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staging: iio: dac: ad5446: Enable driver support for AD5620/AD5640/AD…
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…5660 DA converters

Initial support for single channel, 12-/14-/16-Bit nanoDAC with On-Chip Reference

staging: iio: dac: ad5446: Fix according to review feedback

Review feedback by Jonathan Cameron:
	Use kernel doc style to document headers.
	Turn data into a union
	Add some comments for clarity

Signed-off-by: Michael Hennerich <michael.hennerich@analog.com>
Acked-by: Jonathan Cameron <jic23@cam.ac.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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Michael Hennerich authored and Greg Kroah-Hartman committed Nov 29, 2010
1 parent f386caa commit d846263
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Showing 3 changed files with 167 additions and 31 deletions.
6 changes: 3 additions & 3 deletions drivers/staging/iio/dac/Kconfig
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Original file line number Diff line number Diff line change
Expand Up @@ -11,11 +11,11 @@ config AD5624R_SPI
AD5664R convertors (DAC). This driver uses the common SPI interface.

config AD5446
tristate "Analog Devices AD5444, AD5446 and AD5541A, AD5512A DAC SPI driver"
tristate "Analog Devices AD5444/6, AD5620/40/60 and AD5541A/12A DAC SPI driver"
depends on SPI
help
Say yes here to build support for Analog Devices AD5444, AD5446
and AD5541A, AD5512A DACs.
Say yes here to build support for Analog Devices AD5444, AD5446,
AD5620, AD5640, AD5660 and AD5541A, AD5512A DACs.

To compile this driver as a module, choose M here: the
module will be called ad5446.
120 changes: 102 additions & 18 deletions drivers/staging/iio/dac/ad5446.c
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Original file line number Diff line number Diff line change
Expand Up @@ -23,6 +23,31 @@

#include "ad5446.h"

static void ad5446_store_sample(struct ad5446_state *st, unsigned val)
{
st->data.d16 = cpu_to_be16(AD5446_LOAD |
(val << st->chip_info->left_shift));
}

static void ad5542_store_sample(struct ad5446_state *st, unsigned val)
{
st->data.d16 = cpu_to_be16(val << st->chip_info->left_shift);
}

static void ad5620_store_sample(struct ad5446_state *st, unsigned val)
{
st->data.d16 = cpu_to_be16(AD5620_LOAD |
(val << st->chip_info->left_shift));
}

static void ad5660_store_sample(struct ad5446_state *st, unsigned val)
{
val |= AD5660_LOAD;
st->data.d24[0] = (val >> 16) & 0xFF;
st->data.d24[1] = (val >> 8) & 0xFF;
st->data.d24[2] = val & 0xFF;
}

static ssize_t ad5446_write(struct device *dev,
struct device_attribute *attr,
const char *buf,
Expand All @@ -43,18 +68,7 @@ static ssize_t ad5446_write(struct device *dev,
}

mutex_lock(&dev_info->mlock);
switch (spi_get_device_id(st->spi)->driver_data) {
case ID_AD5444:
case ID_AD5446:
st->data = cpu_to_be16(AD5446_LOAD |
(val << st->chip_info->left_shift));
break;
case ID_AD5542A:
case ID_AD5512A:
st->data = cpu_to_be16(val << st->chip_info->left_shift);
break;
}

st->chip_info->store_sample(st, val);
ret = spi_sync(st->spi, &st->msg);
mutex_unlock(&dev_info->mlock);

