diff options
Diffstat (limited to 'drivers/media/platform/vivid/vivid-rds-gen.c')
| -rw-r--r-- | drivers/media/platform/vivid/vivid-rds-gen.c | 157 |
1 files changed, 157 insertions, 0 deletions
diff --git a/drivers/media/platform/vivid/vivid-rds-gen.c b/drivers/media/platform/vivid/vivid-rds-gen.c new file mode 100644 index 000000000..39ca9a564 --- /dev/null +++ b/drivers/media/platform/vivid/vivid-rds-gen.c @@ -0,0 +1,157 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * vivid-rds-gen.c - rds (radio data system) generator support functions. + * + * Copyright 2014 Cisco Systems, Inc. and/or its affiliates. All rights reserved. + */ + +#include <linux/kernel.h> +#include <linux/ktime.h> +#include <linux/string.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; + unsigned idx; + 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 */ + idx = (grp % 22) % 4; + data[1].lsb |= (rds->ta << 4) | (rds->ms << 3); + data[1].lsb |= vivid_get_di(rds, idx); + 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 * idx + 1]; + data[3].msb = rds->psname[2 * idx]; + break; + case 4 ... 19: + case 26 ... 41: /* Group 2A */ + idx = ((grp - 4) % 22) % 16; + data[1].lsb |= idx; + data[1].msb |= 4 << 3; + data[2].msb = rds->radiotext[4 * idx]; + data[2].lsb = rds->radiotext[4 * idx + 1]; + data[2].block = V4L2_RDS_BLOCK_C | (V4L2_RDS_BLOCK_C << 3); + data[3].msb = rds->radiotext[4 * idx + 2]; + data[3].lsb = rds->radiotext[4 * idx + 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. + */ + time64_to_tm(ktime_get_real_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)); +} |