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linux-next/drivers/iio/dac/m62332.c
Hartmut Knaack 399910534c iio:dac:m62332: use dynamic scale
Some regulators can supply multiple voltages. To take changing voltages
into account, the scale needs to be calculated on every read access.

Signed-off-by: Hartmut Knaack <knaack.h@gmx.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
2015-10-11 15:45:17 +01:00

273 lines
5.8 KiB
C

/*
* m62332.c - Support for Mitsubishi m62332 DAC
*
* Copyright (c) 2014 Dmitry Eremin-Solenikov
*
* Based on max517 driver:
* Copyright (C) 2010, 2011 Roland Stigge <stigge@antcom.de>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/i2c.h>
#include <linux/err.h>
#include <linux/iio/iio.h>
#include <linux/iio/driver.h>
#include <linux/regulator/consumer.h>
#define M62332_CHANNELS 2
struct m62332_data {
struct i2c_client *client;
struct regulator *vcc;
struct mutex mutex;
u8 raw[M62332_CHANNELS];
#ifdef CONFIG_PM_SLEEP
u8 save[M62332_CHANNELS];
#endif
};
static int m62332_set_value(struct iio_dev *indio_dev, u8 val, int channel)
{
struct m62332_data *data = iio_priv(indio_dev);
struct i2c_client *client = data->client;
u8 outbuf[2];
int res;
if (val == data->raw[channel])
return 0;
outbuf[0] = channel;
outbuf[1] = val;
mutex_lock(&data->mutex);
if (val) {
res = regulator_enable(data->vcc);
if (res)
goto out;
}
res = i2c_master_send(client, outbuf, ARRAY_SIZE(outbuf));
if (res >= 0 && res != ARRAY_SIZE(outbuf))
res = -EIO;
if (res < 0)
goto out;
data->raw[channel] = val;
if (!val)
regulator_disable(data->vcc);
mutex_unlock(&data->mutex);
return 0;
out:
mutex_unlock(&data->mutex);
return res;
}
static int m62332_read_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan,
int *val,
int *val2,
long mask)
{
struct m62332_data *data = iio_priv(indio_dev);
int ret;
switch (mask) {
case IIO_CHAN_INFO_SCALE:
/* Corresponds to Vref / 2^(bits) */
ret = regulator_get_voltage(data->vcc);
if (ret < 0)
return ret;
*val = ret / 1000; /* mV */
*val2 = 8;
return IIO_VAL_FRACTIONAL_LOG2;
case IIO_CHAN_INFO_RAW:
*val = data->raw[chan->channel];
return IIO_VAL_INT;
case IIO_CHAN_INFO_OFFSET:
*val = 1;
return IIO_VAL_INT;
default:
break;
}
return -EINVAL;
}
static int m62332_write_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan, int val, int val2,
long mask)
{
switch (mask) {
case IIO_CHAN_INFO_RAW:
if (val < 0 || val > 255)
return -EINVAL;
return m62332_set_value(indio_dev, val, chan->channel);
default:
break;
}
return -EINVAL;
}
#ifdef CONFIG_PM_SLEEP
static int m62332_suspend(struct device *dev)
{
struct i2c_client *client = to_i2c_client(dev);
struct iio_dev *indio_dev = i2c_get_clientdata(client);
struct m62332_data *data = iio_priv(indio_dev);
int ret;
data->save[0] = data->raw[0];
data->save[1] = data->raw[1];
ret = m62332_set_value(indio_dev, 0, 0);
if (ret < 0)
return ret;
return m62332_set_value(indio_dev, 0, 1);
}
static int m62332_resume(struct device *dev)
{
struct i2c_client *client = to_i2c_client(dev);
struct iio_dev *indio_dev = i2c_get_clientdata(client);
struct m62332_data *data = iio_priv(indio_dev);
int ret;
ret = m62332_set_value(indio_dev, data->save[0], 0);
if (ret < 0)
return ret;
return m62332_set_value(indio_dev, data->save[1], 1);
}
static SIMPLE_DEV_PM_OPS(m62332_pm_ops, m62332_suspend, m62332_resume);
#define M62332_PM_OPS (&m62332_pm_ops)
#else
#define M62332_PM_OPS NULL
#endif
static const struct iio_info m62332_info = {
.read_raw = m62332_read_raw,
.write_raw = m62332_write_raw,
.driver_module = THIS_MODULE,
};
#define M62332_CHANNEL(chan) { \
.type = IIO_VOLTAGE, \
.indexed = 1, \
.output = 1, \
.channel = (chan), \
.datasheet_name = "CH" #chan, \
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) | \
BIT(IIO_CHAN_INFO_OFFSET), \
}
static const struct iio_chan_spec m62332_channels[M62332_CHANNELS] = {
M62332_CHANNEL(0),
M62332_CHANNEL(1)
};
static int m62332_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
struct m62332_data *data;
struct iio_dev *indio_dev;
int ret;
indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
if (!indio_dev)
return -ENOMEM;
data = iio_priv(indio_dev);
i2c_set_clientdata(client, indio_dev);
data->client = client;
mutex_init(&data->mutex);
data->vcc = devm_regulator_get(&client->dev, "VCC");
if (IS_ERR(data->vcc))
return PTR_ERR(data->vcc);
/* establish that the iio_dev is a child of the i2c device */
indio_dev->dev.parent = &client->dev;
indio_dev->num_channels = ARRAY_SIZE(m62332_channels);
indio_dev->channels = m62332_channels;
indio_dev->modes = INDIO_DIRECT_MODE;
indio_dev->info = &m62332_info;
ret = iio_map_array_register(indio_dev, client->dev.platform_data);
if (ret < 0)
return ret;
ret = iio_device_register(indio_dev);
if (ret < 0)
goto err;
return 0;
err:
iio_map_array_unregister(indio_dev);
return ret;
}
static int m62332_remove(struct i2c_client *client)
{
struct iio_dev *indio_dev = i2c_get_clientdata(client);
iio_device_unregister(indio_dev);
iio_map_array_unregister(indio_dev);
m62332_set_value(indio_dev, 0, 0);
m62332_set_value(indio_dev, 0, 1);
return 0;
}
static const struct i2c_device_id m62332_id[] = {
{ "m62332", },
{ }
};
MODULE_DEVICE_TABLE(i2c, m62332_id);
static struct i2c_driver m62332_driver = {
.driver = {
.name = "m62332",
.pm = M62332_PM_OPS,
},
.probe = m62332_probe,
.remove = m62332_remove,
.id_table = m62332_id,
};
module_i2c_driver(m62332_driver);
MODULE_AUTHOR("Dmitry Eremin-Solenikov");
MODULE_DESCRIPTION("M62332 8-bit DAC");
MODULE_LICENSE("GPL v2");