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linux/drivers/iio/dac/ad5791.c
Michael Hennerich e737d495b2 iio: dac: ad5791: Add support for controlling RBUF via devicetree 
This patch adds support for an external amplifier to be connected in a
gain of two configuration.

Signed-off-by: Michael Hennerich <michael.hennerich@analog.com>
Signed-off-by: Nuno Sa <nuno.sa@analog.com>
Link: https://lore.kernel.org/r/20231129-ad5791-michael-stuff-v3-2-48e192b00909@analog.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
2023-12-04 13:19:48 +00:00

474 lines
11 KiB
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// SPDX-License-Identifier: GPL-2.0-only
/*
* AD5760, AD5780, AD5781, AD5790, AD5791 Voltage Output Digital to Analog
* Converter
*
* Copyright 2011 Analog Devices Inc.
*/
#include <linux/interrupt.h>
#include <linux/fs.h>
#include <linux/device.h>
#include <linux/kernel.h>
#include <linux/spi/spi.h>
#include <linux/slab.h>
#include <linux/sysfs.h>
#include <linux/regulator/consumer.h>
#include <linux/module.h>
#include <linux/bitops.h>
#include <linux/iio/iio.h>
#include <linux/iio/sysfs.h>
#include <linux/iio/dac/ad5791.h>
#define AD5791_DAC_MASK GENMASK(19, 0)
#define AD5791_CMD_READ BIT(23)
#define AD5791_CMD_WRITE 0
#define AD5791_ADDR(addr) ((addr) << 20)
/* Registers */
#define AD5791_ADDR_NOOP 0
#define AD5791_ADDR_DAC0 1
#define AD5791_ADDR_CTRL 2
#define AD5791_ADDR_CLRCODE 3
#define AD5791_ADDR_SW_CTRL 4
/* Control Register */
#define AD5791_CTRL_RBUF BIT(1)
#define AD5791_CTRL_OPGND BIT(2)
#define AD5791_CTRL_DACTRI BIT(3)
#define AD5791_CTRL_BIN2SC BIT(4)
#define AD5791_CTRL_SDODIS BIT(5)
#define AD5761_CTRL_LINCOMP(x) ((x) << 6)
#define AD5791_LINCOMP_0_10 0
#define AD5791_LINCOMP_10_12 1
#define AD5791_LINCOMP_12_16 2
#define AD5791_LINCOMP_16_19 3
#define AD5791_LINCOMP_19_20 12
#define AD5780_LINCOMP_0_10 0
#define AD5780_LINCOMP_10_20 12
/* Software Control Register */
#define AD5791_SWCTRL_LDAC BIT(0)
#define AD5791_SWCTRL_CLR BIT(1)
#define AD5791_SWCTRL_RESET BIT(2)
#define AD5791_DAC_PWRDN_6K 0
#define AD5791_DAC_PWRDN_3STATE 1
/**
* struct ad5791_chip_info - chip specific information
* @get_lin_comp: function pointer to the device specific function
*/
struct ad5791_chip_info {
int (*get_lin_comp) (unsigned int span);
};
/**
* struct ad5791_state - driver instance specific data
* @spi: spi_device
* @reg_vdd: positive supply regulator
* @reg_vss: negative supply regulator
* @chip_info: chip model specific constants
* @vref_mv: actual reference voltage used
* @vref_neg_mv: voltage of the negative supply
* @ctrl: control register cache
* @pwr_down_mode: current power down mode
* @pwr_down: true if device is powered down
* @data: spi transfer buffers
*/
struct ad5791_state {
struct spi_device *spi;
struct regulator *reg_vdd;
struct regulator *reg_vss;
const struct ad5791_chip_info *chip_info;
