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1 | /* |
2 | * PPS kernel consumer API |
3 | * |
4 | * Copyright (C) 2009-2010 Alexander Gordeev <lasaine@lvk.cs.msu.su> |
5 | * |
6 | * This program is free software; you can redistribute it and/or modify |
7 | * it under the terms of the GNU General Public License as published by |
8 | * the Free Software Foundation; either version 2 of the License, or |
9 | * (at your option) any later version. |
10 | * |
11 | * This program is distributed in the hope that it will be useful, |
12 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
13 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
14 | * GNU General Public License for more details. |
15 | * |
16 | * You should have received a copy of the GNU General Public License |
17 | * along with this program; if not, write to the Free Software |
18 | * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. |
19 | */ |
20 | |
21 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
22 | |
23 | #include <linux/kernel.h> |
24 | #include <linux/module.h> |
25 | #include <linux/device.h> |
26 | #include <linux/init.h> |
27 | #include <linux/spinlock.h> |
28 | #include <linux/pps_kernel.h> |
29 | |
30 | #include "kc.h" |
31 | |
32 | /* |
33 | * Global variables |
34 | */ |
35 | |
36 | /* state variables to bind kernel consumer */ |
37 | DEFINE_SPINLOCK(pps_kc_hardpps_lock); |
38 | /* PPS API (RFC 2783): current source and mode for kernel consumer */ |
39 | struct pps_device *pps_kc_hardpps_dev; /* unique pointer to device */ |
40 | int pps_kc_hardpps_mode; /* mode bits for kernel consumer */ |
41 | |
42 | /* pps_kc_bind - control PPS kernel consumer binding |
43 | * @pps: the PPS source |
44 | * @bind_args: kernel consumer bind parameters |
45 | * |
46 | * This function is used to bind or unbind PPS kernel consumer according to |
47 | * supplied parameters. Should not be called in interrupt context. |
48 | */ |
49 | int pps_kc_bind(struct pps_device *pps, struct pps_bind_args *bind_args) |
50 | { |
51 | /* Check if another consumer is already bound */ |
52 | spin_lock_irq(&pps_kc_hardpps_lock); |
53 | |
54 | if (bind_args->edge == 0) |
55 | if (pps_kc_hardpps_dev == pps) { |
56 | pps_kc_hardpps_mode = 0; |
57 | pps_kc_hardpps_dev = NULL; |
58 | spin_unlock_irq(&pps_kc_hardpps_lock); |
59 | dev_info(pps->dev, "unbound kernel" |
60 | " consumer\n"); |
61 | } else { |
62 | spin_unlock_irq(&pps_kc_hardpps_lock); |
63 | dev_err(pps->dev, "selected kernel consumer" |
64 | " is not bound\n"); |
65 | return -EINVAL; |
66 | } |
67 | else |
68 | if (pps_kc_hardpps_dev == NULL || |
69 | pps_kc_hardpps_dev == pps) { |
70 | pps_kc_hardpps_mode = bind_args->edge; |
71 | pps_kc_hardpps_dev = pps; |
72 | spin_unlock_irq(&pps_kc_hardpps_lock); |
73 | dev_info(pps->dev, "bound kernel consumer: " |
74 | "edge=0x%x\n", bind_args->edge); |
75 | } else { |
76 | spin_unlock_irq(&pps_kc_hardpps_lock); |
77 | dev_err(pps->dev, "another kernel consumer" |
78 | " is already bound\n"); |
79 | return -EINVAL; |
80 | } |
81 | |
82 | return 0; |
83 | } |
84 | |
85 | /* pps_kc_remove - unbind kernel consumer on PPS source removal |
86 | * @pps: the PPS source |
87 | * |
88 | * This function is used to disable kernel consumer on PPS source removal |
89 | * if this source was bound to PPS kernel consumer. Can be called on any |
90 | * source safely. Should not be called in interrupt context. |
91 | */ |
92 | void pps_kc_remove(struct pps_device *pps) |
93 | { |
94 | spin_lock_irq(&pps_kc_hardpps_lock); |
95 | if (pps == pps_kc_hardpps_dev) { |
96 | pps_kc_hardpps_mode = 0; |
97 | pps_kc_hardpps_dev = NULL; |
98 | spin_unlock_irq(&pps_kc_hardpps_lock); |
99 | dev_info(pps->dev, "unbound kernel consumer" |
100 | " on device removal\n"); |
101 | } else |
102 | spin_unlock_irq(&pps_kc_hardpps_lock); |
103 | } |
104 | |
105 | /* pps_kc_event - call hardpps() on PPS event |
106 | * @pps: the PPS source |
107 | * @ts: PPS event timestamp |
108 | * @event: PPS event edge |
109 | * |
110 | * This function calls hardpps() when an event from bound PPS source occurs. |
111 | */ |
112 | void pps_kc_event(struct pps_device *pps, struct pps_event_time *ts, |
113 | int event) |
114 | { |
115 | unsigned long flags; |
116 | |
117 | /* Pass some events to kernel consumer if activated */ |
118 | spin_lock_irqsave(&pps_kc_hardpps_lock, flags); |
119 | if (pps == pps_kc_hardpps_dev && event & pps_kc_hardpps_mode) |
120 | hardpps(&ts->ts_real, &ts->ts_raw); |
121 | spin_unlock_irqrestore(&pps_kc_hardpps_lock, flags); |
122 | } |
123 |
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Tags:
od-2011-09-04
od-2011-09-18
v2.6.34-rc5
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