_chan_spec *chan)
>  {
> @@ -182,11 +188,24 @@ static ssize_t mcp4725_write_powerdown(struct iio_dev *indio_dev,
>  	return len;
>  }
>  
> -static const struct iio_enum mcp4725_powerdown_mode_enum = {
> -	.items = mcp4725_powerdown_modes,
> -	.num_items = ARRAY_SIZE(mcp4725_powerdown_modes),
> -	.get = mcp4725_get_powerdown_mode,
> -	.set = mcp4725_set_powerdown_mode,
> +enum {
> +	MCP4725,
> +	MCP4726,
> +};
> +
> +static const struct iio_enum mcp472x_powerdown_mode_enum[] = {
> +	[MCP4725] = {
> +		.items = mcp4725_powerdown_modes,
> +		.num_items = ARRAY_SIZE(mcp4725_powerdown_modes),
> +		.get = mcp4725_get_powerdown_mode,
> +		.set = mcp4725_set_powerdown_mode,
> +	},
> +	[MCP4726] = {
> +		.items = mcp4726_powerdown_modes,
> +		.num_items = ARRAY_SIZE(mcp4726_powerdown_modes),
> +		.get = mcp4725_get_powerdown_mode,
> +		.set = mcp4725_set_powerdown_mode,
> +	},
>  };
>  
>  static const struct iio_chan_spec_ext_info mcp4725_ext_info[] = {
> @@ -196,19 +215,46 @@ static const struct iio_chan_spec_ext_info mcp4725_ext_info[] = {
>  		.write = mcp4725_write_powerdown,
>  		.shared = IIO_SEPARATE,
>  	},
> -	IIO_ENUM("powerdown_mode", IIO_SEPARATE, &mcp4725_powerdown_mode_enum),
> -	IIO_ENUM_AVAILABLE("powerdown_mode", &mcp4725_powerdown_mode_enum),
> +	IIO_ENUM("powerdown_mode", IIO_SEPARATE,
> +			&mcp472x_powerdown_mode_enum[MCP4725]),
> +	IIO_ENUM_AVAILABLE("powerdown_mode",
> +			&mcp472x_powerdown_mode_enum[MCP4725]),
> +	{ },
> +};
> +
> +static const struct iio_chan_spec_ext_info mcp4726_ext_info[] = {
> +	{
> +		.name = "powerdown",
> +		.read = mcp4725_read_powerdown,
> +		.write = mcp4725_write_powerdown,
> +		.shared = IIO_SEPARATE,
> +	},
> +	IIO_ENUM("powerdown_mode", IIO_SEPARATE,
> +			&mcp472x_powerdown_mode_enum[MCP4726]),
> +	IIO_ENUM_AVAILABLE("powerdown_mode",
> +			&mcp472x_powerdown_mode_enum[MCP4726]),
>  	{ },
>  };
>  
> -static const struct iio_chan_spec mcp4725_channel = {
> -	.type		= IIO_VOLTAGE,
> -	.indexed	= 1,
> -	.output		= 1,
> -	.channel	= 0,
> -	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
> -	.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
> -	.ext_info	= mcp4725_ext_info,
> +static const struct iio_chan_spec mcp472x_channel[] = {
> +	[MCP4725] = {
> +		.type		= IIO_VOLTAGE,
> +		.indexed	= 1,
> +		.output		= 1,
> +		.channel	= 0,
> +		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
> +		.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
> +		.ext_info	= mcp4725_ext_info,
> +	},
> +	[MCP4726] = {
> +		.type		= IIO_VOLTAGE,
> +		.indexed	= 1,
> +		.output		= 1,
> +		.channel	= 0,
> +		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
> +		.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
> +		.ext_info	= mcp4726_ext_info,
> +	},
>  };
>  
>  static int mcp4725_set_value(struct iio_dev *indio_dev, int val)
> @@ -301,7 +347,7 @@ static int mcp4725_probe(struct i2c_client *client,
>  
>  	indio_dev->dev.parent = &client->dev;
>  	indio_dev->info = &mcp4725_info;
> -	indio_dev->channels = &mcp4725_channel;
> +	indio_dev->channels = &mcp472x_channel[id->driver_data];
>  	indio_dev->num_channels = 1;
>  	indio_dev->modes = INDIO_DIRECT_MODE;
>  
> @@ -315,7 +361,7 @@ static int mcp4725_probe(struct i2c_client *client,
>  	}
>  	pd = (inbuf[0] >> 1) & 0x3;
>  	data->powerdown = pd > 0 ? true : false;
> -	data->powerdown_mode = pd ? pd-1 : 2; /* 500kohm_to_gnd */
> +	data->powerdown_mode = pd ? pd - 1 : 2; /* largest register to gnd */
>  	data->dac_value = (inbuf[1] << 4) | (inbuf[2] >> 4);
>  
>  	return iio_device_register(indio_dev);
> @@ -328,7 +374,8 @@ static int mcp4725_remove(struct i2c_client *client)
>  }
>  
>  static const struct i2c_device_id mcp4725_id[] = {
> -	{ "mcp4725", 0 },
> +	{ "mcp4725", MCP4725 },
> +	{ "mcp4726", MCP4726 },
>  	{ }
>  };
>  MODULE_DEVICE_TABLE(i2c, mcp4725_id);
> @@ -345,5 +392,5 @@ static struct i2c_driver mcp4725_driver = {
>  module_i2c_driver(mcp4725_driver);
>  
>  MODULE_AUTHOR("Peter Meerwald <pmeerw@pmeerw.net>");
> -MODULE_DESCRIPTION("MCP4725 12-bit DAC");
> +MODULE_DESCRIPTION("MCP4725/6 12-bit DAC");
>  MODULE_LICENSE("GPL");
>