linux/include/linux/platform_data/cros_ec_sensorhub.h
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   1/* SPDX-License-Identifier: GPL-2.0 */
   2/*
   3 * Chrome OS EC MEMS Sensor Hub driver.
   4 *
   5 * Copyright 2019 Google LLC
   6 */
   7
   8#ifndef __LINUX_PLATFORM_DATA_CROS_EC_SENSORHUB_H
   9#define __LINUX_PLATFORM_DATA_CROS_EC_SENSORHUB_H
  10
  11#include <linux/ktime.h>
  12#include <linux/mutex.h>
  13#include <linux/notifier.h>
  14#include <linux/platform_data/cros_ec_commands.h>
  15
  16struct iio_dev;
  17
  18/**
  19 * struct cros_ec_sensor_platform - ChromeOS EC sensor platform information.
  20 * @sensor_num: Id of the sensor, as reported by the EC.
  21 */
  22struct cros_ec_sensor_platform {
  23        u8 sensor_num;
  24};
  25
  26/**
  27 * typedef cros_ec_sensorhub_push_data_cb_t - Callback function to send datum
  28 *                                            to specific sensors.
  29 *
  30 * @indio_dev: The IIO device that will process the sample.
  31 * @data: Vector array of the ring sample.
  32 * @timestamp: Timestamp in host timespace when the sample was acquired by
  33 *             the EC.
  34 */
  35typedef int (*cros_ec_sensorhub_push_data_cb_t)(struct iio_dev *indio_dev,
  36                                                s16 *data,
  37                                                s64 timestamp);
  38
  39struct cros_ec_sensorhub_sensor_push_data {
  40        struct iio_dev *indio_dev;
  41        cros_ec_sensorhub_push_data_cb_t push_data_cb;
  42};
  43
  44enum {
  45        CROS_EC_SENSOR_LAST_TS,
  46        CROS_EC_SENSOR_NEW_TS,
  47        CROS_EC_SENSOR_ALL_TS
  48};
  49
  50struct cros_ec_sensors_ring_sample {
  51        u8  sensor_id;
  52        u8  flag;
  53        s16 vector[3];
  54        s64 timestamp;
  55} __packed;
  56
  57/* State used for cros_ec_ring_fix_overflow */
  58struct cros_ec_sensors_ec_overflow_state {
  59        s64 offset;
  60        s64 last;
  61};
  62
  63/* Length of the filter, how long to remember entries for */
  64#define CROS_EC_SENSORHUB_TS_HISTORY_SIZE 64
  65
  66/**
  67 * struct cros_ec_sensors_ts_filter_state - Timestamp filetr state.
  68 *
  69 * @x_offset: x is EC interrupt time. x_offset its last value.
  70 * @y_offset: y is the difference between AP and EC time, y_offset its last
  71 *            value.
  72 * @x_history: The past history of x, relative to x_offset.
  73 * @y_history: The past history of y, relative to y_offset.
  74 * @m_history: rate between y and x.
  75 * @history_len: Amount of valid historic data in the arrays.
  76 * @temp_buf: Temporary buffer used when updating the filter.
  77 * @median_m: median value of m_history
  78 * @median_error: final error to apply to AP interrupt timestamp to get the
  79 *                "true timestamp" the event occurred.
  80 */
  81struct cros_ec_sensors_ts_filter_state {
  82        s64 x_offset, y_offset;
  83        s64 x_history[CROS_EC_SENSORHUB_TS_HISTORY_SIZE];
  84        s64 y_history[CROS_EC_SENSORHUB_TS_HISTORY_SIZE];
  85        s64 m_history[CROS_EC_SENSORHUB_TS_HISTORY_SIZE];
  86        int history_len;
  87
  88        s64 temp_buf[CROS_EC_SENSORHUB_TS_HISTORY_SIZE];
  89
  90        s64 median_m;
  91        s64 median_error;
  92};
  93
  94/* struct cros_ec_sensors_ts_batch_state - State of batch of a single sensor.
  95 *
  96 * Use to store information to batch data using median fileter information.
  97 *
  98 * @penul_ts: last but one batch timestamp (penultimate timestamp).
  99 *            Used for timestamp spreading calculations
 100 *            when a batch shows up.
 101 * @penul_len: last but one batch length.
 102 * @last_ts: Last batch timestam.
 103 * @last_len: Last batch length.
