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// SPDX-License-Identifier: GPL-2.0
/*
* HMC425A and similar Gain Amplifiers
*
* Copyright 2020 Analog Devices Inc.
*/
#include <linux/device.h>
#include <linux/err.h>
#include <linux/gpio/consumer.h>
#include <linux/iio/iio.h>
#include <linux/iio/sysfs.h>
#include <linux/kernel.h>
#include <linux/mod_devicetable.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/property.h>
#include <linux/slab.h>
#include <linux/regulator/consumer.h>
#include <linux/sysfs.h>
enum hmc425a_type {
ID_HMC425A,
};
struct hmc425a_chip_info {
const char *name;
const struct iio_chan_spec *channels;
unsigned int num_channels;
unsigned int num_gpios;
int gain_min;
int gain_max;
int default_gain;
};
struct hmc425a_state {
struct mutex lock; /* protect sensor state */
struct hmc425a_chip_info *chip_info;
struct gpio_descs *gpios;
enum hmc425a_type type;
u32 gain;
};
static int hmc425a_write(struct iio_dev *indio_dev, u32 value)
{
struct hmc425a_state *st = iio_priv(indio_dev);
DECLARE_BITMAP(values, BITS_PER_TYPE(value));
values[0] = value;
gpiod_set_array_value_cansleep(st->gpios->ndescs, st->gpios->desc,
NULL, values);
return 0;
}
static int hmc425a_read_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan, int *val,
int *val2, long m)
{
struct hmc425a_state *st = iio_priv(indio_dev);
int code, gain = 0;
int ret;
mutex_lock(&st->lock);
switch (m) {
case IIO_CHAN_INFO_HARDWAREGAIN:
code = st->gain;
switch (st->type) {
case ID_HMC425A:
gain = ~code * -500;
break;
}
*val = gain / 1000;
*val2 = (gain % 1000) * 1000;
ret = IIO_VAL_INT_PLUS_MICRO_DB;
break;
default:
ret = -EINVAL;
}
mutex_unlock(&st->lock);
return ret;
};
static int hmc425a_write_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan, int val,
int val2, long mask)
{
struct hmc425a_state *st = iio_priv(indio_dev);
struct hmc425a_chip_info *inf = st->chip_info;
int code = 0, gain;
int ret;
if (val < 0)
gain = (val * 1000) - (val2 / 1000);
else
gain = (val * 1000) + (val2 / 1000);
if (gain > inf->gain_max || gain < inf->gain_min)
return -EINVAL;
switch (st->type) {
case ID_HMC425A:
code = ~((abs(gain) / 500) & 0x3F);
break;
}
mutex_lock(&st->lock);
switch (mask) {
case IIO_CHAN_INFO_HARDWAREGAIN:
st->gain = code;
ret = hmc425a_write(indio_dev, st->gain);
break;
default:
ret = -EINVAL;
}
mutex_unlock(&st->lock);
return ret;
}
static int hmc425a_write_raw_get_fmt(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan,
long mask)
{
switch (mask) {
case IIO_CHAN_INFO_HARDWAREGAIN:
return IIO_VAL_INT_PLUS_MICRO_DB;
default:
return -EINVAL;
}
}
static const struct iio_info hmc425a_info = {
.read_raw = &hmc425a_read_raw,
.write_raw = &hmc425a_write_raw,
.write_raw_get_fmt = &hmc425a_write_raw_get_fmt,
};
#define HMC425A_CHAN(_channel) \
{ \
.type = IIO_VOLTAGE, \
.output = 1, \
.indexed = 1, \
.channel = _channel, \
.info_mask_separate = BIT(IIO_CHAN_INFO_HARDWAREGAIN), \
}
static const struct iio_chan_spec hmc425a_channels[] = {
HMC425A_CHAN(0),
};
/* Match table for of_platform binding */
static const struct of_device_id hmc425a_of_match[] = {
{ .compatible = "adi,hmc425a", .data = (void *)ID_HMC425A },
{},
};
MODULE_DEVICE_TABLE(of, hmc425a_of_match);
static struct hmc425a_chip_info hmc425a_chip_info_tbl[] = {
[ID_HMC425A] = {
.name = "hmc425a",
.channels = hmc425a_channels,
.num_channels = ARRAY_SIZE(hmc425a_channels),
.num_gpios = 6,
.gain_min = -31500,
.gain_max = 0,
.default_gain = -0x40, /* set default gain -31.5db*/
},
};
static int hmc425a_probe(struct platform_device *pdev)
{
struct iio_dev *indio_dev;
struct hmc425a_state *st;
int ret;
indio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*st));
if (!indio_dev)
return -ENOMEM;
st = iio_priv(indio_dev);
st->type = (uintptr_t)device_get_match_data(&pdev->dev);
st->chip_info = &hmc425a_chip_info_tbl[st->type];
indio_dev->num_channels = st->chip_info->num_channels;
indio_dev->channels = st->chip_info->channels;
indio_dev->name = st->chip_info->name;
st->gain = st->chip_info->default_gain;
st->gpios = devm_gpiod_get_array(&pdev->dev, "ctrl", GPIOD_OUT_LOW);
if (IS_ERR(st->gpios))
return dev_err_probe(&pdev->dev, PTR_ERR(st->gpios),
"failed to get gpios\n");
if (st->gpios->ndescs != st->chip_info->num_gpios) {
dev_err(&pdev->dev, "%d GPIOs needed to operate\n",
st->chip_info->num_gpios);
return -ENODEV;
}
ret = devm_regulator_get_enable(&pdev->dev, "vcc-supply");
if (ret)
return ret;
mutex_init(&st->lock);
indio_dev->info = &hmc425a_info;
indio_dev->modes = INDIO_DIRECT_MODE;
return devm_iio_device_register(&pdev->dev, indio_dev);
}
static struct platform_driver hmc425a_driver = {
.driver = {
.name = KBUILD_MODNAME,
.of_match_table = hmc425a_of_match,
},
.probe = hmc425a_probe,
};
module_platform_driver(hmc425a_driver);
MODULE_AUTHOR("Michael Hennerich <michael.hennerich@analog.com>");
MODULE_DESCRIPTION("Analog Devices HMC425A and similar GPIO control Gain Amplifiers");
MODULE_LICENSE("GPL v2");
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