- 根目录:
- drivers
- iio
- adc
- ad7291.c
/*
* AD7291 8-Channel, I2C, 12-Bit SAR ADC with Temperature Sensor
*
* Copyright 2010-2011 Analog Devices Inc.
*
* Licensed under the GPL-2 or later.
*/
#include <linux/device.h>
#include <linux/err.h>
#include <linux/i2c.h>
#include <linux/interrupt.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/regulator/consumer.h>
#include <linux/slab.h>
#include <linux/sysfs.h>
#include <linux/iio/iio.h>
#include <linux/iio/sysfs.h>
#include <linux/iio/events.h>
#include <linux/platform_data/ad7291.h>
/*
* Simplified handling
*
* If no events enabled - single polled channel read
* If event enabled direct reads disable unless channel
* is in the read mask.
*
* The noise-delayed bit as per datasheet suggestion is always enabled.
*/
/*
* AD7291 registers definition
*/
#define AD7291_COMMAND 0x00
#define AD7291_VOLTAGE 0x01
#define AD7291_T_SENSE 0x02
#define AD7291_T_AVERAGE 0x03
#define AD7291_DATA_HIGH(x) ((x) * 3 + 0x4)
#define AD7291_DATA_LOW(x) ((x) * 3 + 0x5)
#define AD7291_HYST(x) ((x) * 3 + 0x6)
#define AD7291_VOLTAGE_ALERT_STATUS 0x1F
#define AD7291_T_ALERT_STATUS 0x20
#define AD7291_BITS 12
#define AD7291_VOLTAGE_LIMIT_COUNT 8
/*
* AD7291 command
*/
#define AD7291_AUTOCYCLE BIT(0)
#define AD7291_RESET BIT(1)
#define AD7291_ALERT_CLEAR BIT(2)
#define AD7291_ALERT_POLARITY BIT(3)
#define AD7291_EXT_REF BIT(4)
#define AD7291_NOISE_DELAY BIT(5)
#define AD7291_T_SENSE_MASK BIT(7)
#define AD7291_VOLTAGE_MASK GENMASK(15, 8)
#define AD7291_VOLTAGE_OFFSET 8
/*
* AD7291 value masks
*/
#define AD7291_VALUE_MASK GENMASK(11, 0)
/*
* AD7291 alert register bits
*/
#define AD7291_T_LOW BIT(0)
#define AD7291_T_HIGH BIT(1)
#define AD7291_T_AVG_LOW BIT(2)
#define AD7291_T_AVG_HIGH BIT(3)
#define AD7291_V_LOW(x) BIT((x) * 2)
#define AD7291_V_HIGH(x) BIT((x) * 2 + 1)
struct ad7291_chip_info {
struct i2c_client *client;
struct regulator *reg;
u16 command;
u16 c_mask; /* Active voltage channels for events */
struct mutex state_lock;
};
static int ad7291_i2c_read(struct ad7291_chip_info *chip, u8 reg, u16 *data)
{
struct i2c_client *client = chip->client;
int ret = 0;
ret = i2c_smbus_read_word_swapped(client, reg);
if (ret < 0) {
dev_err(&client->dev, "I2C read error\n");
return ret;
}
*data = ret;
return 0;
}
static int ad7291_i2c_write(struct ad7291_chip_info *chip, u8 reg, u16 data)
{
return i2c_smbus_write_word_swapped(chip->client, reg, data);
}
static irqreturn_t ad7291_event_handler(int irq, void *private)
{
struct iio_dev *indio_dev = private;
struct ad7291_chip_info *chip = iio_priv(private);
u16 t_status, v_status;
u16 command;
int i;
s64 timestamp = iio_get_time_ns();
if (ad7291_i2c_read(chip, AD7291_T_ALERT_STATUS, &t_status))
return IRQ_HANDLED;
if (ad7291_i2c_read(chip, AD7291_VOLTAGE_ALERT_STATUS, &v_status))
return IRQ_HANDLED;
if (!(t_status || v_status))
return IRQ_HANDLED;
command = chip->command | AD7291_ALERT_CLEAR;
ad7291_i2c_write(chip, AD7291_COMMAND, command);
command = chip->command & ~AD7291_ALERT_CLEAR;
ad7291_i2c_write(chip, AD7291_COMMAND, command);
/* For now treat t_sense and t_sense_average the same */
if ((t_status & AD7291_T_LOW) || (t_status & AD7291_T_AVG_LOW))
