xref: /openbmc/linux/include/media/cec-pin.h (revision 1a18374f)
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  * @read_5v:	read the 5V pin. Return true if high, false if low or
29  *		an error if negative. If NULL or -ENOTTY is returned,
30  *		then this is not supported.
31  *
32  * @received:	optional. High-level CEC message callback. Allows the driver
33  *		to process CEC messages.
34  *
35  * These operations (except for the @received op) are used by the
36  * cec pin framework to manipulate the CEC pin.
37  */
38 struct cec_pin_ops {
39 	bool (*read)(struct cec_adapter *adap);
40 	void (*low)(struct cec_adapter *adap);
41 	void (*high)(struct cec_adapter *adap);
42 	bool (*enable_irq)(struct cec_adapter *adap);
43 	void (*disable_irq)(struct cec_adapter *adap);
44 	void (*free)(struct cec_adapter *adap);
45 	void (*status)(struct cec_adapter *adap, struct seq_file *file);
46 	int  (*read_hpd)(struct cec_adapter *adap);
47 	int  (*read_5v)(struct cec_adapter *adap);
48 
49 	/* High-level CEC message callback */
50 	int (*received)(struct cec_adapter *adap, struct cec_msg *msg);
51 };
52 
53 /**
54  * cec_pin_changed() - update pin state from interrupt
55  *
56  * @adap:	pointer to the cec adapter
57  * @value:	when true the pin is high, otherwise it is low
58  *
59  * If changes of the CEC voltage are detected via an interrupt, then
60  * cec_pin_changed is called from the interrupt with the new value.
61  */
62 void cec_pin_changed(struct cec_adapter *adap, bool value);
63 
64 /**
65  * cec_pin_allocate_adapter() - allocate a pin-based cec adapter
66  *
67  * @pin_ops:	low-level pin operations
68  * @priv:	will be stored in adap->priv and can be used by the adapter ops.
69  *		Use cec_get_drvdata(adap) to get the priv pointer.
70  * @name:	the name of the CEC adapter. Note: this name will be copied.
71  * @caps:	capabilities of the CEC adapter. This will be ORed with
72  *		CEC_CAP_MONITOR_ALL and CEC_CAP_MONITOR_PIN.
73  *
74  * Allocate a cec adapter using the cec pin framework.
75  *
76  * Return: a pointer to the cec adapter or an error pointer
77  */
78 struct cec_adapter *cec_pin_allocate_adapter(const struct cec_pin_ops *pin_ops,
79 					void *priv, const char *name, u32 caps);
80 
81 #endif
82