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| author | Arnd Bergmann <arnd@arndb.de> | 2017-11-27 16:25:56 +0100 |
|---|---|---|
| committer | Mauro Carvalho Chehab <mchehab@s-opensource.com> | 2017-12-08 17:26:24 +0100 |
| commit | aad2fa4c8b1d99a737f97b031cc3e262f158b02e (patch) | |
| tree | b82e5566477b2c7af406f43dbe7654c4391415c5 /drivers/media/platform/vivid/vivid-radio-rx.c | |
| parent | media: staging: imx: use ktime_t for timestamps (diff) | |
| download | linux-aad2fa4c8b1d99a737f97b031cc3e262f158b02e.tar.xz linux-aad2fa4c8b1d99a737f97b031cc3e262f158b02e.zip | |
media: vivid: use ktime_t for timestamp calculation
timespec is generally deprecated because of the y2038 overflow.
In vivid, the usage is fine, since we are dealing with monotonic
timestamps, but we can also simplify the code by going to ktime_t.
Using ktime_divns() should be roughly as efficient as the old code,
since the constant 64-bit division gets turned into a multiplication
on modern platforms, and we save multiple 32-bit divisions that can be
expensive e.g. on ARMv7.
Tested-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Diffstat (limited to 'drivers/media/platform/vivid/vivid-radio-rx.c')
| -rw-r--r-- | drivers/media/platform/vivid/vivid-radio-rx.c | 11 |
1 files changed, 5 insertions, 6 deletions
diff --git a/drivers/media/platform/vivid/vivid-radio-rx.c b/drivers/media/platform/vivid/vivid-radio-rx.c index 47c36c26096b..35fbff490535 100644 --- a/drivers/media/platform/vivid/vivid-radio-rx.c +++ b/drivers/media/platform/vivid/vivid-radio-rx.c @@ -38,9 +38,9 @@ ssize_t vivid_radio_rx_read(struct file *file, char __user *buf, size_t size, loff_t *offset) { struct vivid_dev *dev = video_drvdata(file); - struct timespec ts; struct v4l2_rds_data *data = dev->rds_gen.data; bool use_alternates; + ktime_t timestamp; unsigned blk; int perc; int i; @@ -64,17 +64,16 @@ ssize_t vivid_radio_rx_read(struct file *file, char __user *buf, } retry: - ktime_get_ts(&ts); - use_alternates = ts.tv_sec % 10 >= 5; + timestamp = ktime_sub(ktime_get(), dev->radio_rds_init_time); + blk = ktime_divns(timestamp, VIVID_RDS_NSEC_PER_BLK); + use_alternates = (blk % VIVID_RDS_GEN_BLOCKS) & 1; + if (dev->radio_rx_rds_last_block == 0 || dev->radio_rx_rds_use_alternates != use_alternates) { dev->radio_rx_rds_use_alternates = use_alternates; /* Re-init the RDS generator */ vivid_radio_rds_init(dev); } - ts = timespec_sub(ts, dev->radio_rds_init_ts); - blk = ts.tv_sec * 100 + ts.tv_nsec / 10000000; - blk = (blk * VIVID_RDS_GEN_BLOCKS) / 500; if (blk >= dev->radio_rx_rds_last_block + VIVID_RDS_GEN_BLOCKS) dev->radio_rx_rds_last_block = blk - VIVID_RDS_GEN_BLOCKS + 1; |