Add support for CEC hardware that relies on low-level pin polling or
GPIO interrupts.
One example is the Allwinner SoC. But any GPIO-based CEC implementation can
use this as well.
A GPIO implementation is very suitable as well for debugging: it can use
interrupts to detect state changes and report it. Userspace can then verify
if the bus traffic is correct. This also makes error injection possible.
The disadvantage is that it is hard to get the timings right since linux
isn't a hard realtime system.
In general on an idle system it works quite well, but under load the timer
will miss its mark every so often.
The debugfs file /sys/kernel/debug/cec/cecX/status gives some statistics
with respect to the timer overruns.
When the adapter is unconfigured and the low-level driver supports
interrupts, then the interrupt will be used to detect changes. This should
be quite accurate. But when the adapter is configured a hrtimer has to be
used.
The hrtimer implements a state machine where for each state the code will
read the bus or drive the bus and go on to the next state. It will re-arm
the timer with a delay based on the next state.
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Reviewed-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Add support for the new MONITOR_PIN mode.
Add the cec_pin_event function that the CEC pin code will call to queue pin
change events.
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Reviewed-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Event handling was always fairly simplistic since there were only
two events. With the addition of pin events this needed to be redesigned.
The state_change and lost_msgs events are now core events with the
guarantee that the last state is always available. The new pin events
are a queue of events (up to 64 for each event) and the oldest event
will be dropped if the application cannot keep up. Lost events are
marked with a new event flag.
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Reviewed-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
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Merge tag 'v4.12-rc6' into patchwork
Linux 4.12-rc6
* tag 'v4.12-rc6': (813 commits)
Linux 4.12-rc6
mm: larger stack guard gap, between vmas
virtio_balloon: disable VIOMMU support
mm: correct the comment when reclaimed pages exceed the scanned pages
userfaultfd: shmem: handle coredumping in handle_userfault()
mm: numa: avoid waiting on freed migrated pages
swap: cond_resched in swap_cgroup_prepare()
mm/memory-failure.c: use compound_head() flags for huge pages
perf unwind: Report module before querying isactivation in dwfl unwind
fs: pass on flags in compat_writev
objtool: Add fortify_panic as __noreturn function
powerpc/debug: Add missing warn flag to WARN_ON's non-builtin path
USB: gadgetfs, dummy-hcd, net2280: fix locking for callbacks
drm: mxsfb_crtc: Reset the eLCDIF controller
drm/mgag200: Fix to always set HiPri for G200e4 V2
i2c: ismt: fix wrong device address when unmap the data buffer
i2c: rcar: use correct length when unmapping DMA
powerpc/xive: Fix offset for store EOI MMIOs
drm/tegra: Correct idr_alloc() minimum id
drm/tegra: Fix lockup on a use of staging API
...
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Add a new capability CEC_CAP_NEEDS_HPD. If this capability is set
then the hardware can only use CEC if the HDMI Hotplug Detect pin
is high. Such hardware cannot handle the corner case in the CEC specification
where it is possible to transmit messages even if no hotplug signal is
present (needed for some displays that turn off the HPD when in standby,
but still have CEC enabled).
Typically hardware that needs this capability have the HPD wired to the CEC
block, often to a 'power' or 'active' pin.
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
When calling CEC_RECEIVE do not check if the adapter is configured.
Typically CEC_RECEIVE is called after a select() and if that indicates
that there are messages in the receive queue, then you should always be
able to dequeue a message.
The race condition here is that a message has been received and is
queued, so select() tells userspace that a message is available. But
before the application calls CEC_RECEIVE the adapter is unconfigured
(e.g. the HDMI cable is removed). Now select will always report that
there is a message, but calling CEC_RECEIVE will always return -ENONET
because the adapter is no longer configured and so will never actually
dequeue the message.
There is really no need for this check, and in fact the ENONET error
code was never documented for CEC_RECEIVE. This may have been a left-over
of old code that was never updated.
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Cc: <stable@vger.kernel.org> # for v4.10 and up
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Several error paths didn't log why an error was returned. Add this.
Also handle the corner case of "adapter is unconfigured AND the message
is from Unregistered to TV AND reply is non-zero" separately and return
EINVAL in that case, since it really is an invalid value and not an
unconfigured CEC device.
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
The CEC_TRANSMIT ioctl now returns -EPERM if an attempt is made to
transmit a message for an unconfigured adapter (i.e. userspace
never called CEC_ADAP_S_LOG_ADDRS).
This differentiates this case from when LAs are configured, but no
physical address is set. In that case -ENONET is returned.
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
The CEC specifications explicitly allows you to send poll messages and
Image/Text View On messages to a TV, even when unconfigured (i.e. there is
no hotplug signal detected). Some TVs will pull the HPD low when switching
to another input, or when going into standby, but CEC should still be
allowed to wake up such a display.
Add support for sending messages with initiator 0xf (Unregistered) and
destination 0 (TV) when no physical address is present.
This also required another change: the CEC adapter has to stay enabled as
long as 1) the CEC device is configured or 2) at least one filehandle is open
for the CEC device.
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
The cec_allocate_adapter function doesn't need the parent device, only the
cec_register_adapter function needs it.
Drop the cec_devnode parent field, since devnode.dev.parent can be used
instead.
This change makes the framework consistent with other frameworks where the
parent device is not used until the device is registered.
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
The CEC_MSG_FL_REPLY_TO_FOLLOWERS message flag only makes sense for transmitted
messages where you want to wait for the reply.
Clear the flag in all other cases.
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
The last open issues have been addressed, so it is time to move
this out of staging and into the mainline and to move the public
cec headers to include/uapi/linux.
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Hans Verkuil