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74ba9207 | 1 | // SPDX-License-Identifier: GPL-2.0-or-later |
717c0336 AG |
2 | /* |
3 | * PPS kernel consumer API | |
4 | * | |
5 | * Copyright (C) 2009-2010 Alexander Gordeev <lasaine@lvk.cs.msu.su> | |
717c0336 AG |
6 | */ |
7 | ||
8 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt | |
9 | ||
10 | #include <linux/kernel.h> | |
11 | #include <linux/module.h> | |
12 | #include <linux/device.h> | |
13 | #include <linux/init.h> | |
14 | #include <linux/spinlock.h> | |
15 | #include <linux/pps_kernel.h> | |
16 | ||
17 | #include "kc.h" | |
18 | ||
19 | /* | |
20 | * Global variables | |
21 | */ | |
22 | ||
23 | /* state variables to bind kernel consumer */ | |
97439d0f | 24 | static DEFINE_SPINLOCK(pps_kc_hardpps_lock); |
717c0336 | 25 | /* PPS API (RFC 2783): current source and mode for kernel consumer */ |
97439d0f FW |
26 | static struct pps_device *pps_kc_hardpps_dev; /* unique pointer to device */ |
27 | static int pps_kc_hardpps_mode; /* mode bits for kernel consumer */ | |
717c0336 AG |
28 | |
29 | /* pps_kc_bind - control PPS kernel consumer binding | |
30 | * @pps: the PPS source | |
31 | * @bind_args: kernel consumer bind parameters | |
32 | * | |
33 | * This function is used to bind or unbind PPS kernel consumer according to | |
34 | * supplied parameters. Should not be called in interrupt context. | |
35 | */ | |
36 | int pps_kc_bind(struct pps_device *pps, struct pps_bind_args *bind_args) | |
37 | { | |
38 | /* Check if another consumer is already bound */ | |
39 | spin_lock_irq(&pps_kc_hardpps_lock); | |
40 | ||
41 | if (bind_args->edge == 0) | |
42 | if (pps_kc_hardpps_dev == pps) { | |
43 | pps_kc_hardpps_mode = 0; | |
44 | pps_kc_hardpps_dev = NULL; | |
45 | spin_unlock_irq(&pps_kc_hardpps_lock); | |
46 | dev_info(pps->dev, "unbound kernel" | |
47 | " consumer\n"); | |
48 | } else { | |
49 | spin_unlock_irq(&pps_kc_hardpps_lock); | |
50 | dev_err(pps->dev, "selected kernel consumer" | |
51 | " is not bound\n"); | |
52 | return -EINVAL; | |
53 | } | |
54 | else | |
55 | if (pps_kc_hardpps_dev == NULL || | |
56 | pps_kc_hardpps_dev == pps) { | |
57 | pps_kc_hardpps_mode = bind_args->edge; | |
58 | pps_kc_hardpps_dev = pps; | |
59 | spin_unlock_irq(&pps_kc_hardpps_lock); | |
60 | dev_info(pps->dev, "bound kernel consumer: " | |
61 | "edge=0x%x\n", bind_args->edge); | |
62 | } else { | |
63 | spin_unlock_irq(&pps_kc_hardpps_lock); | |
64 | dev_err(pps->dev, "another kernel consumer" | |
65 | " is already bound\n"); | |
66 | return -EINVAL; | |
67 | } | |
68 | ||
69 | return 0; | |
70 | } | |
71 | ||
72 | /* pps_kc_remove - unbind kernel consumer on PPS source removal | |
73 | * @pps: the PPS source | |
74 | * | |
75 | * This function is used to disable kernel consumer on PPS source removal | |
76 | * if this source was bound to PPS kernel consumer. Can be called on any | |
77 | * source safely. Should not be called in interrupt context. | |
78 | */ | |
79 | void pps_kc_remove(struct pps_device *pps) | |
80 | { | |
81 | spin_lock_irq(&pps_kc_hardpps_lock); | |
82 | if (pps == pps_kc_hardpps_dev) { | |
83 | pps_kc_hardpps_mode = 0; | |
84 | pps_kc_hardpps_dev = NULL; | |
85 | spin_unlock_irq(&pps_kc_hardpps_lock); | |
86 | dev_info(pps->dev, "unbound kernel consumer" | |
87 | " on device removal\n"); | |
88 | } else | |
89 | spin_unlock_irq(&pps_kc_hardpps_lock); | |
90 | } | |
91 | ||
92 | /* pps_kc_event - call hardpps() on PPS event | |
93 | * @pps: the PPS source | |
94 | * @ts: PPS event timestamp | |
95 | * @event: PPS event edge | |
96 | * | |
97 | * This function calls hardpps() when an event from bound PPS source occurs. | |
98 | */ | |
99 | void pps_kc_event(struct pps_device *pps, struct pps_event_time *ts, | |
100 | int event) | |
101 | { | |
102 | unsigned long flags; | |
103 | ||
104 | /* Pass some events to kernel consumer if activated */ | |
105 | spin_lock_irqsave(&pps_kc_hardpps_lock, flags); | |
106 | if (pps == pps_kc_hardpps_dev && event & pps_kc_hardpps_mode) | |
107 | hardpps(&ts->ts_real, &ts->ts_raw); | |
108 | spin_unlock_irqrestore(&pps_kc_hardpps_lock, flags); | |
109 | } |