Android Hardware Abstraction Layer
local_time_hal.h
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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  */
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  */
55 };
56 
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 
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