iio_push_event(indio_dev,
IIO_UNMOD_EVENT_CODE(IIO_TEMP,
0,
IIO_EV_TYPE_THRESH,
IIO_EV_DIR_FALLING),
timestamp);
if ((t_status & AD7291_T_HIGH) || (t_status & AD7291_T_AVG_HIGH))
iio_push_event(indio_dev,
IIO_UNMOD_EVENT_CODE(IIO_TEMP,
0,
IIO_EV_TYPE_THRESH,
IIO_EV_DIR_RISING),
timestamp);
for (i = 0; i < AD7291_VOLTAGE_LIMIT_COUNT; i++) {
if (v_status & AD7291_V_LOW(i))
iio_push_event(indio_dev,
IIO_UNMOD_EVENT_CODE(IIO_VOLTAGE,
i,
IIO_EV_TYPE_THRESH,
IIO_EV_DIR_FALLING),
timestamp);
if (v_status & AD7291_V_HIGH(i))
iio_push_event(indio_dev,
IIO_UNMOD_EVENT_CODE(IIO_VOLTAGE,
i,
IIO_EV_TYPE_THRESH,
IIO_EV_DIR_RISING),
timestamp);
}
return IRQ_HANDLED;
}
static unsigned int ad7291_threshold_reg(const struct iio_chan_spec *chan,
enum iio_event_direction dir,
enum iio_event_info info)
{
unsigned int offset;
switch (chan->type) {
case IIO_VOLTAGE:
offset = chan->channel;
break;
case IIO_TEMP:
offset = AD7291_VOLTAGE_OFFSET;
break;
default:
return 0;
}
switch (info) {
case IIO_EV_INFO_VALUE:
if (dir == IIO_EV_DIR_FALLING)
return AD7291_DATA_HIGH(offset);
else
return AD7291_DATA_LOW(offset);
case IIO_EV_INFO_HYSTERESIS:
return AD7291_HYST(offset);
default:
break;
}
return 0;
}
static int ad7291_read_event_value(struct iio_dev *indio_dev,
const struct iio_chan_spec *chan,
enum iio_event_type type,
enum iio_event_direction dir,
enum iio_event_info info,
int *val, int *val2)
{
struct ad7291_chip_info *chip = iio_priv(indio_dev);
int ret;
u16 uval;
ret = ad7291_i2c_read(chip, ad7291_threshold_reg(chan, dir, info),
&uval);
if (ret < 0)
return ret;
if (info == IIO_EV_INFO_HYSTERESIS || chan->type == IIO_VOLTAGE)
*val = uval & AD7291_VALUE_MASK;
else
*val = sign_extend32(uval, 11);
return IIO_VAL_INT;
}
static int ad7291_write_event_value(struct iio_dev *indio_dev,
const struct iio_chan_spec *chan,
enum iio_event_type type,
enum iio_event_direction dir,
enum iio_event_info info,
int val, int val2)
{
struct ad7291_chip_info *chip = iio_priv(indio_dev);
if (info == IIO_EV_INFO_HYSTERESIS || chan->type == IIO_VOLTAGE) {
if (val > AD7291_VALUE_MASK || val < 0)
return -EINVAL;
} else {
if (val > 2047 || val < -2048)
return -EINVAL;
}
return ad7291_i2c_write(chip, ad7291_threshold_reg(chan, dir, info),
val);
}
static int ad7291_read_event_config(struct iio_dev *indio_dev,
const struct iio_chan_spec *chan,
enum iio_event_type type,
enum iio_event_direction dir)
{
struct ad7291_chip_info *chip = iio_priv(indio_dev);
/*
* To be enabled the channel must simply be on. If any are enabled
* we are in continuous sampling mode
*/
switch (chan->type) {
case IIO_VOLTAGE:
return !!(chip->c_mask & BIT(15 - chan->channel));
case IIO_TEMP:
/* always on */
return 1;
default:
return -EINVAL;
}
}
static int ad7291_write_event_config(struct iio_dev *indio_dev,
const struct iio_chan_spec *chan,
enum iio_event_type type,
enum iio_event_direction dir,
int state)
{
int ret = 0;
struct ad7291_chip_info *chip = iio_priv(indio_dev);
unsigned int mask;
u16 regval;
mutex_lock(&chip->state_lock);
regval = chip->command;
/*
* To be enabled the channel must simply be on. If any are enabled
* use continuous sampling mode.
