/**
* Sensortek STK8312 3-Axis Accelerometer
*
* Copyright (c) 2015, Intel Corporation.
*
* This file is subject to the terms and conditions of version 2 of
* the GNU General Public License. See the file COPYING in the main
* directory of this archive for more details.
*
* IIO driver for STK8312; 7-bit I2C address: 0x3D.
*/
#include <linux/acpi.h>
#include <linux/i2c.h>
#include <linux/interrupt.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/delay.h>
#include <linux/iio/buffer.h>
#include <linux/iio/iio.h>
#include <linux/iio/sysfs.h>
#include <linux/iio/trigger.h>
#include <linux/iio/triggered_buffer.h>
#include <linux/iio/trigger_consumer.h>
#define STK8312_REG_XOUT 0x00
#define STK8312_REG_YOUT 0x01
#define STK8312_REG_ZOUT 0x02
#define STK8312_REG_INTSU 0x06
#define STK8312_REG_MODE 0x07
#define STK8312_REG_SR 0x08
#define STK8312_REG_STH 0x13
#define STK8312_REG_RESET 0x20
#define STK8312_REG_AFECTRL 0x24
#define STK8312_REG_OTPADDR 0x3D
#define STK8312_REG_OTPDATA 0x3E
#define STK8312_REG_OTPCTRL 0x3F
#define STK8312_MODE_ACTIVE BIT(0)
#define STK8312_MODE_STANDBY 0x00
#define STK8312_MODE_INT_AH_PP 0xC0 /* active-high, push-pull */
#define STK8312_DREADY_BIT BIT(4)
#define STK8312_RNG_6G 1
#define STK8312_RNG_SHIFT 6
#define STK8312_RNG_MASK GENMASK(7, 6)
#define STK8312_SR_MASK GENMASK(2, 0)
#define STK8312_SR_400HZ_IDX 0
#define STK8312_ALL_CHANNEL_MASK GENMASK(2, 0)
#define STK8312_ALL_CHANNEL_SIZE 3
#define STK8312_DRIVER_NAME "stk8312"
#define STK8312_IRQ_NAME "stk8312_event"
/*
* The accelerometer has two measurement ranges:
*
* -6g - +6g (8-bit, signed)
* -16g - +16g (8-bit, signed)
*
* scale1 = (6 + 6) * 9.81 / (2^8 - 1) = 0.4616
* scale2 = (16 + 16) * 9.81 / (2^8 - 1) = 1.2311
*/
#define STK8312_SCALE_AVAIL "0.4616 1.2311"
static const int stk8312_scale_table[][2] = {
{0, 461600}, {1, 231100}
};
static const struct {
int val;
int val2;
} stk8312_samp_freq_table[] = {
{400, 0}, {200, 0}, {100, 0}, {50, 0}, {25, 0},
{12, 500000}, {6, 250000}, {3, 125000}
};
#define STK8312_ACCEL_CHANNEL(index, reg, axis) { \
.type = IIO_ACCEL, \
.address = reg, \
.modified = 1, \
.channel2 = IIO_MOD_##axis, \
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) | \
BIT(IIO_CHAN_INFO_SAMP_FREQ), \
.scan_index = index, \
.scan_type = { \
.sign = 's', \
.realbits = 8, \
.storagebits = 8, \
.endianness = IIO_CPU, \
}, \
}
static const struct iio_chan_spec stk8312_channels[] = {
STK8312_ACCEL_CHANNEL(0, STK8312_REG_XOUT, X),
STK8312_ACCEL_CHANNEL(1, STK8312_REG_YOUT, Y),
STK8312_ACCEL_CHANNEL(2, STK8312_REG_ZOUT, Z),
IIO_CHAN_SOFT_TIMESTAMP(3),
};
struct stk8312_data {
struct i2c_client *client;
struct mutex lock;
u8 range;
u8 sample_rate_idx;
u8 mode;
struct iio_trigger *dready_trig;
bool dready_trigger_on;
s8 buffer[16]; /* 3x8-bit channels + 5x8 padding + 64-bit timestamp */
};
static IIO_CONST_ATTR(in_accel_scale_available, STK8312_SCALE_AVAIL);
static IIO_CONST_ATTR_SAMP_FREQ_AVAIL("3.125 6.25 12.5 25 50 100 200 400");
static struct attribute *stk8312_attributes[] = {
&iio_const_attr_in_accel_scale_available.dev_attr.attr,
