1/* SPDX-License-Identifier: GPL-2.0-only */
2/*
3 * soundbus generic definitions
4 *
5 * Copyright 2006 Johannes Berg <johannes@sipsolutions.net>
6 */
7#ifndef __SOUNDBUS_H
8#define __SOUNDBUS_H
9
10#include <linux/platform_device.h>
11#include <sound/pcm.h>
12#include <linux/list.h>
13
14
15/* When switching from master to slave or the other way around,
16 * you don't want to have the codec chip acting as clock source
17 * while the bus still is.
18 * More importantly, while switch from slave to master, you need
19 * to turn off the chip's master function first, but then there's
20 * no clock for a while and other chips might reset, so we notify
21 * their drivers after having switched.
22 * The constants here are codec-point of view, so when we switch
23 * the soundbus to master we tell the codec we're going to switch
24 * and give it CLOCK_SWITCH_PREPARE_SLAVE!
25 */
26enum clock_switch {
27	CLOCK_SWITCH_PREPARE_SLAVE,
28	CLOCK_SWITCH_PREPARE_MASTER,
29	CLOCK_SWITCH_SLAVE,
30	CLOCK_SWITCH_MASTER,
31	CLOCK_SWITCH_NOTIFY,
32};
33
34/* information on a transfer the codec can take */
35struct transfer_info {
36	u64 formats;		/* SNDRV_PCM_FMTBIT_* */
37	unsigned int rates;	/* SNDRV_PCM_RATE_* */
38	/* flags */
39	u32 transfer_in:1, /* input = 1, output = 0 */
40	    must_be_clock_source:1;
41	/* for codecs to distinguish among their TIs */
42	int tag;
43};
44
45struct codec_info_item {
46	struct codec_info *codec;
47	void *codec_data;
48	struct soundbus_dev *sdev;
49	/* internal, to be used by the soundbus provider */
50	struct list_head list;
51};
52
53/* for prepare, where the codecs need to know
54 * what we're going to drive the bus with */
55struct bus_info {
56	/* see below */
57	int sysclock_factor;
58	int bus_factor;
59};
60
61/* information on the codec itself, plus function pointers */
62struct codec_info {
63	/* the module this lives in */
64	struct module *owner;
65
66	/* supported transfer possibilities, array terminated by
67	 * formats or rates being 0. */
68	struct transfer_info *transfers;
69
70	/* Master clock speed factor
71	 * to be used (master clock speed = sysclock_factor * sampling freq)
72	 * Unused if the soundbus provider has no such notion.
73	 */
74	int sysclock_factor;
75
76	/* Bus factor, bus clock speed = bus_factor * sampling freq)
77	 * Unused if the soundbus provider has no such notion.
78	 */
79	int bus_factor;
80
81	/* operations */
82	/* clock switching, see above */
83	int (*switch_clock)(struct codec_info_item *cii,
84			    enum clock_switch clock);
85
86	/* called for each transfer_info when the user
87	 * opens the pcm device to determine what the
88	 * hardware can support at this point in time.
89	 * That can depend on other user-switchable controls.
90	 * Return 1 if usable, 0 if not.
91	 * out points to another instance of a transfer_info
92	 * which is initialised to the values in *ti, and
93	 * it's format and rate values can be modified by
94	 * the callback if it is necessary to further restrict
95	 * the formats that can be used at the moment, for
96	 * example when one codec has multiple logical codec
97	 * info structs for multiple inputs.
98	 */
99	int (*usable)(struct codec_info_item *cii,
100		      struct transfer_info *ti,
101		      struct transfer_info *out);
102
103	/* called when pcm stream is opened, probably not implemented
104	 * most of the time since it isn't too useful */
105	int (*open)(struct codec_info_item *cii,
106		    struct snd_pcm_substream *substream);
107
108	/* called when the pcm stream is closed, at this point
109	 * the user choices can all be unlocked (see below) */
110	int (*close)(struct codec_info_item *cii,
111		     struct snd_pcm_substream *substream);
112
113	/* if the codec must forbid some user choices because
114	 * they are not valid with the substream/transfer info,
115	 * it must do so here. Example: no digital output for
116	 * incompatible framerate, say 8KHz, on Onyx.
117	 * If the selected stuff in the substream is NOT
118	 * compatible, you have to reject this call! */
119	int (*prepare)(struct codec_info_item *cii,
120		       struct bus_info *bi,
121		       struct snd_pcm_substream *substream);
122
123	/* start() is called before data is pushed to the codec.
124	 * Note that start() must be atomic! */
125	int (*start)(struct codec_info_item *cii,
126		     struct snd_pcm_substream *substream);
127
128	/* stop() is called after data is no longer pushed to the codec.
129	 * Note that stop() must be atomic! */
130	int (*stop)(struct codec_info_item *cii,
131		    struct snd_pcm_substream *substream);
132
133	int (*suspend)(struct codec_info_item *cii, pm_message_t state);
134	int (*resume)(struct codec_info_item *cii);
135};
136
137/* information on a soundbus device */
138struct soundbus_dev {
139	/* the bus it belongs to */
140	struct list_head onbuslist;
141
142	/* the of device it represents */
143	struct platform_device ofdev;
144
145	/* what modules go by */
146	char modalias[32];
147
148	/* These fields must be before attach_codec can be called.
149	 * They should be set by the owner of the alsa card object
150	 * that is needed, and whoever sets them must make sure
151	 * that they are unique within that alsa card object. */
152	char *pcmname;
153	int pcmid;
154
155	/* this is assigned by the soundbus provider in attach_codec */
156	struct snd_pcm *pcm;
157
158	/* operations */
159	/* attach a codec to this soundbus, give the alsa
160	 * card object the PCMs for this soundbus should be in.
161	 * The 'data' pointer must be unique, it is used as the
162	 * key for detach_codec(). */
163	int (*attach_codec)(struct soundbus_dev *dev, struct snd_card *card,
164			    struct codec_info *ci, void *data);
165	void (*detach_codec)(struct soundbus_dev *dev, void *data);
166	/* TODO: suspend/resume */
167
168	/* private for the soundbus provider */
169	struct list_head codec_list;
170	u32 have_out:1, have_in:1;
171};
172#define to_soundbus_device(d) container_of(d, struct soundbus_dev, ofdev.dev)
173#define of_to_soundbus_device(d) container_of(d, struct soundbus_dev, ofdev)
174
175extern int soundbus_add_one(struct soundbus_dev *dev);
176extern void soundbus_remove_one(struct soundbus_dev *dev);
177
178extern struct soundbus_dev *soundbus_dev_get(struct soundbus_dev *dev);
179extern void soundbus_dev_put(struct soundbus_dev *dev);
180
181struct soundbus_driver {
182	char *name;
183	struct module *owner;
184
185	/* we don't implement any matching at all */
186
187	int	(*probe)(struct soundbus_dev* dev);
188	void	(*remove)(struct soundbus_dev *dev);
189
190	int	(*shutdown)(struct soundbus_dev* dev);
191
192	struct device_driver driver;
193};
194#define to_soundbus_driver(drv) container_of(drv,struct soundbus_driver, driver)
195
196extern int soundbus_register_driver(struct soundbus_driver *drv);
197extern void soundbus_unregister_driver(struct soundbus_driver *drv);
198
199extern struct attribute *soundbus_dev_attrs[];
200
201#endif /* __SOUNDBUS_H */
202