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iio: dac: mcp4725: Add basic support for MCP4726 

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
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
hifive-unleashed-5.1
Akinobu Mita 2015-12-26 21:17:22 +09:00 committed by Jonathan Cameron
parent 505abf99c7
commit 35f739679a
3 changed files with 71 additions and 22 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
Documentation/ABI/testing/sysfs-bus-iio
View File

@ -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

4
drivers/iio/dac/Kconfig
View File

@ -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

87
drivers/iio/dac/mcp4725.c
View File

@ -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 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_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 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");