local_time_hal.h
Go to the documentation of this file.
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 
58  /**
59  * Common methods of the local time hardware device. This *must* be the first member of
60  * local_time_hw_device as users of this structure will cast a hw_device_t to
61  * local_time_hw_device pointer in contexts where it's known the hw_device_t references a
62  * local_time_hw_device.
63  */
65 
66  /**
67  *
68  * Returns the current value of the system wide local time counter
69  */
70  int64_t (*get_local_time)(struct local_time_hw_device* dev);
71 
72  /**
73  *
74  * Returns the nominal frequency (in hertz) of the system wide local time
75  * counter
76  */
77  uint64_t (*get_local_freq)(struct local_time_hw_device* dev);
78 
79  /**
80  *
81  * Sets the HW slew rate of oscillator which drives the system wide local
82  * time counter. On success, platforms should return 0. Platforms which
83  * do not support HW slew should leave this method set to NULL.
84  *
85  * Valid values for rate range from MIN_INT16 to MAX_INT16. Platform
86  * implementations should attempt map this range linearly to the min/max
87  * slew rate of their hardware.
88  */
89  int (*set_local_slew)(struct local_time_hw_device* dev, int16_t rate);
90 
91  /**
92  *
93  * A method used to collect low level sync data in a lab environments.
94  * Most HAL implementations will simply set this member to NULL, or return
95  * -EINVAL to indicate that this functionality is not supported.
96  * Production HALs should never support this method.
97  */
98  int (*get_debug_log)(struct local_time_hw_device* dev,
99  struct local_time_debug_event* records,
100  int max_records);
101 };
102 
104 
105 /** convenience API for opening and closing a supported device */
106 
107 static inline int local_time_hw_device_open(
108  const struct hw_module_t* module,
109  struct local_time_hw_device** device)
110 {
111  return module->methods->open(module, LOCAL_TIME_HARDWARE_INTERFACE,
112  (struct hw_device_t**)device);
113 }
114 
115 static inline int local_time_hw_device_close(struct local_time_hw_device* device)
116 {
117  return device->common.close(&device->common);
118 }
119 
120 
121 __END_DECLS
122 
123 #endif // ANDROID_LOCAL_TIME_INTERFACE_H
int(* open)(const struct hw_module_t *module, const char *id, struct hw_device_t **device)
Definition: hardware.h:158
int(* get_debug_log)(struct local_time_hw_device *dev, struct local_time_debug_event *records, int max_records)
uint64_t(* get_local_freq)(struct local_time_hw_device *dev)
int(* close)(struct hw_device_t *device)
Definition: hardware.h:200
struct hw_device_t common
int64_t(* get_local_time)(struct local_time_hw_device *dev)
#define LOCAL_TIME_HARDWARE_INTERFACE
struct hw_module_methods_t * methods
Definition: hardware.h:142
int(* set_local_slew)(struct local_time_hw_device *dev, int16_t rate)
struct hw_module_t common