 104 * @newest_sensor_event: Last sensor timestamp.
 105 */
 106struct cros_ec_sensors_ts_batch_state {
 107        s64 penul_ts;
 108        int penul_len;
 109        s64 last_ts;
 110        int last_len;
 111        s64 newest_sensor_event;
 112};
 113
 114/*
 115 * struct cros_ec_sensorhub - Sensor Hub device data.
 116 *
 117 * @dev: Device object, mostly used for logging.
 118 * @ec: Embedded Controller where the hub is located.
 119 * @sensor_num: Number of MEMS sensors present in the EC.
 120 * @msg: Structure to send FIFO requests.
 121 * @params: Pointer to parameters in msg.
 122 * @resp: Pointer to responses in msg.
 123 * @cmd_lock : Lock for sending msg.
 124 * @notifier: Notifier to kick the FIFO interrupt.
 125 * @ring: Preprocessed ring to store events.
 126 * @fifo_timestamp: Array for event timestamp and spreading.
 127 * @fifo_info: Copy of FIFO information coming from the EC.
 128 * @fifo_size: Size of the ring.
 129 * @batch_state: Per sensor information of the last batches received.
 130 * @overflow_a: For handling timestamp overflow for a time (sensor events)
 131 * @overflow_b: For handling timestamp overflow for b time (ec interrupts)
 132 * @filter: Medium fileter structure.
 133 * @tight_timestamps: Set to truen when EC support tight timestamping:
 134 *                    The timestamps reported from the EC have low jitter.
 135 *                    Timestamps also come before every sample. Set either
 136 *                    by feature bits coming from the EC or userspace.
 137 * @future_timestamp_count: Statistics used to compute shaved time.
 138 *                          This occurs when timestamp interpolation from EC
 139 *                          time to AP time accidentally puts timestamps in
 140 *                          the future. These timestamps are clamped to
 141 *                          `now` and these count/total_ns maintain the
 142 *                          statistics for how much time was removed in a
 143 *                          given period.
 144 * @future_timestamp_total_ns: Total amount of time shaved.
 145 * @push_data: Array of callback to send datums to iio sensor object.
 146 */
 147struct cros_ec_sensorhub {
 148        struct device *dev;
 149        struct cros_ec_dev *ec;
 150        int sensor_num;
 151
 152        struct cros_ec_command *msg;
 153        struct ec_params_motion_sense *params;
 154        struct ec_response_motion_sense *resp;
 155        struct mutex cmd_lock;  /* Lock for protecting msg structure. */
 156
 157        struct notifier_block notifier;
 158
 159        struct cros_ec_sensors_ring_sample *ring;
 160
 161        ktime_t fifo_timestamp[CROS_EC_SENSOR_ALL_TS];
 162        struct ec_response_motion_sense_fifo_info *fifo_info;
 163        int fifo_size;
 164
 165        struct cros_ec_sensors_ts_batch_state *batch_state;
 166
 167        struct cros_ec_sensors_ec_overflow_state overflow_a;
 168        struct cros_ec_sensors_ec_overflow_state overflow_b;
 169
 170        struct cros_ec_sensors_ts_filter_state filter;
 171
 172        int tight_timestamps;
 173
 174        s32 future_timestamp_count;
 175        s64 future_timestamp_total_ns;
 176
 177        struct cros_ec_sensorhub_sensor_push_data *push_data;
 178};
 179
 180int cros_ec_sensorhub_register_push_data(struct cros_ec_sensorhub *sensorhub,
 181                                         u8 sensor_num,
 182                                         struct iio_dev *indio_dev,
 183                                         cros_ec_sensorhub_push_data_cb_t cb);
 184
 185void cros_ec_sensorhub_unregister_push_data(struct cros_ec_sensorhub *sensorhub,
 186                                            u8 sensor_num);
 187
 188int cros_ec_sensorhub_ring_allocate(struct cros_ec_sensorhub *sensorhub);
 189int cros_ec_sensorhub_ring_add(struct cros_ec_sensorhub *sensorhub);
 190void cros_ec_sensorhub_ring_remove(void *arg);
 191int cros_ec_sensorhub_ring_fifo_enable(struct cros_ec_sensorhub *sensorhub,
 192                                       bool on);
 193
 194#endif   /* __LINUX_PLATFORM_DATA_CROS_EC_SENSORHUB_H */
 195
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