unsigned short vref_mv;
unsigned int vref_neg_mv;
unsigned ctrl;
unsigned pwr_down_mode;
bool pwr_down;
union {
__be32 d32;
u8 d8[4];
} data[3] __aligned(IIO_DMA_MINALIGN);
};
enum ad5791_supported_device_ids {
ID_AD5760,
ID_AD5780,
ID_AD5781,
ID_AD5791,
};
static int ad5791_spi_write(struct ad5791_state *st, u8 addr, u32 val)
{
st->data[0].d32 = cpu_to_be32(AD5791_CMD_WRITE |
AD5791_ADDR(addr) |
(val & AD5791_DAC_MASK));
return spi_write(st->spi, &st->data[0].d8[1], 3);
}
static int ad5791_spi_read(struct ad5791_state *st, u8 addr, u32 *val)
{
int ret;
struct spi_transfer xfers[] = {
{
.tx_buf = &st->data[0].d8[1],
.bits_per_word = 8,
.len = 3,
.cs_change = 1,
}, {
.tx_buf = &st->data[1].d8[1],
.rx_buf = &st->data[2].d8[1],
.bits_per_word = 8,
.len = 3,
},
};
st->data[0].d32 = cpu_to_be32(AD5791_CMD_READ |
AD5791_ADDR(addr));
st->data[1].d32 = cpu_to_be32(AD5791_ADDR(AD5791_ADDR_NOOP));
ret = spi_sync_transfer(st->spi, xfers, ARRAY_SIZE(xfers));
*val = be32_to_cpu(st->data[2].d32);
return ret;
}
static const char * const ad5791_powerdown_modes[] = {
"6kohm_to_gnd",
"three_state",
};
static int ad5791_get_powerdown_mode(struct iio_dev *indio_dev,
const struct iio_chan_spec *chan)
{
struct ad5791_state *st = iio_priv(indio_dev);
return st->pwr_down_mode;
}
static int ad5791_set_powerdown_mode(struct iio_dev *indio_dev,
const struct iio_chan_spec *chan, unsigned int mode)
{
struct ad5791_state *st = iio_priv(indio_dev);
st->pwr_down_mode = mode;
return 0;
}
static const struct iio_enum ad5791_powerdown_mode_enum = {
.items = ad5791_powerdown_modes,
.num_items = ARRAY_SIZE(ad5791_powerdown_modes),
.get = ad5791_get_powerdown_mode,
.set = ad5791_set_powerdown_mode,
};
static ssize_t ad5791_read_dac_powerdown(struct iio_dev *indio_dev,
uintptr_t private, const struct iio_chan_spec *chan, char *buf)
{
struct ad5791_state *st = iio_priv(indio_dev);
return sysfs_emit(buf, "%d\n", st->pwr_down);
}
static ssize_t ad5791_write_dac_powerdown(struct iio_dev *indio_dev,
uintptr_t private, const struct iio_chan_spec *chan, const char *buf,
size_t len)
{
bool pwr_down;
int ret;
struct ad5791_state *st = iio_priv(indio_dev);
ret = kstrtobool(buf, &pwr_down);
if (ret)
return ret;
if (!pwr_down) {
st->ctrl &= ~(AD5791_CTRL_OPGND | AD5791_CTRL_DACTRI);
} else {
if (st->pwr_down_mode == AD5791_DAC_PWRDN_6K)
st->ctrl |= AD5791_CTRL_OPGND;
else if (st->pwr_down_mode == AD5791_DAC_PWRDN_3STATE)
st->ctrl |= AD5791_CTRL_DACTRI;
}
st->pwr_down = pwr_down;
ret = ad5791_spi_write(st, AD5791_ADDR_CTRL, st->ctrl);
return ret ? ret : len;
}
static int ad5791_get_lin_comp(unsigned int span)
{
if (span <= 10000)
return AD5791_LINCOMP_0_10;
else if (span <= 12000)
return AD5791_LINCOMP_10_12;
else if (span <= 16000)
return AD5791_LINCOMP_12_16;
else if (span <= 19000)
return AD5791_LINCOMP_16_19;
else
return AD5791_LINCOMP_19_20;
