2 * vivid-rds-gen.c - rds (radio data system) generator support functions.
4 * Copyright 2014 Cisco Systems, Inc. and/or its affiliates. All rights reserved.
6 * This program is free software; you may redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; version 2 of the License.
10 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
11 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
12 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
13 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
14 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
15 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
16 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
20 #include <linux/kernel.h>
21 #include <linux/ktime.h>
22 #include <linux/videodev2.h>
24 #include "vivid-rds-gen.h"
26 static u8 vivid_get_di(const struct vivid_rds_gen *rds, unsigned grp)
30 return (rds->dyn_pty << 2) | (grp & 3);
32 return (rds->compressed << 2) | (grp & 3);
34 return (rds->art_head << 2) | (grp & 3);
36 return (rds->mono_stereo << 2) | (grp & 3);
42 * This RDS generator creates 57 RDS groups (one group == four RDS blocks).
43 * Groups 0-3, 22-25 and 44-47 (spaced 22 groups apart) are filled with a
44 * standard 0B group containing the PI code and PS name.
46 * Groups 4-19 and 26-41 use group 2A for the radio text.
48 * Group 56 contains the time (group 4A).
50 * All remaining groups use a filler group 15B block that just repeats
51 * the PI and PTY codes.
53 void vivid_rds_generate(struct vivid_rds_gen *rds)
55 struct v4l2_rds_data *data = rds->data;
62 for (grp = 0; grp < VIVID_RDS_GEN_GROUPS; grp++, data += VIVID_RDS_GEN_BLKS_PER_GRP) {
63 data[0].lsb = rds->picode & 0xff;
64 data[0].msb = rds->picode >> 8;
65 data[0].block = V4L2_RDS_BLOCK_A | (V4L2_RDS_BLOCK_A << 3);
66 data[1].lsb = rds->pty << 5;
67 data[1].msb = (rds->pty >> 3) | (rds->tp << 2);
68 data[1].block = V4L2_RDS_BLOCK_B | (V4L2_RDS_BLOCK_B << 3);
69 data[3].block = V4L2_RDS_BLOCK_D | (V4L2_RDS_BLOCK_D << 3);
74 case 44 ... 47: /* Group 0B */
75 data[1].lsb |= (rds->ta << 4) | (rds->ms << 3);
76 data[1].lsb |= vivid_get_di(rds, grp % 22);
77 data[1].msb |= 1 << 3;
78 data[2].lsb = rds->picode & 0xff;
79 data[2].msb = rds->picode >> 8;
80 data[2].block = V4L2_RDS_BLOCK_C_ALT | (V4L2_RDS_BLOCK_C_ALT << 3);
81 data[3].lsb = rds->psname[2 * (grp % 22) + 1];
82 data[3].msb = rds->psname[2 * (grp % 22)];
85 case 26 ... 41: /* Group 2A */
86 data[1].lsb |= (grp - 4) % 22;
87 data[1].msb |= 4 << 3;
88 data[2].msb = rds->radiotext[4 * ((grp - 4) % 22)];
89 data[2].lsb = rds->radiotext[4 * ((grp - 4) % 22) + 1];
90 data[2].block = V4L2_RDS_BLOCK_C | (V4L2_RDS_BLOCK_C << 3);
91 data[3].msb = rds->radiotext[4 * ((grp - 4) % 22) + 2];
92 data[3].lsb = rds->radiotext[4 * ((grp - 4) % 22) + 3];
98 * Uses the algorithm from Annex G of the RDS standard
99 * EN 50067:1998 to convert a UTC date to an RDS Modified
102 time_to_tm(get_seconds(), 0, &tm);
104 date = 14956 + tm.tm_mday + ((tm.tm_year - l) * 1461) / 4 +
105 ((tm.tm_mon + 2 + l * 12) * 306001) / 10000;
106 time = (tm.tm_hour << 12) |
108 (sys_tz.tz_minuteswest >= 0 ? 0x20 : 0) |
109 (abs(sys_tz.tz_minuteswest) / 30);
111 data[1].lsb |= date >> 15;
112 data[1].msb |= 8 << 3;
113 data[2].lsb = (date << 1) & 0xfe;
114 data[2].lsb |= (time >> 16) & 1;
115 data[2].msb = (date >> 7) & 0xff;
116 data[2].block = V4L2_RDS_BLOCK_C | (V4L2_RDS_BLOCK_C << 3);
117 data[3].lsb = time & 0xff;
118 data[3].msb = (time >> 8) & 0xff;
120 default: /* Group 15B */
121 data[1].lsb |= (rds->ta << 4) | (rds->ms << 3);
122 data[1].lsb |= vivid_get_di(rds, grp % 22);
123 data[1].msb |= 0x1f << 3;
124 data[2].lsb = rds->picode & 0xff;
125 data[2].msb = rds->picode >> 8;
126 data[2].block = V4L2_RDS_BLOCK_C_ALT | (V4L2_RDS_BLOCK_C_ALT << 3);
127 data[3].lsb = rds->pty << 5;
128 data[3].lsb |= (rds->ta << 4) | (rds->ms << 3);
129 data[3].lsb |= vivid_get_di(rds, grp % 22);
130 data[3].msb |= rds->pty >> 3;
131 data[3].msb |= 0x1f << 3;
137 void vivid_rds_gen_fill(struct vivid_rds_gen *rds, unsigned freq,
140 /* Alternate PTY between Info and Weather */
142 rds->picode = 0x2e75; /* 'KLNX' call sign */
143 rds->pty = alt ? 29 : 2;
145 rds->picode = 0x8088;
146 rds->pty = alt ? 16 : 3;
148 rds->mono_stereo = true;
149 rds->art_head = false;
150 rds->compressed = false;
151 rds->dyn_pty = false;
155 snprintf(rds->psname, sizeof(rds->psname), "%6d.%1d",
156 freq / 16, ((freq & 0xf) * 10) / 16);
158 strlcpy(rds->radiotext,
159 " The Radio Data System can switch between different Radio Texts ",
160 sizeof(rds->radiotext));
162 strlcpy(rds->radiotext,
163 "An example of Radio Text as transmitted by the Radio Data System",
164 sizeof(rds->radiotext));