Expand Down Expand Up @@ -105,24 +119,76 @@ static const struct ad5446_chip_info ad5446_chip_info_tbl[] = {
.storagebits = 16,
.left_shift = 2,
.sign = 'u', /* IIO_SCAN_EL_TYPE_UNSIGNED */
.store_sample = ad5446_store_sample,
},
[ID_AD5446] = {
.bits = 14,
.storagebits = 16,
.left_shift = 0,
.sign = 'u', /* IIO_SCAN_EL_TYPE_UNSIGNED */
.store_sample = ad5446_store_sample,
},
[ID_AD5542A] = {
.bits = 16,
.storagebits = 16,
.left_shift = 0,
.sign = 'u', /* IIO_SCAN_EL_TYPE_UNSIGNED */
.store_sample = ad5542_store_sample,
},
[ID_AD5512A] = {
.bits = 12,
.storagebits = 16,
.left_shift = 4,
.sign = 'u', /* IIO_SCAN_EL_TYPE_UNSIGNED */
.store_sample = ad5542_store_sample,
},
[ID_AD5620_2500] = {
.bits = 12,
.storagebits = 16,
.left_shift = 2,
.sign = 'u', /* IIO_SCAN_EL_TYPE_UNSIGNED */
.int_vref_mv = 2500,
.store_sample = ad5620_store_sample,
},
[ID_AD5620_1250] = {
.bits = 12,
.storagebits = 16,
.left_shift = 2,
.sign = 'u', /* IIO_SCAN_EL_TYPE_UNSIGNED */
.int_vref_mv = 1250,
.store_sample = ad5620_store_sample,
},
[ID_AD5640_2500] = {
.bits = 14,
.storagebits = 16,
.left_shift = 0,
.sign = 'u', /* IIO_SCAN_EL_TYPE_UNSIGNED */
.int_vref_mv = 2500,
.store_sample = ad5620_store_sample,
},
[ID_AD5640_1250] = {
.bits = 14,
.storagebits = 16,
.left_shift = 0,
.sign = 'u', /* IIO_SCAN_EL_TYPE_UNSIGNED */
.int_vref_mv = 1250,
.store_sample = ad5620_store_sample,
},
[ID_AD5660_2500] = {
.bits = 16,
.storagebits = 24,
.left_shift = 0,
.sign = 'u', /* IIO_SCAN_EL_TYPE_UNSIGNED */
.int_vref_mv = 2500,
.store_sample = ad5660_store_sample,
},
[ID_AD5660_1250] = {
.bits = 16,
.storagebits = 24,
.left_shift = 0,
.sign = 'u', /* IIO_SCAN_EL_TYPE_UNSIGNED */
.int_vref_mv = 1250,
.store_sample = ad5660_store_sample,
},
};

Expand Down Expand Up @@ -168,16 +234,28 @@ static int __devinit ad5446_probe(struct spi_device *spi)

/* Setup default message */

st->xfer.tx_buf = &st->data,
st->xfer.len = 2,
st->xfer.tx_buf = &st->data;
st->xfer.len = st->chip_info->storagebits / 8;

spi_message_init(&st->msg);
spi_message_add_tail(&st->xfer, &st->msg);

if (voltage_uv)
st->vref_mv = voltage_uv / 1000;
else
dev_warn(&spi->dev, "reference voltage unspecified\n");
switch (spi_get_device_id(spi)->driver_data) {
case ID_AD5620_2500:
case ID_AD5620_1250:
case ID_AD5640_2500:
case ID_AD5640_1250:
case ID_AD5660_2500:
case ID_AD5660_1250:
st->vref_mv = st->chip_info->int_vref_mv;
break;
default:
if (voltage_uv)
st->vref_mv = voltage_uv / 1000;
else
dev_warn(&spi->dev,
"reference voltage unspecified\n");
}

ret = iio_device_register(st->indio_dev);
if (ret)
Expand Down Expand Up @@ -217,6 +295,12 @@ static const struct spi_device_id ad5446_id[] = {
{"ad5446", ID_AD5446},
{"ad5542a", ID_AD5542A},
{"ad5512a", ID_AD5512A},
{"ad5620-2500", ID_AD5620_2500}, /* AD5620/40/60: */
{"ad5620-1250", ID_AD5620_1250}, /* part numbers may look differently */
{"ad5640-2500", ID_AD5640_2500},
{"ad5640-1250", ID_AD5640_1250},
{"ad5660-2500", ID_AD5660_2500},
{"ad5660-1250", ID_AD5660_1250},
{}
};

