1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * ImgTec IR Raw Decoder found in PowerDown Controller.
4 *
5 * Copyright 2010-2014 Imagination Technologies Ltd.
6 *
7 * This ties into the input subsystem using the RC-core in raw mode. Raw IR
8 * signal edges are reported and decoded by generic software decoders.
9 */
10
11#include <linux/spinlock.h>
12#include <media/rc-core.h>
13#include "img-ir.h"
14
15#define ECHO_TIMEOUT_MS 150 /* ms between echos */
16
17/* must be called with priv->lock held */
18static void img_ir_refresh_raw(struct img_ir_priv *priv, u32 irq_status)
19{
20 struct img_ir_priv_raw *raw = &priv->raw;
21 struct rc_dev *rc_dev = priv->raw.rdev;
22 int multiple;
23 u32 ir_status;
24
25 /* find whether both rise and fall was detected */
26 multiple = ((irq_status & IMG_IR_IRQ_EDGE) == IMG_IR_IRQ_EDGE);
27 /*
28 * If so, we need to see if the level has actually changed.
29 * If it's just noise that we didn't have time to process,
30 * there's no point reporting it.
31 */
32 ir_status = img_ir_read(priv, IMG_IR_STATUS) & IMG_IR_IRRXD;
33 if (multiple && ir_status == raw->last_status)
34 return;
35 raw->last_status = ir_status;
36
37 /* report the edge to the IR raw decoders */
38 if (ir_status) /* low */
39 ir_raw_event_store_edge(dev: rc_dev, pulse: false);
40 else /* high */
41 ir_raw_event_store_edge(dev: rc_dev, pulse: true);
42 ir_raw_event_handle(dev: rc_dev);
43}
44
45/* called with priv->lock held */
46void img_ir_isr_raw(struct img_ir_priv *priv, u32 irq_status)
47{
48 struct img_ir_priv_raw *raw = &priv->raw;
49
50 /* check not removing */
51 if (!raw->rdev)
52 return;
53
54 img_ir_refresh_raw(priv, irq_status);
55
56 /* start / push back the echo timer */
57 mod_timer(timer: &raw->timer, expires: jiffies + msecs_to_jiffies(ECHO_TIMEOUT_MS));
58}
59
60/*
61 * Echo timer callback function.
62 * The raw decoders expect to get a final sample even if there are no edges, in
63 * order to be assured of the final space. If there are no edges for a certain
64 * time we use this timer to emit a final sample to satisfy them.
65 */
66static void img_ir_echo_timer(struct timer_list *t)
67{
68 struct img_ir_priv *priv = from_timer(priv, t, raw.timer);
69
70 spin_lock_irq(lock: &priv->lock);
71
72 /* check not removing */
73 if (priv->raw.rdev)
74 /*
75 * It's safe to pass irq_status=0 since it's only used to check
76 * for double edges.
77 */
78 img_ir_refresh_raw(priv, irq_status: 0);
79
80 spin_unlock_irq(lock: &priv->lock);
81}
82
83void img_ir_setup_raw(struct img_ir_priv *priv)
84{
85 u32 irq_en;
86
87 if (!priv->raw.rdev)
88 return;
89
90 /* clear and enable edge interrupts */
91 spin_lock_irq(lock: &priv->lock);
92 irq_en = img_ir_read(priv, IMG_IR_IRQ_ENABLE);
93 irq_en |= IMG_IR_IRQ_EDGE;
94 img_ir_write(priv, IMG_IR_IRQ_CLEAR, IMG_IR_IRQ_EDGE);
95 img_ir_write(priv, IMG_IR_IRQ_ENABLE, data: irq_en);
96 spin_unlock_irq(lock: &priv->lock);
97}
98
99int img_ir_probe_raw(struct img_ir_priv *priv)
100{
101 struct img_ir_priv_raw *raw = &priv->raw;
102 struct rc_dev *rdev;
103 int error;
104
105 /* Set up the echo timer */
106 timer_setup(&raw->timer, img_ir_echo_timer, 0);
107
108 /* Allocate raw decoder */
109 raw->rdev = rdev = rc_allocate_device(RC_DRIVER_IR_RAW);
110 if (!rdev) {
111 dev_err(priv->dev, "cannot allocate raw input device\n");
112 return -ENOMEM;
113 }
114 rdev->priv = priv;
115 rdev->map_name = RC_MAP_EMPTY;
116 rdev->device_name = "IMG Infrared Decoder Raw";
117
118 /* Register raw decoder */
119 error = rc_register_device(dev: rdev);
120 if (error) {
121 dev_err(priv->dev, "failed to register raw IR input device\n");
122 rc_free_device(dev: rdev);
123 raw->rdev = NULL;
124 return error;
125 }
126
127 return 0;
128}
129
130void img_ir_remove_raw(struct img_ir_priv *priv)
131{
132 struct img_ir_priv_raw *raw = &priv->raw;
133 struct rc_dev *rdev = raw->rdev;
134 u32 irq_en;
135
136 if (!rdev)
137 return;
138
139 /* switch off and disable raw (edge) interrupts */
140 spin_lock_irq(lock: &priv->lock);
141 raw->rdev = NULL;
142 irq_en = img_ir_read(priv, IMG_IR_IRQ_ENABLE);
143 irq_en &= ~IMG_IR_IRQ_EDGE;
144 img_ir_write(priv, IMG_IR_IRQ_ENABLE, data: irq_en);
145 img_ir_write(priv, IMG_IR_IRQ_CLEAR, IMG_IR_IRQ_EDGE);
146 spin_unlock_irq(lock: &priv->lock);
147
148 rc_unregister_device(dev: rdev);
149
150 del_timer_sync(timer: &raw->timer);
151}
152

source code of linux/drivers/media/rc/img-ir/img-ir-raw.c