1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Copyright (C) 2012 Invensense, Inc.
4 */
5
6 #include <linux/module.h>
7 #include <linux/slab.h>
8 #include <linux/err.h>
9 #include <linux/delay.h>
10 #include <linux/sysfs.h>
11 #include <linux/jiffies.h>
12 #include <linux/irq.h>
13 #include <linux/interrupt.h>
14 #include <linux/poll.h>
15 #include <linux/math64.h>
16
17 #include <linux/iio/common/inv_sensors_timestamp.h>
18
19 #include "inv_mpu_iio.h"
20
inv_reset_fifo(struct iio_dev * indio_dev)21 static int inv_reset_fifo(struct iio_dev *indio_dev)
22 {
23 int result;
24 struct inv_mpu6050_state *st = iio_priv(indio_dev);
25
26 /* disable fifo and reenable it */
27 inv_mpu6050_prepare_fifo(st, false);
28 result = inv_mpu6050_prepare_fifo(st, true);
29 if (result)
30 goto reset_fifo_fail;
31
32 return 0;
33
34 reset_fifo_fail:
35 dev_err(regmap_get_device(st->map), "reset fifo failed %d\n", result);
36 return regmap_update_bits(st->map, st->reg->int_enable,
37 INV_MPU6050_BIT_DATA_RDY_EN, INV_MPU6050_BIT_DATA_RDY_EN);
38 }
39
40 /*
41 * inv_mpu6050_read_fifo() - Transfer data from hardware FIFO to KFIFO.
42 */
inv_mpu6050_read_fifo(int irq,void * p)43 irqreturn_t inv_mpu6050_read_fifo(int irq, void *p)
44 {
45 struct iio_poll_func *pf = p;
46 struct iio_dev *indio_dev = pf->indio_dev;
47 struct inv_mpu6050_state *st = iio_priv(indio_dev);
48 size_t bytes_per_datum;
49 int result;
50 u16 fifo_count;
51 u32 fifo_period;
52 s64 timestamp;
53 u8 data[INV_MPU6050_OUTPUT_DATA_SIZE];
54 size_t i, nb;
55
56 mutex_lock(&st->lock);
57
58 if (!(st->chip_config.accl_fifo_enable |
59 st->chip_config.gyro_fifo_enable |
60 st->chip_config.magn_fifo_enable))
61 goto end_session;
62 bytes_per_datum = 0;
63 if (st->chip_config.accl_fifo_enable)
64 bytes_per_datum += INV_MPU6050_BYTES_PER_3AXIS_SENSOR;
65
66 if (st->chip_config.gyro_fifo_enable)
67 bytes_per_datum += INV_MPU6050_BYTES_PER_3AXIS_SENSOR;
68
69 if (st->chip_config.temp_fifo_enable)
70 bytes_per_datum += INV_MPU6050_BYTES_PER_TEMP_SENSOR;
71
72 if (st->chip_config.magn_fifo_enable)
73 bytes_per_datum += INV_MPU9X50_BYTES_MAGN;
74
75 /*
76 * read fifo_count register to know how many bytes are inside the FIFO
77 * right now
78 */
79 result = regmap_bulk_read(st->map, st->reg->fifo_count_h,
80 st->data, INV_MPU6050_FIFO_COUNT_BYTE);
81 if (result)
82 goto end_session;
83 fifo_count = be16_to_cpup((__be16 *)&st->data[0]);
84
85 /*
86 * Handle fifo overflow by resetting fifo.
87 * Reset if there is only 3 data set free remaining to mitigate
88 * possible delay between reading fifo count and fifo data.
89 */
90 nb = 3 * bytes_per_datum;
91 if (fifo_count >= st->hw->fifo_size - nb) {
92 dev_warn(regmap_get_device(st->map), "fifo overflow reset\n");
93 goto flush_fifo;
94 }
95
96 /* compute and process only all complete datum */
97 nb = fifo_count / bytes_per_datum;
98 fifo_count = nb * bytes_per_datum;
99 if (nb == 0)
100 goto end_session;
101 /* Each FIFO data contains all sensors, so same number for FIFO and sensor data */
102 fifo_period = NSEC_PER_SEC / INV_MPU6050_DIVIDER_TO_FIFO_RATE(st->chip_config.divider);
103 inv_sensors_timestamp_interrupt(&st->timestamp, 1, pf->timestamp);
104 inv_sensors_timestamp_apply_odr(&st->timestamp, fifo_period, 1, 0);
105
106 /* clear internal data buffer for avoiding kernel data leak */
107 memset(data, 0, sizeof(data));
108
109 /* read all data once and process every samples */
110 result = regmap_noinc_read(st->map, st->reg->fifo_r_w, st->data, fifo_count);
111 if (result)
112 goto flush_fifo;
113 for (i = 0; i < nb; ++i) {
114 /* skip first samples if needed */
115 if (st->skip_samples) {
116 st->skip_samples--;
117 continue;
118 }
119 memcpy(data, &st->data[i * bytes_per_datum], bytes_per_datum);
120 timestamp = inv_sensors_timestamp_pop(&st->timestamp);
121 iio_push_to_buffers_with_timestamp(indio_dev, data, timestamp);
122 }
123
124 end_session:
125 mutex_unlock(&st->lock);
126 iio_trigger_notify_done(indio_dev->trig);
127
128 return IRQ_HANDLED;
129
130 flush_fifo:
131 /* Flush HW and SW FIFOs. */
132 inv_reset_fifo(indio_dev);
133 mutex_unlock(&st->lock);
134 iio_trigger_notify_done(indio_dev->trig);
135
136 return IRQ_HANDLED;
137 }
138