linux/drivers/iio/dac/ds4424.c
Ismail H. Kose d632a2bd8f iio: dac: ds4422/ds4424 dac driver
This patch provides an iio device driver for DS4422/DS4424 chips that support
two/four channel 7-bit Sink/Source Current DAC.

Signed-off-by: Ismail H. Kose <Ismail.Kose@maximintegrated.com>
Signed-off-by: Ismail H. Kose <ihkose@gmail.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
2017-10-09 20:49:39 +01:00

342 lines
7.4 KiB
C

/*
* Maxim Integrated
* 7-bit, Multi-Channel Sink/Source Current DAC Driver
* Copyright (C) 2017 Maxim Integrated
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/i2c.h>
#include <linux/regulator/consumer.h>
#include <linux/err.h>
#include <linux/delay.h>
#include <linux/iio/iio.h>
#include <linux/iio/driver.h>
#include <linux/iio/machine.h>
#include <linux/iio/consumer.h>
#define DS4422_MAX_DAC_CHANNELS 2
#define DS4424_MAX_DAC_CHANNELS 4
#define DS4424_DAC_ADDR(chan) ((chan) + 0xf8)
#define DS4424_SOURCE_I 1
#define DS4424_SINK_I 0
#define DS4424_CHANNEL(chan) { \
.type = IIO_CURRENT, \
.indexed = 1, \
.output = 1, \
.channel = chan, \
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
}
/*
* DS4424 DAC control register 8 bits
* [7] 0: to sink; 1: to source
* [6:0] steps to sink/source
* bit[7] looks like a sign bit, but the value of the register is
* not a two's complement code considering the bit[6:0] is a absolute
* distance from the zero point.
*/
union ds4424_raw_data {
struct {
u8 dx:7;
u8 source_bit:1;
};
u8 bits;
};
enum ds4424_device_ids {
ID_DS4422,
ID_DS4424,
};
struct ds4424_data {
struct i2c_client *client;
struct mutex lock;
uint8_t save[DS4424_MAX_DAC_CHANNELS];
struct regulator *vcc_reg;
uint8_t raw[DS4424_MAX_DAC_CHANNELS];
};
static const struct iio_chan_spec ds4424_channels[] = {
DS4424_CHANNEL(0),
DS4424_CHANNEL(1),
DS4424_CHANNEL(2),
DS4424_CHANNEL(3),
};
static int ds4424_get_value(struct iio_dev *indio_dev,
int *val, int channel)
{
struct ds4424_data *data = iio_priv(indio_dev);
int ret;
mutex_lock(&data->lock);
ret = i2c_smbus_read_byte_data(data->client, DS4424_DAC_ADDR(channel));
if (ret < 0)
goto fail;
*val = ret;
fail:
mutex_unlock(&data->lock);
return ret;
}
static int ds4424_set_value(struct iio_dev *indio_dev,
int val, struct iio_chan_spec const *chan)
{
struct ds4424_data *data = iio_priv(indio_dev);
int ret;
mutex_lock(&data->lock);
ret = i2c_smbus_write_byte_data(data->client,
DS4424_DAC_ADDR(chan->channel), val);
if (ret < 0)
goto fail;
data->raw[chan->channel] = val;
fail:
mutex_unlock(&data->lock);
return ret;
}
static int ds4424_read_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan,
int *val, int *val2, long mask)
{
union ds4424_raw_data raw;
int ret;
switch (mask) {
case IIO_CHAN_INFO_RAW:
ret = ds4424_get_value(indio_dev, val, chan->channel);
if (ret < 0) {
pr_err("%s : ds4424_get_value returned %d\n",
__func__, ret);
return ret;
}
raw.bits = *val;
*val = raw.dx;
if (raw.source_bit == DS4424_SINK_I)
*val = -*val;
return IIO_VAL_INT;
default:
return -EINVAL;
}
}
static int ds4424_write_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan,
int val, int val2, long mask)
{
union ds4424_raw_data raw;
if (val2 != 0)
return -EINVAL;
switch (mask) {
case IIO_CHAN_INFO_RAW:
if (val < S8_MIN || val > S8_MAX)
return -EINVAL;
if (val > 0) {
raw.source_bit = DS4424_SOURCE_I;
raw.dx = val;
} else {
raw.source_bit = DS4424_SINK_I;
raw.dx = -val;
}
return ds4424_set_value(indio_dev, raw.bits, chan);
default:
return -EINVAL;
}
}
static int ds4424_verify_chip(struct iio_dev *indio_dev)
{
int ret, val;
ret = ds4424_get_value(indio_dev, &val, DS4424_DAC_ADDR(0));
if (ret < 0)
dev_err(&indio_dev->dev,
"%s failed. ret: %d\n", __func__, ret);
