cros_ec_sensorhub.h

  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 */