&iio_const_attr_sampling_frequency_available.dev_attr.attr,
NULL,
};
static const struct attribute_group stk8312_attribute_group = {
.attrs = stk8312_attributes
};
static int stk8312_otp_init(struct stk8312_data *data)
{
int ret;
int count = 10;
struct i2c_client *client = data->client;
ret = i2c_smbus_write_byte_data(client, STK8312_REG_OTPADDR, 0x70);
if (ret < 0)
goto exit_err;
ret = i2c_smbus_write_byte_data(client, STK8312_REG_OTPCTRL, 0x02);
if (ret < 0)
goto exit_err;
do {
usleep_range(1000, 5000);
ret = i2c_smbus_read_byte_data(client, STK8312_REG_OTPCTRL);
if (ret < 0)
goto exit_err;
count--;
} while (!(ret & BIT(7)) && count > 0);
if (count == 0) {
ret = -ETIMEDOUT;
goto exit_err;
}
ret = i2c_smbus_read_byte_data(client, STK8312_REG_OTPDATA);
if (ret == 0)
ret = -EINVAL;
if (ret < 0)
goto exit_err;
ret = i2c_smbus_write_byte_data(data->client, STK8312_REG_AFECTRL, ret);
if (ret < 0)
goto exit_err;
msleep(150);
return 0;
exit_err:
dev_err(&client->dev, "failed to initialize sensor\n");
return ret;
}
static int stk8312_set_mode(struct stk8312_data *data, u8 mode)
{
int ret;
struct i2c_client *client = data->client;
if (mode == data->mode)
return 0;
ret = i2c_smbus_write_byte_data(client, STK8312_REG_MODE, mode);
if (ret < 0) {
dev_err(&client->dev, "failed to change sensor mode\n");
return ret;
}
data->mode = mode;
if (mode & STK8312_MODE_ACTIVE) {
/* Need to run OTP sequence before entering active mode */
usleep_range(1000, 5000);
ret = stk8312_otp_init(data);
}
return ret;
}
static int stk8312_set_interrupts(struct stk8312_data *data, u8 int_mask)
{
int ret;
u8 mode;
struct i2c_client *client = data->client;
mode = data->mode;
/* We need to go in standby mode to modify registers */
ret = stk8312_set_mode(data, STK8312_MODE_STANDBY);
if (ret < 0)
return ret;
ret = i2c_smbus_write_byte_data(client, STK8312_REG_INTSU, int_mask);
if (ret < 0) {
dev_err(&client->dev, "failed to set interrupts\n");
stk8312_set_mode(data, mode);
return ret;
}
return stk8312_set_mode(data, mode);
}
static int stk8312_data_rdy_trigger_set_state(struct iio_trigger *trig,
bool state)
{
struct iio_dev *indio_dev = iio_trigger_get_drvdata(trig);
struct stk8312_data *data = iio_priv(indio_dev);
int ret;
if (state)
ret = stk8312_set_interrupts(data, STK8312_DREADY_BIT);
else
ret = stk8312_set_interrupts(data, 0x00);
if (ret < 0) {
dev_err(&data->client->dev, "failed to set trigger state\n");
return ret;
}
data->dready_trigger_on = state;
return 0;
}
static const struct iio_trigger_ops stk8312_trigger_ops = {
.set_trigger_state = stk8312_data_rdy_trigger_set_state,
};
static int stk8312_set_sample_rate(struct stk8312_data *data, u8 rate)
{
int ret;
u8 masked_reg;
u8 mode;
struct i2c_client *client = data->client;
if (rate == data->sample_rate_idx)
return 0;
mode = data->mode;
/* We need to go in standby mode to modify registers */
ret = stk8312_set_mode(data, STK8312_MODE_STANDBY);
if (ret < 0)
return ret;
ret = i2c_smbus_read_byte_data(client, STK8312_REG_SR);
if (ret < 0)
goto err_activate;
masked_reg = (ret & (~STK8312_SR_MASK)) | rate;
ret = i2c_smbus_write_byte_data(client, STK8312_REG_SR, masked_reg);
