drivers/media/platform/vivid/vivid-radio-tx.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * vivid-radio-tx.c - radio transmitter support functions.
   4  *
   5  * Copyright 2014 Cisco Systems, Inc. and/or its affiliates. All rights reserved.
   6  */
   7
   8 #include <linux/errno.h>
   9 #include <linux/kernel.h>
  10 #include <linux/sched/signal.h>
  11 #include <linux/delay.h>
  12 #include <linux/videodev2.h>
  13 #include <linux/v4l2-dv-timings.h>
  14 #include <media/v4l2-common.h>
  15 #include <media/v4l2-event.h>
  16 #include <media/v4l2-dv-timings.h>
  17
  18 #include "vivid-core.h"
  19 #include "vivid-ctrls.h"
  20 #include "vivid-radio-common.h"
  21 #include "vivid-radio-tx.h"
  22
  23 ssize_t vivid_radio_tx_write(struct file *file, const char __user *buf,
  24                           size_t size, loff_t *offset)
  25 {
  26         struct vivid_dev *dev = video_drvdata(file);
  27         struct v4l2_rds_data *data = dev->rds_gen.data;
  28         ktime_t timestamp;
  29         unsigned blk;
  30         int i;
  31
  32         if (dev->radio_tx_rds_controls)
  33                 return -EINVAL;
  34
  35         if (size < sizeof(*data))
  36                 return -EINVAL;
  37         size = sizeof(*data) * (size / sizeof(*data));
  38
  39         if (mutex_lock_interruptible(&dev->mutex))
  40                 return -ERESTARTSYS;
  41         if (dev->radio_tx_rds_owner &&
  42             file->private_data != dev->radio_tx_rds_owner) {
  43                 mutex_unlock(&dev->mutex);
  44                 return -EBUSY;
  45         }
  46         dev->radio_tx_rds_owner = file->private_data;
  47
  48 retry:
  49         timestamp = ktime_sub(ktime_get(), dev->radio_rds_init_time);
  50         blk = ktime_divns(timestamp, VIVID_RDS_NSEC_PER_BLK);
  51         if (blk - VIVID_RDS_GEN_BLOCKS >= dev->radio_tx_rds_last_block)
  52                 dev->radio_tx_rds_last_block = blk - VIVID_RDS_GEN_BLOCKS + 1;
  53
  54         /*
  55          * No data is available if there hasn't been time to get new data,
  56          * or if the RDS receiver has been disabled, or if we use the data
  57          * from the RDS transmitter and that RDS transmitter has been disabled,
  58          * or if the signal quality is too weak.
  59          */
  60         if (blk == dev->radio_tx_rds_last_block ||
  61             !(dev->radio_tx_subchans & V4L2_TUNER_SUB_RDS)) {
  62                 mutex_unlock(&dev->mutex);
  63                 if (file->f_flags & O_NONBLOCK)
  64                         return -EWOULDBLOCK;
  65                 if (msleep_interruptible(20) && signal_pending(current))
  66                         return -EINTR;
  67                 if (mutex_lock_interruptible(&dev->mutex))
  68                         return -ERESTARTSYS;
  69                 goto retry;
  70         }
  71
  72         for (i = 0; i < size && blk > dev->radio_tx_rds_last_block;
  73                         dev->radio_tx_rds_last_block++) {
  74                 unsigned data_blk = dev->radio_tx_rds_last_block % VIVID_RDS_GEN_BLOCKS;
  75                 struct v4l2_rds_data rds;
  76
  77                 if (copy_from_user(&rds, buf + i, sizeof(rds))) {
  78                         i = -EFAULT;
  79                         break;
  80                 }
  81                 i += sizeof(rds);
  82                 if (!dev->radio_rds_loop)
  83                         continue;
  84                 if ((rds.block & V4L2_RDS_BLOCK_MSK) == V4L2_RDS_BLOCK_INVALID ||
  85                     (rds.block & V4L2_RDS_BLOCK_ERROR))
  86                         continue;
  87                 rds.block &= V4L2_RDS_BLOCK_MSK;
  88                 data[data_blk] = rds;
  89         }
  90         mutex_unlock(&dev->mutex);
  91         return i;
  92 }
  93
  94 __poll_t vivid_radio_tx_poll(struct file *file, struct poll_table_struct *wait)
  95 {
  96         return EPOLLOUT | EPOLLWRNORM | v4l2_ctrl_poll(file, wait);
  97 }
  98
  99 int vidioc_g_modulator(struct file *file, void *fh, struct v4l2_modulator *a)
 100 {
 101         struct vivid_dev *dev = video_drvdata(file);
 102
 103         if (a->index > 0)
 104                 return -EINVAL;
 105
 106         strlcpy(a->name, "AM/FM/SW Transmitter", sizeof(a->name));
 107         a->capability = V4L2_TUNER_CAP_LOW | V4L2_TUNER_CAP_STEREO |
 108                         V4L2_TUNER_CAP_FREQ_BANDS | V4L2_TUNER_CAP_RDS |
 109                         (dev->radio_tx_rds_controls ?
 110                                 V4L2_TUNER_CAP_RDS_CONTROLS :
 111                                 V4L2_TUNER_CAP_RDS_BLOCK_IO);
 112         a->rangelow = AM_FREQ_RANGE_LOW;
 113         a->rangehigh = FM_FREQ_RANGE_HIGH;
 114         a->txsubchans = dev->radio_tx_subchans;
 115         return 0;
 116 }
 117
 118 int vidioc_s_modulator(struct file *file, void *fh, const struct v4l2_modulator *a)
 119 {
 120         struct vivid_dev *dev = video_drvdata(file);
 121
 122         if (a->index)
 123                 return -EINVAL;
 124         if (a->txsubchans & ~0x13)
 125                 return -EINVAL;
 126         dev->radio_tx_subchans = a->txsubchans;
 127         return 0;
 128 }