}
static int ad5780_get_lin_comp(unsigned int span)
{
if (span <= 10000)
return AD5780_LINCOMP_0_10;
else
return AD5780_LINCOMP_10_20;
}
static const struct ad5791_chip_info ad5791_chip_info_tbl[] = {
[ID_AD5760] = {
.get_lin_comp = ad5780_get_lin_comp,
},
[ID_AD5780] = {
.get_lin_comp = ad5780_get_lin_comp,
},
[ID_AD5781] = {
.get_lin_comp = ad5791_get_lin_comp,
},
[ID_AD5791] = {
.get_lin_comp = ad5791_get_lin_comp,
},
};
static int ad5791_read_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan,
int *val,
int *val2,
long m)
{
struct ad5791_state *st = iio_priv(indio_dev);
u64 val64;
int ret;
switch (m) {
case IIO_CHAN_INFO_RAW:
ret = ad5791_spi_read(st, chan->address, val);
if (ret)
return ret;
*val &= AD5791_DAC_MASK;
*val >>= chan->scan_type.shift;
return IIO_VAL_INT;
case IIO_CHAN_INFO_SCALE:
*val = st->vref_mv;
*val2 = (1 << chan->scan_type.realbits) - 1;
return IIO_VAL_FRACTIONAL;
case IIO_CHAN_INFO_OFFSET:
val64 = (((u64)st->vref_neg_mv) << chan->scan_type.realbits);
do_div(val64, st->vref_mv);
*val = -val64;
return IIO_VAL_INT;
default:
return -EINVAL;
}
};
static const struct iio_chan_spec_ext_info ad5791_ext_info[] = {
{
.name = "powerdown",
.shared = IIO_SHARED_BY_TYPE,
.read = ad5791_read_dac_powerdown,
.write = ad5791_write_dac_powerdown,
},
IIO_ENUM("powerdown_mode", IIO_SHARED_BY_TYPE,
&ad5791_powerdown_mode_enum),
IIO_ENUM_AVAILABLE("powerdown_mode", IIO_SHARED_BY_TYPE, &ad5791_powerdown_mode_enum),
{ },
};
#define AD5791_CHAN(bits, _shift) { \
.type = IIO_VOLTAGE, \
.output = 1, \
.indexed = 1, \
.address = AD5791_ADDR_DAC0, \
.channel = 0, \
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) | \
BIT(IIO_CHAN_INFO_OFFSET), \
.scan_type = { \
.sign = 'u', \
.realbits = (bits), \
.storagebits = 24, \
.shift = (_shift), \
}, \
.ext_info = ad5791_ext_info, \
}
static const struct iio_chan_spec ad5791_channels[] = {
[ID_AD5760] = AD5791_CHAN(16, 4),
[ID_AD5780] = AD5791_CHAN(18, 2),
[ID_AD5781] = AD5791_CHAN(18, 2),
[ID_AD5791] = AD5791_CHAN(20, 0)
};
static int ad5791_write_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan,
int val,
int val2,
long mask)
{
struct ad5791_state *st = iio_priv(indio_dev);
switch (mask) {
case IIO_CHAN_INFO_RAW:
val &= GENMASK(chan->scan_type.realbits - 1, 0);
val <<= chan->scan_type.shift;
return ad5791_spi_write(st, chan->address, val);
default:
return -EINVAL;
}
}
static const struct iio_info ad5791_info = {
.read_raw = &ad5791_read_raw,
.write_raw = &ad5791_write_raw,
};
static int ad5791_probe(struct spi_device *spi)
{
struct ad5791_platform_data *pdata = spi->dev.platform_data;
struct iio_dev *indio_dev;
struct ad5791_state *st;
int ret, pos_voltage_uv = 0, neg_voltage_uv = 0;
bool use_rbuf_gain2;
indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
if (!indio_dev)
return -ENOMEM;
st = iio_priv(indio_dev);
st->reg_vdd = devm_regulator_get(&spi->dev, "vdd");