if (ret < 0)
goto err_activate;
data->sample_rate_idx = rate;
return stk8312_set_mode(data, mode);
err_activate:
dev_err(&client->dev, "failed to set sampling rate\n");
stk8312_set_mode(data, mode);
return ret;
}
static int stk8312_set_range(struct stk8312_data *data, u8 range)
{
int ret;
u8 masked_reg;
u8 mode;
struct i2c_client *client = data->client;
if (range != 1 && range != 2)
return -EINVAL;
else if (range == data->range)
return 0;
mode = data->mode;
/* We need to go in standby mode to modify registers */
ret = stk8312_set_mode(data, STK8312_MODE_STANDBY);
if (ret < 0)
return ret;
ret = i2c_smbus_read_byte_data(client, STK8312_REG_STH);
if (ret < 0)
goto err_activate;
masked_reg = ret & (~STK8312_RNG_MASK);
masked_reg |= range << STK8312_RNG_SHIFT;
ret = i2c_smbus_write_byte_data(client, STK8312_REG_STH, masked_reg);
if (ret < 0)
goto err_activate;
data->range = range;
return stk8312_set_mode(data, mode);
err_activate:
dev_err(&client->dev, "failed to change sensor range\n");
stk8312_set_mode(data, mode);
return ret;
}
static int stk8312_read_accel(struct stk8312_data *data, u8 address)
{
int ret;
struct i2c_client *client = data->client;
if (address > 2)
return -EINVAL;
ret = i2c_smbus_read_byte_data(client, address);
if (ret < 0)
dev_err(&client->dev, "register read failed\n");
return ret;
}
static int stk8312_read_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan,
int *val, int *val2, long mask)
{
struct stk8312_data *data = iio_priv(indio_dev);
int ret;
switch (mask) {
case IIO_CHAN_INFO_RAW:
if (iio_buffer_enabled(indio_dev))
return -EBUSY;
mutex_lock(&data->lock);
ret = stk8312_set_mode(data, data->mode | STK8312_MODE_ACTIVE);
if (ret < 0) {
mutex_unlock(&data->lock);
return ret;
}
ret = stk8312_read_accel(data, chan->address);
if (ret < 0) {
stk8312_set_mode(data,
data->mode & (~STK8312_MODE_ACTIVE));
mutex_unlock(&data->lock);
return ret;
}
*val = sign_extend32(ret, 7);
ret = stk8312_set_mode(data,
data->mode & (~STK8312_MODE_ACTIVE));
mutex_unlock(&data->lock);
if (ret < 0)
return ret;
return IIO_VAL_INT;
case IIO_CHAN_INFO_SCALE:
*val = stk8312_scale_table[data->range - 1][0];
*val2 = stk8312_scale_table[data->range - 1][1];
return IIO_VAL_INT_PLUS_MICRO;
case IIO_CHAN_INFO_SAMP_FREQ:
*val = stk8312_samp_freq_table[data->sample_rate_idx].val;
*val2 = stk8312_samp_freq_table[data->sample_rate_idx].val2;
return IIO_VAL_INT_PLUS_MICRO;
}
return -EINVAL;
}
static int stk8312_write_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan,
int val, int val2, long mask)
{
int i;
int index = -1;
int ret;
struct stk8312_data *data = iio_priv(indio_dev);
switch (mask) {
case IIO_CHAN_INFO_SCALE:
for (i = 0; i < ARRAY_SIZE(stk8312_scale_table); i++)
if (val == stk8312_scale_table[i][0] &&
val2 == stk8312_scale_table[i][1]) {
index = i + 1;
break;
}
if (index < 0)
return -EINVAL;
mutex_lock(&data->lock);
ret = stk8312_set_range(data, index);
mutex_unlock(&data->lock);
return ret;
case IIO_CHAN_INFO_SAMP_FREQ:
for (i = 0; i < ARRAY_SIZE(stk8312_samp_freq_table); i++)
if (val == stk8312_samp_freq_table[i].val &&