return ret;
}
static int __maybe_unused ds4424_suspend(struct device *dev)
{
struct i2c_client *client = to_i2c_client(dev);
struct iio_dev *indio_dev = i2c_get_clientdata(client);
struct ds4424_data *data = iio_priv(indio_dev);
int ret = 0;
int i;
for (i = 0; i < indio_dev->num_channels; i++) {
data->save[i] = data->raw[i];
ret = ds4424_set_value(indio_dev, 0,
&indio_dev->channels[i]);
if (ret < 0)
return ret;
}
return ret;
}
static int __maybe_unused ds4424_resume(struct device *dev)
{
struct i2c_client *client = to_i2c_client(dev);
struct iio_dev *indio_dev = i2c_get_clientdata(client);
struct ds4424_data *data = iio_priv(indio_dev);
int ret = 0;
int i;
for (i = 0; i < indio_dev->num_channels; i++) {
ret = ds4424_set_value(indio_dev, data->save[i],
&indio_dev->channels[i]);
if (ret < 0)
return ret;
}
return ret;
}
static SIMPLE_DEV_PM_OPS(ds4424_pm_ops, ds4424_suspend, ds4424_resume);
static const struct iio_info ds4424_info = {
.read_raw = ds4424_read_raw,
.write_raw = ds4424_write_raw,
};
static int ds4424_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
struct ds4424_data *data;
struct iio_dev *indio_dev;
int ret;
indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
if (!indio_dev) {
dev_err(&client->dev, "iio dev alloc failed.\n");
return -ENOMEM;
}
data = iio_priv(indio_dev);
i2c_set_clientdata(client, indio_dev);
data->client = client;
indio_dev->name = id->name;
indio_dev->dev.of_node = client->dev.of_node;
indio_dev->dev.parent = &client->dev;
if (!client->dev.of_node) {
dev_err(&client->dev,
"Not found DT.\n");
return -ENODEV;
}
data->vcc_reg = devm_regulator_get(&client->dev, "vcc");
if (IS_ERR(data->vcc_reg)) {
dev_err(&client->dev,
"Failed to get vcc-supply regulator. err: %ld\n",
PTR_ERR(data->vcc_reg));
return PTR_ERR(data->vcc_reg);
}
mutex_init(&data->lock);
ret = regulator_enable(data->vcc_reg);
if (ret < 0) {
dev_err(&client->dev,
"Unable to enable the regulator.\n");
return ret;
}
usleep_range(1000, 1200);
ret = ds4424_verify_chip(indio_dev);
if (ret < 0)
goto fail;
switch (id->driver_data) {
case ID_DS4422:
indio_dev->num_channels = DS4422_MAX_DAC_CHANNELS;
break;
case ID_DS4424:
indio_dev->num_channels = DS4424_MAX_DAC_CHANNELS;
break;
default:
dev_err(&client->dev,
"ds4424: Invalid chip id.\n");
ret = -ENXIO;
goto fail;
}
indio_dev->channels = ds4424_channels;
indio_dev->modes = INDIO_DIRECT_MODE;
indio_dev->info = &ds4424_info;
ret = iio_device_register(indio_dev);
if (ret < 0) {
dev_err(&client->dev,
"iio_device_register failed. ret: %d\n", ret);
goto fail;
}
return ret;
fail:
regulator_disable(data->vcc_reg);
return ret;
}
static int ds4424_remove(struct i2c_client *client)
{
struct iio_dev *indio_dev = i2c_get_clientdata(client);
struct ds4424_data *data = iio_priv(indio_dev);
iio_device_unregister(indio_dev);
regulator_disable(data->vcc_reg);
return 0;
}
static const struct i2c_device_id ds4424_id[] = {
{ "ds4422", ID_DS4422 },
{ "ds4424", ID_DS4424 },
{ }
};
MODULE_DEVICE_TABLE(i2c, ds4424_id);
static const struct of_device_id ds4424_of_match[] = {
{ .compatible = "maxim,ds4422" },
{ .compatible = "maxim,ds4424" },
{ },
};
MODULE_DEVICE_TABLE(of, ds4424_of_match);
static struct i2c_driver ds4424_driver = {
.driver = {
.name = "ds4424",
.of_match_table = ds4424_of_match,
.pm = &ds4424_pm_ops,
},
.probe = ds4424_probe,
.remove = ds4424_remove,
.id_table = ds4424_id,
};
module_i2c_driver(ds4424_driver);
MODULE_DESCRIPTION("Maxim DS4424 DAC Driver");
MODULE_AUTHOR("Ismail H. Kose <ismail.kose@maximintegrated.com>");
MODULE_AUTHOR("Vishal Sood <vishal.sood@maximintegrated.com>");
MODULE_AUTHOR("David Jung <david.jung@maximintegrated.com>");
MODULE_LICENSE("GPL v2");