hardware/local_time_hal.h

   1 /*
   2  * Copyright (C) 2011 The Android Open Source Project
   3  *
   4  * Licensed under the Apache License, Version 2.0 (the "License");
   5  * you may not use this file except in compliance with the License.
   6  * You may obtain a copy of the License at
   7  *
   8  *      http://www.apache.org/licenses/LICENSE-2.0
   9  *
  10  * Unless required by applicable law or agreed to in writing, software
  11  * distributed under the License is distributed on an "AS IS" BASIS,
  12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  13  * See the License for the specific language governing permissions and
  14  * limitations under the License.
  15  */
  16
  17
  18 #ifndef ANDROID_LOCAL_TIME_HAL_INTERFACE_H
  19 #define ANDROID_LOCAL_TIME_HAL_INTERFACE_H
  20
  21 #include <stdint.h>
  22
  23 #include <hardware/hardware.h>
  24
  25 __BEGIN_DECLS
  26
  27 /**
  28  * The id of this module
  29  */
  30 #define LOCAL_TIME_HARDWARE_MODULE_ID "local_time"
  31
  32 /**
  33  * Name of the local time devices to open
  34  */
  35 #define LOCAL_TIME_HARDWARE_INTERFACE "local_time_hw_if"
  36
  37 /**********************************************************************/
  38
  39 /**
  40  * A structure used to collect low level sync data in a lab environment.  Most
  41  * HAL implementations will never need this structure.
  42  */
  43 struct local_time_debug_event {
  44     int64_t local_timesync_event_id;
  45     int64_t local_time;
  46 };
  47
  48 /**
  49  * Every hardware module must have a data structure named HAL_MODULE_INFO_SYM
  50  * and the fields of this data structure must begin with hw_module_t
  51  * followed by module specific information.
  52  */
  53 struct local_time_module {
  54     struct hw_module_t common;
  55 };
  56
  57 struct local_time_hw_device {
  58     struct hw_device_t common;
  59
  60     /**
  61      *
  62      * Returns the current value of the system wide local time counter
  63      */
  64     int64_t (*get_local_time)(struct local_time_hw_device* dev);
  65
  66     /**
  67      *
  68      * Returns the nominal frequency (in hertz) of the system wide local time
  69      * counter
  70      */
  71     uint64_t (*get_local_freq)(struct local_time_hw_device* dev);
  72
  73     /**
  74      *
  75      * Sets the HW slew rate of oscillator which drives the system wide local
  76      * time counter.  On success, platforms should return 0.  Platforms which
  77      * do not support HW slew should leave this method set to NULL.
  78      *
  79      * Valid values for rate range from MIN_INT16 to MAX_INT16.  Platform
  80      * implementations should attempt map this range linearly to the min/max
  81      * slew rate of their hardware.
  82      */
  83     int (*set_local_slew)(struct local_time_hw_device* dev, int16_t rate);
  84
  85     /**
  86      *
  87      * A method used to collect low level sync data in a lab environments.
  88      * Most HAL implementations will simply set this member to NULL, or return
  89      * -EINVAL to indicate that this functionality is not supported.
  90      * Production HALs should never support this method.
  91      */
  92     int (*get_debug_log)(struct local_time_hw_device* dev,
  93                          struct local_time_debug_event* records,
  94                          int max_records);
  95 };
  96
  97 typedef struct local_time_hw_device local_time_hw_device_t;
  98
  99 /** convenience API for opening and closing a supported device */
 100
 101 static inline int local_time_hw_device_open(
 102         const struct hw_module_t* module,
 103         struct local_time_hw_device** device)
 104 {
 105     return module->methods->open(module, LOCAL_TIME_HARDWARE_INTERFACE,
 106                                  (struct hw_device_t**)device);
 107 }
 108
 109 static inline int local_time_hw_device_close(struct local_time_hw_device* device)
 110 {
 111     return device->common.close(&device->common);
 112 }
 113
 114
 115 __END_DECLS
 116
 117 #endif  // ANDROID_LOCAL_TIME_INTERFACE_H