aboutsummaryrefslogtreecommitdiffstats
path: root/drivers/media/platform/vivid/vivid-rds-gen.c
blob: dab5463e26faf115f169311f5d7a11af38cb3c28 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
/*
 * vivid-rds-gen.c - rds (radio data system) generator support functions.
 *
 * Copyright 2014 Cisco Systems, Inc. and/or its affiliates. All rights reserved.
 *
 * This program is free software; you may redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; version 2 of the License.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */

#include <linux/kernel.h>
#include <linux/ktime.h>
#include <linux/videodev2.h>

#include "vivid-rds-gen.h"

static u8 vivid_get_di(const struct vivid_rds_gen *rds, unsigned grp)
{
	switch (grp) {
	case 0:
		return (rds->dyn_pty << 2) | (grp & 3);
	case 1:
		return (rds->compressed << 2) | (grp & 3);
	case 2:
		return (rds->art_head << 2) | (grp & 3);
	case 3:
		return (rds->mono_stereo << 2) | (grp & 3);
	}
	return 0;
}

/*
 * This RDS generator creates 57 RDS groups (one group == four RDS blocks).
 * Groups 0-3, 22-25 and 44-47 (spaced 22 groups apart) are filled with a
 * standard 0B group containing the PI code and PS name.
 *
 * Groups 4-19 and 26-41 use group 2A for the radio text.
 *
 * Group 56 contains the time (group 4A).
 *
 * All remaining groups use a filler group 15B block that just repeats
 * the PI and PTY codes.
 */
void vivid_rds_generate(struct vivid_rds_gen *rds)
{
	struct v4l2_rds_data *data = rds->data;
	unsigned grp;
	struct tm tm;
	unsigned date;
	unsigned time;
	int l;

	for (grp = 0; grp < VIVID_RDS_GEN_GROUPS; grp++, data += VIVID_RDS_GEN_BLKS_PER_GRP) {
		data[0].lsb = rds->picode & 0xff;
		data[0].msb = rds->picode >> 8;
		data[0].block = V4L2_RDS_BLOCK_A | (V4L2_RDS_BLOCK_A << 3);
		data[1].lsb = rds->pty << 5;
		data[1].msb = (rds->pty >> 3) | (rds->tp << 2);
		data[1].block = V4L2_RDS_BLOCK_B | (V4L2_RDS_BLOCK_B << 3);
		data[3].block = V4L2_RDS_BLOCK_D | (V4L2_RDS_BLOCK_D << 3);

		switch (grp) {
		case 0 ... 3:
		case 22 ... 25:
		case 44 ... 47: /* Group 0B */
			data[1].lsb |= (rds->ta << 4) | (rds->ms << 3);
			data[1].lsb |= vivid_get_di(rds, grp % 22);
			data[1].msb |= 1 << 3;
			data[2].lsb = rds->picode & 0xff;
			data[2].msb = rds->picode >> 8;
			data[2].block = V4L2_RDS_BLOCK_C_ALT | (V4L2_RDS_BLOCK_C_ALT << 3);
			data[3].lsb = rds->psname[2 * (grp % 22) + 1];
			data[3].msb = rds->psname[2 * (grp % 22)];
			break;
		case 4 ... 19:
		case 26 ... 41: /* Group 2A */
			data[1].lsb |= (grp - 4) % 22;
			data[1].msb |= 4 << 3;
			data[2].msb = rds->radiotext[4 * ((grp - 4) % 22)];
			data[2].lsb = rds->radiotext[4 * ((grp - 4) % 22) + 1];
			data[2].block = V4L2_RDS_BLOCK_C | (V4L2_RDS_BLOCK_C << 3);
			data[3].msb = rds->radiotext[4 * ((grp - 4) % 22) + 2];
			data[3].lsb = rds->radiotext[4 * ((grp - 4) % 22) + 3];
			break;
		case 56:
			/*
			 * Group 4A
			 *
			 * Uses the algorithm from Annex G of the RDS standard
			 * EN 50067:1998 to convert a UTC date to an RDS Modified
			 * Julian Day.
			 */
			time_to_tm(get_seconds(), 0, &tm);
			l = tm.tm_mon <= 1;
			date = 14956 + tm.tm_mday + ((tm.tm_year - l) * 1461) / 4 +
				((tm.tm_mon + 2 + l * 12) * 306001) / 10000;
			time = (tm.tm_hour << 12) |
			       (tm.tm_min << 6) |
			       (sys_tz.tz_minuteswest >= 0 ? 0x20 : 0) |
			       (abs(sys_tz.tz_minuteswest) / 30);
			data[1].lsb &= ~3;
			data[1].lsb |= date >> 15;
			data[1].msb |= 8 << 3;
			data[2].lsb = (date << 1) & 0xfe;
			data[2].lsb |= (time >> 16) & 1;
			data[2].msb = (date >> 7) & 0xff;
			data[2].block = V4L2_RDS_BLOCK_C | (V4L2_RDS_BLOCK_C << 3);
			data[3].lsb = time & 0xff;
			data[3].msb = (time >> 8) & 0xff;
			break;
		default: /* Group 15B */
			data[1].lsb |= (rds->ta << 4) | (rds->ms << 3);
			data[1].lsb |= vivid_get_di(rds, grp % 22);
			data[1].msb |= 0x1f << 3;
			data[2].lsb = rds->picode & 0xff;
			data[2].msb = rds->picode >> 8;
			data[2].block = V4L2_RDS_BLOCK_C_ALT | (V4L2_RDS_BLOCK_C_ALT << 3);
			data[3].lsb = rds->pty << 5;
			data[3].lsb |= (rds->ta << 4) | (rds->ms << 3);
			data[3].lsb |= vivid_get_di(rds, grp % 22);
			data[3].msb |= rds->pty >> 3;
			data[3].msb |= 0x1f << 3;
			break;
		}
	}
}

void vivid_rds_gen_fill(struct vivid_rds_gen *rds, unsigned freq,
			  bool alt)
{
	/* Alternate PTY between Info and Weather */
	if (rds->use_rbds) {
		rds->picode = 0x2e75; /* 'KLNX' call sign */
		rds->pty = alt ? 29 : 2;
	} else {
		rds->picode = 0x8088;
		rds->pty = alt ? 16 : 3;
	}
	rds->mono_stereo = true;
	rds->art_head = false;
	rds->compressed = false;
	rds->dyn_pty = false;
	rds->tp = true;
	rds->ta = alt;
	rds->ms = true;
	snprintf(rds->psname, sizeof(rds->psname), "%6d.%1d",
		 freq / 16, ((freq & 0xf) * 10) / 16);
	if (alt)
		strlcpy(rds->radiotext,
			" The Radio Data System can switch between different Radio Texts ",
			sizeof(rds->radiotext));
	else
		strlcpy(rds->radiotext,
			"An example of Radio Text as transmitted by the Radio Data System",
			sizeof(rds->radiotext));
}

Privacy Policy