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linux_dsm_epyc7002/include/media/cec-pin.h

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media: include/(uapi/)media: add SPDX license info Replace the old license information with the corresponding SPDX license for those headers that I authored. Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2018-02-07 21:05:46 +07:00
/* SPDX-License-Identifier: GPL-2.0-only */
media: cec-pin: add low-level pin hardware support 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>
2017-07-11 13:30:42 +07:00
/*
* cec-pin.h - low-level CEC pin control
*
* Copyright 2017 Cisco Systems, Inc. and/or its affiliates. All rights reserved.
*/
#ifndef LINUX_CEC_PIN_H
#define LINUX_CEC_PIN_H
#include <linux/types.h>
#include <media/cec.h>
/**
* struct cec_pin_ops - low-level CEC pin operations
* @read: read the CEC pin. Return true if high, false if low.
* @low: drive the CEC pin low.
* @high: stop driving the CEC pin. The pull-up will drive the pin
* high, unless someone else is driving the pin low.
* @enable_irq: optional, enable the interrupt to detect pin voltage changes.
* @disable_irq: optional, disable the interrupt.
* @free: optional. Free any allocated resources. Called when the
* adapter is deleted.
* @status: optional, log status information.
media: cec: add CEC_EVENT_PIN_HPD_LOW/HIGH events Add support for two new low-level events: PIN_HPD_LOW and PIN_HPD_HIGH. This is specifically meant for use with the upcoming cec-gpio driver and makes it possible to trace when the HPD pin changes. Some HDMI sinks do strange things with the HPD and this makes it easy to debug this. Note that this also moves the initialization of a devnode mutex and list to the allocate_adapter function: if the HPD is high, then as soon as the HPD interrupt is created an interrupt occurs and cec_queue_pin_hpd_event() is called which requires that the devnode mutex and list are initialized. Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-08-15 21:07:25 +07:00
* @read_hpd: read the HPD pin. Return true if high, false if low or
* an error if negative. If NULL or -ENOTTY is returned,
* then this is not supported.
media: cec-pin: add low-level pin hardware support 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>
2017-07-11 13:30:42 +07:00
*
* These operations are used by the cec pin framework to manipulate
* the CEC pin.
*/
struct cec_pin_ops {
bool (*read)(struct cec_adapter *adap);
void (*low)(struct cec_adapter *adap);
void (*high)(struct cec_adapter *adap);
bool (*enable_irq)(struct cec_adapter *adap);
void (*disable_irq)(struct cec_adapter *adap);
void (*free)(struct cec_adapter *adap);
void (*status)(struct cec_adapter *adap, struct seq_file *file);
media: cec: add CEC_EVENT_PIN_HPD_LOW/HIGH events Add support for two new low-level events: PIN_HPD_LOW and PIN_HPD_HIGH. This is specifically meant for use with the upcoming cec-gpio driver and makes it possible to trace when the HPD pin changes. Some HDMI sinks do strange things with the HPD and this makes it easy to debug this. Note that this also moves the initialization of a devnode mutex and list to the allocate_adapter function: if the HPD is high, then as soon as the HPD interrupt is created an interrupt occurs and cec_queue_pin_hpd_event() is called which requires that the devnode mutex and list are initialized. Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-08-15 21:07:25 +07:00
int (*read_hpd)(struct cec_adapter *adap);
media: cec-pin: add low-level pin hardware support 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>
2017-07-11 13:30:42 +07:00
};
/**
* cec_pin_changed() - update pin state from interrupt
*
* @adap: pointer to the cec adapter
* @value: when true the pin is high, otherwise it is low
*
* If changes of the CEC voltage are detected via an interrupt, then
* cec_pin_changed is called from the interrupt with the new value.
*/
void cec_pin_changed(struct cec_adapter *adap, bool value);
/**
* cec_pin_allocate_adapter() - allocate a pin-based cec adapter
*
* @pin_ops: low-level pin operations
* @priv: will be stored in adap->priv and can be used by the adapter ops.
* Use cec_get_drvdata(adap) to get the priv pointer.
* @name: the name of the CEC adapter. Note: this name will be copied.
* @caps: capabilities of the CEC adapter. This will be ORed with
* CEC_CAP_MONITOR_ALL and CEC_CAP_MONITOR_PIN.
*
* Allocate a cec adapter using the cec pin framework.
*
* Return: a pointer to the cec adapter or an error pointer
*/
struct cec_adapter *cec_pin_allocate_adapter(const struct cec_pin_ops *pin_ops,
void *priv, const char *name, u32 caps);
#endif
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