* Possible to disable temp as well but that makes single read tricky.
*/
mask = BIT(15 - chan->channel);
switch (chan->type) {
case IIO_VOLTAGE:
if ((!state) && (chip->c_mask & mask))
chip->c_mask &= ~mask;
else if (state && (!(chip->c_mask & mask)))
chip->c_mask |= mask;
else
break;
regval &= ~AD7291_AUTOCYCLE;
regval |= chip->c_mask;
if (chip->c_mask) /* Enable autocycle? */
regval |= AD7291_AUTOCYCLE;
ret = ad7291_i2c_write(chip, AD7291_COMMAND, regval);
if (ret < 0)
goto error_ret;
chip->command = regval;
break;
default:
ret = -EINVAL;
}
error_ret:
mutex_unlock(&chip->state_lock);
return ret;
}
static int ad7291_read_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan,
int *val,
int *val2,
long mask)
{
int ret;
struct ad7291_chip_info *chip = iio_priv(indio_dev);
u16 regval;
switch (mask) {
case IIO_CHAN_INFO_RAW:
switch (chan->type) {
case IIO_VOLTAGE:
mutex_lock(&chip->state_lock);
/* If in autocycle mode drop through */
if (chip->command & AD7291_AUTOCYCLE) {
mutex_unlock(&chip->state_lock);
return -EBUSY;
}
/* Enable this channel alone */
regval = chip->command & (~AD7291_VOLTAGE_MASK);
regval |= BIT(15 - chan->channel);
ret = ad7291_i2c_write(chip, AD7291_COMMAND, regval);
if (ret < 0) {
mutex_unlock(&chip->state_lock);
return ret;
}
/* Read voltage */
ret = i2c_smbus_read_word_swapped(chip->client,
AD7291_VOLTAGE);
if (ret < 0) {
mutex_unlock(&chip->state_lock);
return ret;
}
*val = ret & AD7291_VALUE_MASK;
mutex_unlock(&chip->state_lock);
return IIO_VAL_INT;
case IIO_TEMP:
/* Assumes tsense bit of command register always set */
ret = i2c_smbus_read_word_swapped(chip->client,
AD7291_T_SENSE);
if (ret < 0)
return ret;
*val = sign_extend32(ret, 11);
return IIO_VAL_INT;
default:
return -EINVAL;
}
case IIO_CHAN_INFO_AVERAGE_RAW:
ret = i2c_smbus_read_word_swapped(chip->client,
AD7291_T_AVERAGE);
if (ret < 0)
return ret;
*val = sign_extend32(ret, 11);
return IIO_VAL_INT;
case IIO_CHAN_INFO_SCALE:
switch (chan->type) {
case IIO_VOLTAGE:
if (chip->reg) {
int vref;
vref = regulator_get_voltage(chip->reg);
if (vref < 0)
return vref;
*val = vref / 1000;
} else {
*val = 2500;
}
*val2 = AD7291_BITS;
return IIO_VAL_FRACTIONAL_LOG2;
case IIO_TEMP:
/*
* One LSB of the ADC corresponds to 0.25 deg C.
