2 * Copyright (C) 2012 Invensense, Inc.
4 * This software is licensed under the terms of the GNU General Public
5 * License version 2, as published by the Free Software Foundation, and
6 * may be copied, distributed, and modified under those terms.
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
11 * GNU General Public License for more details.
14 #include <linux/module.h>
15 #include <linux/slab.h>
16 #include <linux/i2c.h>
17 #include <linux/err.h>
18 #include <linux/delay.h>
19 #include <linux/sysfs.h>
20 #include <linux/jiffies.h>
21 #include <linux/irq.h>
22 #include <linux/interrupt.h>
23 #include <linux/kfifo.h>
24 #include <linux/poll.h>
25 #include "inv_mpu_iio.h"
27 int inv_reset_fifo(struct iio_dev *indio_dev)
31 struct inv_mpu6050_state *st = iio_priv(indio_dev);
33 /* disable interrupt */
34 result = inv_mpu6050_write_reg(st, st->reg->int_enable, 0);
36 dev_err(&st->client->dev, "int_enable failed %d\n", result);
39 /* disable the sensor output to FIFO */
40 result = inv_mpu6050_write_reg(st, st->reg->fifo_en, 0);
43 /* disable fifo reading */
44 result = inv_mpu6050_write_reg(st, st->reg->user_ctrl, 0);
49 result = inv_mpu6050_write_reg(st, st->reg->user_ctrl,
50 INV_MPU6050_BIT_FIFO_RST);
53 /* enable interrupt */
54 if (st->chip_config.accl_fifo_enable ||
55 st->chip_config.gyro_fifo_enable) {
56 result = inv_mpu6050_write_reg(st, st->reg->int_enable,
57 INV_MPU6050_BIT_DATA_RDY_EN);
61 /* enable FIFO reading and I2C master interface*/
62 result = inv_mpu6050_write_reg(st, st->reg->user_ctrl,
63 INV_MPU6050_BIT_FIFO_EN);
66 /* enable sensor output to FIFO */
68 if (st->chip_config.gyro_fifo_enable)
69 d |= INV_MPU6050_BITS_GYRO_OUT;
70 if (st->chip_config.accl_fifo_enable)
71 d |= INV_MPU6050_BIT_ACCEL_OUT;
72 result = inv_mpu6050_write_reg(st, st->reg->fifo_en, d);
79 dev_err(&st->client->dev, "reset fifo failed %d\n", result);
80 result = inv_mpu6050_write_reg(st, st->reg->int_enable,
81 INV_MPU6050_BIT_DATA_RDY_EN);
86 static void inv_clear_kfifo(struct inv_mpu6050_state *st)
90 /* take the spin lock sem to avoid interrupt kick in */
91 spin_lock_irqsave(&st->time_stamp_lock, flags);
92 kfifo_reset(&st->timestamps);
93 spin_unlock_irqrestore(&st->time_stamp_lock, flags);
97 * inv_mpu6050_irq_handler() - Cache a timestamp at each data ready interrupt.
99 irqreturn_t inv_mpu6050_irq_handler(int irq, void *p)
101 struct iio_poll_func *pf = p;
102 struct iio_dev *indio_dev = pf->indio_dev;
103 struct inv_mpu6050_state *st = iio_priv(indio_dev);
106 timestamp = iio_get_time_ns();
107 kfifo_in_spinlocked(&st->timestamps, ×tamp, 1,
108 &st->time_stamp_lock);
110 return IRQ_WAKE_THREAD;
114 * inv_mpu6050_read_fifo() - Transfer data from hardware FIFO to KFIFO.
116 irqreturn_t inv_mpu6050_read_fifo(int irq, void *p)
118 struct iio_poll_func *pf = p;
119 struct iio_dev *indio_dev = pf->indio_dev;
120 struct inv_mpu6050_state *st = iio_priv(indio_dev);
121 size_t bytes_per_datum;
123 u8 data[INV_MPU6050_OUTPUT_DATA_SIZE];
127 mutex_lock(&indio_dev->mlock);
128 if (!(st->chip_config.accl_fifo_enable |
129 st->chip_config.gyro_fifo_enable))
132 if (st->chip_config.accl_fifo_enable)
133 bytes_per_datum += INV_MPU6050_BYTES_PER_3AXIS_SENSOR;
135 if (st->chip_config.gyro_fifo_enable)
136 bytes_per_datum += INV_MPU6050_BYTES_PER_3AXIS_SENSOR;
139 * read fifo_count register to know how many bytes inside FIFO
142 result = i2c_smbus_read_i2c_block_data(st->client,
143 st->reg->fifo_count_h,
144 INV_MPU6050_FIFO_COUNT_BYTE, data);
145 if (result != INV_MPU6050_FIFO_COUNT_BYTE)
147 fifo_count = be16_to_cpup((__be16 *)(&data[0]));
148 if (fifo_count < bytes_per_datum)
150 /* fifo count can't be odd number, if it is odd, reset fifo*/
153 if (fifo_count > INV_MPU6050_FIFO_THRESHOLD)
155 /* Timestamp mismatch. */
156 if (kfifo_len(&st->timestamps) >
157 fifo_count / bytes_per_datum + INV_MPU6050_TIME_STAMP_TOR)
159 while (fifo_count >= bytes_per_datum) {
160 result = i2c_smbus_read_i2c_block_data(st->client,
162 bytes_per_datum, data);
163 if (result != bytes_per_datum)
166 result = kfifo_out(&st->timestamps, ×tamp, 1);
167 /* when there is no timestamp, put timestamp as 0 */
171 result = iio_push_to_buffers_with_timestamp(indio_dev, data,
175 fifo_count -= bytes_per_datum;
179 mutex_unlock(&indio_dev->mlock);
180 iio_trigger_notify_done(indio_dev->trig);
185 /* Flush HW and SW FIFOs. */
186 inv_reset_fifo(indio_dev);
188 mutex_unlock(&indio_dev->mlock);
189 iio_trigger_notify_done(indio_dev->trig);