val2 == stk8312_samp_freq_table[i].val2) {
index = i;
break;
}
if (index < 0)
return -EINVAL;
mutex_lock(&data->lock);
ret = stk8312_set_sample_rate(data, index);
mutex_unlock(&data->lock);
return ret;
}
return -EINVAL;
}
static const struct iio_info stk8312_info = {
.read_raw = stk8312_read_raw,
.write_raw = stk8312_write_raw,
.attrs = &stk8312_attribute_group,
};
static irqreturn_t stk8312_trigger_handler(int irq, void *p)
{
struct iio_poll_func *pf = p;
struct iio_dev *indio_dev = pf->indio_dev;
struct stk8312_data *data = iio_priv(indio_dev);
int bit, ret, i = 0;
mutex_lock(&data->lock);
/*
* Do a bulk read if all channels are requested,
* from 0x00 (XOUT) to 0x02 (ZOUT)
*/
if (*(indio_dev->active_scan_mask) == STK8312_ALL_CHANNEL_MASK) {
ret = i2c_smbus_read_i2c_block_data(data->client,
STK8312_REG_XOUT,
STK8312_ALL_CHANNEL_SIZE,
data->buffer);
if (ret < STK8312_ALL_CHANNEL_SIZE) {
dev_err(&data->client->dev, "register read failed\n");
mutex_unlock(&data->lock);
goto err;
}
} else {
for_each_set_bit(bit, indio_dev->active_scan_mask,
indio_dev->masklength) {
ret = stk8312_read_accel(data, bit);
if (ret < 0) {
mutex_unlock(&data->lock);
goto err;
}
data->buffer[i++] = ret;
}
}
mutex_unlock(&data->lock);
iio_push_to_buffers_with_timestamp(indio_dev, data->buffer,
pf->timestamp);
err:
iio_trigger_notify_done(indio_dev->trig);
return IRQ_HANDLED;
}
static irqreturn_t stk8312_data_rdy_trig_poll(int irq, void *private)
{
struct iio_dev *indio_dev = private;
struct stk8312_data *data = iio_priv(indio_dev);
if (data->dready_trigger_on)
iio_trigger_poll(data->dready_trig);
return IRQ_HANDLED;
}
static int stk8312_buffer_preenable(struct iio_dev *indio_dev)
{
struct stk8312_data *data = iio_priv(indio_dev);
return stk8312_set_mode(data, data->mode | STK8312_MODE_ACTIVE);
}
static int stk8312_buffer_postdisable(struct iio_dev *indio_dev)
{
struct stk8312_data *data = iio_priv(indio_dev);
return stk8312_set_mode(data, data->mode & (~STK8312_MODE_ACTIVE));
}
static const struct iio_buffer_setup_ops stk8312_buffer_setup_ops = {
.preenable = stk8312_buffer_preenable,
.postenable = iio_triggered_buffer_postenable,
.predisable = iio_triggered_buffer_predisable,
.postdisable = stk8312_buffer_postdisable,
};
static int stk8312_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
int ret;
struct iio_dev *indio_dev;
struct stk8312_data *data;
indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
if (!indio_dev) {
dev_err(&client->dev, "iio allocation failed!\n");
return -ENOMEM;
}
data = iio_priv(indio_dev);
data->client = client;
i2c_set_clientdata(client, indio_dev);
mutex_init(&data->lock);
indio_dev->dev.parent = &client->dev;
indio_dev->info = &stk8312_info;
indio_dev->name = STK8312_DRIVER_NAME;
indio_dev->modes = INDIO_DIRECT_MODE;
indio_dev->channels = stk8312_channels;
indio_dev->num_channels = ARRAY_SIZE(stk8312_channels);
/* A software reset is recommended at power-on */
ret = i2c_smbus_write_byte_data(data->client, STK8312_REG_RESET, 0x00);
if (ret < 0) {
dev_err(&client->dev, "failed to reset sensor\n");
return ret;
}
data->sample_rate_idx = STK8312_SR_400HZ_IDX;
