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/of_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 */
26 enum 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 */
35 struct 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
45 struct 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 */
55 struct bus_info {
56 /* see below */
57 int sysclock_factor;
58 int bus_factor;
59 };
60
61 /* information on the codec itself, plus function pointers */
62 struct 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 */
138 struct 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
175 extern int soundbus_add_one(struct soundbus_dev *dev);
176 extern void soundbus_remove_one(struct soundbus_dev *dev);
177
178 extern struct soundbus_dev *soundbus_dev_get(struct soundbus_dev *dev);
179 extern void soundbus_dev_put(struct soundbus_dev *dev);
180
181 struct 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 int (*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
196 extern int soundbus_register_driver(struct soundbus_driver *drv);
197 extern void soundbus_unregister_driver(struct soundbus_driver *drv);
198
199 extern struct attribute *soundbus_dev_attrs[];
200
201 #endif /* __SOUNDBUS_H */