if (!IS_ERR(st->reg_vdd)) {
ret = regulator_enable(st->reg_vdd);
if (ret)
return ret;
ret = regulator_get_voltage(st->reg_vdd);
if (ret < 0)
goto error_disable_reg_pos;
pos_voltage_uv = ret;
}
st->reg_vss = devm_regulator_get(&spi->dev, "vss");
if (!IS_ERR(st->reg_vss)) {
ret = regulator_enable(st->reg_vss);
if (ret)
goto error_disable_reg_pos;
ret = regulator_get_voltage(st->reg_vss);
if (ret < 0)
goto error_disable_reg_neg;
neg_voltage_uv = ret;
}
st->pwr_down = true;
st->spi = spi;
if (pdata)
use_rbuf_gain2 = pdata->use_rbuf_gain2;
else
use_rbuf_gain2 = device_property_read_bool(&spi->dev,
"adi,rbuf-gain2-en");
if (!IS_ERR(st->reg_vss) && !IS_ERR(st->reg_vdd)) {
st->vref_mv = (pos_voltage_uv + neg_voltage_uv) / 1000;
st->vref_neg_mv = neg_voltage_uv / 1000;
} else if (pdata) {
st->vref_mv = pdata->vref_pos_mv + pdata->vref_neg_mv;
st->vref_neg_mv = pdata->vref_neg_mv;
} else {
dev_warn(&spi->dev, "reference voltage unspecified\n");
}
ret = ad5791_spi_write(st, AD5791_ADDR_SW_CTRL, AD5791_SWCTRL_RESET);
if (ret)
goto error_disable_reg_neg;
st->chip_info = &ad5791_chip_info_tbl[spi_get_device_id(spi)
->driver_data];
st->ctrl = AD5761_CTRL_LINCOMP(st->chip_info->get_lin_comp(st->vref_mv))
| (use_rbuf_gain2 ? 0 : AD5791_CTRL_RBUF) |
AD5791_CTRL_BIN2SC;
ret = ad5791_spi_write(st, AD5791_ADDR_CTRL, st->ctrl |
AD5791_CTRL_OPGND | AD5791_CTRL_DACTRI);
if (ret)
goto error_disable_reg_neg;
spi_set_drvdata(spi, indio_dev);
indio_dev->info = &ad5791_info;
indio_dev->modes = INDIO_DIRECT_MODE;
indio_dev->channels
= &ad5791_channels[spi_get_device_id(spi)->driver_data];
indio_dev->num_channels = 1;
indio_dev->name = spi_get_device_id(st->spi)->name;
ret = iio_device_register(indio_dev);
if (ret)
goto error_disable_reg_neg;
return 0;
error_disable_reg_neg:
if (!IS_ERR(st->reg_vss))
regulator_disable(st->reg_vss);
error_disable_reg_pos:
if (!IS_ERR(st->reg_vdd))
regulator_disable(st->reg_vdd);
return ret;
}
static void ad5791_remove(struct spi_device *spi)
{
struct iio_dev *indio_dev = spi_get_drvdata(spi);
struct ad5791_state *st = iio_priv(indio_dev);
iio_device_unregister(indio_dev);
if (!IS_ERR(st->reg_vdd))
regulator_disable(st->reg_vdd);
if (!IS_ERR(st->reg_vss))
regulator_disable(st->reg_vss);
}
static const struct spi_device_id ad5791_id[] = {
{"ad5760", ID_AD5760},
{"ad5780", ID_AD5780},
{"ad5781", ID_AD5781},
{"ad5790", ID_AD5791},
{"ad5791", ID_AD5791},
{}
};
MODULE_DEVICE_TABLE(spi, ad5791_id);
static struct spi_driver ad5791_driver = {
.driver = {
.name = "ad5791",
},
.probe = ad5791_probe,
.remove = ad5791_remove,
.id_table = ad5791_id,
};
module_spi_driver(ad5791_driver);
MODULE_AUTHOR("Michael Hennerich <michael.hennerich@analog.com>");
MODULE_DESCRIPTION("Analog Devices AD5760/AD5780/AD5781/AD5790/AD5791 DAC");
MODULE_LICENSE("GPL v2");
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