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/*
* Copyright (C) 2012 Invensense, Inc.
*
* This software is licensed under the terms of the GNU General Public
* License version 2, as published by the Free Software Foundation, and
* may be copied, distributed, and modified under those terms.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/i2c.h>
#include <linux/err.h>
#include <linux/delay.h>
#include <linux/sysfs.h>
#include <linux/jiffies.h>
#include <linux/irq.h>
#include <linux/interrupt.h>
#include <linux/kfifo.h>
#include <linux/poll.h>
#include "inv_mpu_iio.h"
static void inv_clear_kfifo(struct inv_mpu6050_state *st)
{
unsigned long flags;
/* take the spin lock sem to avoid interrupt kick in */
spin_lock_irqsave(&st->time_stamp_lock, flags);
kfifo_reset(&st->timestamps);
spin_unlock_irqrestore(&st->time_stamp_lock, flags);
}
int inv_reset_fifo(struct iio_dev *indio_dev)
{
int result;
u8 d;
struct inv_mpu6050_state *st = iio_priv(indio_dev);
/* disable interrupt */
result = inv_mpu6050_write_reg(st, st->reg->int_enable, 0);
if (result) {
dev_err(&st->client->dev, "int_enable failed %d\n", result);
return result;
}
/* disable the sensor output to FIFO */
result = inv_mpu6050_write_reg(st, st->reg->fifo_en, 0);
if (result)
goto reset_fifo_fail;
/* disable fifo reading */
result = inv_mpu6050_write_reg(st, st->reg->user_ctrl, 0);
if (result)
goto reset_fifo_fail;
/* reset FIFO*/
result = inv_mpu6050_write_reg(st, st->reg->user_ctrl,
INV_MPU6050_BIT_FIFO_RST);
if (result)
goto reset_fifo_fail;
/* clear timestamps fifo */
inv_clear_kfifo(st);
/* enable interrupt */
if (st->chip_config.accl_fifo_enable ||
st->chip_config.gyro_fifo_enable) {
result = inv_mpu6050_write_reg(st, st->reg->int_enable,
INV_MPU6050_BIT_DATA_RDY_EN);
if (result)
return result;
}
/* enable FIFO reading and I2C master interface*/
result = inv_mpu6050_write_reg(st, st->reg->user_ctrl,
INV_MPU6050_BIT_FIFO_EN);
if (result)
goto reset_fifo_fail;
/* enable sensor output to FIFO */
d = 0;
if (st->chip_config.gyro_fifo_enable)
d |= INV_MPU6050_BITS_GYRO_OUT;
if (st->chip_config.accl_fifo_enable)
d |= INV_MPU6050_BIT_ACCEL_OUT;
result = inv_mpu6050_write_reg(st, st->reg->fifo_en, d);
if (result)
goto reset_fifo_fail;
return 0;
reset_fifo_fail:
dev_err(&st->client->dev, "reset fifo failed %d\n", result);
result = inv_mpu6050_write_reg(st, st->reg->int_enable,
INV_MPU6050_BIT_DATA_RDY_EN);
return result;
}
/**
* inv_mpu6050_irq_handler() - Cache a timestamp at each data ready interrupt.
*/
irqreturn_t inv_mpu6050_irq_handler(int irq, void *p)
{
struct iio_poll_func *pf = p;
struct iio_dev *indio_dev = pf->indio_dev;
struct inv_mpu6050_state *st = iio_priv(indio_dev);
s64 timestamp;
timestamp = iio_get_time_ns();
kfifo_in_spinlocked(&st->timestamps, ×tamp, 1,
&st->time_stamp_lock);
return IRQ_WAKE_THREAD;
}
/**
* inv_mpu6050_read_fifo() - Transfer data from hardware FIFO to KFIFO.
*/
irqreturn_t inv_mpu6050_read_fifo(int irq, void *p)
{
struct iio_poll_func *pf = p;
struct iio_dev *indio_dev = pf->indio_dev;
struct inv_mpu6050_state *st = iio_priv(indio_dev);
size_t bytes_per_datum;
int result;
u8 data[INV_MPU6050_OUTPUT_DATA_SIZE];
u16 fifo_count;
s64 timestamp;
mutex_lock(&indio_dev->mlock);
if (!(st->chip_config.accl_fifo_enable |
st->chip_config.gyro_fifo_enable))
goto end_session;
bytes_per_datum = 0;
if (st->chip_config.accl_fifo_enable)
bytes_per_datum += INV_MPU6050_BYTES_PER_3AXIS_SENSOR;
if (st->chip_config.gyro_fifo_enable)
bytes_per_datum += INV_MPU6050_BYTES_PER_3AXIS_SENSOR;
/*
* read fifo_count register to know how many bytes inside FIFO
* right now
*/
result = i2c_smbus_read_i2c_block_data(st->client,
st->reg->fifo_count_h,
INV_MPU6050_FIFO_COUNT_BYTE, data);
if (result != INV_MPU6050_FIFO_COUNT_BYTE)
goto end_session;
fifo_count = be16_to_cpup((__be16 *)(&data[0]));
if (fifo_count < bytes_per_datum)
goto end_session;
/* fifo count can't be odd number, if it is odd, reset fifo*/
if (fifo_count & 1)
goto flush_fifo;
if (fifo_count > INV_MPU6050_FIFO_THRESHOLD)
goto flush_fifo;
/* Timestamp mismatch. */
if (kfifo_len(&st->timestamps) >
fifo_count / bytes_per_datum + INV_MPU6050_TIME_STAMP_TOR)
goto flush_fifo;
while (fifo_count >= bytes_per_datum) {
result = i2c_smbus_read_i2c_block_data(st->client,
st->reg->fifo_r_w,
bytes_per_datum, data);
if (result != bytes_per_datum)
goto flush_fifo;
result = kfifo_out(&st->timestamps, ×tamp, 1);
/* when there is no timestamp, put timestamp as 0 */
if (0 == result)
timestamp = 0;
result = iio_push_to_buffers_with_timestamp(indio_dev, data,
timestamp);
if (result)
goto flush_fifo;
fifo_count -= bytes_per_datum;
}
end_session:
mutex_unlock(&indio_dev->mlock);
iio_trigger_notify_done(indio_dev->trig);
return IRQ_HANDLED;
flush_fifo:
/* Flush HW and SW FIFOs. */
inv_reset_fifo(indio_dev);
mutex_unlock(&indio_dev->mlock);
iio_trigger_notify_done(indio_dev->trig);
return IRQ_HANDLED;
}
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