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linux/drivers/iio/adc/ad7291.c
Lars-Peter Clausen 3b1cae7c2c staging:iio:ad7291: Move out of staging 
The ad7291 driver is in a reasonable shape. It does not use non-standard API/ABI
and there are no major style issues with the driver. So this patch moves it out
of staging.

There is one small warning from checkpatch which is also fixed in this patch.
The patch also sorts the #include directives in alphabetical order.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
2014-07-08 21:17:30 +01:00

586 lines
14 KiB
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/*
* 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 = 0;
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 ret;
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");
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