The current CEC pin value (0 or 1) was part of the cec_pin struct,
but that assumes that CEC pin monitoring can only be used with
a driver that uses the low-level CEC pin framework.
But hardware that has both a high-level API and can monitor the
CEC pin at low-level at the same time does not need to depend on
the cec pin framework.
To support such devices remove the cur_value field from struct cec_pin
and add a cec_pin_is_high field to cec_adapter. This also makes it
possible to drop the '#ifdef CONFIG_CEC_PIN' in cec-api.c.
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
The free_irq() function could be called from interrupt context,
which is invalid. Move this to the thread.
In the interrupt handler we just request that the thread disables
the irq. This is done through an atomic so we don't need to add
any spinlocks.
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
The CEC_EVENT_PIN_LOW/HIGH defines and the cec_queue_pin_event() function
did not specify that these were about CEC pin events.
Since in the future there will also be HPD pin events it is wise to rename
the event defines and function to CEC_EVENT_PIN_CEC_LOW/HIGH and
cec_queue_pin_cec_event() now before these become part of the ABI.
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
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>
Hans Verkuil