xref: /openbmc/linux/include/media/cec-pin.h (revision 98ddec80)
1 /* SPDX-License-Identifier: GPL-2.0-only */
2 /*
3  * cec-pin.h - low-level CEC pin control
4  *
5  * Copyright 2017 Cisco Systems, Inc. and/or its affiliates. All rights reserved.
6  */
7 
8 #ifndef LINUX_CEC_PIN_H
9 #define LINUX_CEC_PIN_H
10 
11 #include <linux/types.h>
12 #include <media/cec.h>
13 
14 /**
15  * struct cec_pin_ops - low-level CEC pin operations
16  * @read:	read the CEC pin. Return true if high, false if low.
17  * @low:	drive the CEC pin low.
18  * @high:	stop driving the CEC pin. The pull-up will drive the pin
19  *		high, unless someone else is driving the pin low.
20  * @enable_irq:	optional, enable the interrupt to detect pin voltage changes.
21  * @disable_irq: optional, disable the interrupt.
22  * @free:	optional. Free any allocated resources. Called when the
23  *		adapter is deleted.
24  * @status:	optional, log status information.
25  * @read_hpd:	read the HPD pin. Return true if high, false if low or
26  *		an error if negative. If NULL or -ENOTTY is returned,
27  *		then this is not supported.
28  *
29  * These operations are used by the cec pin framework to manipulate
30  * the CEC pin.
31  */
32 struct cec_pin_ops {
33 	bool (*read)(struct cec_adapter *adap);
34 	void (*low)(struct cec_adapter *adap);
35 	void (*high)(struct cec_adapter *adap);
36 	bool (*enable_irq)(struct cec_adapter *adap);
37 	void (*disable_irq)(struct cec_adapter *adap);
38 	void (*free)(struct cec_adapter *adap);
39 	void (*status)(struct cec_adapter *adap, struct seq_file *file);
40 	int  (*read_hpd)(struct cec_adapter *adap);
41 };
42 
43 /**
44  * cec_pin_changed() - update pin state from interrupt
45  *
46  * @adap:	pointer to the cec adapter
47  * @value:	when true the pin is high, otherwise it is low
48  *
49  * If changes of the CEC voltage are detected via an interrupt, then
50  * cec_pin_changed is called from the interrupt with the new value.
51  */
52 void cec_pin_changed(struct cec_adapter *adap, bool value);
53 
54 /**
55  * cec_pin_allocate_adapter() - allocate a pin-based cec adapter
56  *
57  * @pin_ops:	low-level pin operations
58  * @priv:	will be stored in adap->priv and can be used by the adapter ops.
59  *		Use cec_get_drvdata(adap) to get the priv pointer.
60  * @name:	the name of the CEC adapter. Note: this name will be copied.
61  * @caps:	capabilities of the CEC adapter. This will be ORed with
62  *		CEC_CAP_MONITOR_ALL and CEC_CAP_MONITOR_PIN.
63  *
64  * Allocate a cec adapter using the cec pin framework.
65  *
66  * Return: a pointer to the cec adapter or an error pointer
67  */
68 struct cec_adapter *cec_pin_allocate_adapter(const struct cec_pin_ops *pin_ops,
69 					void *priv, const char *name, u32 caps);
70 
71 #endif
72