Expand Down
72 changes: 62 additions & 10 deletions drivers/staging/iio/dac/ad5446.h
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Original file line number Diff line number Diff line change
Expand Up @@ -5,8 +5,8 @@
*
* Licensed under the GPL-2 or later.
*/
#ifndef IIO_ADC_AD5446_H_
#define IIO_ADC_AD5446_H_
#ifndef IIO_DAC_AD5446_H_
#define IIO_DAC_AD5446_H_

/* DAC Control Bits */

Expand All @@ -15,14 +15,30 @@
#define AD5446_NOP (0x2 << 14) /* No operation */
#define AD5446_CLK_RISING (0x3 << 14) /* Clock data on rising edge */

#define AD5620_LOAD (0x0 << 14) /* Load and update Norm Operation*/
#define AD5620_PWRDWN_1k (0x1 << 14) /* Power-down: 1kOhm to GND */
#define AD5620_PWRDWN_100k (0x2 << 14) /* Power-down: 100kOhm to GND */
#define AD5620_PWRDWN_TRISTATE (0x3 << 14) /* Power-down: Three-state */

#define AD5660_LOAD (0x0 << 16) /* Load and update Norm Operation*/
#define AD5660_PWRDWN_1k (0x1 << 16) /* Power-down: 1kOhm to GND */
#define AD5660_PWRDWN_100k (0x2 << 16) /* Power-down: 100kOhm to GND */
#define AD5660_PWRDWN_TRISTATE (0x3 << 16) /* Power-down: Three-state */

#define RES_MASK(bits) ((1 << (bits)) - 1)

struct ad5446_chip_info {
u8 bits; /* number of DAC bits */
u8 storagebits; /* number of bits written to the DAC */
u8 left_shift; /* number of bits the datum must be shifted */
char sign; /* [s]igned or [u]nsigned */
};
/**
* struct ad5446_state - driver instance specific data
* @indio_dev: the industrial I/O device
* @spi: spi_device
* @chip_info: chip model specific constants, available modes etc
* @reg: supply regulator
* @poll_work: bottom half of polling interrupt handler
* @vref_mv: actual reference voltage used
* @xfer: default spi transfer
* @msg: default spi message
* @data: spi transmit buffer
*/

struct ad5446_state {
struct iio_dev *indio_dev;
Expand All @@ -33,14 +49,50 @@ struct ad5446_state {
unsigned short vref_mv;
struct spi_transfer xfer;
struct spi_message msg;
unsigned short data;
union {
unsigned short d16;
unsigned char d24[3];
} data;
};

/**
* struct ad5446_chip_info - chip specifc information
* @bits: accuracy of the DAC in bits
* @storagebits: number of bits written to the DAC
* @left_shift: number of bits the datum must be shifted
* @sign: data representation [s]igned or [u]nsigned
* @int_vref_mv: AD5620/40/60: the internal reference voltage
* @store_sample: chip specifc helper function to store the datum
*/

struct ad5446_chip_info {
u8 bits;
u8 storagebits;
u8 left_shift;
char sign;
u16 int_vref_mv;
void (*store_sample) (struct ad5446_state *st, unsigned val);
};

/**
* ad5446_supported_device_ids:
* The AD5620/40/60 parts are available in different fixed internal reference
* voltage options. The actual part numbers may look differently
* (and a bit cryptic), however this style is used to make clear which
* parts are supported here.
*/

enum ad5446_supported_device_ids {
ID_AD5444,
ID_AD5446,
ID_AD5542A,
ID_AD5512A,
ID_AD5620_2500,
ID_AD5620_1250,
ID_AD5640_2500,
ID_AD5640_1250,
ID_AD5660_2500,
ID_AD5660_1250,
};

#endif /* IIO_ADC_AD5446_H_ */
#endif /* IIO_DAC_AD5446_H_ */

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