Commit Graph

4 Commits

Author SHA1 Message Date
Hans Verkuil
e113d65ae4 media: tegra-cec: reset rx_buf_cnt when start bit detected
If a start bit is detected, then reset the receive buffer counter to 0.

This ensures that no stale data is in the buffer if a message is
broken off midstream due to e.g. a Low Drive condition and then
retransmitted.

The only Rx interrupts we need to listen to are RX_REGISTER_FULL (i.e.
a valid byte was received) and RX_START_BIT_DETECTED (i.e. a new
message starts and we need to reset the counter).

Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Cc: <stable@vger.kernel.org>      # for v4.15 and up
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2018-03-05 07:46:24 -05:00
Jesse Chan
20772c1a6f media: tegra-cec: add missing MODULE_DESCRIPTION/AUTHOR/LICENSE
This change resolves a new compile-time warning
when built as a loadable module:

WARNING: modpost: missing MODULE_LICENSE() in drivers/media/platform/tegra-cec/tegra_cec.o
see include/linux/module.h for more information

This adds the license as "GPL v2", which matches the header of the file.

MODULE_DESCRIPTION and MODULE_AUTHOR are also added.

Signed-off-by: Jesse Chan <jc@linux.com>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-12-08 11:15:17 -05:00
Hans Verkuil
3ddad1ae10 media: tegra-cec: fix messy probe() cleanup
The probe() cleanup code ('goto foo_error') was very messy. It appears
that this code wasn't updated when I switched to the devm_ functions
in an earlier version.

Update the code to use 'return error' where it can and do proper cleanup
where it needs to.

Note that the original code wasn't buggy, it was just messy.

Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-10-31 07:23:52 -04:00
Hans Verkuil
9d2d60687c media: tegra-cec: add Tegra HDMI CEC driver
This driver adds support for the Tegra CEC IP. It is based on the
NVIDIA drivers/misc/tegra-cec driver in their 3.10 kernel.

This has been converted to the CEC framework and cleaned up.

Tested with my Jetson TK1 board. It has also been tested with the
Tegra X1 in an embedded product.

Note of warning for the Tegra X2: this SoC supports two HDMI outputs,
but only one CEC adapter and the CEC bus is shared between the
two outputs. This is a design mistake and the CEC adapter can
control only one HDMI output. Never hook up both HDMI outputs
to the CEC bus in a hardware design: this is illegal as per the
CEC specification.

The CEC bus can be shared between multiple inputs and zero or one
outputs, but not between multiple outputs.

Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Acked-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
2017-10-27 15:48:57 +02:00