* The temperature reading is in 12-bit twos
* complement format
*/
*val = 250;
return IIO_VAL_INT;
default:
return -EINVAL;
}
default:
return -EINVAL;
}
}
static const struct iio_event_spec ad7291_events[] = {
{
.type = IIO_EV_TYPE_THRESH,
.dir = IIO_EV_DIR_RISING,
.mask_separate = BIT(IIO_EV_INFO_VALUE) |
BIT(IIO_EV_INFO_ENABLE),
}, {
.type = IIO_EV_TYPE_THRESH,
.dir = IIO_EV_DIR_FALLING,
.mask_separate = BIT(IIO_EV_INFO_VALUE) |
BIT(IIO_EV_INFO_ENABLE),
}, {
.type = IIO_EV_TYPE_THRESH,
.dir = IIO_EV_DIR_EITHER,
.mask_separate = BIT(IIO_EV_INFO_HYSTERESIS),
},
};
#define AD7291_VOLTAGE_CHAN(_chan) \
{ \
.type = IIO_VOLTAGE, \
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
.indexed = 1, \
.channel = _chan, \
.event_spec = ad7291_events, \
.num_event_specs = ARRAY_SIZE(ad7291_events), \
}
static const struct iio_chan_spec ad7291_channels[] = {
AD7291_VOLTAGE_CHAN(0),
AD7291_VOLTAGE_CHAN(1),
AD7291_VOLTAGE_CHAN(2),
AD7291_VOLTAGE_CHAN(3),
AD7291_VOLTAGE_CHAN(4),
AD7291_VOLTAGE_CHAN(5),
AD7291_VOLTAGE_CHAN(6),
AD7291_VOLTAGE_CHAN(7),
{
.type = IIO_TEMP,
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
BIT(IIO_CHAN_INFO_AVERAGE_RAW) |
BIT(IIO_CHAN_INFO_SCALE),
.indexed = 1,
.channel = 0,
.event_spec = ad7291_events,
.num_event_specs = ARRAY_SIZE(ad7291_events),
}
};
static const struct iio_info ad7291_info = {
.read_raw = &ad7291_read_raw,
.read_event_config = &ad7291_read_event_config,
.write_event_config = &ad7291_write_event_config,
.read_event_value = &ad7291_read_event_value,
.write_event_value = &ad7291_write_event_value,
.driver_module = THIS_MODULE,
};
static int ad7291_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
struct ad7291_platform_data *pdata = client->dev.platform_data;
struct ad7291_chip_info *chip;
struct iio_dev *indio_dev;
int ret;
indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*chip));
if (!indio_dev)
return -ENOMEM;
chip = iio_priv(indio_dev);
if (pdata && pdata->use_external_ref) {
chip->reg = devm_regulator_get(&client->dev, "vref");
if (IS_ERR(chip->reg))
return PTR_ERR(chip->reg);
ret = regulator_enable(chip->reg);
if (ret)
return ret;
}
mutex_init(&chip->state_lock);
/* this is only used for device removal purposes */
i2c_set_clientdata(client, indio_dev);
chip->client = client;
chip->command = AD7291_NOISE_DELAY |
AD7291_T_SENSE_MASK | /* Tsense always enabled */
AD7291_ALERT_POLARITY; /* set irq polarity low level */
if (pdata && pdata->use_external_ref)
chip->command |= AD7291_EXT_REF;
indio_dev->name = id->name;
indio_dev->channels = ad7291_channels;
indio_dev->num_channels = ARRAY_SIZE(ad7291_channels);
indio_dev->dev.parent = &client->dev;
indio_dev->info = &ad7291_info;
indio_dev->modes = INDIO_DIRECT_MODE;
ret = ad7291_i2c_write(chip, AD7291_COMMAND, AD7291_RESET);
if (ret) {
ret = -EIO;
goto error_disable_reg;
}
ret = ad7291_i2c_write(chip, AD7291_COMMAND, chip->command);
if (ret) {
ret = -EIO;
goto error_disable_reg;
}
if (client->irq > 0) {
ret = request_threaded_irq(client->irq,
NULL,
&ad7291_event_handler,
IRQF_TRIGGER_LOW | IRQF_ONESHOT,
id->name,
indio_dev);
if (ret)
goto error_disable_reg;
}
ret = iio_device_register(indio_dev);
if (ret)
goto error_unreg_irq;
return 0;
error_unreg_irq:
if (client->irq)
free_irq(client->irq, indio_dev);
error_disable_reg:
if (chip->reg)
regulator_disable(chip->reg);
return ret;
}
static int ad7291_remove(struct i2c_client *client)
{
struct iio_dev *indio_dev = i2c_get_clientdata(client);
struct ad7291_chip_info *chip = iio_priv(indio_dev);
iio_device_unregister(indio_dev);
if (client->irq)
free_irq(client->irq, indio_dev);
if (chip->reg)
regulator_disable(chip->reg);
return 0;
}
static const struct i2c_device_id ad7291_id[] = {
{ "ad7291", 0 },
{}
};
MODULE_DEVICE_TABLE(i2c, ad7291_id);
static struct i2c_driver ad7291_driver = {
.driver = {
.name = KBUILD_MODNAME,
},
.probe = ad7291_probe,
.remove = ad7291_remove,
.id_table = ad7291_id,
};
module_i2c_driver(ad7291_driver);
MODULE_AUTHOR("Sonic Zhang <sonic.zhang@analog.com>");
MODULE_DESCRIPTION("Analog Devices AD7291 ADC driver");
MODULE_LICENSE("GPL v2");