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/**
* 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
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