#include <linux/delay.h>
#include <linux/gpio/consumer.h>
#include <linux/i2c.h>
#include <linux/iio/iio.h>
#include <linux/module.h>
#include <linux/mod_devicetable.h>
#define AD5272_RDAC_WR 1
#define AD5272_RDAC_RD 2
#define AD5272_RESET 4
#define AD5272_CTL 7
#define AD5272_RDAC_WR_EN BIT(1)
struct ad5272_cfg {
int max_pos;
int kohms;
int shift;
};
enum ad5272_type {
AD5272_020,
AD5272_050,
AD5272_100,
AD5274_020,
AD5274_100,
};
static const struct ad5272_cfg ad5272_cfg[] = {
[AD5272_020] = { .max_pos = 1024, .kohms = 20 },
[AD5272_050] = { .max_pos = 1024, .kohms = 50 },
[AD5272_100] = { .max_pos = 1024, .kohms = 100 },
[AD5274_020] = { .max_pos = 256, .kohms = 20, .shift = 2 },
[AD5274_100] = { .max_pos = 256, .kohms = 100, .shift = 2 },
};
struct ad5272_data {
struct i2c_client *client;
struct mutex lock;
const struct ad5272_cfg *cfg;
u8 buf[2] __aligned(IIO_DMA_MINALIGN);
};
static const struct iio_chan_spec ad5272_channel = {
.type = IIO_RESISTANCE,
.output = 1,
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
};
static int ad5272_write(struct ad5272_data *data, int reg, int val)
{
int ret;
data->buf[0] = (reg << 2) | ((val >> 8) & 0x3);
data->buf[1] = (u8)val;
mutex_lock(&data->lock);
ret = i2c_master_send(data->client, data->buf, sizeof(data->buf));
mutex_unlock(&data->lock);
return ret < 0 ? ret : 0;
}
static int ad5272_read(struct ad5272_data *data, int reg, int *val)
{
int ret;
data->buf[0] = reg << 2;
data->buf[1] = 0;
mutex_lock(&data->lock);
ret = i2c_master_send(data->client, data->buf, sizeof(data->buf));
if (ret < 0)
goto error;
ret = i2c_master_recv(data->client, data->buf, sizeof(data->buf));
if (ret < 0)
goto error;
*val = ((data->buf[0] & 0x3) << 8) | data->buf[1];
ret = 0;
error:
mutex_unlock(&data->lock);
return ret;
}
static int ad5272_read_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan,
int *val, int *val2, long mask)
{
struct ad5272_data *data = iio_priv(indio_dev);
int ret;
switch (mask) {
case IIO_CHAN_INFO_RAW: {
ret = ad5272_read(data, AD5272_RDAC_RD, val);
*val = *val >> data->cfg->shift;
return ret ? ret : IIO_VAL_INT;
}
case IIO_CHAN_INFO_SCALE:
*val = 1000 * data->cfg->kohms;
*val2 = data->cfg->max_pos;
return IIO_VAL_FRACTIONAL;
}
return -EINVAL;
}
static int ad5272_write_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan,
int val, int val2, long mask)
{
struct ad5272_data *data = iio_priv(indio_dev);
if (mask != IIO_CHAN_INFO_RAW)
return -EINVAL;
if (val >= data->cfg->max_pos || val < 0 || val2)
return -EINVAL;
return ad5272_write(data, AD5272_RDAC_WR, val << data->cfg->shift);
}
static const struct iio_info ad5272_info = {
.read_raw = ad5272_read_raw,
.write_raw = ad5272_write_raw,
};
static int ad5272_reset(struct ad5272_data *data)
{
struct gpio_desc *reset_gpio;
reset_gpio = devm_gpiod_get_optional(&data->client->dev, "reset",
GPIOD_OUT_HIGH);
if (IS_ERR(reset_gpio))
return PTR_ERR(reset_gpio);
if (reset_gpio) {
udelay(1);
gpiod_set_value(reset_gpio, 0);
} else {
ad5272_write(data, AD5272_RESET, 0);
}
usleep_range(1000, 2000);
return 0;
}
static int ad5272_probe(struct i2c_client *client)
{
const struct i2c_device_id *id = i2c_client_get_device_id(client);
struct device *dev = &client->dev;
struct iio_dev *indio_dev;
struct ad5272_data *data;
int ret;
indio_dev = devm_iio_device_alloc(dev, sizeof(*data));
if (!indio_dev)
return -ENOMEM;
i2c_set_clientdata(client, indio_dev);
data = iio_priv(indio_dev);
data->client = client;
mutex_init(&data->lock);
data->cfg = &ad5272_cfg[id->driver_data];
ret = ad5272_reset(data);
if (ret)
return ret;
ret = ad5272_write(data, AD5272_CTL, AD5272_RDAC_WR_EN);
if (ret < 0)
return -ENODEV;
indio_dev->info = &ad5272_info;
indio_dev->channels = &ad5272_channel;
indio_dev->num_channels = 1;
indio_dev->name = client->name;
return devm_iio_device_register(dev, indio_dev);
}
static const struct of_device_id ad5272_dt_ids[] = {
{ .compatible = "adi,ad5272-020", .data = (void *)AD5272_020 },
{ .compatible = "adi,ad5272-050", .data = (void *)AD5272_050 },
{ .compatible = "adi,ad5272-100", .data = (void *)AD5272_100 },
{ .compatible = "adi,ad5274-020", .data = (void *)AD5274_020 },
{ .compatible = "adi,ad5274-100", .data = (void *)AD5274_100 },
{ }
};
MODULE_DEVICE_TABLE(of, ad5272_dt_ids);
static const struct i2c_device_id ad5272_id[] = {
{ "ad5272-020", AD5272_020 },
{ "ad5272-050", AD5272_050 },
{ "ad5272-100", AD5272_100 },
{ "ad5274-020", AD5274_020 },
{ "ad5274-100", AD5274_100 },
{ }
};
MODULE_DEVICE_TABLE(i2c, ad5272_id);
static struct i2c_driver ad5272_driver = {
.driver = {
.name = "ad5272",
.of_match_table = ad5272_dt_ids,
},
.probe = ad5272_probe,
.id_table = ad5272_id,
};
module_i2c_driver(ad5272_driver);
MODULE_AUTHOR("Phil Reid <preid@eletromag.com.au>");
MODULE_DESCRIPTION("AD5272 digital potentiometer");
MODULE_LICENSE("GPL v2");