ret = stk8312_set_range(data, STK8312_RNG_6G);
if (ret < 0)
return ret;
ret = stk8312_set_mode(data,
STK8312_MODE_INT_AH_PP | STK8312_MODE_ACTIVE);
if (ret < 0)
return ret;
if (client->irq > 0) {
ret = devm_request_threaded_irq(&client->dev, client->irq,
stk8312_data_rdy_trig_poll,
NULL,
IRQF_TRIGGER_RISING |
IRQF_ONESHOT,
STK8312_IRQ_NAME,
indio_dev);
if (ret < 0) {
dev_err(&client->dev, "request irq %d failed\n",
client->irq);
goto err_power_off;
}
data->dready_trig = devm_iio_trigger_alloc(&client->dev,
"%s-dev%d",
indio_dev->name,
indio_dev->id);
if (!data->dready_trig) {
ret = -ENOMEM;
goto err_power_off;
}
data->dready_trig->dev.parent = &client->dev;
data->dready_trig->ops = &stk8312_trigger_ops;
iio_trigger_set_drvdata(data->dready_trig, indio_dev);
ret = iio_trigger_register(data->dready_trig);
if (ret) {
dev_err(&client->dev, "iio trigger register failed\n");
goto err_power_off;
}
}
ret = iio_triggered_buffer_setup(indio_dev,
iio_pollfunc_store_time,
stk8312_trigger_handler,
&stk8312_buffer_setup_ops);
if (ret < 0) {
dev_err(&client->dev, "iio triggered buffer setup failed\n");
goto err_trigger_unregister;
}
ret = iio_device_register(indio_dev);
if (ret < 0) {
dev_err(&client->dev, "device_register failed\n");
goto err_buffer_cleanup;
}
return 0;
err_buffer_cleanup:
iio_triggered_buffer_cleanup(indio_dev);
err_trigger_unregister:
if (data->dready_trig)
iio_trigger_unregister(data->dready_trig);
err_power_off:
stk8312_set_mode(data, STK8312_MODE_STANDBY);
return ret;
}
static int stk8312_remove(struct i2c_client *client)
{
struct iio_dev *indio_dev = i2c_get_clientdata(client);
struct stk8312_data *data = iio_priv(indio_dev);
iio_device_unregister(indio_dev);
iio_triggered_buffer_cleanup(indio_dev);
if (data->dready_trig)
iio_trigger_unregister(data->dready_trig);
return stk8312_set_mode(data, STK8312_MODE_STANDBY);
}
#ifdef CONFIG_PM_SLEEP
static int stk8312_suspend(struct device *dev)
{
struct stk8312_data *data;
data = iio_priv(i2c_get_clientdata(to_i2c_client(dev)));
return stk8312_set_mode(data, data->mode & (~STK8312_MODE_ACTIVE));
}
static int stk8312_resume(struct device *dev)
{
struct stk8312_data *data;
data = iio_priv(i2c_get_clientdata(to_i2c_client(dev)));
return stk8312_set_mode(data, data->mode | STK8312_MODE_ACTIVE);
}
static SIMPLE_DEV_PM_OPS(stk8312_pm_ops, stk8312_suspend, stk8312_resume);
#define STK8312_PM_OPS (&stk8312_pm_ops)
#else
#define STK8312_PM_OPS NULL
#endif
static const struct i2c_device_id stk8312_i2c_id[] = {
{"STK8312", 0},
{}
};
MODULE_DEVICE_TABLE(i2c, stk8312_i2c_id);
static const struct acpi_device_id stk8312_acpi_id[] = {
{"STK8312", 0},
{}
};
MODULE_DEVICE_TABLE(acpi, stk8312_acpi_id);
static struct i2c_driver stk8312_driver = {
.driver = {
.name = STK8312_DRIVER_NAME,
.pm = STK8312_PM_OPS,
.acpi_match_table = ACPI_PTR(stk8312_acpi_id),
},
.probe = stk8312_probe,
.remove = stk8312_remove,
.id_table = stk8312_i2c_id,
};
module_i2c_driver(stk8312_driver);
MODULE_AUTHOR("Tiberiu Breana <tiberiu.a.breana@intel.com>");
MODULE_DESCRIPTION("STK8312 3-Axis Accelerometer driver");
MODULE_LICENSE("GPL v2");
